ABSTRACT
An active glycoprotein fraction containing 58 % protein was isolated from Aloe vera gel by precipitation with 55 % ammonium sulfate followed by gel permeation using DEAE-Sephacel A-25, Sepharose 6B and Sephadex G-50 columns in a yield of 3 x 10 -3 %. The glycoprotein fraction showed a single band corresponding to a subunit of verectin at the same position when stained with both Coomassie brilliant blue and periodic acid-Schiff reagents on 18 % SDS-PAGE. The molecular weight (14 kDa) was confirmed by Sephadex G-50 column chromatography. The glycoprotein fraction showed a radical scavenging activity against superoxide anion generated by the xanthine-xanthine oxidase system as well as inhibition of cyclooxygenase-2 and reduction of thromboxane A 2 synthase level in vitro.
Subject(s)
Aloe , Cyclooxygenase Inhibitors/pharmacology , Free Radical Scavengers/pharmacology , Glycoproteins/pharmacology , Isoenzymes/drug effects , Phytotherapy , Plant Preparations/pharmacology , Prostaglandin-Endoperoxide Synthases/drug effects , Thromboxane-A Synthase/drug effects , Cyclooxygenase 2 , Cyclooxygenase 2 Inhibitors , Gels , Humans , Isoenzymes/antagonists & inhibitors , Membrane Proteins , Plant Leaves , Superoxides/metabolism , Thromboxane-A Synthase/antagonists & inhibitorsABSTRACT
Antioxidant components in Aloe vera were examined for lipid peroxidation using rat liver microsomal and mitochondrial enzymes. Among the aloesin derivatives examined, isorabaichromone showed a potent antioxidative activity. The DPPH radical and superoxide anion scavenging activities were determined. As one of the most potent components, isorabaichromone together with feruloylaloesin and p-coumaroylaloesin showed potent DPPH radical and superoxide anion scavenging activities. Electron spin resonance (ESR) using the spin trapping method suggested that the potent superoxide anion scavenging activity of isorabaichromone may have been due to its caffeoyl group. As A. vera has long been used to promote wound healing, the inhibitory effects of aloesin derivatives for cyclooxygenase (Cox)-2 and thromboxane (Tx) A 2 synthase were examined and the participation of p-coumaroyl and feruloyl ester groups in the aloesin skeleton was demonstrated. These findings may explain, at least in part, the wound healing effects of A.vera. Abbreviations. ADP:adenosine diphosphate ASA:ascorbic acid BHT:butylated hydroxytoluene BSA:bovine serum albumin DMPO:5,5-dimethyl-1-pyrroline N-oxide DPPH:1,1-diphenyl-2-picrylhydrazyl EDTA:edetic acid HEPES: N-(2-hydroxyethyl)-piperazine- N-2'-ethane-sulfonic acid NADH:reduced nicotinamide adenine dinucleotide NADPH:reduced nicotinamide adenine dinucleotide phosphate NBT:nitroblue tetrazolium Pg:prostaglandin SOD:superoxide dismutase TBA:thiobarbituric acid TCA:trichloroacetic acid XOD:xanthine oxidase
Subject(s)
Aloe , Anti-Inflammatory Agents/pharmacology , Antioxidants/pharmacology , Chromones/pharmacology , Free Radical Scavengers/pharmacology , Glucosides/pharmacology , Lipid Peroxidation/drug effects , Phytotherapy , Animals , Biphenyl Compounds , Cyclooxygenase 2 , Electron Spin Resonance Spectroscopy , Inhibitory Concentration 50 , Isoenzymes/drug effects , Male , Microsomes, Liver/drug effects , Microsomes, Liver/enzymology , Mitochondria, Liver/drug effects , Mitochondria, Liver/enzymology , Picrates , Prostaglandin-Endoperoxide Synthases/drug effects , Rats , Rats, Wistar , Superoxide Dismutase/drug effects , Thromboxane A2ABSTRACT
Twelve hydrocarbons, four sterols, three triterpenes, nineteen fatty acids, two phenolic acids, and five flavonoids have been detected and identified in Salvia triloba. Among the isolated flavonoids, 8-methoxygenistein 7-O-alpha-L-rhamnoside 4'-O-beta-D-glucoside (1), is reported for the first time.
Subject(s)
Fatty Acids/chemistry , Flavonoids/chemistry , Lamiaceae , Phytotherapy , Sterols/chemistry , Triterpenes/chemistry , Humans , Plant StructuresABSTRACT
The novel iridoid glycosides, isounedoside and grandifloric acid, were isolated from Thunbergia grandiflora. Grandifloric acid contains C-10 as a carboxylic acid group, the presence of which was predicted by recent iridoid biosynthesis studies carried out within T. alata. Isounedoside contains a rare 6,7-epoxide functional group. A revision in some of the NMR spectral assignments for the known iridoid glycoside alatoside was also made.
Subject(s)
Diterpenes/chemistry , Glucosides/chemistry , Plants, Medicinal , Pyrans/chemistry , Diterpenes/isolation & purification , Glucosides/isolation & purification , Molecular Structure , Plant Extracts , Pyrans/isolation & purificationABSTRACT
The new phenylethanoid glycosides 2-O-acetyl-3'''-O-methylverbascoside and 2,4"-di-O-acetyl-3'''-O-methylverbascoside were isolated and identified from Penstemon crandallii. The major iridoid glycoside was plantarenaloside and no aucubin type iridoids were found. This contrasted with a previous analysis of P. teucrioides, from the same Penstemon subsection, which was dominated by aucubin derivatives.
