Antifungal activity of medicinal plants, Adathoda vasica and Andrographis paniculata against Colletotrichum capsici, the chilli fruit rot pathogen

Abstract

Aim: The objective was formulated to screen the extracts of medicinal plants for tapping the antimicrobial activity against Collectotrichum capsici. Further, the work was planned to characterize and identify the nature of antimicrobial compounds and their functional groups. Methodology: Extracts of eleven medicinal plants were tested against the mycelial growth and spore germination of C. capsici under in-vitro conditions. Based on these results, the potential plant extracts of A. vasica and A. paniculata found effective against C. capsici were assayed for the presence of antimicrobial metabolites through TLC, GC-MS and FTIR analysis. Results: Among the medicinal plants screened, the crude extracts from Adathoda vasica and Andrographis paniculata inhibited mycelial growth and spore germination of C. capsici by 53.33% and 38.14%, respectively, under in-vitro conditions. GC-MS analysis of ethyl acetate extracts of A. vasica indicated antimicrobial compound, 1H-Pyrrolo[2,1-b]quinazolin-9-one,3-hydroxy-2,3-dihydro- and A. paniculata showed the presence of two compounds, docosahexaenoic acid and oleic acid. Similarly, FTIR analysis revealed esters, alcohols, and halide groups, which are known antimicrobials. Interpretation: The medicinal plants, A. paniculata and A. vasica possessed antimicrobial metabolites, which was responsible for inhibiting the mycelial growth and spore germination of C. capsici.