Preparation of bergenin from Ardisia crenata sims and Rodgersia sambucifolia
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西宁“PEP”24年小学4年级英语第五单元暑期作业考试时间:90分钟(总分:120)B卷考试人:_________题号一二三四五总分得分一、综合题(共计100题)1、What do we call the big bang event that created the universe?A. Cosmic ExplosionB. Big BangC. Stellar BirthD. Galactic Formation2、听力题:A _______ is a visual representation of a chemical reaction.3、填空题:The _____ (小鸭) waddles around the pond.4、听力题:We are having a ___. (family gathering) soon.5、填空题:A flamingo stands on one leg to ______ (平衡).6、听力题:The __________ of a substance is how much space it takes up.7、填空题:The capital of Aruba is ________ (奥拉涅斯塔德).8、听力题:The chemical formula for propanoic acid is ______.9、填空题:The __________ (历史的挑战) requires courage.10、听力题:He is playing in the ___. (sandbox)11、填空题:We should appreciate the beauty of ______ (自然).12、听力题:I see a __ in the garden. (flower)13、填空题:My ________ (玩具名称) is designed for indoor fun.14、听力题:He ___ to school every day. (walk, walks, walking)15、填空题:When it snows, I always wear my __________. (冬衣)16、听力题:A solar panel converts sunlight into ______.17、填空题:My sister is learning to __________ (游泳) this summer.18、填空题:My friend has a ___ (小宠物), which is a cute rabbit.19、听力题:We will go to the ________ tomorrow.20、填空题:He _______ (总是) helps me with my homework.21、听力题:I like to ________ (research) topics of interest.22、听力题:The _____ (ball) is bouncing.23、What do we call the place where we watch movies?A. TheaterB. MuseumC. LibraryD. Park24、What do we call the time when we eat in the morning?A. BreakfastB. LunchC. DinnerD. Snack答案:A25、填空题:________ (植物适应性管理) is critical for success.26、填空题:I have a dinosaur ________ (玩具名称) that roars.27、听力题:The city of Seoul is the capital of _______.28、听力题:He likes to draw ___. (pictures)29、填空题:The armadillo curls into a ______ (球) for protection.30、填空题:The flowers are _______ (很美丽)。
小学上册英语第二单元真题(有答案)英语试题一、综合题(本题有100小题,每小题1分,共100分.每小题不选、错误,均不给分)1.I enjoy learning about ________ in science class.2.The _____ (pond) is calm.3.Have you ever seen a _______ (小老鼠) eat cheese?4.What do we call the study of plants?A. BiologyB. BotanyC. ZoologyD. Ecology答案: B5.The __________ (历史的框架) shapes understanding.6.She is a _____ (翻译) who speaks multiple languages.7. A period in the periodic table represents elements with the same number of ______.8.The _____ (植物) needs water.9.I like _____ (chocolate/vanilla) ice cream.10. A ________ (冰川) can create valleys as it moves.11.I love wearing my __________ when it snows. (厚外套)12. A ________ (湖泊) can be fresh or saltwater.13.My teacher encourages us to be polite by calling her ______. (我的老师鼓励我们通过称呼她为____来表现礼貌。
)14.What do we use to write?A. BrushB. PencilC. HammerD. Spoon答案: B15.The flowers smell ______ (sweet) in spring.16.The Earth's surface is shaped by both climatic and ______ factors.17.What is the opposite of "sweet"?A. BitterB. SourC. SaltyD. Spicy答案: A18.The Mississippi River flows through __________.19.My toy ________ can move by itself.20.What is the opposite of "fast"?A. SlowB. SmallC. HighD. Long答案:A Slow21.The baby is in the ___ (crib/chair).22.My favorite cereal is _______ (我最喜欢的谷物是_______).23.Galaxies can collide and merge with ______.24.World War II began in __________. (1939年)25.The chemical formula for potassium sulfate is ______.26.In winter, it gets very ______ (冷) and sometimes it snows. I love to make a ______ (雪人) and ______ (打雪仗) with my friends.27. A _______ is a device used to measure the concentration of a solution.28.The teacher is very ________.29.I enjoy cooking simple meals like ________ (意大利面) and ________ (沙拉) with my family.30.Metallic elements are usually good ______ of heat.31.The bee buzzes around the ______.32.My brother, ______ (我弟弟), loves to play chess.33.The chemical symbol for antimony is ______.34.The tortoise moves very _______ (慢).35.We will go ________ (海边) this summer.36.She is ___ (good/bad) at math.37. A __________ is a city that is not the capital but is important for trade.38.The goldfish swims to greet me when I arrive with ______ (食物).39.The process of ______ involves the breaking down of rocks into smaller pieces.40.The owl has specialized ______ (视觉) for seeing in darkness.41. A dilute solution contains a small amount of ______.42.What is the name of the mountain range that separates Europe and Asia?A. AndesB. HimalayasC. RockiesD. Ural Mountains答案:D43.My ________ (玩具) is fun to play with alone or with friends.44.I have two ___ and one brother. (sisters)45. A ______ (植物博物馆) can educate visitors about species.46.The Earth's atmosphere is vital for supporting ______.47.What is the main ingredient in a salad?A. MeatB. VegetablesC. RiceD. Bread答案:B48.My dad is a _____ (医生).49.My favorite activity is ______ (旅行).50.The ________ (土壤) is rich for farming.51.The ________ (城市功能) serves many needs.52.The __________ (古代波斯) was known for its great emperors.53.My dog likes to chase ______ (球).54.I enjoy _______ (看电视) after dinner.55. A heterogeneous mixture has visibly ______ components.56.The __________ (法兰西帝国) was established by Napoleon Bonaparte.57. A _____ (雨林) has many layers of vegetation.58. A solvent is the substance that dissolves a ______.59.My grandmother makes the best __________. (蛋糕)60.I like to collect ________ (玩具名称) from my favorite shows.61. A frog can jump _______.62.environmental psychology) studies human interactions with nature. The ____63.The __________ (历史的启迪) guides our journey.64.What is the name of the famous scientist known for his work on the laws of thermodynamics?A. Rudolf ClausiusB. Lord KelvinC. Albert EinsteinD. James Clerk Maxwell答案: A65.He is _______ at playing soccer.66. A solution is created when a solute is ______ in a solvent.67.My brother is a great ________.68.I have a _____ (gift) for you.69.What is the scientific name for the common house cat?A. Canis lupusB. Felis catusC. Ursus arctosD. Equus ferus答案:B70.The ______ (小龟) is very slow.71.My cousin is a ______. She loves to travel.72.The process of a liquid turning into a gas is called _______.73.My ________ (玩具名称) helps me learn about history.74.The country famous for its castles is ________ (法国).75.The chemical formula for calcium chloride is _______.76.The _______ (The Space Shuttle) program enabled human spaceflight.77.The __________ Mountains are found in North America. (落基山)78.I have a ________ (玩具火箭) that I pretend to launch into space.79.The chemical symbol for magnesium is ____.80.The process of sublimation is when a solid changes directly to a _____.81.I like to _____ at the park. (play)82.The _____ (画) is stunning.83.What do we call the area of land that is covered by vegetation?A. FloraB. FaunaC. BiomeD. Ecosystem答案: C. Biome84.The first man to reach the North Pole was _______. (皮尔·阿蒙森)85. A __________ is formed when sediments are compacted over time.86.In the winter, I love to go __________. (滑雪)87.My ______ is very adventurous.88. A ______ can be trained to help humans.89. (Pledge) of Allegiance was written in the 19th century. The ____90.The chemical reaction that occurs in batteries is an example of a _____ reaction.91. A zebra is known for its black and ______ stripes.92. A __________ is an area of land rich in resources.93.The car is ___. (fast)94.I can ______ (sing) a song for you.95.Many plants are ______ (适应性强) to their surroundings.96.The process of ______ can cause landslides and avalanches.97.The ________ (气候变化影响) is studied globally.98.The ancient Egyptians had a god for _______. (每个方面的生活)99. A __________ has a long neck and legs, often found in Africa.100.I like to organize my ________ (玩具) collection.。
