Antimicrobial activities of endophytic fungi obtained from the arid zone invasive plant Opuntia dillenii and the isolation of equisetin, from endophytic Fusarium sp.

O. dillenii, harbors several endophytic fungi capable of producing antimicrobial substances with selective antibacterial properties. By producing biologically active secondary metabolites, such as equisetin isolated from the endophytic Fusarium sp., the endophytic fungal population may be assisting the host to successfully withstand stressful environmental conditions. Further investigations on the secondary metabolites produced by these endophytes may provide additional drug leads.