Phytochemical Tests, Assessment of Antioxidant Properties and Isolation of Two Compounds of Ethyl Acetate Extract of Chadian Propolis: Case of Bebotho (Southern Chad)

The present work deals with the research of chemical constituents and evaluation of antioxidant properties of Bebotho propolis. From the ethyl acetate extract, we isolated, using various chromatographic techniques, a mixture of two identical compounds (isomers) indexed PBy4a and PByb. The structures of these compounds were elucidated by means of spectroscopic analysis techniques (MS, IR, 1H-NMR, 13C-NMR, HMBC and HSQC) and by comparison of the spectral data with those described in the literature. Thus, these compounds were identified to a mixture of two chromones namely 5,7-dihydroxy-2-methylchromone-6-C-α-D-glucopyranoside and 5,7-dihydroxy-2-methylchromone-8-C-β-D-glucopyranoside, first reported in propolis. The study of the antiradical power, chelating power and the quantification of phenolic compound of these same extracts, showed interesting properties that propolis extracts have to scavenge free radicals.

铁皮石斛化学成分的研究

目的研究铁皮石斛（Dendrobium officinale Kimuraet Migo）的化学成分。方法采用反相硅胶色谱柱色谱、聚酰胺色谱柱色谱、凝胶色谱柱色谱等方法分离化合物，运用现代光谱技术鉴定化合物结构。结果从铁皮石斛中分离得到7个化合物，分别鉴定为：apigenin-6，8-di—C-pD—glucopyranoside（I），apigenin-6—0d-三-arabinopyranosyl-8-C-β-D—xylopyranoside（Ⅱ），apige-nin-6-C-（2＂-O-β-D—glucopyranosyl）-α—L—arabinopyranoside（Ⅲ），apigenin-8-C-（2＂-O-β-D—glucopyranosyl）-OL—L—arabinopyranoside（Ⅳ），quercetin-3-O-β-D—rutinoside（V），D—SUCrOSe（Ⅵ），3-sitosterol-3—O-β-D—glucopyranoside（Ⅶ）。结论化合物I—V均为首次从该植物中分离得到。