小学上册英语第四单元期中试卷英语试题一、综合题(本题有100小题,每小题1分,共100分.每小题不选、错误,均不给分)1.The __________ is a famous city known for its art and culture. (巴黎)2.My ________ (祖父) tells me stories about his childhood.3.The chemical formula for silicate is ______.4.The _______ (青蛙) likes to jump around.5.I like to ______ after school.6.What is the melting point of ice?A. 0°CB. 100°CC. 32°CD. 50°CA7.My sister enjoys learning about ____ (geography).8. A _______ is a type of chemical reaction that releases energy in the form of light. (发光反应)9.I want to learn how to ________ (制作视频).10.The ancient Romans are known for their ________ and contributions to law.11.What do we call the leader of a country?A. PresidentB. GovernorC. MayorD. Senator12.The ________ (研究) of geography is important.13.We have a ______ (丰富的) curriculum that includes arts.14.What is the capital of Somalia?A. MogadishuB. HargeisaC. KismayoD. BaidoaA15. A _______ is a solid that forms from a chemical reaction in a solution.16.What is the shape of a stop sign?A. CircleB. TriangleC. SquareD. Octagon17. A _______ is a reaction that produces a pungent aroma.18.I can speak ________ languages.19.The ancient Romans held gladiatorial _______ in the Colosseum. (比赛)20.I enjoy ______ on rainy days.21.How do you say "dog" in Spanish?A. PerroB. ChienC. HundD. Cane22.The owl is wise and can turn its _________ (头) 180 degrees.23.What is the name of the famous American national park known for its canyons?A. YellowstoneB. Grand CanyonC. YosemiteD. ZionB24.What color is a banana?A. RedB. YellowC. BlueD. GreenB Yellow25.We should _______ (支持) local businesses.26. A _______ can help to visualize the concept of thermal energy.27.The chemical formula for ethylene glycol is ______.28.The __________ (历史的探究) broadens horizons.29. A ______ is a structured approach to inquiry.30. A strong base has a pH value greater than _______.31.My sister loves to create ____ (art projects).32.The _____ (邮局) is nearby.33.The __________ (国会大厦) symbolizes democracy in the United States.34.What is the name of the famous art museum in Paris?A. LouvreB. Musée d'OrsayC. Centre PompidouD. Palais de Tokyo35.I love the way my __________ (玩具名) __________ (动词).36.The children are _______ (在玩耍).37.The __________ is a famous shopping district.38.What is the main function of the stomach?A. To pump bloodB. To digest foodC. To filter wasteD. To store energyB39.What is the name of the famous American author known for "The Color Purple"?A. Alice WalkerB. Toni MorrisonC. Zora Neale HurstonD. Maya AngelouA40.________ (植物适应性策略) are employed for success.41.Mixtures can be homogeneous or _____.42.The ancient pyramids were built as ________ (墓葬) for pharaohs.43.The __________ is the capital city of Finland. (赫尔辛基)44.What do you call a person who collects stamps?A. PhilatelistB. CollectorC. DealerD. HistorianA45.What is the name of the famous bear that loves honey?A. Paddington BearB. Winnie-the-PoohC. Yogi BearD. BalooB Winnie-the-Pooh46. A ____(canyon) is a deep valley with steep sides.47.The ________ (多样性) of species is crucial for balance.48.The _____ (broccoli) is a nutritious vegetable.49.What is the currency used in the United States?A. EuroB. DollarC. PoundD. YenB50.What is the currency used in Japan?A. YuanB. WonC. YenD. DollarC51.Leaves use sunlight to make ______.52.The chemical symbol for samarium is _______.53.The Earth's surface is constantly being reshaped by natural ______.54.My brother is my silly _______ who makes jokes.55.The process of distillation separates liquids based on their ______.56.What is the capital of Colombia?A. BogotaB. MedellinC. CaliD. CartagenaA57.The capital city of Uganda is __________.58.What is the currency used in the United States?A. EuroB. YenC. DollarD. PesoC59.What is the capital of Italy?A. AthensB. MadridC. RomeD. Paris60.Which animal is known for its speed?A. ElephantB. CheetahC. SlothD. TurtleB61.Learning about plant relationships can deepen your appreciation for ______. (了解植物之间的关系可以加深你对自然的欣赏。
广西朱砂根不同部位中岩白菜素含量的研究范卫锋,石勇新,张文,罗国琼【摘要】目的通过对广西不同地域朱砂根的根和茎中岩白菜素含量的研究,对其药用部位提出建议。
方式采纳薄层色谱法对其不同部位的要紧成份进行定性分析,采纳高效液相色谱法对其不同部位的要紧成份岩白菜素进行定量分析。
结果同一株朱砂根中根和茎成份大体一致,而且茎中的岩白菜素含量大于根,叶中的岩白菜素含量最低。
结论朱砂根的茎具有综合利用价值。
【关键词】朱砂根;岩白菜素;高效液相色谱法;含量测定Abstract:Objective To find out the differences of bergenin content in Ardisia crenata from different regions and its different parts, and suggest its medicinal parts. Methods The bergenin content in different parts of Ardisia crenata was identified by TLC and determined by HPLC. Results The difference of bergenin content in different parts of Ardisia crenata was significant, and that in stems was better than in roots, which in the leaves was the lest. Conclusion The stem was regarded as the available medicinal resources and is worth exploiting.Key words:Ardisia crenata;bergenin;HPLC;contant determination朱砂根为紫金牛科植物朱砂根Ardisia crenata Sims的干燥根。
2023年教师资格之中学英语学科知识与教学能力题库及精品答案单选题(共100题)1、请阅读Passage 2,完成第小题。
A.hoaxB.hard workC.irksome taskD.special mission【答案】 A2、 Listening to loud music at rock concerts__________caused hearing loss in some teenagers.A.isB.areC.hasD.have【答案】 C3、Evidence came up ____ specific sounds are recognized by babies as young as six months old.A.whatB.thatC.whichD.whose【答案】 B4、Which of the following is closest in meaning to the underlined word "ambient" in Paragraph 2?A.SurroundingB.FamiliarC.ForeignD.Local【答案】 A5、Without your help, we would not __________ the work in time.A.have completedB.had completedpletedpleting【答案】 A6、Which of the following about teaching assessment isinappropriate?A.Diagnostic assessment is a kind of test carried out after a teaching activityB.Formative assessment should be student-orientedC.Summative assessment is often carried out at the end of a termD.Portfolios,daily reports,and delivering speeches are all formative assessment【答案】 A7、Which of the following activities does not belong topre-reading activities?A.scanningB.setting the sceneC.skimmingD.paraphrasing【答案】 D8、Everyone knows that English departments are in trouble, but you can't appreciate just howmuch trouble until you read the new report from the Modern Language Association. The report is about Ph.D. programs, which have been indecline since 2008. These programs have gotten both more difficult and less rewarding: today, it can take almost a decade to get a doctorate, and, at the end of your program, you're unlikely to find a tenure-track job.A.The idea of designing a shorter programB.The completion of a degree in five yearsC.The idea of drafting a shorter dissertationD.The suggestions given in the M.L.A. report【答案】 A9、请阅读Passage l。
