Phenolic compounds and antimicrobial properties of Begonia grandis Dryand. subsp. grandis leaves

Abstract

We studied the leaves of Begonia grandis Dryand. subsp. grandis, the northernmost and most cold-resistant representative of the predominantly tropical genus Begonia, by histochemical methods. In glandular and nonglandular trichomes as well as in the epidermal cells of B. grandis Dryand. subsp. grandis leaves, phenolic compounds, including flavonoids, as well as terpenoids and carbonyl compounds were detected. The patterns of phenolic compounds in the acetone and ethanol leaf exudates and in leaves as a whole were similar and contained oxalic, citric, and gallic acids, isoquercitrin, and orientin. Concentrations of phenolic compounds in the acetone and ethanol exudates constituted 0.10 % and 2.59 % of all phenolic compounds in the leaves, respectively. Antimicrobial effects of the aqueous ethanol extract and of the ethanol exudate against reference strains of Bacillus subtilis, Staphylococcus aureus, and Candida albicans were detected at the disc contents of 50.0 and 45.8 μg, respectively. The observed set of characteristics can be used in a targeted search for highly antimicrobial species of Begoniaceaye.