Secondary metabolites and antimycobacterial activities from Amischotolype hispida

Amischotolype hispida Less. & A. Rich. (Commelinaceae) is a perennial herb, distributed over forest floors at altitudes of 150 to 1600 m throughout Taiwan. Approximately 1400 species of Formosan plants have been screened for anti-tubercular activity against Mycobacterium tuberculosis H37Rv in vitro, and the methanolic extract of the whole plant of this plant was shown with anti-tubercular activity. However, the phytochemistry and biological activities of Amischotolype genus have never been studied and the aims of this study are the isolation of chemical constituents and their antimycobacterial activity. Bioassay-guided fractionation of the active ethyl acetate-soluble layer has led to the isolation of four new compounds, including one benzenoid, amisbenzoic acid (1), one butenolide derivative, amisnolide (2), one chlorin analogue, amisphytin (3), one lignan, amislignol (4) and one compound first isolated from nature, (-)-glaberide I (5), along with 20 known compounds (6 – 25) from the whole plant of this species. Some isolates were evaluated for their antimycobacterial activities. Among these isolates, plamitic acid (13) showed antimycobacterial activity with an MIC value of 20.0 mg/ml against M. tuberculosis H37Rv. Among these isolates, palmitic acid (13) showed antimycobacterial activity with an MIC value of 20.0 µg/ml against Mycobacterium tuberculosis H37Rv. Comparing the antimycobacterial activities of four commercial available saturated fatty acids, a chain length of 14 and 16 carbons is associated with antimycobacterial activity.

Keywords: Amischotolype hispida, Commelinaceae, whole plant, antimycobacterial activity