title: Antibacterial and Synergistic Activity of Pentacyclic Triterpenoids Isolated from Alstonia scholaris.
abstract: (1) BACKGROUND: Alstonia scholaris (Apocynaceae) is an important medicinal plant that has been historically used in "Dai" ethnopharmacy to treat infectious diseases in China. Although various pharmacological activities have been reported, the antimicrobial constitutes of A. scholaris have not yet been identified. The objective of this study is to evaluate the antibacterial constitutes from the leaf extract of A. scholaris and to assess the synergistic effects of isolated compounds with antibiotics against bacterial pathogens.; (2) METHODS: The chemical constitutes isolated from the leaf extract of A. scholaris were structurally identified by NMR. The antibacterial and synergistic effect of compounds was assessed by calculating the minimal inhibitory concentration (MIC), checkerboard dilution test, and time-kill assay.; (3) RESULTS: Six pentacyclic triterpenoids were structurally identified as (1) lupeol, (2) betulin, (3) 3-hydroxy-11-ursen-28,13-olide, (4) betulinic acid, (5) oleanolic acid and (6) ursolic acid. Both oleanolic and ursolic acid showed antibacterial activity but were limited to Gram-positive bacteria. Ursolic acid showed a synergistic effect with ampicillin and tetracycline against both Bacillus cereus and S. aureus.; (4) CONCLUSION: These findings reflect that pentacyclic triterpenoids are the antibacterial chemicals in A. scholaris. The ability of ursolic acid to enhance the activity of antibiotics can constitute a valuable group of therapeutic agents in the future.
authors.affiliation: Research Center for Biodiversity, China Medical University, Taichung, 40402, Taiwan. wangchaomin@mail.cmu.edu.tw.
authors.forename: Chao-Min
authors.initials: CM
authors.lastname: Wang
authors.affiliation: Research Center for Biodiversity, China Medical University, Taichung, 40402, Taiwan. shine_5201314@yahoo.com.tw.
authors.forename: Hsiao-Ting
authors.initials: HT
authors.lastname: Chen
authors.affiliation: Department of Veterinary Medicine, College of Veterinary Medicine, National Chung-Hsing University, Taichung, 40402, Taiwan. zongyan630@yahoo.com.tw.
authors.forename: Zong-Yen
authors.initials: ZY
authors.lastname: Wu
authors.affiliation: Research Center for Biodiversity, China Medical University, Taichung, 40402, Taiwan. ah_giu@yahoo.com.tw.
authors.forename: Yun-Lian
authors.initials: YL
authors.lastname: Jhan
authors.affiliation: Department of Veterinary Medicine, College of Veterinary Medicine, National Chung-Hsing University, Taichung, 40402, Taiwan. clshyu@nchu.edu.tw.
authors.forename: Ching-Lin
authors.initials: CL
authors.lastname: Shyu
authors.affiliation: Research Center for Biodiversity, China Medical University, Taichung, 40402, Taiwan. choumasa@mail.cmu.edu.tw.
authors.forename: Chang-Hung
authors.initials: CH
authors.lastname: Chou
mesh_terms: D031051:Alstonia / Q000737:chemistry*; D000667:Ampicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000302:isolation & purification* / Q000494:pharmacology*; D001409:Bacillus cereus / Q000187:drug effects; D004357:Drug Synergism; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D053978:Pentacyclic Triterpenes / Q000302:isolation & purification* / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D013211:Staphylococcus aureus / Q000187:drug effects; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D053978:Pentacyclic Triterpenes; D010936:Plant Extracts; D000667:Ampicillin; D013752:Tetracycline
keywords: Alstonia scholaris; MRSA; antibacterial; synergistic; triterpenoid; ursolic acid
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