2024年高二英语学科全球合作研究的合作机制构建分析单选题30题1.International cooperation is crucial for addressing global challenges. The ______ of different countries is essential.A.effortsanizationsC.cooperationsD.initiatives答案:B。
“国际合作对于应对全球挑战至关重要。
不同国家的组织是必不可少的。
”A 选项“efforts”努力;C 选项“cooperations”合作,此处与前文重复;D 选项“initiatives”倡议。
根据语境,这里强调不同国家的组织,所以选B。
2.Global cooperation requires strong ______ among nations.A.associationsB.partnershipsC.connectionsD.relationships答案:B。
“全球合作需要国家之间强大的伙伴关系。
”A 选项“associations”协会;C 选项“connections”联系;D 选项“relationships”关系,而伙伴关系更能体现全球合作的需求,所以选B。
3.The success of global cooperation depends on effective ______.A.coordinationsB.arrangementsanizationsD.plans答案:C。
“全球合作的成功取决于有效的组织。
”A 选项“coordinations”协调;B 选项“arrangements”安排;D 选项“plans”计划。
这里强调组织的重要性,所以选C。
4.In global cooperation, ______ play an important role in promoting common development.A.institutionspaniesC.factoriesD.schools答案:A。
“PEP”24年小学4年级下册英语第5单元测验试卷(有答案)考试时间:80分钟(总分:140)B卷考试人:_________题号一二三四五总分得分一、综合题(共计100题共100分)1. 听力题:The _______ of a wave can be influenced by the properties of the medium.2. 选择题:Which animal can change its color?A. DogB. ChameleonC. ElephantD. Tiger3. 填空题:My ________ (玩具名称) is a fun way to learn about cultures.4. 选择题:What is the name of the famous mountain in India?A. K2B. Mount EverestC. KilimanjaroD. Kanchenjunga5. 选择题:What fruit is known for having a pit in the center?A. AppleB. PeachC. GrapeD. Banana6. 听力题:The chemical symbol for nitrogen is __________.7. 听力题:A __________ is a mixture that can be separated by filtration.What is the term for a period of ten years?A. CenturyB. DecadeC. MillenniumD. Era答案: B9. 选择题:How many colors are in a traffic light?A. 2B. 3C. 4D. 5答案:B10. 听力题:This is my ___ (friend).11. 听力题:My cousin is a ______. She enjoys riding horses.12. 填空题:The ______ (小鸟) flies south for the ______ (冬天) to find warmer weather.13. 听力题:Metamorphic rocks are formed from existing rocks that change due to ______ and pressure.14. 听力题:My brother is a great ________.15. 填空题:I enjoy ______ during the holidays.16. 听力题:The __________ helps some birds to swim in water.17. 填空题:A _____ (盆栽) can be placed indoors.18. 填空题:My rabbit loves to dig in the ______ (草地).19. 听力题:A star's life cycle includes stages like protostar, main sequence, and ______.The hedgehog rolls into a ______ (球) when scared.21. 填空题:My favorite thing to do at home is ______.22. 填空题:A _______ (青蛙) lives in wet areas.23. 选择题:What do we call a person who creates furniture?A. CarpenterB. ArtisanC. CraftsmanD. Woodworker答案: A24. 填空题:I like to _______ my toys after playing.25. 听力题:My ______ is a writer who tells great stories.26. 选择题:What is the main language spoken in Brazil?A. SpanishB. PortugueseC. EnglishD. French答案:B27. 选择题:Where do we go to learn?A. ParkB. SchoolC. StoreD. Home答案:B28. 填空题:The ______ (狼) hunts for food at night.29. 选择题:Which animal is known for its ability to change colors?A. ChameleonB. FrogD. Snake30. 填空题:I can create different characters with my ________ (玩具名称).31. 选择题:What do we call a small, round fruit that is often red or green?A. BananaB. GrapeC. AppleD. Orange32. 听力题:The dog is ______ with its favorite toy. (playing)33. 选择题:What is the name of the famous American author who wrote "To Kill a Mockingbird"?A. Harper LeeB. F. Scott FitzgeraldC. Ernest HemingwayD. Mark Twain答案:A34. 填空题:The parrot can be very ________________ (吵闹).35. 听力题:The man likes to ________.36. 听力题:A nonmetallic element is one that lacks the properties of _______.37. 听力题:The _____ (teacher/student) is helpful.38. 听力题:The _______ is a great way to learn about nature.39. 听力题:She is learning to ___. (swim)40. 选择题:What is the capital of Vietnam?A. Ho Chi Minh CityB. HanoiD. Nha Trang答案:B41. 选择题:What do we call a person who studies animals?A. BotanistB. ZoologistC. GeologistD. Archaeologist42. 填空题:A goldfish can recognize its own _______ (影子).43. 听力题:My ______ loves to travel and take photos.44. 选择题:What is the name of the famous landmark in Paris?A. Eiffel TowerB. Big BenC. Statue of LibertyD. Colosseum答案: A45. 选择题:What is the name of the famous American singer known for "I Want to Dance with Somebody"?A. Whitney HoustonB. Mariah CareyC. Janet JacksonD. Celine Dion答案: A46. 选择题:What do we call the first meal of the day?A. LunchB. DinnerC. BreakfastD. Snack47. 填空题:A ____(collaborative project) combines resources for greater impact.48. 填空题:The ________ is a popular choice for pets.When iron rusts, it combines with ______.50. 填空题:My favorite candy is ________ (巧克力).51. 填空题:The clock says it is ________ (三点).52. 选择题:What do you call a person who studies the human mind?A. PsychologistB. SociologistC. AnthropologistD. Biologist答案: A53. 填空题:I want to __________ (动词) my favorite __________ (玩具名) with you!54. f Exploration saw many __________ (探险家) travel the world. 填空题:The Age55. 听力题:The _____ (绘画) is famous.56. 听力题:A ______ is a measurement of the amount of matter in an object.57. 选择题:What do you call a place where you borrow books?A. LibraryB. MuseumC. ParkD. School答案:A58. 听力题:I like to _____ with my friends. (hang out)59. 选择题:What do we call the layer of gases surrounding the Earth?A. AtmosphereB. HydrosphereC. LithosphereD. BiosphereMy sister is a great _____ (演讲者).61. 填空题:My favorite sport is ________.62. 填空题:My sister is passionate about __________ (环保).63. 填空题:I love _____ (eating) fresh fruits and vegetables.64. 填空题:I have a special ______ (笔) that changes color when I write.65. 听力题:A catalyst is a substance that speeds up a ______.66. 选择题:What do we call the process of water turning into ice?A. MeltingB. FreezingC. EvaporatingD. Condensing67. 填空题:A _____ (植物管理) plan can optimize resources and efforts.68. 填空题:The _____ (拼图) is colorful and fun.69. 选择题:What is the name of the largest reptile in the world?A. Komodo DragonB. Saltwater CrocodileC. Green AnacondaD. Leatherback Turtle答案: B70. 选择题:What do you call the first month of the year?A. FebruaryB. JanuaryC. MarchD. April答案:B71. 听力题:The baby is ___ (crying/laughing).72. 听力题:A __________ can live on land or in water.73. 听力题:The chemical formula for calcium carbonate is __________.74. 听力题:Metals are typically good ________ of heat and electricity.75. 填空题:古代的________ (scientists) 对自然现象进行了深入研究。
