The Role of Pentacyclic Triterpenoids in the Allelopathic Effects of Alstonia scholaris

摘要: Alstonia scholaris is a tropical evergreen tree native to South and Southeast Asia. forests frequently lack understory species. However, potential mechanisms—particularly the allelochemicals involved—remain unclear. In present study, we identified of A. scholaris, clarified role allelopathic substances from in interactions with neighboring plants. We showed that leaves, litter, soil inhibited growth Bidens pilosa—a weed found growing abundantly near forests. The were as pentacyclic triterpenoids, including betulinic acid, oleanolic ursolic acid by using 1H 13C-NMR spectroscopy. half-maximal inhibitory concentration (IC50) for radicle B. pilosa Lactuca sativa ranged 78.8 μM 735.2 μM, seed germination pilosa. triterpenoid concentrations quantified liquid chromatography-electrospray ionization/tandem mass spectrometry. Ursolic was forest at 3,095 μg/g, i.e., exceeding IC50. field, accumulated forests, suppressed during summer winter. Our results indicate triterpenoids influence weeds inhibiting germination, growth, functioning photosystem II.