Enzyme mediated-transesterification of verbascoside and evaluation of antifungal activity of synthesised compounds

Abstract

Enzymatic acylation of verbascoside, a polyhydroxylated natural product, has been reported in this study using five different commercial lipases and taking p-nitrophenyl alkanoates as acyl donors. Out of these enzymes, the immobilised Candida antarctica lipase B was found as the enzyme of choice. Mono-and diacylated products were formed, with mono as major product indicating high regioselective nature of such transformations. A series of acyl esters of verbascoside have been synthesised by this enzymatic transesterification methodology. The lipophilicity of the synthesised analogues was also checked. The analogues were further subjected to synergistic antifungal activity with amphotericin B (AmB) against Candida albicans. Fourfold reduction in minimum inhibitory concentration of AmB was observed with few synthesised analogues such as verbascoside 4 00 -octanoate (3b), verbascoside 4 00 -palmitate (3d) and verbascoside 4 00 ,4 0 -dipalmitate (4d) at a concentration of 0.5 mg/mL.

Antimicrobial activity and molecular docking screening of bioactive components of Antirrhinum majus (snapdragon) aerial parts

“…Oyourou et al (2013) has confirmed the in-vivo antifungal activity of verbascoside (I07) from Lantana camara leaves, where they suggested its potential use as an alternative fungicide in agriculture against Penicillium digitatum infections. The synergistic antifungal activity of some verbascoside (I07) acyl esters derivatives and amphotericin B against C. albicans has been studied, and up to a four-fold reduction in the MIC was demonstrated (Khazir et al, 2015).…”