小学上册英语第四单元真题(含答案)考试时间:90分钟(总分:100)A卷一、综合题(共计100题共100分)1. 填空题:A canary is a small _______ (鸟).2. 选择题:What is the first letter of the English alphabet?A. AB. BC. CD. D答案: A. A3. 填空题:The __________ (历史的延续) shapes our future.4. 填空题:The sky is ______ (蓝色) on sunny days.5. 填空题:I love visiting the aquarium to learn about ________ (海洋生物) and their habitats.6. 填空题:I appreciate my parents’ support in ____.7. 填空题:I enjoy making new friends with my toy ________ (玩具名称).8. 听力题:The dog is ___ (wagging) its tail.9. 选择题:What is the name of the animal known for its black and white stripes?A. ZebraB. HorseC. DonkeyD. Tiger答案: A10. 填空题:I can ______ (克服) challenges with determination.11. 听力题:We are going to the ______. (zoo)12. 选择题:What do we call a celebration of someone's birth?A. AnniversaryB. BirthdayC. HolidayD. Festival13. 听力题:I want to ________ (lead) community projects.14. 填空题:My dad teaches me the importance of __________ (诚实).15. 选择题:Which month has Halloween?A. JanuaryB. FebruaryC. OctoberD. December答案:C16. 选择题:What is the capital of Malaysia?A. JakartaB. Kuala LumpurC. ManilaD. Bangkok答案:B17. 听力题:A comet's tail always points away from the ______.18. 填空题:My _____ (妈妈) is the best cook.19. 填空题:We have ________ (家庭作业) to do tonight.20. 听力题:The atomic weight of an element is measured in ______.21. 听力题:The ______ is a predator of many small animals.22. 听力题:We have ___ (fun) at the party.23. 选择题:What is the name of the famous bear in "The Jungle Book"?A. BalooB. MowgliC. Shere KhanD. Bagheera答案:A24. 填空题:A _____ (植物资源利用) can promote sustainability.25. 填空题:We visit the ______ (博物馆) for educational trips.26. 填空题:I enjoy _______ (烹饪) new recipes.27. 填空题:My brother loves __________ (进行科学实验).28. 填空题:The invention of the compass aided in navigation at _____.29. 听力题:My friend is a ______. She loves to paint.30. 听力题:I want to ______ how to skate. (learn)31. 听力题:His favorite sport is ________.32. 选择题:Which planet is famous for its beautiful rings?A. NeptuneB. SaturnC. MarsD. Mercury33. 选择题:What do you need to keep your teeth clean?A. SoapB. ToothbrushC. TowelD. Shampoo34. 听力题:We have _____ (two/four) eyes.35. 听力题:I enjoy _____ (参加) community events.36. 填空题:My favorite _____ is a colorful butterfly.37. 选择题:Which shape has no corners?A. SquareB. TriangleC. CircleD. Rectangle38. 填空题:The discovery of penicillin was made by _____.39. 听力题:The stars are ___ (twinkling) in the sky.40. 选择题:What do you call a baby cow?A. CalfB. LambC. KidD. Foal答案: A41. 填空题:The owl rests during the ______ (白天).The _______ (猴子) swings from branch to branch effortlessly.43. 听力题:The antelope runs _______ across the plains.44. 填空题:The ______ (植物的生态价值) cannot be overstated.45. 选择题:What is the capital of Greece?A. AthensB. SpartaC. ThessalonikiD. Corinth46. 听力题:The ______ is where weather phenomena occur.47. 听力题:A reaction that occurs when an acid and base neutralize each other is called ______.48. 选择题:What do you call a large area covered with trees?A. DesertB. ForestC. OceanD. Mountain答案:B49. 填空题:The _____ (老虎) is a majestic creature.50. 听力题:I _____ (love/hate) homework.51. 听力题:I like to ride my ______ (skateboard).52. 选择题:What do we wear on our feet?A. HatsB. ShoesC. GlovesD. ScarvesWhat is the capital of Russia?A. MoscowB. St. PetersburgC. KievD. Minsk54. 听力题:The _____ (家庭) is important.55. 选择题:What do we call a young female horse?A. FillyB. ColtC. FoalD. Mare56. 听力题:The chemical formula for calcium carbonate is ______.57. 听力题:A soluble substance can easily _______ in a liquid.58. 选择题:What do we call the area of a city where people live?A. SuburbB. Urban areaC. Rural areaD. Metropolis答案: B. Urban area59. 听力题:The __________ is a region known for its wildlife safaris.60. 填空题:Certain plants have unique characteristics that help them ______ in their native habitats. (某些植物有独特的特征,帮助它们在原生栖息地生存。
2024年04版小学3年级英语第三单元期末试卷[含答案]考试时间:80分钟(总分:120)A卷考试人:_________题号一二三四五总分得分一、综合题(共计100题)1、填空题:The sun is shining in the ______.2、填空题:I also like to ________ (动词) new toys. Sometimes, I go to the store with my ________ (家人关系) to look for new games.3、What is the name of the famous archaeological site in Italy?A. PompeiiB. HerculaneumC. Ostia AnticaD. All of the above答案: D. All of the above4、填空题:The ________ is celebrated for its independence from Britain.5、听力题:The main ingredient in vinegar is ______ acid.6、听力题:Metals tend to lose ______ in chemical reactions.7、填空题:The __________ (历史的塑造) is a continuous process.8、听力题:I want to ________ (inspire) others.9、听力题:The ____ has a fluffy tail and loves to dig.The ______ (猴子) is very playful and curious.11、听力题:The _______ can be a perfect subject for drawing.12、听力题:The chemical formula for bismuth trioxide is _____.13、听力题:The book is ______ (about) a magical world.14、What do we call the person who teaches students?A. DoctorB. TeacherC. FarmerD. Baker答案:B15、填空题:My ________ (玩具名称) is designed for indoor fun.16、填空题:I can ______ (画) a picture of my family.17、听力题:The sun is ______ (shiny) during the day.18、听力题:A reaction that produces a change in color indicates a ______ reaction.19、听力题:She is drawing a ___. (sun)20、multimodal transport) integrates different travel methods. 填空题:The ____21、填空题:The owl looks for food in the _________. (夜晚)22、What is 10 - 4?a. 5b. 6c. 7d. 8答案:bShe is a good _____ (朋友) to me.24、What do you call a person who writes poetry?A. PoetB. AuthorC. WriterD. Lyricist25、ts are ______ (多年生) and return every year. 填空题:Some pla26、听力题:The __________ of a substance is its ability to dissolve in water.27、填空题:_____ (wind) can help disperse seeds.28、听力题:The Earth's crust is constantly being shaped by ______ forces.29、What is the name of the famous bear in the children's book series byA. A. Milne?A. PaddingtonB. Winnie the PoohC. Yogi BearD. Baloo30、填空题:Flowers often symbolize __________ (爱情和友情).31、 Carta was signed in ________. 填空题:The Magn32、What is the main source of energy for the Earth?A. WindB. SolarC. WaterD. Coal答案:B33、填空题:We have a ______ (快乐的) time during family vacations.34、填空题:My friend is a talented _________ (音乐家).Minerals are naturally occurring __________ that make up rocks.36、听力题:The symbol for praseodymium is _____.37、What do we call the place where we watch movies?A. TheaterB. MuseumC. LibraryD. Park38、What do you call a group of birds?A. SwarmB. FlockC. PackD. Gaggle答案:B39、听力题:The classroom is ______ and organized. (clean)40、What do you call a person who designs buildings?A. ArchitectB. EngineerC. ContractorD. Artist41、What do you call a place where books are kept?A. LibraryB. MuseumC. ParkD. Theater答案:A42、听力题:My sister enjoys taking ____ (art) classes.43、听力题:The ____ is known for its long neck and eating leaves from trees.44、听力题:The energy required to break bonds is known as ______ energy.45、听力题:A compound that contains carbon is called an _____ compound.She is ___ (cooking/cleaning) the kitchen.47、What is the sum of 4 + 4?A. 6B. 7C. 8D. 9答案:C48、听力题:A ______ is created when water erodes the land over time.49、填空题:I like to ________ (做) puzzles.50、填空题:The actor, ______ (演员), performs in movies.51、听力题:They are ___ a picnic today. (having, eat, eats)52、glacial) landforms were shaped by ice. 