R. Christov3, V. Bankova3, A. Hegazib, F. Abd El Hadyc and S. Popov3 a Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria b Dept. Parasitology and Animal Diseases, National Research Centre, Dokki, Giza, Egypt c Dept, of Natural Products, National Research Centre, Dokki, Giza, Egypt Z. Naturforsch. 53c, 197-200 (1998); received October 27/December 30, 1997 Propolis, Polyphenols, GC/MS A sample from Egyptian propolis was investigated by TLC and GC/MS. 39 compounds were identified, 8 being new for propolis. Partial structures of four new esters of caffeic acid have been proposed. Chemical Composition of Egyptian Propolis Introduction Propolis (bee glue) is a resinous hive product collected by bees from plant exudates. It performs defensive functions in the hive and has recently found wide application in medicine and cosmetics, due to its versatile biological activities: antibacte rial, antiviral, fungicidal, antiulcer, immunostimu- lating, hypotensive, cytostatic, etc. (Marcucci, 1995). Recently, propolis is extensively used also in beverages and foods intended to maintain or improve human health (Matsuda, 1994). The chemical composition of bee glue is ex tremely complex and more than 180 constituents have been identified so far (Marcucci, 1995). The most important ones appeared to be polyphenols, which are the main biologically active propolis components (Ghisalberti, 1979; Marcucci, 1995). In the temperate zone, the main plant source of propolis are poplar buds and propolis samples from these regions possess similar chemical com position: flavonoids (mainly flavanones), phenolic acids and their esters. Recently, some studies were published on tropical propolis from Brazil (Aga et al., 1994, Bankova et al., 1995; Bankova et al., 1996) and Venezuela (Tomas-Barberan et al., 1993), where no poplars grow. As expected, bees have found other sources of propolis (at least 2 - 3 plants) in this region and bee glue from different locations shows significant differences in its quali- Reprint requests to Prof. Popov. Fax: 003592-700-225; e-mail: IOCHNP@BGCICT.ACAD.BG. tative composition. In general it differs from Euro pean propolis by the lower content of flavonoids, and absence of esters of phenolic acids. Instead, dihydrocinnamic acid in high concentrations was identified, together with prenylated p-coumaric acids, some diterpenes, etc. (Aga et al., 1994; Ban kova et al., 1992; Bankova et al., 1996; Boudour- ova-Krasteva, 1997). Unill now, there are only some preliminary in vestigations on the composition and biological ac tivity of African propolis, performed in Egypt (Hegazi et al., 1993; Abd El-Hady, 1994; Abd El- Hady and Hegazi, 1994). In this country there are poplars, but the subtropical and tropical climate and the connected with it specific flora could af fect the chemical composition of Egyptian propo lis. This assumption is in agreement with the above mentioned reports. For this reason we performed a detailed investigation on the composition of the so called “balsam” (extract with 70% alcohol) from Egyptian propolis. Experimental Propolis Propolis was collected in Bani Swaief near Giza. Extraction and sample preparation Propolis (2 g), cut into small pieces, was ex tracted with 20 ml 70% ethanol (twice x 24h) at room temperature. The extract was evaporated to dryness (0.77 g) and analyzed by TLC. About 2.5 mg of the alcohol extract was dissolved in 20 [il dry pyridine, 30 |il N,0-bis(trimethylsilyl)triflu- oroacetamide (BSTFA) were added and the mix- 0939-5075/98/0300-0197 $ 06.00 © 1998 Verlag der Zeitschrift für Naturforschung. All rights reserved. D Unauthenticated Download Date | 11/8/15 1:56 AM