Chemical Constituents and Antioxidant Properties of Phyllostachys prominens Gramineae (W Y Xiong) Leaf Extracts

Purpose: To isolate and identify chemical components of Phyllostachys prominens (Poaceae) leaf extracts, and measure their antioxidant activities. Methods: Ethanol extracts of P. prominens leaves were subjected to different chromatographic methods: macroporous resin column chromatography, Sephadex LH-20 column chromatography, and semi- preparative, reversed-phase (RP) high performance liquid chromatography (HPLC). Plant extract components were identified by ultraviolet spectroscopy (UV), mass spectrometry (MS), and nuclear magnetic resonance spectroscopy (NMR). DPPH (1,1-diphenyl-2-picrylhydrazyl) assay was used to measure the radical scavenging activity of the compounds. Results: We isolated fourteen compounds including six flavonoids, two lignans, two phenolic glycosides, a phenolic acid, a phenylpropanoid, a monoterpene glycoside, and amarusine from the leaves of Phyllostachys prominens. The DPPH assay showed that eleven compounds (compounds 1, 4, 6, 7, 8, 9, 10, 11, 12, 13, and 14) exhibited radical scavenging activity. (The half maximal inhibitory concentration ranged from 33.52 to 100.58 mu g/mL). The half maximal inhibitory concentration (IC50) values of compounds 1, 4, 6 and 7 were 33.52, 40.61, 47.10, and 35.84 mu g/mL respectively, while the IC50 of the positive control, butylated hydroxytoluene, was 46.32 mu g/mL. Conclusion: Fourteen compounds have been successfully all isolated from Phyllostachys prominens for the first time. Eleven of the compounds have radical scavenging activity.