A GC/MS Study of the Propolis Phenolic Constituents

Propolis is a resinous hive product Kv bees. The versatile biological activities of propolis, such as its antibacterial, antiviral, fungicidal, anti­ ulcer, immunostimulating, hypotensive and cytosta­ tic properties, as well as its successful clinical applica­ tions [1 — 3] have created an increasing interest in its chemical composition. The last appears to be very complex — the bees collect propolis from resinous buds of various trees [4—6]. Till now, more than a hundred propolis constituents have been identified. A substantial part of the physiological activity of propolis is connected with the phenolic compounds in it, which constitute more than 50% of its composi­ tion. The main phenolic constituents of propolis are flavonoids flavanones, dihydroflavonols, flavones and flavonols. There are other phenolic compounds too — simple phenols, phenolic acids and their es­ ters, phenolic alcohols, aldehydes and ketones, stilbenes, coumarins and phenolic triglycerides. Though in small quantities, these compounds can be very im­ portant for the biological activity of propolis. Till now, Bulgarian propolis has been charac­ terized only on the basis of its flavonoid composition [7, 8]. Now, we studied the GC/MS behaviour of the silylated phenolic constituents of propolis. In this paper we report the possible partial or total struc­ tures of these compounds which can be deduced from the mass spectral data obtained. This approach was applied for the identification of propolis phenols in the hope, that it could lead to the discovery of