Chemical composition and antifungal potential of medicinal plants against seedborne mycoflora of eggplant (Solanum melongena L.)

Abstract

Antifungal activities of medicinal plants were observed against seedborne mycofl ora of eggplant (Solanum melongena). The effect of ethanolic leaf extracts of Mangifera indica, Mentha spicata, Citrus limon, Eucalyptus camaldulensis against four isolated fungal species including Fusarium oxysporum, Aspergillus flavus, Rhizopus stolonifer and Penicillium digitatum was evaluated at various concentrations, by using the poisoned food technique. The impact of the extracts on seed germination and growth of eggplant was assessed by seed treatment and growth in a greenhouse experiment. Total flavonoids of E. camaldulensis were analyzed through spectrophotometer, using quercetin as a standard. Physico-chemical parameters were also determined. Antifungal activity showed that maximum inhibition percentage of P. digitatum (67.78%) and F. oxysporum (64.44%) was observed at the highest concentration (80%) of C. limon and E. camaldulensis extracts, respectively, followed by M. spicata extract against A. flavus (63.33%) and R. stolonifer (52.22%). Least inhibition percentage of F. oxysporum, P. digitatum, R. stolonifer and A. flavus was 6.67, 7.78, 14.44 and 16.67%, respectively, at the lowest (20%) concentration of M. spicata. The greenhouse experiment showed variations in seedling germination and post-germination growth. E. camaldulensis extract showed an increase in percent germination (78.98%) over untreated control (62.83%), root and shoot length and fresh and dry weight of root and shoot with the consequent reduction in disease symptoms. Phytochemical analysis depicted the presence of alkaloids, flavonoids, tannins, saponins in all extracts while steroids and glycosides were absent. A fair amount (10.38 mg QE g–1 DF) of flavonoid was present in leaf extract of E. camaldulensis. Physico-chemical analysis showed pH of 4.6, ash content of 0.41% and weight loss on drying of 8.14%.