Antibacterial activity, cytotoxicity and chemotaxonomic significance of chemical constituents from Alsophila manniana Hook R.M.Tryon (Cyatheaceae) rhizomes

Phytochemical investigation of Alsophila manniana rhizomes led to the isolation of twelve known compounds, including two triterpenes (1 and 2), four steroids (3–6), one glycerol (7), three phenols (8–10), and two flavonoids (11 and 12). Their structures were elucidated by analyses of the NMR and MS data and by comparisons with those in the literature. Their antibacterial and cytotoxic activities were evaluated against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Bacillus subtilis; and on human lung A549, cervical HeLa, and breast MCF-7 cancer cell lines, respectively. Fractions F_D and F_F had significant activities against E. coli (MIC = 75 μg/mL) and K. pneumoniae (MICs = 75 and 37.5 μg/mL). Compounds 3 and 7–12 had moderate antibacterial activities with MIC values ranging from 75 to 150 μg/mL against the bacteria. All samples were inactive against all tested human cancer cell lines, even at 100 μg/mL. This is the first investigation of the chemical constituents of A. manniana, as well as the first report of compounds 3, 7, and 10–12 from the genus Alsophila. The chemotaxonomic significance of these compounds is discussed.