title: Study of antimalarial activity of chemical constituents from Diospyros quaesita.
abstract: Bioassay-directed fractionation led to the isolation of seven compounds from a sample of the dried leaves, twigs, and branches of Diospyros quaesita Thw. (Ebenaceae). One of the isolates, betulinic acid 3-caffeate (1), showed in vitro antimalarial activity against Plasmodium falciparum clones D(6) (chloroquine-sensitive) and W(2) (chloroquine-resistant) with IC(50) values of 1.40 and 0.98 microM, respectively. Evaluation of compound 1 in the human oral epidermoid (KB) cancer cell line revealed cytotoxicity at ED(50) of 4.0 microM. In an attempt to reduce the cytotoxicity of 1, the acetylated derivative 1a and betulinic acid (1b) were prepared. Of the seven isolates, diospyrosin (2) was determined to be a new neolignan. In addition to 1, other known compounds isolated in this study were pinoresinol, lariciresinol, N-benzoyl-L-phenylalaninol, scopoletin, and poriferast-5-en-3beta,7alpha-diol. The structure of 2 was elucidated based on spectroscopic data analysis including 1D- and 2D-NMR, and HR-ESI-MS.
authors.affiliation: Program for Collaborative Research in the Pharmaceutical Sciences, M/C 781, Department of Medical Chemistry & Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, Illinois 60612, USA.
authors.forename: Cui-Ying
authors.initials: CY
authors.lastname: Ma
authors.forename: Sebisubi Fred
authors.initials: SF
authors.lastname: Musoke
authors.forename: Ghee Teng
authors.initials: GT
authors.lastname: Tan
authors.forename: Kongmany
authors.initials: K
authors.lastname: Sydara
authors.forename: Somsanith
authors.initials: S
authors.lastname: Bouamanivong
authors.forename: Bounhoong
authors.initials: B
authors.lastname: Southavong
authors.forename: D Doel
authors.initials: DD
authors.lastname: Soejarto
authors.forename: Harry H S
authors.initials: HH
authors.lastname: Fong
authors.forename: Hong-Jie
authors.initials: HJ
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D002109:Caffeic Acids / Q000737:chemistry*; D002478:Cells, Cultured; D029788:Diospyros / Q000737:chemistry*; D006801:Humans; D018515:Plant Leaves / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry; D010963:Plasmodium falciparum / Q000187:drug effects; D014315:Triterpenes / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D000962:Antimalarials; D002109:Caffeic Acids; D014315:Triterpenes