Elemental allelopathy and antifungal activities of Inula falconeri from Himalaya Pakistan

The leaf leachate of Inula falconeri Hook. f. has been reported to carry allelopathic potential. To analyse its further effects, it was fractionated into five subfractions, i.e. hexane, chloroform, ethyl acetate, n-butanol, and water. The hexane subfraction had the highest specific activity compared with the other four fractions and presented 100% inhibitory effect to germination of lettuce seeds. Chloroform subfraction presented a dose-response effect, and the ethyl acetate subfraction exhibited insignificant inhibitory effect, while n-butanol and water subfractions presented stimulatory effects. Elemental analysis through energy-dispersive X-ray spectroscopy (EDX) showed the composition of 15 different elements with carbon, oxygen, and potassium showing highest weight percentages. In the case of hexane subfraction, highest percentages of silver (1.22%), cadmium (1.44%), manganese (0.71%), and chromium (0.70%) were observed, compared with other subfractions. Chloroform subfraction has high proportions of copper (0.63%), nickel (0.45%), iron (0.37%), calcium (0.22%), and cobalt (0.08%). In the case of ethyl acetate subfraction oxygen (49.66%) and sodium (0.33%) percentage was the highest of all the subfractions, while the other elements were observed in lesser amounts than in other subfractions. The n-butanol subfraction has recorded highest weight of zinc (0.79%) compared with other subfractions while in water subfraction significant amounts of other elements were not observed. To investigate the behaviour of these subfractions against plant pathogens, hexane subfraction (concentration gradients of 1.25, 2.5, and 5 mg/disc) demonstrated significant zones of inhibition against Alternaria alternata and Rhizoctonia solani while only an insignificant effect against Fusarium oxysporum. Thus, using active natural inhibitors of plant pathogens reveals broader perspectives and interests in avoiding losses to cash crops in the local area.