GC-MS Profiling of Tinospora cordifolia (Giloy) stem extract for identification of antifungal compounds against Macrophomina phaseolina causing dry root rot of Mungbean [Vigna radiata (L.) Wilczek]

Abstract Macrophomina phaseolina, a necrotrophic fungus causes multiple diseases in mungbean and other economically important crops throughout the world. The pathogen remains in soil or crop residues for up to 3 years as microsclerotia. To search for an alternative to current conventional practices against diseases that are limited and are associated with toxicity and resistance. The application of medicinal plant extracts has shown enormous antifungal potential against many sclerotial-forming phytopathogens. In the present study, a total of five concentrations (10, 20, 30, 40, and 50%) of ten different medicinal plant extracts were tested against the per cent mycelial inhibition of M. phaseolina under in-vitro conditions. The results revealed that all the plant extracts showed significant mycelial inhibition at all concentrations over the check. The maximum per cent mycelial inhibition was recorded in giloy (70.5%) followed by curry leaf (60.7%) which was at par with eucalyptus (56.0%) followed by lemon grass (50.8%) and bhang (46.5%) at 50% concentration. Maximum, total phenol (291 mg GAE/g) and flavonoid (179 mg QE/g) content exhibited in giloy. The qualitative analysis of plant extracts indicates the presence of flavonoids, alkaloids, phenols and proteins. GC-MS analysis of the giloy (Tinospora cordifolia) showed the presence of 32 phytochemical compounds, whereas cyclopentadecanone was the predominant compound with 28.45% peak area followed by 2- bromododecane (25.93%), palmitic acid, TMS derivative (10.78%), 2-hexadeccen-1-ol,3,7,11,15-tetramethyl (5.04%), 2-hexadecen-1-ol, 3,7,11,15-tetramethyl (5.04%), tetracosane (4.88%), hexanoic acid, 4-hexadecyl ester (4.12) and butylated hydroxytoluene (0.79%). Some of these major compounds might be responsible for the antifungal properties of Tinospora cordifolia against M. phaseolina.