Antifungal activity of the termite alkaloid norharmane against the mycelial growth of Metarhizium anisopliae and Aspergillus nomius.

Antifungal activity of norharmane, a beta-carboline alkaloid found in termites (Isoptera, Rhinotermitidae) was tested against two entomopathogenic fungi, Metarhizium anisopliae and Aspergillus nomius. It was determined that, at physiological concentration (10 microg ml(-1)), norharmane had no significant effect on A. nomius mycelial growth rate but reduced M. anisopliae growth rate by 11.9%. Contrary to previous findings, we suggest that norharmane has a limited role in disease resistance against fungal pathogens in individual subterranean termites, and we discuss the potential role of this chemical at a colony level.