填空题:The ____53、What do you call a person who travels into space?A. AstronautB. PilotC. EngineerD. Scientist答案: A. Astronaut54、听力题:A mixture is made up of two or more __________ combined together.55、听力题:The book is ___. (interesting)56、听力题:A __________ is formed when a gas turns into a liquid.57、听力题:A _______ is a fun project for children.58、What is the process of a caterpillar becoming a butterfly called?A. MetamorphosisB. EvolutionC. TransformationD. Development答案: A59、听力题:A mineral’s hardness is measured on the ______ scale.60、听力题:The Great Lakes are located in ________ America.61、选择题:What is the capital of the United Kingdom?A. LondonB. EdinburghC. CardiffD. Belfast62、听力题:My friend is a ______. He loves to write stories.63、What is the main ingredient in a burger?A. BreadB. MeatC. CheeseD. Vegetables答案:B64、听力题:She wants to be a ________.65、填空题:The __________ (历史的社区) foster collective memory.66、听力题:A ______ is a type of mammal that can swim.67、听力题:She is wearing a ________ dress.68、填空题:The chameleon can hide in the _________. (树叶)69、What do you call the process by which plants lose water?A. AbsorptionB. EvaporationC. TranspirationD. Condensation答案: C70、What is the smallest unit of life?A. CellB. TissueC. OrganD. Organism答案: A71、What is the capital city of the Czech Republic?A. PragueB. BratislavaC. BudapestD. Vienna72、What do we call the scientific study of plants?A. BotanyB. ZoologyC. EcologyD. Geography答案: A73、What is the name of the famous scientist who discovered penicillin?A. Louis PasteurB. Alexander FlemingC. Marie CurieD. Robert Koch答案:B74、听力题:Asia is the largest _______ by land area.75、选择题:What is the capital of the Central African Republic?A. BanguiB. BerbératiC. BambariD. Bouar76、听力题:He likes to _______ (ride) his skateboard.77、听力题:I need to _____ (finish/start) my homework.78、What is the capital of Thailand?a. Bangkokb. Chiang Maic. Phuketd. Pattaya答案:a79、d Nations was established after ________ (第二次世界大战). 填空题:The Unit80、听力题:The _____ (snow) is white.81、What do you call a small, round fruit that is usually red or green?A. PearB. AppleC. CherryD. Plum答案:B82、填空题:My _____ (表妹) is very funny.83、填空题:The explorer traveled to many _____ (国家).84、听力题:A catalyst is a substance that speeds up a ______.85、填空题:I can ______ (帮助) my friends.86、听力题:The _____ is where the sun's energy is produced.87、What do you call the process of removing hair?A. ShavingB. CuttingC. TrimmingD. Styling答案:A88、填空题:Plants are essential for __________ (生态平衡)._____ (植物维护) ensures their health and beauty.90、听力题:My friend is a ______. He loves to play football.91、What is the primary color that is not a secondary color?A. GreenB. PurpleC. BlueD. Orange92、选择题:What do we call a sweet baked dish made from flour, sugar, and eggs?A. CakeB. BreadC. BiscuitD. Pie93、Which device do we use to see things that are far away?A. MicroscopeB. TelescopeC. BinocularsD. Magnifying glass答案: B94、听力题:I have ___ (three) pets.95、填空题:I like to __________ (动词) my __________ (玩具名) with my family.96、Which animal is known for its ability to swim well?A. CatB. DogC. FishD. Horse答案:C97、填空题:At the party, we had a _________ (气球) fight and it was so _________ (有趣的).98、填空题:I like to go ______ (滑雪) in the mountains during winter.I can ___ the answer. (find)100、填空题:My favorite drink is ________ (奶茶).。
Separation and Purification Technology 74 (2010) 155–159Contents lists available at ScienceDirectSeparation and PurificationTechnologyj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /s e p p urPreparation of bergenin from Ardisia crenata sims and Rodgersia sambucifolia hemsl based on microwave-assisted extraction/high-speed counter-current chromatographyJianchao Deng,Xiaohua Xiao,Xing Tong,Gongke Li ∗School of Chemistry and Chemical Engineering,Sun Yat-sen University,Xingang Xi Road 135,Guangzhou 510275,Chinaa r t i c l e i n f o Article history:Received 22February 2010Received in revised form 15May 2010Accepted 22May 2010Keywords:BergeninMicrowave-assisted extraction (MAE)High-speed counter-current chromatography (HSCCC)Ardisia crenata simsRodgersia sambucifolia hemsla b s t r a c tIn this paper,a simple method for the rapid extraction,separation and purification of bergenin from Ardisia crenata sims and Rodgersia sambucifolia hemsl by microwave-assisted extraction (MAE)coupled with high-speed counter-current chromatography (HSCCC)was developed.The MAE conditions were optimized and 2.0g sample was extracted using 60%(v/v)aqueous methanol as extraction solvent with liquid/solid ratio of 10/1(mL/g)at 60◦C for 15min.The crude extract of MAE was separated and purified directly by HSCCC using ethyl acetate–n -butanol–water (3:2:5,v/v/v)solvent system.In less than 3.5h,18.6or 25.0mg of bergenin was obtained from 160mg crude extract of A.creanta or R.sambucifolia in one-step separation,respectively.The purity of bergenin was over 99%determined by HPLC and its chemical structure was further identified by ESI-MS,1H NMR and UV.The results indicate that microwave-assisted extraction coupled with high-speed counter-current chromatography is very suitable for the extraction,separation and purification of bergenin from A.creanta and R.sambucifolia .© 2010 Elsevier B.V. All rights reserved.1.IntroductionBergenin is the major component of Ardisia creanta sims (A.cre-anta )and Rodgersia sambucifolia hemsl (R.sambucifolia )which are popular medicinal plants listed in the 2005Edition of the Chinese Pharmacopoeia.Bergenin (Fig.1)possesses a wide range of biolog-ical activities such as antiulcer [1],hepatoprotective [2,3],anti-HIV [4],antidiabetic [5,6],antiarrhythmic [7],anti-inflammatory [8],anti-arthritic and antitussive activities [9,10].In view of its good pharmacological activities,the study on the separation and purifi-cation of bergenin from Chinese medicinal plant is necessary.The conventional methods for the separation and purification of bergenin are maceration [3,9],heat reflux [11]and soxhlet extrac-tion (SE)[12],followed by silica gel column [2,8].These methods are time-consuming and require relatively large quantities of organic solvents.Microwave-assisted extraction (MAE)was widely used in food [13],agriculture [14]and natural products [15,16]due to its high extraction efficiency.High-speed counter-current chromatog-raphy (HSCCC)invented by Ito [17]is a support-free liquid–liquid partition chromatographic technique.It eliminates the irreversible adsorptive loss of samples onto the solid support matrix used in conventional chromatographic columns,and offers excellent sam-∗Corresponding author.Tel.:+862084110922;fax:+862084112245.E-mail addresses:xiaoxhua@ (X.Xiao),cesgkl@ (G.Li).ple recovery compared with silica gel column method.So it is very suitable for the separation and purification of components from Chinese herbal medicines [18].Microwave-assisted extraction cou-pled with high-speed counter-current chromatography had been successfully used for preparative separation of active components from Radix angelicae sinensis [19],Anoectochilu roxburghii (wall )Lindl [20],Sarcandra glabra [21]and Corydalis saxicola bunting [22].In this paper,a simple method for the rapid extraction,separation and purification of bergenin from A.creanta and R.sam-bucifolia by microwave-assisted extraction (MAE)coupled with high-speed counter-current chromatography (HSCCC)was devel-oped.Bergenin obtained was determined by HPLC and its chemical structure was further identified by ESI-MS,1H NMR and UV.2.Experimental 2.1.InstrumentationThe MAS-II microwave oven (2450MHz,Sineo Microwave Chemistry Technology Company,Shanghai,China)was used.The preparative HSCCC instrument was a GS10A HSCCC (Beijing UE Biotechnology,Beijing,China).The apparatus was equipped with a PTFE multilayer coil of 110m ×1.6mm i.d.with a total capacity of 240mL and a 12mL sample loop.The revolution radius or the distance between the holder axis and central axis of the centrifuge (R )was 5cm,and the value varied from 0.5at the internal termi-nal to 0.8at the external terminal (ˇ=r /R ,where r is the distance1383-5866/$–see front matter © 2010 Elsevier B.V. All rights reserved.doi:10.1016/j.seppur.2010.05.018156J.Deng et al./Separation and Purification Technology74 (2010) 155–159Fig.1.Chemical structure of bergenin.from the coil to the holder shaft,and R,is the revolution radius or the distance between the holder axis and central axis of the cen-trifuge).The revolution speed of the apparatus can be regulated with a speed controller in the range0–1000rpm.The HSCCC system was equipped with a model NS-1007constant-flow pump(Beijing UE Biotech.,Beijing,China),a model8823A UV detector(Beijing Institute of New Technology Application,Beijing,China)operat-ing at254nm and a model HW2000chromatography workstation software(Qianpu Co.,Ltd.,Shanghai,China).A HPLC system(Shimadzu,Kyoto,Japan)consisted of two LC-20AT pump,a SPD-M20A photodiode array detector,an SIL-20 A auto injector,a DGU-20A3degasser and a CBM-20A system controller.Identification of bergenin was carried out by ESI-MS (ThermoFisher,Waltham,USA)and Nuclear Magnetic Resonance (NMR)spectrometer(Mercury-plus300,Varian,USA).2.2.Reagents and materialsHPLC grade acetonitrile was used(Merck,Darmstadt,Ger-many).Methanol,ethyl acetate and n-butanol were of analytical grade(Guangzhou Chemical Factory,Guangdong,China).Standard bergenin was purchased from National Institute for the Control of Pharmaceutical and Biological Products(Beijing,China).The dried A.creanta and R.sambucifolia were collected from Chengdu,Sichuan,China and was ground into powder(40–60 mesh)before use.2.3.Optimization of MAE conditionsAn orthogonal test design L9(3)4was employed for the opti-mization of MAE conditions.The experiment was carried out with four factors and three levels,namely extraction temperature(40, 50and60◦C),liquid/solid ratio(10/1,15/1and20/1mL/g),extrac-tion time(5,10and15min)and concentration of methanol(60%, 80%and100%,v/v).Moreover,microwave power and concentration of methanol were also optimized with single factor experiment. For each test,2.0g sample was added to a50-mL glass vessel with appropriate solvent volume and stirred at500rpm using a magnetic stirring bar for MAE.At the same time,2.0g sample was refluxed with100mL methanol for12h by soxhlet extraction(SE).After MAE or SE,the extract wasfiltered,and then thefiltrate was diluted and used for HPLC analysis.All the experiments were performed in triplicate.The extraction solution was concentrated to dryness by rotary evaporator under reduced pressure.Dried extract was used for sub-sequent HSCCC separation.2.4.Measurement of partition coefficient(K)K values were determined by HPLC method.Approximately2mg of the dried extract was dissolved with10mL solution composed of the upper and lower phases(1:1,v/v)of the HSCCC solvent system in a10mL test tube.The test tube was capped and shaken violently for several minutes.Then bergenin in the upper layer and lower layer were analyzed by HPLC.The K value is defined as the peak areas in the upper phase divided by that in the lower phase.2.5.HSCCC procedureIn this study,two-phase solvent system of ethyl acetate–n-butanol–water(3:2:5v/v/v)was used for HSCCC.Solvent mixture was thoroughly equilibrated in a separated funnel at room temper-ature and the two phases were separated before use.The sample solution was prepared by dissolving dried extract in5mL lower phase of solvent system for the separation and purification of bergenin.HSCCC separation was performed as follows:the coiled column wasfirst entirelyfilled with the upper phase of the solvent system. The lower phase was then pumped into the head end of the col-umn at aflow rate of2.0mL/min,while the apparatus was run at a revolution speed of900rpm.After hydrodynamic equilibrium was reached,as indicated by a clear mobile phase eluting at the tail out-let,5mL sample solution was introduced into the column through the injection valve.The effluent of the column was continuously monitored with UV–vis detector at254nm.The retention of the stationary phase was computed from the volume of the stationary phase collected from the column after the separation.2.6.HPLC analysis and identification of HSCCC fractionsThe extracts and the fractions obtained from HSCCC were analyzed by HPLC.The column was a Diamonsil C18column (200mm×4.6mm I.D.,5m,Dikma,China).The mobile phase was acetonitrile and water(10/90,v/v).Theflow rate was set at 1.0mL/min,and the temperature was30◦C.The detection wave-length was270nm.The identification of HSCCC peak fractions was further carried out by ESI-MS and1H NMR spectra.The external standard method was used for quantitative analy-sis of bergenin.The linear range of the method was0.8–160mg/L with correlation coefficient(r)0.9999,the relative standard devi-ation(RSD)for six replicates was0.5%,the detection limit was 0.24mg/L which was evaluated on the basis of a signal-to-noise ratio of3.0.The recoveries were98.4%and99.3%with RSD0.5% and1.3%for A.creanta and R.sambucifolia,respectively.The typical HPLC chromatograms of bergenin standard and the MAE extracts of A.creanta and R.sambucifolia are shown in Fig.2.Briefly,the extraction yield of bergenin was defined as follow-ing:Extraction yield(mg/g)=quantity of bergenin in MAE extraction(mg)quantity of original sample(g)3.Results and discussion3.1.Optimization of MAE conditionsThe primary step in MAE is to optimize the operating condi-tions to obtain an efficient extraction of target compounds and avoid the co-extraction of undesired compounds such as starch, saponin,etc.Extraction temperature(A),ratio of liquid to solid(B),J.Deng et al./Separation and Purification Technology74 (2010) 155–159157Fig.2.