Isolation of a bioactive compound from a Philippine actinomycete strain and Comparison of its antifungal activity with Nystatin against Candida albicans

Abstract

Recent studies reveal that Actinomycetes obtained from different environments, such as marine ecosystem, mangrove areas and desert soils, can be possible sources of new drugs with low possibility of pathogenic resistance. This study was conducted to extract and isolate the bioactive metabolite from a Philippine actinomycete strain and test its inhibitory effect against Candida albicans as well as to compare its antifungal activity with Nystatin. Extraction of actinomycete metabolites was carried out using ethyl acetate as the solvent. The collected crude extract was subjected to two consecutive column chromatography steps to further isolate and purify the bioactive compound. Thin-layer chromatography and bioautography were later performed to detect the location of the bioactive compound. A total of 0.0347 grams of partially purified bioactive fraction was accumulated and compared with other commercially available antifungal drugs using cup cylinder assay. Three replicates of each treatment were used and measured for their zones of inhibition. The bioactive compound from the local actinomycete strain was observed to have approximately the same inhibitory effects against Candida albicans as that of Nystatin. It was also observed in the cup cylinder assay that the bioactive compound of the local actinomycete strain displayed smaller inhibition zone at 10,000 ppm; comparable inhibition zone with Nystatin at 1000 ppm; and wider inhibition zone at 100 ppm. Structural framework of the bioactive compound was tentatively identified through the UV-Vis and Infrared Spectral Chart. Several functional groups such as alcohol, ketone, carbonyl, carboxylic acids, alkene and alkane were noted.