Effect of Zhumeria majdae aerial parts extract and fractions on morphinetolerance in mice

ABSTRACT

In this research, the effects of methanolic extract of aerial parts of Zhumeria majdae and its fraction, on the development of tolerance to the antinociceptive action of morphine were examined in mice. Morphine tolerance in mice was developed by injecting morphine sulfate [20 mg/Kg, S.C.] twice a day for 4 days. Vehicle injected mice was considered as control. To determine the effect of intraperitoneally administered methanolic extract of Z majdae and its fractions on tolerance development, they were injected in the appropriate dose twice a day. The development of tolerance to the antinociceptive effect of morphine sulfate [10 mg/Kg, S.C.] was measured on days 1 and 6 using the tail-flick test. The methanolic extract showed a significant activity and attenuated tolerance development at 0.14, 0.28 and 0.56 g/Kg doses. The methanolic extract of plant was suspended in methanol-water [32] and extracted with chloroform. The activity of hydroalcoholic fraction was more than the chloroformic one, and showed significant activity. Further fraction on silica gel column chromatography was obtained. Three fractions [A, B and C, similar Rf in each group] were obtained; fraction A and B were more effective. The methanolic extract of plant and its fractions themselves, at dose employed in the study, did not exert any effect on antinoeiceptive activity. These results indicated that the extracts of Z majdae contain component [s] that can attenuate tolerance development to the antinociceptive action of morphine