title: Red Algae (Rhodophyta) from the Coast of Madagascar: Preliminary Bioactivity Studies and Isolation of Natural Products.
abstract: Several species of red algae (Rhodophyta) from the coastal regions of Madagascar have been investigated for their natural products. The most abundant compound was cholesterol (5) in combination with a series of oxidized congeners. The brominated indoles 1-3 along with the sesquiterpene debilone (4) have been isolated from Laurencia complanata. For the first time, debilone (4) has been obtained from a marine plant. From the methanol extract of Calloseris sp., we have achieved the second isolation of the unusual A-ring contracted steroids (-)-2-ethoxycarbonyl-2β-hydroxy-A-nor-cholest-5-en-4-one (9) and phorbasterone B (10). The crude extracts of Laurencia complanata exhibited antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Streptococcus pneumoniae, and Candida albicans.
authors.affiliation: Department Chemie, Technische Universität Dresden, Bergstr. 66, 01069 Dresden, Germany. mariepsa@yahoo.fr.
authors.forename: Marie Pascaline
authors.initials: MP
authors.lastname: Rahelivao
authors.affiliation: Department Chemie, Technische Universität Dresden, Bergstr. 66, 01069 Dresden, Germany. margit.Gruner@tu-dresden.de.
authors.forename: Margit
authors.initials: M
authors.lastname: Gruner
authors.affiliation: Centre National de Recherche sur l'Environnement, MESupRes, BP 1739, Antananarivo 101, Madagascar. andriamanantoanina@yahoo.fr.
authors.forename: Hanta
authors.initials: H
authors.lastname: Andriamanantoanina
authors.affiliation: Laboratoire de Chimie Appliquée aux Substances Naturelles, Faculté des Sciences, Université d'Antananarivo, BP 566, Antananarivo 101, Madagascar. b.andriamihaja@moov.mg.
authors.forename: Bakolinirina
authors.initials: B
authors.lastname: Andriamihaja
authors.affiliation: Department Chemie, Technische Universität Dresden, Bergstr. 66, 01069 Dresden, Germany. ingmar.bauer@chemie.tu-dresden.de.
authors.forename: Ingmar
authors.initials: I
authors.lastname: Bauer
authors.affiliation: Department Chemie, Technische Universität Dresden, Bergstr. 66, 01069 Dresden, Germany. hans-joachim.knoelker@tu-dresden.de.
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Knölker
mesh_terms: D000890:Anti-Infective Agents / Q000302:isolation & purification / Q000494:pharmacology; D001688:Biological Products / Q000302:isolation & purification* / Q000494:pharmacology; D006090:Gram-Negative Bacteria / Q000187:drug effects; D044722:Laurencia / Q000737:chemistry; D008270:Madagascar; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D000461:Rhodophyta / Q000737:chemistry*
chemical_list: D000890:Anti-Infective Agents; D001688:Biological Products
keywords: NMR spectroscopy; algae; antimicrobial activity; indole alkaloids; steroids