title: Antimycobacterial cycloartanes from Borrichia frutescens.
abstract: In a bioassay-guided search for antimycobacterial compounds from higher plants of the southeastern United States, we have chemically investigated the sea daisy (Borrichia frutescens) from coastal marshes of Louisiana for their active constituents. Bioactive chromatographic fractions provided two new triterpenes, (24R)-24,25-epoxycycloartan-3-one (1) and (23R)-3-oxolanosta-8,24-dien-23-ol (4), and (3 alpha H, 24R)-24,25-epoxycycloartan-3-ol (3a). Compound 3a had been previously isolated as a mixture of C-24 epimers. The structures of 1, 3a, and 4 were established by spectroscopic methods and chemical transformations, and the molecular structures of 1 and 4 were determined by single-crystal X-ray diffraction. In a radiorespirometric bioassay against Mycobacterium tuberculosis, the epoxycycloartanes 1 and 3a exhibited minimum inhibitory concentrations of 8 micrograms/mL. In contrast, the lanostadiene-type triterpene 4 showed no significant inhibition at 128 micrograms/mL, as did the acetate 3b. Cytotoxicity for Vero cells gave IC50 values of 71.8, 39.8, and 103.6 micrograms/mL for triterpenes 1, 3a, and 4, respectively.
authors.affiliation: Department of Chemistry, Louisiana State University, Baton Rouge 70803-1804, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Cantrell
authors.forename: T
authors.initials: T
authors.lastname: Lu
authors.forename: F R
authors.initials: FR
authors.lastname: Fronczek
authors.forename: N H
authors.initials: NH
authors.lastname: Fischer
authors.forename: L B
authors.initials: LB
authors.lastname: Adams
authors.forename: S G
authors.initials: SG
authors.lastname: Franzblau
mesh_terms: D000107:Acetylation; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D000995:Antitubercular Agents / Q000302:isolation & purification* / Q000494:pharmacology*; D002522:Chlorocebus aethiops; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D009161:Mycobacterium / Q000187:drug effects*; D018515:Plant Leaves / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D010944:Plants / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D014315:Triterpenes / Q000302:isolation & purification / Q000494:pharmacology*; D014709:Vero Cells
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D000995:Antitubercular Agents; D014315:Triterpenes