title: Guaiane sesquiterpenes from seaweed Ulva fasciata Delile and their antibacterial properties.
abstract: Two new guaiane sesquiterpene derivatives, guai-2-en-10alpha-ol (1) and guai-2-en-10alpha-methanol (2), were chromatographically purified as major constituents of the CHCl3/CH3OH (1:1, v/v) soluble fraction of Ulva fasciata. Acetylation of 2 furnished guai-2-en-10alpha-methyl methanoate (3) with acetyl group at C11 position. The structures of the compounds were elucidated using one and two-dimensional NMR and mass spectrometric analysis. Compounds 2 and 3 exhibited significant inhibition to the growth of Vibrio parahaemolyticus with minimum inhibitory concentrations of 25 and 35 microg/mL, respectively. The electronegative C10 acetyl group with high polarisability (7.02x10(-24) cm3) in 3 appeared to withdraw electron cloud from substituted cycloheptyl ring and (R)-3-methylcyclohept-1-ene moiety, thus acting as the nucleophilic center of the molecule resulting in high bioactivity.
authors.affiliation: Marine Biotechnology Division, Central Marine Fisheries Research Institute, Ernakulam North P.O., P.B. No. 1603, Cochin 682018, Kerala, India. kajal_cmfri@yahoo.com
authors.forename: Kajal
authors.initials: K
authors.lastname: Chakraborty
authors.forename: A P
authors.initials: AP
authors.lastname: Lipton
authors.forename: R
authors.initials: R
authors.lastname: Paulraj
authors.forename: Rekha D
authors.initials: RD
authors.lastname: Chakraborty
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D045789:Sesquiterpenes, Guaiane / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D044445:Ulva / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D045789:Sesquiterpenes, Guaiane