(A)HPLC chromatograms of standard solution of80mg/L bergenin(A), the MAE extract of A.crenata(B)and R.sambucifolia(C).Experiment conditions: Diamonsil C18column(200mm×4.6mm I.D.,5m);column temperature:30◦C; mobile phase:acetonitrile–water(10:90,v/v);flow rate:1.0mL/min;detection wavelength:270nm;injection volume:5L;peak1:bergenin.extraction time(C)and concentration of methanol(D)were impor-tant factors and optimized using an orthogonal L9(3)4test design, and the results are shown in Table1.The influence to the mean extraction yield of bergenin decreased with the order of D>A>C>B according to the R values.The concentration of methanol was found to be the key factor for MAE.Since the choice of solvent is fundamental for obtaining an optimal extraction process,some consideration should be give to the microwave absorbing proper-ties of the solvent,the interaction of the solvent with the matrix and the analyte solubility in the solvent[23].Further systemati-cal investigation on the effect of concentration of methanol from 0%to100%(v/v)on the extraction of bergenin was performed.20.43,23.60,24.39,24.16and20.19mg/g bergenin was obtained from0,30%,60%,80%and100%(v/v)aqueous methanol,respec-tively.The results showed that the extraction yield improved with the concentration of methanol was60%(v/v),while the yield of bergenin was decreased as100%methanol or pure water was used. Extraction temperature is also an important factor contributing to improve sample wetting,matrix penetration and extraction effi-ciency.The extraction yield of bergenin was increased with the temperature in the range of40–60◦C.Higher temperature could accelerate the solvent transfer between the sample and solvent,and better extraction yield was obtained.The ratio of liquid to solid and extraction time only showed slightly effect on the extraction yield of bergenin in comparison with the other two factors.A liq-uid/solid ratio of10/1(mL/g)and extraction time of15min were adopted in the present work.Moreover,the effect of microwave power on the extraction yield of bergenin was also optimized by single factor experiment and the extraction yield was almost steady and23.74±0.34mg/g bergenin was obtained from300to 900W.Therefore,the optimized MAE conditions for extraction of bergenin from Ardisia crenata was performed using60%(v/v) aqueous methanol as extraction solvent with liquid/solid ratio of 10/1(mL/g)at60◦C for15min under500W microwave power. Since the amount of starch in R.sambucifolia was higher than that in A.crenata[24],lower extraction temperature coupled with higher liquid/solid ratio in a fast procedure would be benefit from avoiding the effect of starch on the extraction of bergenin from R.sambucifolia.And then,the optimized extraction conditions for R.sambucifolia were extraction temperature of50◦C,liquid/solid ratio of15/1(mL/g)and5min of extraction time,the main MAE condition,60%(v/v)aqueous methanol as extraction solvent,was the same as that for A.crenata.Under the optimum MAE conditions,the extraction yields of bergenin in A.crenata and R.sambucifolia were26.5±0.3and 32.3±0.1mg/g,respectively.Moreover,to evaluate the extraction efficiency of MAE,bergenin was also extracted with the typical tra-ditional SE method.The extraction yields of bergenin by SE from A.crenata and R.sambucifolia were27.7±0.4and32.6±0.1mg/g, pared with SE method,similar extraction yield of bergenin by MAE was obtained with the greatly reducing time (15min instead of12h).Therefore,MAE was validated as a rapid, efficient and reliable method for extraction of bergenin from A. creanta and R.sambucifolia.3.2.Selection of two-phase solvent system in HSCCCIn order to determine the optimal two-phase solvent system for the HSCCC separation,a series of optimization experiments were performed in the present study.According to the gold rules in selecting optimum conditions introduced by Ito[25],solvent sys-tem of ethyl acetate–n-butanol–water would be suitable for polar compound such as bergenin.And then,several kinds of solvent systems composed of ethyl acetate–n-butanol–water at different volume ratios were selected and assessed for K values.The K val-ues of bergenin were1.53,1.38,1.20,0.68and0.19for the ethyl acetate–n-butanol–water solvent system under the volume ratiosTable1The results of orthogonal design L9(3)4(n=3)for MAE of bergenin from A.crenata.No.Factors Yield of bergenin inA.crenata(mg/g)A(extraction temperature,◦C)B(liquid/solid ratio,mL/g)C(extraction time,min)D(concentration of methanol,%)1401056024.2±0.6 24015108023.4±0.2 340201510020.3±0.4 450101010022.1±0.5 55015156026.3±0.6 6502058024.5±0.2 76010158026.9±0.6 86015510021.3±0.1 96020106026.3±0.3k122.63324.40023.33325.600k224.30023.66723.93324.933k324.83323.70024.50021.233R 2.2000.733 1.167 4.367Optimal level A3B1C3D1k A i =(yield of bergenin at A i)3,R Ai=max{k Ai}−min{k Ai}.158J.Deng et al./Separation and Purification Technology74 (2010) 155–159Table2Effect of sample loading on the retention of the stationary phase of HSCCC and the purity of bergenin.Chinese medicinal plant Original sample(g)Dry extract(mg)Bergenin in extract(mg)Bergenin in obtainedfrom HSCCC(mg)Retention of thestationary phase(%)Purity(%)A.crenata 0.240 4.7 4.241.7>99 0.4809.59.435.0>99 0.612014.213.931.7>99 0.816018.918.628.3>99R.sambucifolia 0.240 6.5 6.439.2>99 0.48012.912.735.8>99 0.612019.418.930.0>99 0.816025.925.027.5>99of1:4:5,2:3:5,3:2:5,4:1:5and5:0:5(v/v/v),respectively.It can be seen that the solvent system of ethyl acetate–n-butanol–water at the volume ratio of5:0:5and4:1:5had minor K value,and the retention of the stationary phase was less than30%.The other sol-vent systems of ethyl acetate–n-butanol–water at volume ratio of1:4:5,2:3:5and3:2:5had appropriate K values.Further experiment was performed and the results showed that two-phase solvent system composed of ethyl acetate–n-butanol–water(3:2:5,v/v/v) could obtain relative better the retention of stationary phase of40% for preparative HSCCC,along with its good separation and accept-able separation time,it was selected as the solvent system of HSCCC in the following studies.3.3.Optimization of sample concentration of HSCCCSuccessful separation in HSCCC greatly depends on the reten-tion of the stationary phase,in general,the higher the retention of the stationary phase,the better the peak resolution[23].Although high sample loading can enlarge the yield of obtained analytes in a single separation and purification procedure,it is commonly unfavorable to the retention of the stationary phase,resulting in reducing the separation and purification efficiency in HSCCC.The sample loading was optimized under the sample concentration of8,16,24and32mg/mL,i.e.40,80,120and160mg of dried extract dissolved in5mL of the HSCCC lower phase,respectively. The effect of sample loading on the retention of the stationary phase and purity of obtained bergenin is shown in Table2.It was found that,with the increase of the sample loading from40 to160mg,the corresponding peaks were similar and the purity of obtained bergenin was over99%,but the peak resolution of bergenin decreased slightly.Meanwhile,the retention of the sta-tionary phase greatly decreased from41.7%to28.3%and39.2%to 27.5%for A.creanta and R.sambucifolia,rger sample loading(>160mg)could lead to excessive lost of the retention of the stationary phase,and it was not suitable for the separation and purification.Thus,the maximum sample loading was160mg dried extract.3.4.Purity determination of the separated peakUnder the optimum MAE and HSCCC conditions,bergenin was separated and purified from A.creanta and R.sambucifolia.The HSCCC chromatograms of A.creanta and R.sambucifolia are shown in Figs.3A and4A,respectively.18.6or25.0mg of bergenin was obtained from160mg dried extract of A.creanta or R.sambucifolia, respectively,within3.5h.Peak fractions from HSCCC were analyzed by HPLC,the HPLC chromatograms and UV spectra of the collected fractions from A. creanta and R.sambucifolia are shown Figs.3B and4B,respec-tively.The obtained bergenin wasdetermined according to the peak area with the standard.The purity of bergenin was defined as the amount determined with HPLC by the peak area divided by the measured mass of bergenin in the collected effluent.The results of HPLC showed that peak1which corresponded to bergenin possessed the purity of more than99%.The structural identification of peak fractions was performed with ESI-MS and1H NMR spectra follows.ESI-MS(m/z):328[M+];Fig.3.