myricetin-3-o-rhamnoside and 1-1-diphenyl-2-picrylhydrazyl

Chrysophyllum albidum G. is a tropical plant and commonly found in Nigeria. It belongs to the sapotaceae family and used in folklore in the treatment of yellow fever, malaria, diarrhea, vaginal and dermatological infections. The study was aimed at investigating the antioxidant properties of this plant by employing the in vitro and in vivo experimental models. The effect of DPPH free radical scavenging activity on the fractions of petroleum ether, ethanol, butanol, ethylacetate, and water of C. albidum was determined. The ethyl acetate fraction was purified in column chromatography to obtain myricetin rhamnoside. Structure elucidation was done by NMR and mass spectroscopic techniques. Furthermore, ethanol extract was administered to five groups of eight rats per group. The animals in the normal group were administered with vehicle alone for 7 days. The positive control animals were given vehicle on the first four days, and with the vehicle and hepatotoxin (CCl(4)) on the fifth, sixth and seventh day. The animals in the treatment category were respectively administered with 500, 1000 and 1500 mg/kg b.w. of extract & distilled water for the first four days, and with distilled water, extract and CCl(4) on the last three days. Animals were subsequently anaesthetized and blood samples were collected for catalase (CAT), malondialdehyde (MDA), reduced gluthathione (GSH) and superoxide dismutase (SOD) assays. The petroleum ether fraction showed the least antiradical activity (4057.5 ± 809.6 g/kg) while ethyl ether exhibited the highest activity (414.4 ± 92.0 g/kg). Myricetin rhamnoside also exhibited an excellent radical scavenging activity (314.1 ± 60.2) which was comparable to the positive control. Result from animal study showed that C. albidum exhibited significant (p < 0.05) differences on the activity of CAT, MDA and GSH. The plant could therefore be employed as sources of natural antioxidant boosters and for the treatment of some oxidative stress disorders in which free radicals are implicated.

Topics: Animals; Antioxidants; Biphenyl Compounds; Carbon Tetrachloride; Catalase; Chemical and Drug Induced Liver Injury; Free Radical Scavengers; Free Radicals; Glutathione; Male; Malondialdehyde; Mannosides; Molecular Structure; Picrates; Plant Extracts; Plant Leaves; Rats; Rats, Wistar; Sapotaceae; Superoxide Dismutase

Antioxidant activity of myricetin-3-o-galactoside and myricetin-3-o-rhamnoside, isolated from the leaves of Myrtus communis, was determined by the ability of each compound to inhibit xanthine oxidase activity, lipid peroxidation and to scavenge the free radical 1,1-diphenyl-2-picrylhydrazyl. Antimutagenic activity was assessed using the SOS chromotest and the Comet assay. The IC50 values of lipid peroxidation by myricetin-3-o-galactoside and myricetin-3-o-rhamnoside are respectively 160 microg/ml and 220 microg/ml. At a concentration of 100 microg/ml, the two compounds showed the most potent inhibitory effect of xanthine oxidase activity by respectively, 57% and 59%. Myricetin-3-o-rhamnoside was a very potent radical scavenger with an IC50 value of 1.4 microg/ml. Moreover, these two compounds induced an inhibitory activity against nifuroxazide, aflatoxine B1 and H2O2 induced mutagenicity. The protective effect exhibited by these molecules was also determined by analysis of gene expression as response to an oxidative stress using a cDNA micro-array. Myricetin-3-o-galactoside and myricetin-3-o-rhamnoside modulated the expression patterns of cellular genes involved in oxidative stress, respectively (GPX1, TXN, AOE372, SEPW1, SHC1) and (TXNRD1, TXN, SOD1 AOE372, SEPW1), in DNA damaging repair, respectively (XPC, LIG4, RPA3, PCNA, DDIT3, POLD1, XRCC5, MPG) and (TDG, PCNA, LIG4, XRCC5, DDIT3, MSH2, ERCC5, RPA3, POLD1), and in apoptosis (PARP).

Topics: Antimutagenic Agents; Antioxidants; Biphenyl Compounds; Cell Survival; Comet Assay; DNA Repair; DNA, Complementary; Enzyme Inhibitors; Flavonoids; Galactosides; Gene Expression Regulation; Humans; Image Processing, Computer-Assisted; In Situ Hybridization; K562 Cells; Lipid Peroxidation; Mannosides; Mutagenicity Tests; Myrtus; Oligonucleotide Array Sequence Analysis; Picrates; Plant Extracts; Xanthine Oxidase