Bioprospecting medicinal plants for the isolation and screening of lovastatin producing endophytic fungi

Abstract

Endophytic fungi reside within the plant tissues asymptomatically and produce various secondary metabolites of pharmaceutical interest. The current study aims to bio-prospect medicinal plants for the isolation and screening of lovastatin producing endophytic fungi. Endophytic population in the leaf, stem, root and flower (as applicable) of ten medicinal plants has been studied and their potential to produce the anti-hypercholesterolemia drug, lovastatin has been evaluated. A total of 98 fungal isolates were obtained from the plant tissues and lovastatin yield from them was quantified to be within the range of 5 mg/L to 71.5 mg/L in the first round of submerged fermentation. The subsequent levels of screening witnessed a great change in the yield which could be attributed to gene attenuation, a usual phenomenon in endophytes. A novel lovastatin producer, designated as HL1, belonging to candida sp. residing within the leaves of Hibiscus rosa-sinensis was found to consistently yield higher amounts of lovastatin i.e., 40 mg/L through all rounds of screening, alongside two strains of Aspergillus sp., designated as HL4 and HL5, from the same tissue with a yield of 21.5 and 18 mg/L respectively. Preliminary confirmation of lovastatin presence in the fungal extract was done by Thin Layer Chromatography (TLC) and yeast growth inhibition bioassay.