Fractional inhibitory concentration index of the allicin and flavonoids combinations against Ganoderma boninense

Abstract

Abstract Allicin and several flavonoids were known to have antifungal activity against various fungi. The antifungal capability of allicin and flavonoids varies depending on the target fungi; the combination of both compounds was expected to increase its antifungal activity. As a major disease of oil palm, basal stem rot (BSR) caused by Ganoderma boninense always be a top concern of oil palm farmers. This study aimed to evaluate the effect of combining allicin with hesperidin and rutin on antifungal activity against G. boninense through the fractional inhibitory concentration (FIC) index. The FIC index was determined using a checkerboard assay with media poisoning methods. The allicin concentration tested was 0.1%, 0.2%, 0.4%, and 0.8%, while the hesperidin and rutin concentrations were 1.25%, 2.5%, 5%, and 10%. All combinations were done in triplicate and incubated for twelve days. The result showed that a combination of allicin with hesperidin or rutin was the additive interaction that lowers the concentration of each compound with similar inhibition rate of G. boninense in vitro. Combining allicin with rutin was considered better than hesperidin due to the higher inhibition rate of G. boninense. The allicin-rutin combination has a lower concentration with a 100% inhibition rate of G. boninense in vitro.