ABSTRACT
One yeast strain, SY16, was selected as a potential producer of a biosurfactant, and identified as a Candida species. A biosurfactant produced from Candida sp. SY16 was purified and confirmed to be a glycolipid. This glycolipid-type biosurfactant lowered the surface tension of water to 29 dyne/cm at critical micelle concentration of 10 mg/l (1.5 x 10(-5) M), and the minimum interfacial tension was 0.1 dyne/cm against kerosene. Thin-layer and high-pressure liquid chromatography studies demonstrated that the glycolipid contained mannosylerythritol as a hydrophilic moiety. The hydrophilic sugar moiety of the biosurfactant was determined to be beta-D-mannopyranosyl-(1-->4)-O-meso-erythritol by nuclear magnetic resonance (NMR) and fast atom bombardment mass-spectroscopy analyses. The hydrophobic moiety, fatty acids, of the biosurfactant was determined to be hexanoic, dodecanoic, tetradecanoic, and tetradecenoic acid by gas chromatography-mass spectroscopy. The structure of the native biosurfactant was determined to be 6-O-acetyl-2,3-di-O-alkanoyl-beta-D-mannopyranosyl-(1-->4)-O-meso- erythritol by NMR analyses. We newly determined that an acetyl group was linked to the C-6 position of the D-mannose unit in the hydrophilic sugar moiety.
Subject(s)
Candida/metabolism , Erythritol/analogs & derivatives , Glycolipids/chemistry , Surface-Active Agents/chemistry , Candida/isolation & purification , Caproates/analysis , Chromatography, Gas , Chromatography, High Pressure Liquid , Chromatography, Thin Layer , Erythritol/analysis , Glycolipids/metabolism , Lauric Acids/analysis , Mannose/analysis , Mass Spectrometry , Myristic Acid/analysis , Soil Microbiology , Surface Tension , Surface-Active Agents/metabolismABSTRACT
Two new triterpene caffeates have been isolated from the root bark of Hibiscus syriacus. Their structures were established through various spectral studies as 3beta,23,28-trihydroxy-12-oleanene 23-caffeate (1) and 3beta,23,28-trihydroxy-12-oleanene 3beta-caffeate (2). Compounds 1 and 2 showed lipid peroxidation inhibitory activity and significant cytotoxicity against a panel of human cancer cell lines.
Subject(s)
Antineoplastic Agents, Phytogenic/isolation & purification , Antioxidants/isolation & purification , Malvaceae/chemistry , Triterpenes/pharmacology , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Antioxidants/chemistry , Antioxidants/pharmacology , Drug Screening Assays, Antitumor , Humans , Lipid Peroxidation/drug effects , Magnetic Resonance Spectroscopy , Plant Roots/chemistry , Spectrometry, Mass, Fast Atom Bombardment , Triterpenes/chemistry , Triterpenes/isolation & purification , Tumor Cells, CulturedABSTRACT
Three new naphthalenes, designated as syriacusins A-C, were isolated from the root bark of Hibiscus syriacus. These compounds were identified as 2,7-dihydroxy-6-methyl-8-methoxy-1-naphthalenecarbaldehyde, 2-hydroxy-6-hydroxymethyl-7,8-dimethoxy-1-naphthalenecarbaldehyde, 1-carboxy-2,8-dihydroxy-6-methyl-7-methoxynaphthalenecarbolactone (1-->8), respectively, on the basis of various spectral studies. The compounds inhibited lipid peroxidation with IC50s of 0.54, 5.90 and 1.02 micrograms ml-1, respectively. The first compound also showed cytotoxicity against some human cancer cell lines with an ED50 of 1.5-2.4 micrograms ml-1.
