Antidermatophyte and antimelanogenesis compound from Eleutherine americana grown in Indonesia

An active compound from the bulb of Eleutherine americana L. Merr. (Iridaceae) collected from East Kalimantan, Indonesia, was tested for its antidermatophyte and antimelanogenesis activity. Antifungal assay-directed fractionation of the n-hexane-soluble fraction of the methanolic extract of the bulb of E. americana led to the isolation of 1 as an active compound. The compound was identified as the naphthoquinone eleutherin by EI-MS and (1)H-, (13)C-, and two-dimensional NMR analyses. Antidermatophyte assay of 1 at concentrations of 10, 20, 40, 60, and 80 microg/disk and myconazole, a commercial antidermatophyte, at 10 microg/disk displayed 7, 8, 13, 16, 17, and 14 mm of inhibition zone against Trichophyton mentagrophytes, respectively. In a melanin formation inhibition assay, compound 1 displayed potent antimelanogenesis activity at 5 ppm with low toxicity compared with arbutin, a commercial skin-whitening agent. The results showed the high potential of 1, an active compound from E. americana, to be applied as an antidermatophyte and antimelanogenesis agent.