Identification of Phenolic Compounds in Conocarpus lancifolius and Hedera helix by High-Performance Liquid Chromatography and Evaluation of Antifungal Activity Against Pathogenic Fungal Isolates

Abstract

Because clinical isolates show variability in susceptibility and most commercial synthetic antifungals are associated with resistance, toxicity and recrudescence, management of opportunistic fungal infections due to Candida spp. and similar yeast pathogens will become increasingly challenging. Therefore, this research evaluated and compared the composition of phenolic components in Conocarpus lancifolius and Hedera helix leaf extracts by High Performance Liquid Chromatography (HPLC) and determined the antifungal potential of ethanol and butanol extracts of both plants against clinically significant fungal isolates. Phenols were extracted from dry leaves using an Ultrasonic-Assisted Extraction method and each compound was measured individually using reversed phase-HPLC at 280 nm. Clinical isolates were cultured from one hundred patient samples collected from urine, sputum, and skin and subsequently isolated on Sabouraud dextrose agar. Each isolate was identified through morphological characteristics, microscopy, and chromogenic Candida agar. Isolate susceptibility to each plant extract (concentration of 250, 500, 750, and 1000 mg/ml) was examined. Responses of gallic acid and quercitin in relation to minimum inhibitory concentrations against C. albicans and C. tropicalis were demonstrated by plotting Principal Component Analysis (PCA) plots. In total, rutin, gallic acid, ferulic acid, sinapic acid, p-coumaric acid, caffeic acid were found in higher levels in the ethanol extract of C. lancifolius while the ethanol extract of H. helix showed gallic acid, kaempferol, quercitin, apigenin, caffeic acid, rutin and ferulic acid depending upon the extracting solvents. A maximum zone of inhibition was observed in C. albicans with C. lancifolius ethanol extract and in C. glabrata with H. helix ethanol extract, each reaching a zone of 12mm; however, all Talaromyces isolates were consistently resistant. Based on these results it appears that the ethanol extracts containing phenolics from both plants could represent potential antifungal candidates and therefore require further purification, determination of the minimum inhibitory concentrations and evaluation of cytotoxicity.