Journal Article

Role of Pentacyclic Triterpenoids in the Allelopathic Effects of Alstonia scholaris

Chen, Hsiao-Ting, Wang, Chao-Min, Li, Tsai-Chi, Weng, Jen-Hsien, Jhan, Yun-Lian, Chou, Chang-Hung, Lin, Shi-Xun

2014

Overview

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

• Publisher: Springer-Verlag,Springer US,Springer Nature B.V
• Subject: Acids / Agriculture / allelochemicals / Allelopathy / Alstonia / Alstonia - metabolism / Alstonia scholaris / analysis / betulinic acid / Bidens / Bidens - drug effects / Bidens - growth & development / Bidens - metabolism / Bidens pilosa / Biochemistry / Biological Microscopy / Biomedical and Life Sciences / chemistry / drug effects / Ecology / Entomology / Evergreen trees / Flowers & plants / Forest soils / Forests / Germination / Germination - drug effects / growth & development / growth retardation / inhibitory concentration 50 / Ionization / Lactuca sativa / Leaves / Life Sciences / Liquid chromatography / Litter / Mass spectrometry / metabolism / oleanolic acid / pharmacology / Pheromones / Pheromones - analysis / Pheromones - chemistry / Pheromones - metabolism / Pheromones - pharmacology / Photosynthesis / Photosynthesis - drug effects / Plant Leaves / Plant Leaves - metabolism / Plant Weeds / Plant Weeds - drug effects / Plant Weeds - growth & development / Plant Weeds - metabolism / Seed germination / Soil / Soil - chemistry / South East Asia / summer / trees / Triterpenes / Triterpenes - analysis / Triterpenes - chemistry / Triterpenes - metabolism / Triterpenes - pharmacology / Understory / Ursolic Acid / Weeds / winter