title: Cytotoxic diterpenoids from Vietnamese medicinal plant Croton tonkinensis GAGNEP.
abstract: Six new ent-kaurane-type diterpenoids were isolated from the leaves of the endemic Vietnamese medicinal plant Croton tonkinensis GAGNEP. (Euphorbiaceae) together with three known ent-11alpha-acetoxy-7beta,14alpha-dihydroxykaur-16-en-15-one (1), ent-kaur-16-en-15-one 18-oic acid (5) and ent-18-hydroxykaur-16-ene (7). Their structures were determined by spectroscopic analyses to be ent-7beta-acetoxy-11alpha-hydroxykaur-16-en-15-one (2), ent-18-acetoxy-11alpha-hydroxykaur-16-en-15-one (3), ent-11alpha-acetoxykaur-16-en-18-oic acid (4), ent-15alpha,18-dihydroxykaur-16-ene (6), ent-11alpha,18-diacetoxy-7beta-hydroxykaur-16-en-15-one (8), and ent-(16S)-1alpha,14alpha-diacetoxy-7beta-hydroxy-17-methoxykauran-15-one (14). ent-Kaurane-type diterpenoids from Croton tonkinensis 2-4, 6, and 9-13, were tested for toxicity in the brine shrimp lethality assay. Compounds 9, 10, and 12 demonstrated significant activity, compounds 2, 3, 6, and 11 showed weak activity, and compounds 4 and 13 were inactive.
authors.affiliation: Faculty of Chemistry, College of Natural Science, Vietnam National University, Hanoi.
authors.forename: Minh Giang
authors.initials: MG
authors.lastname: Phan
authors.forename: Tong Son
authors.initials: TS
authors.lastname: Phan
authors.forename: Yumi
authors.initials: Y
authors.lastname: Hamada
authors.forename: Hideaki
authors.initials: H
authors.lastname: Otsuka
mesh_terms: D000818:Animals; D001156:Artemia / Q000187:drug effects; D029802:Croton / Q000737:chemistry*; D045786:Diterpenes, Kaurane / Q000737:chemistry* / Q000633:toxicity*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry; D014744:Vietnam
chemical_list: D045786:Diterpenes, Kaurane; D010936:Plant Extracts