title: New antimycobacterial and antimalarial 8,9-secokaurane diterpenes from Croton kongensis.
abstract: Two new 8,9-secokaurane diterpenes, ent-8,9-seco-7alpha,11beta-diacetoxykaura-8(14),16-dien-9,15-dione (1) and ent-8,9-seco-8,14-epoxy-7alpha-hydroxy-11beta-acetoxy-16-kauren-9,15-dione (2), together with two known compounds, ent-8,9-seco-7alpha-hydroxy-11beta-acetoxykaura-8(14),16-dien-9,15-dione (3) and ent-7beta-hydroxy-15-oxokaur-16-en-18-yl acetate, were isolated from Croton kongensis. This is the first report on the presence of 8,9-secokauranes in the plant genus Croton. Diterpenes 1-3 exhibited antimycobacterial activity with minimum inhibitory concentrations (MICs) of 25.0, 6.25, and 6.25 microg/mL, respectively, and possessed antimalarial activity with IC(50) ranges of 1.0-2.8 microg/mL. They also demonstrated comparable cytotoxicity toward the Vero (IC(50) ranged from 0.9 to 3.2 microg/mL), KB (IC(50) from 1.2 to 13.8 microg/mL), and BC cell lines (IC(50) from 1.1 to 2.2 microg/mL, except for compound 1, which was inactive against BC cells).
authors.affiliation: Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Jirabhorn
authors.initials: J
authors.lastname: Thongtan
authors.forename: Prasat
authors.initials: P
authors.lastname: Kittakoop
authors.forename: Nijsiri
authors.initials: N
authors.lastname: Ruangrungsi
authors.forename: Janya
authors.initials: J
authors.lastname: Saenboonrueng
authors.forename: Yodhathai
authors.initials: Y
authors.lastname: Thebtaranonth
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D029802:Croton / Q000737:chemistry*; D045786:Diterpenes, Kaurane / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D020128:Inhibitory Concentration 50; D007624:KB Cells; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D010963:Plasmodium falciparum / Q000187:drug effects; D013237:Stereoisomerism; D013785:Thailand; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000962:Antimalarials; D045786:Diterpenes, Kaurane; C478831:ent-8,9-seco-7alpha,11beta-diacetoxykaura-8(14),16-dien-9,15-dione; C478834:ent-8,9-seco-8,14-epoxy-7alpha-hydroxy-11beta-acetoxy-16-kauren-9,15-dione