title: Saponin rich fractions from Polygonatum odoratum (Mill.) Druce with more potential hypoglycemic effects.
abstract: OBJECTIVE
  The root of Polygonatum odoratum (YuZhu), also a medicinal food has long been used for the treatment of diabetes. The objective of the study was to characterize the anti-diabetic active fractions or compounds in this herb.
  
  
  METHODS
  Fractions with a different polarity were prepared by solvent extraction and macroporous absorptive resin (D101) column and their anti-diabetic potentials were evaluated by glucose uptake in HepG2 cells and STZ-induced diabetic rats. In addition, α-glycosidase inhibitory activities of active fractions were measured in vitro and chemical compositions including saponin, total flavonoids and total sugar in the fractions were determined.
  
  
  RESULTS
  The n-buthanol fraction, a saponin-rich fraction obtained by partitioning the ethanol extract with n-buthanol after petroleum ether and acetic ether showed the highest anti-diabetic potential in glucose uptake in HepG2 cells followed by acetic ether fraction which was rich in flavonoids. Further fractionation the saponin-rich fraction using macroporous resin column (D101), polysaccharide, flavonoid and saponin rich fractions were obtained by elution with water, 40% and 60% ethanol, respectively and their anti-diabetic potentials proved by glucose uptake test in HepG2 cells and STZ-induced diabetic rats were in the order of saponin rich fraction>flavonoid rich fraction>polysaccharide rich fraction. Long-term therapy test (60d) in severe diabetic rats indicated that saponin-rich fraction significantly ameliorated clinical symptoms of diabetes including the elevated blood glucose, body weight loss as well as the increased food and water intake while flavonoid-rich fraction was more potential than saponin-rich fraction to increase superoxide dismutase (SOD) activity and decrease malondialdehyde (MDA) level in rat plasma. Additionally, saponin-rich fraction and flavonoid-rich fraction showed α-glycosidase inhibitory activity with IC(50) value of 2.05±0.32 and 3.92±0.65mg/ml, respectively.
  
  
  CONCLUSIONS
  The results suggested that saponin in this herb was more important than flavonoid in exhibiting anti-diabetic activity and flavonoid contributed more to anti-oxidant activity in vivo.
authors.affiliation: Chemistry Institute of Pharmaceutical Resources, College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, PR China.
authors.forename: Yafei
authors.initials: Y
authors.lastname: Deng
authors.forename: Kai
authors.initials: K
authors.lastname: He
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Ye
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Huang
authors.forename: Xuegang
authors.initials: X
authors.lastname: Li
authors.forename: Lujiang
authors.initials: L
authors.lastname: Yuan
authors.forename: Yalan
authors.initials: Y
authors.lastname: Jin
authors.forename: Qing
authors.initials: Q
authors.lastname: Jin
authors.forename: Panpan
authors.initials: P
authors.lastname: Li
mesh_terms: D020001:1-Butanol / Q000737:chemistry; D000473:Alkanes / Q000737:chemistry; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D005591:Chemical Fractionation; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000737:chemistry; D005419:Flavonoids / Q000494:pharmacology; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism; D056945:Hep G2 Cells; D006801:Humans; D007004:Hypoglycemic Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008517:Phytotherapy; D010946:Plants, Medicinal; D031384:Polygonatum / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D027343:Rhizome; D012503:Saponins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D012997:Solvents / Q000737:chemistry; D013482:Superoxide Dismutase / Q000097:blood; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000473:Alkanes; D001786:Blood Glucose; D005419:Flavonoids; D007004:Hypoglycemic Agents; D012503:Saponins; D012997:Solvents; D014867:Water; D000431:Ethanol; D008315:Malondialdehyde; D020001:1-Butanol; D013482:Superoxide Dismutase; D006026:Glycoside Hydrolases; C004544:naphtha