Polyphenolic compounds and antimicrobial activity of Quercus aucheri leaves


Sakar M. K. , Sohretoglu D. , Ozalp M. A. , Ekizoglu M. , Piacente S., Pizza C.

TURKISH JOURNAL OF CHEMISTRY, vol.29, no.5, pp.555-559, 2005 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 29 Issue: 5
  • Publication Date: 2005
  • Title of Journal : TURKISH JOURNAL OF CHEMISTRY
  • Page Numbers: pp.555-559

Abstract

Chromatographic studies (CC, VLC, MPLC, and PTLC) on ethyl acetate extract from the leaves of Quercus aucheri yielded 2 flavonoids (quercetin 3-O-alpha-L-arabinopyranoside (1), quercetin 3-O-beta-D-galactopyranoside (2)) and 2 tannin precursors and a procyanidin [(isolated as peracetates of (+)-catechin (3a), (+)-gallocatechin (4a) and epicatechin-(4 beta -> 8)-catechin (5a))]. The structures of the compounds were elucidated by UV, 1D-NMR (H-1, C-13, TOCSY) and 2D-NAIR (COSY; HSQC: HMBC) techniques. Different extracts (80% MeOH, EtOAc, n-BuOH and H2O) from the leaves of Q. aucheri were investigated for their antimicrobial activity against 2 Gram-positive and 2 Gram-negative bacteria and 3 yeast-like fungi by a broth microdilution method. EtOAc extract, which showed the highest antimicrobial activity, was further used for isolation.