Anti-inflammatory and antibacterial profiles of selected compounds found in South African propolis

Abstract

Propolis is a complex resinous substance manufactured by honey bees to scaffold and protect the hive against pathogens. Although it has been widely used for its medicinal properties, it is unknown whether the activity depends on the concentrations of specific constituents or on potentiation between these. This study describes (1) the individual topical anti-inflammatory activities of selected flavonoids commonly found in propolis, and (2) their antibacterial activities, alone or in combination with the non-flavonoid caffeic acid phenethyl ester (CAPE). For the anti-inflammatory activities, the reduction in croton oil-induced oedema in a mouse model, after topical application of quercetin and galangin for 3 h, was more than 50%, while after 6 h of treatment the reduction was less then 50%. By contrast, the suppressive activity of luteolin was about 30% and 50%, for treatments of 3 h and 6 h, respectively. The maximum inhibition of the growth of Staphylococcus aureus by each of CAPE, eriodictyol and quercetin was about 20%, while luteolin was inactive. When combined with CAPE, potentiation of the antibacterial effect was observed in the case of luteolin, but antagonism was observed when combined with either eriodictyol or quercetin. The propolis flavonoids each appear to have significant anti-inflammatory activity while their antibacterial activities are somewhat weaker and significant only when luteolin was combined with CAPE.