A comparative evaluation of Kumaun Himalayan Gymnosperms for their Antifungal potential against plant pathogenic fungi

Abstract

Fungicidal activity of 10 ethnobotanically known Kumaun Himalayan gymnospermous plants namely Araucaria cunninghamii, Biota orientalis, Cedrus deodara, Cephalotaxus griffithi, Cryptomeria japonica Cupressus torulosa, Ginkgo biloba, Juniperus communis, Picea smithiana and Pinus wallichiana were tested against six plant disease causing fungal pathogens by agar well-diffusion method. Forty extracts of these gymnospermic leaves in different organic solvents (methanol, ethanol, chloroform and hexane) were studied by performing the 160 sets of experiments. The MIC values of each extract (where % inhibition ≥ 40%) were also determined. All the plant extracts exhibited strong antifungal activity. Results indicated that all leaves extracts of C. griffithi and G. biloba were found most effective among the tested plants extracts. Hexane extract of C. griffithi was showed highest inhibitory activity against C. falcatum (72%; MIC, 7.81µg/ml) and T. indica (70%; MIC, 15.62µg/ml). On the other hand, ethanol extract of G. biloba also showed remarkable activity against P. oryzae (66% with MIC, 7.81g/ml). While P. wallichiana leave extracts were found less active among the studied plants against all the tested fungal strains. The chloroform extracts were found the most effective against all the tested fungi (10% to 60%), followed by ethanol extract (30-50%), methanol extract (20-40%), while in hexane extracts ranged 10-30% only. The extracts of C. griffithi exhibited superior Relative Antifungal Activity (RAA, 20%), followed by G. biloba and A. cunninghamii (RAA, 19 and 12%, respectively). All data were also analyzed for determination of total activity of plant for each studied species of gymnosperm. C. griffithi had maximum activity i.e. 71 % followed by G. biloba (54%) and A. cunninghamii (33%). C. torulosa showed the least total activity and RAA i.e. 8% and 3%, respectively. All the plant species assayed possess definite antifungal properties and suggested for phytochemical analysis to identify the active principles responsible for their antifungal activity.