title: In vitro and in vivo effects of three different Mitragyna speciosa korth leaf extracts on phase II drug metabolizing enzymes--glutathione transferases (GSTs).
abstract: In the present study, we investigate the effects of three different Mitragyna speciosa extracts, namely methanolic, aqueous and total alkaloid extracts, on glutathione transferase-specific activity in male Sprague Dawley rat liver cytosol in vitro and in vivo. In the in vitro study, the effect of Mitragyna speciosa extracts (0.01 to 750 microg/mL) against the specific activity of glutathione transferases was examined in rat liver cytosolic fraction from untreated rats. Our data show concentration dependent inhibition of cytosolic GSTs when Mitragyna speciosa extract was added into the reaction mixture. At the highest concentration used, the methanolic extract showed the highest GSTs specific activity inhibition (61%), followed by aqueous (50%) and total alkaloid extract (43%), respectively. In in vivo study, three different dosages; 50, 100 and 200 mg/kg for methanolic and aqueous extracts and 5, 10 and 20 mg/kg for total alkaloid extract were given orally for 14 days. An increase in GST specific activity was generally observed. However, only Mitragyna speciosa aqueous extract with a dosage of 100 mg/kg showed significant results: 129% compared to control.
authors.affiliation: Centre for Drug Research, Universiti Sains Malaysia, 11800 USM Penang, Malaysia.
authors.forename: Juzaili
authors.initials: J
authors.lastname: Azizi
authors.forename: Sabariah
authors.initials: S
authors.lastname: Ismail
authors.forename: Mohd Nizam
authors.initials: MN
authors.lastname: Mordi
authors.forename: Surash
authors.initials: S
authors.lastname: Ramanathan
authors.forename: Mohd Ikram Mohd
authors.initials: MI
authors.lastname: Said
authors.forename: Sharif Mahsufi
authors.initials: SM
authors.lastname: Mansor
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D005982:Glutathione Transferase / Q000378:metabolism*; D008099:Liver / Q000033:anatomy & histology / Q000187:drug effects / Q000201:enzymology; D008297:Male; D050217:Metabolic Detoxication, Phase II; D032065:Mitragyna / Q000737:chemistry*; D009929:Organ Size / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D010936:Plant Extracts; D005982:Glutathione Transferase