Allelopathic Activity of a Novel Compound, 5,6-Dihydrogen-11?-O-acetyl-12?-O-tigloyl-17?-marsdenin, and a Known Steroidal Glycoside from the Leaves of Marsdenia tenacissima (Roxb.) Moon

Medicinal plants are rich sources of bioactive substances that can be used to develop environmentally friendly weed control alternatives. Marsdenia tenacissima (Roxb.) Moon is a traditional medicinal plant well known for its pharmacological activities and several compounds. However, allelopathy related have not been reported. Hence, the present study was conducted explore allelopathic potential from M. leaves. Aqueous methanol extracts showed significant inhibitory against growth cress (Lepidium sativum L.) Italian ryegrass (Lolium multiflorum Lam.). The were purified through various chromatography steps, two isolated determined by spectral data steroidal glycoside 1 (5,6-dihydrogen-11?-O-acetyl-12?-O-tigloyl-17?-marsdenin), novel compound, 2 (5,6-dihydrogen-11?,12?-di-O-tigloyl-17?-marsdenin). Both compounds significantly inhibited seedlings. Steroidal 1.6- 4-times greater shoots roots than 2. concentrations needed 50% inhibition seedling 0.46 0.03 mM 1, respectively, 0.74 0.12 2, respectively. Therefore, these results suggest glycosides may responsible