title: Flavonol glycosides and other phenolic compounds from Viola tianshanica and their anti-complement activities.
abstract: BACKGROUND
  Viola tianshanica Maxim. (Violaceae) is a perennial herb distributed in Central Asia, especially in the Xinjiang Uygur Autonomous Region (XUAR) of China. Preliminary study showed that the ethanol extract of the herb exhibited the anti-complement activity against the classical pathway, but the active components responsible for this capacity remain unknown and are yet to be studied.
  
  
  OBJECTIVE
  The objective of this study was the isolation and identification of the anti-complement constituents of V. tianshanica.
  
  
  METHODS
  The ethyl acetate and n-butanol fractions from the ethanol extract of V. tianshanica were purified. The structures of the isolates were identified by spectroscopic methods, and comparing their spectral data with those reported in the literature. All the isolates (0.02-2.50 mg/mL) were evaluated for their anti-complement activity against the classical and alternative pathways.
  
  
  RESULTS
  Twenty-one phenolic compounds including 15 flavonol O-glycosides (1-15), one flavone 6,8-di-C-glycoside (16), one flavone aglycone (17), and four phenolic acid derivatives (18-21) were isolated and identified. Bioassay showed that 11 compounds inhibited the classical pathway and the alternative pathway with CH50 and AP50 values of 0.113-1.210 mM and 0.120-1.579 mM, respectively. Preliminary mechanistic study using complement-depleted sera demonstrated that 1 acted on C1q, C2, C4, and C9 components, 16 on C1q, C4, and C5, and 21 on C1q, C3, C4, and C9.
  
  
  CONCLUSIONS
  All isolated compounds except 1 and 10 were reported for the first time from V. tianshanica. Compound 16 is the first flavone C-glycoside isolated from the herb. Flavonol O-glycosides and phenolic acids contributed the anti-complement activity of the herb.
authors.affiliation: a Department of Pharmacognosy , School of Pharmacy, Fudan University , Shanghai , China and.|b Zhongshan Hospital, Fudan University , Shanghai , China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Qin
authors.affiliation: a Department of Pharmacognosy , School of Pharmacy, Fudan University , Shanghai , China and.
authors.forename: Quan
authors.initials: Q
authors.lastname: Wen
authors.affiliation: a Department of Pharmacognosy , School of Pharmacy, Fudan University , Shanghai , China and.
authors.forename: Jie
authors.initials: J
authors.lastname: Cao
authors.affiliation: a Department of Pharmacognosy , School of Pharmacy, Fudan University , Shanghai , China and.
authors.forename: Chengle
authors.initials: C
authors.lastname: Yin
authors.affiliation: a Department of Pharmacognosy , School of Pharmacy, Fudan University , Shanghai , China and.
authors.forename: Daofeng
authors.initials: D
authors.lastname: Chen
authors.affiliation: a Department of Pharmacognosy , School of Pharmacy, Fudan University , Shanghai , China and.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Cheng
mesh_terms: D020001:1-Butanol / Q000737:chemistry; D000085:Acetates / Q000737:chemistry; D000818:Animals; D051056:Complement Inactivating Agents / Q000302:isolation & purification / Q000494:pharmacology*; D003170:Complement Pathway, Alternative / Q000187:drug effects*; D003171:Complement Pathway, Classical / Q000187:drug effects*; D003165:Complement System Proteins / Q000276:immunology / Q000378:metabolism*; D000431:Ethanol / Q000737:chemistry; D044948:Flavonols / Q000302:isolation & purification / Q000494:pharmacology*; D006027:Glycosides / Q000302:isolation & purification / Q000494:pharmacology*; D006168:Guinea Pigs; D015394:Molecular Structure; D010636:Phenols / Q000302:isolation & purification / Q000494:pharmacology*; D008517:Phytotherapy; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D011817:Rabbits; D012997:Solvents / Q000737:chemistry; D032413:Viola / Q000737:chemistry
chemical_list: D000085:Acetates; D051056:Complement Inactivating Agents; D044948:Flavonols; D006027:Glycosides; D010636:Phenols; D010936:Plant Extracts; D012997:Solvents; D000431:Ethanol; C007650:ethyl acetate; D020001:1-Butanol; D003165:Complement System Proteins
keywords: Flavone C-glycoside; flavonoid; rutin; structure elucidation