Demonstration of antifungal and anti-human immunodeficiency virus reverse transcriptase activities of 6-methoxy-2-benzoxazolinone and antibacterial activity of the pineal indole 5-methoxyindole-3-acetic acid.

6-methoxy-2-benzoxazolinone (6-MBOA), a naturally occurring progonadal compound present in grasses with structural resemblance to melatonin, was tested for antifungal activity against Fusarium oxysporum, Rhizoctonia solani and Coprinus comatus. A variety of pineal products was also examined for the sake of comparison, including 5-methoxytryptamine, melatonin, 5-methoxytryptophol, 5-hydroxytryptamine, 5-methoxyindole-3-acetic acid and 5-hydroxytryptophol. The assay for antifungal activity was carried out in Petri plates containing potato dextrose agar. It was found that 6-MBOA most potently inhibited the growth of C. comatus, R. solani and F. oxysporum. When 6-MBOA and pineal indoles were tested for antibacterial activity against the bacterium Agrobacterium tumefaciens, 5-methoxyindole-3-acetic acid was found to be the most potent. 6-MBOA most potently inhibited human immunodeficiency virus-1 reverse transcriptase.