(A)HSCCC chromatogram of the crude extract from A.creanta;(B)HPLC analy-sis and UV spectrum of bergenin obtained from A.crenata;HSCCC conditions:solvent system:ethyl acetate–n-butanol–water(3:2:5,v/v/v);column volume:240mL; mobile phase:lower phase;flow rate:2mL/min;rotation speed:900rpm;sample loading:160mg,sample volume:5mL;temperature,25◦C;detection wavelength, 254nm.HPLC conditions were the same as shown in Fig.2.Fig.4.(A)HSCCC chromatogram of the crude extract from R.sambucifolia;(B) HPLC analysis and UV spectrum of bergenin obtained from R.sambucifolia.HSCCC conditions:solvent system:ethyl acetate–n-butanol–water(3:2:5,v/v/v);column volume:240mL;mobile phase:lower phase;flow rate:2mL/min;rotation speed: 900rpm;sample loading:160mg,sample volume:5mL;temperature,25◦C;detec-tion wavelength,254nm.HPLC conditions were the same as shown in Fig.2.J.Deng et al./Separation and Purification Technology74 (2010) 155–1591591H NMR(DMSO-d6,300MHz):ı6.98(1H,s,H-7),5.62(1H,d, H-10b),4.98(1H,d,H-4a),3.98(1H,d,H-4),3.86(2H,d,H-11), 3.77(3H,s,H-12),3.65(1H,m,H-2),3.56(1H,d,H-3),which was accorded with the literature[26],indicating the structural identi-fication of bergenin.4.ConclusionA new MAE coupled with HSCCC method was developed for the preparation of bergenin from the traditional Chinese medicine of A.creanta and R.sambucifolia.The crude extract of MAE was separated and purified directly by HSCCC using ethyl acetate–n-butanol–water(3:2:5,v/v/v)solvent system.Under optimum conditions,18.6or25.0mg of bergenin was obtained from160mg dried extract of A.creanta or R.sambucifolia within3.5h with purity over99%.The results indicated that the present method of MAE cou-pled with HSCCC was suitable for the separation and purification of bergenin from A.creanta and R.sambucifolia.AcknowledgementsThis work supported by the project of the National Key Technologies R&D Programme of the11th-five-year Plan(No. 2006BAK03A08),by the National Natural Science Foundation of China(No.20905080),and by Science and Technology Planning Project of Guangdong Province of China(No.2009B010900021). Special thanks to Mr.Zhou Xiaonan for his useful advices on the design of the LTV-MAE device.References[1]K.Abe,K.Sakai,M.Uchida,Effects of bergenin on experimental ulcers-prevention of stress induced ulcers in rats,Gen.Pharmacol.11(1980)361–368.[2]H.K.Lim,H.S.Kim,H.S.Choi,J.Choi,S.H.Kim,M.J.Chang,Effects of bergenin,the major constituent of Mallotus japonicus against d-galactosamine-induced hepatotoxicity in rats,Pharmacology63(2001)71–75.[3]H.S.Kim,H.K.Lim,M.W.Chung,Y.C.Kim,Antihepatotoxic activity of bergenin,the major constituent of Mallotus japonicus,on carb,J.Ethnopharmacol.69 (2000)79–83.[4]S.Piacente,C.Pizza,N.DeTommasi,N.Mahmood,Constituents of Ardisia japon-ica and their in vitro anti-HIV activity,J.Nat.Prod.59(1996)565–569.[5]Z.Y.Zhang,S.Y.Lee,PTP1B inhibitors as potential therapeutics in the treatmentof type2diabetes and obesity,Expert Opin.Investig.Drugs12(2003)223–233.[6]Y.F.Li,L.H.Hu,F.C.Lou,J.Li,Q.Shen,PTP1B inhibitors from Ardisia japonica,J.Asian Nat.Prod.Res.7(2005)13–18.[7]H.L.Pu,X.Huang,J.H.Zhao,A.Hong,Bergenin is the antiarrhythmic principleof Fluggea virosa,Planta Med.68(2002)372–374.[8]R.W.Li,D.N.Leach,S.P.Myers,G.D.Lin,G.J.Leach,P.G.Waterman,A newanti-inflammatory glucoside from Ficus racemosa L.,Planta Med.70(2004) 421–426.[9]N.Nazir,S.Koul,M.A.Qurishi,S.C.Taneja,S.F.Ahmad,S.Bani,G.N.Qzai,Immunomodulatory effect of bergenin and norbergenin against adjuvant-induced arthritis—aflow cytometric study,J.Ethnopharmacol.112(2007) 401–405.[10]J.X.Xie,L.Wang,C.X.Liu,D.Y.Zhang,The identification total synthesis ofaichasu,an antitussive agent,Acta Pharmacol.Sin.6(1981)425–428.[11]V.S.Rana,M.S.Rawat,G.Pant,A.Nagatsu,Chemical constituents and antiox-idant activity of Mallotus roxburghianus leaves,Chem.Biodivers.2(2005) 792–798.[12]R.Srinivasan,M.J.N.Chandrasekar,M.J.Nanjan,B.Suresh,Antioxidant activityof Caesalpinia digyna root,J.Ethnopharmacol.113(2007)284–291.[13]H.Zhang,M.Xue,Y.Lu,Z.Dai,H.Wang,Microwave-assisted extraction forthe simultaneous determination of Novolac glycidyl ethers,bisphenol A digly-cidyl ether,and its derivatives in canned food using HPLC withfluorescence detection,J.Sep.Sci.33(2010)235–243.[14]E.Fuentes,M.E.Báez,bra,Parameters affecting microwave-assisted extrac-tion of organophosphorus pesticides from agricultural soil,J.Chromatogr.A 1169(2007)40–46.[15]J.G.Gujar,S.J.Wagh,V.G.Gaikar,Experimental and modeling studies onmicrowave-assisted extraction of thymol from seeds of Trachyspermum ammi (TA),Sep.Purif.Technol.70(2010)257–264.[16]W.Ma,Y.Lu,R.Hu,J.Chen,Z.Zhang,Y.Pan,Application of ionic liquidsbased microwave-assisted extraction of three alkaloids N-nornuciferine,O-nornuciferine,and nuciferine from lotus leaf,Talanta80(2010)1292–1297. [17]Y.Ito,Efficient preparative countercurrent chromatography with a coil planetcentrifuge,J.Chromatogr.214(1981)122–125.[18]I.A.Sutherland,D.Fisher,Role of counter-current chromatography in the mod-ernisation of Chinese herbal medicines,J.Chromatogr.A1216(2009)740–753.[19]Z.L.Liu,J.Wang,P.N.Shen,C.Y.Wang,Y.J.Shen,Microwave-assisted extractionand high-speed counter-current chromatography purification of ferulic acid from Radix angelicae sinensis,Sep.Purif.Technol.52(2006)18–21.[20]L.Huang,Y.Cao,G.Chen,Purification of quercetin in Anoectochilu roxburghii(wall)Lindl using UMAE by high-speed counter-current chromatography and subsequent structure identification,Sep.Purif.Technol.64(2008)101–107. [21]X.H.Xiao,Z.N.Guo,J.C.Deng,G.K.Li,Separation and purification of isofraxi-din from Sarcandra glabra by microwave assisted extraction coupled with high speed counter current chromatography,Sep.Purif.Technol.68(2009)250–254.[22]J.C.Deng,X.H.Xiao,G.K.Li,G.H.Ruan,Application of microwave assistedextraction coupled with high speed counter current chromatography for sep-aration and purification of dehydrocavidine from Corydalis saxicola bunting, Phytochem.Anal.20(2009)498–502.[23]C.S.Eskilsson,E.Bjorklund,Analytical-scale microwave-assisted extraction,J.Chromatogr.A902(2000)227–250.[24]P.P.Li,S.C.Yang,Y.H.Zeng,Advances in studies on resources for medicinalsource plants with bergenin,Chin.Trad.Herb.Drugs40(2009)1500–1505. [25]Y.Ito,Golden rules and pitfalls in selecting optimum conditions for high-speedcounter-current chromatography,J.Chromatogr.A1065(2005)145–168. [26]J.A.Nasser,W.A.Yaacob,L.B.Din,B.M.Yamin,tip,Isolation of atranorin,bergenin and goniothalamin from Hopea sangal,J.Eng.Appl.Sci.4(2009)92–95.。