Stress metabolites from Corchorus olitorius L. leaves in response to certain stress agents

Five coumarins were found to be produced as phytoalexins (stress metabolites) from the fresh young leaves of Corchorus olitorius L. plant, in response to inoculation with biotic stress agent, such as the spore suspension of the fungus Helminthosporium turcicum and with chemical stress agents, such as aqueous solutions of mercuric chloride and cupric chloride. The five compounds were isolated, purified and subjected to melting point and spectroscopic determinations. They were identified as scopoletin, fraxinol, isopimpinellin, xanthotoxol and peucedanol. They were tested for their antimicrobial activities. The volatile components of the natural fresh leaves and the cupric chloride-treated leaves were prepared and subjected to GC/MS analysis. Fifty five and 49 components were identified in the control and treated leaves, respectively. cis-3-Hexen-1-ol, cis-4-hexen-1-ol, terpinolene, sabinene and phytol were the major compounds in the control leaves, while those of the treated leaves were cis-4-hexen-1-ol, cis-3-hexen-1-ol, tetradecanal and phytol. The percentage of the total oxygenated compounds were found to be increased in the cupric chloride-treated leaves much more than the control leaves (77.3 and 47.4%, respectively).