title: Inhibitory effects of ent-kauranes from the stems of Annona squamosa on superoxide anion generation by human neutrophils.
abstract: Eleven ent-kauranes, isolated from the fresh stems of Annona squamosa L. (Annonaceae), were subjected to assays on the generation of superoxide anion (O2.--) by human neutrophils. Except for ent-kaur-16-en-19-oic acid, 16beta,17-dihydroxy- ent-kauran-19-al, and 16alpha,17-dihydroxy -ent-kauran-19-al, all ent-kauranes showed significant inhibitory effect on O2.-- generation in response to formyl- L-methionyl- L-leucyl- L-phenylalanine (fMLP/CB). In contrast, phorbol myristate acetate (PMA)-induced O2.-- generation was not suppressed by any ent-kauranes. Especially, ent-kaur-16-en-19-oic acid could significantly increase O2.-- production. The structure-activity relationship of these compounds is also discussed herein. Furthermore, the effect of ent-kauranes on nitric oxide generation by NR8383 macrophages in response to lipopolysaccharide (LPS) was examined. None of the compounds showed an inhibitory effect on nitric oxide generation.
authors.affiliation: Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan, R.O.C.
authors.forename: Yu-Liang
authors.initials: YL
authors.lastname: Yang
authors.forename: Fang-Rong
authors.initials: FR
authors.lastname: Chang
authors.forename: Tsong-Long
authors.initials: TL
authors.lastname: Hwang
authors.forename: Wen-Te
authors.initials: WT
authors.lastname: Chang
authors.forename: Yang-Chang
authors.initials: YC
authors.lastname: Wu
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D031041:Annona; D045786:Diterpenes, Kaurane / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D016166:Free Radical Scavengers / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D018547:Plant Stems; D051381:Rats; D013481:Superoxides / Q000378:metabolism*
chemical_list: D045786:Diterpenes, Kaurane; D016166:Free Radical Scavengers; D010936:Plant Extracts; D013481:Superoxides; D009569:Nitric Oxide