Acute toxicity study and wound healing potential of Gynura procumbens leaf xtract in rats

This study was conducted to evaluate the effects of topical application of ethanol extract of Gynura procumbens leaf extract on the rate of wound healing closure and histology of wound area. An area of uniform wound 2.00 cm in diameter using circular stamp was excised from the nape of the dorsal neck of all rats with the aid of round seal. The animal groups were topically treated with 0.2 ml of each vehicle (gum acacia),Intrasite gel,100 and 200 mg/ml of ethanol extract,respectively.Macroscopically,wound dressed with G. procumbens leaf extract and Intrasite gel significantly healed earlier than those treated with vehicle. On day 14 post-surgery, 6 animals from each group were sacrificed and histological analysis of wounds area showed that wounds dressed with leaf extract showed comparatively less scar width at wound closure and granulation tissue contained less inflammatory cells and more collagen with angiogenesis compared to wounds dressed with vehicle. Furthermore, acute toxicity study has indicated no mortality with 5 g/kg dose of G. procumbens leaf extract in Sprague Dawley and did not produce any major clinical signs of toxicity. In conclusion, wounds dressed with leaf extract significantly enhanced and accelerated the rate of wound healing enclosure in rats. © 2011 Academic Journals

Different effects of L-arginine on morphine tolerance in sham and ovariectomized female mice*

Objective: The roles of gonadal hormones and nitric oxide (NO) on the analgesic effects of morphine, tolerance to morphine, and their interactions have been widely investigated. In the present study, the effect of L-arginine (an NO precursor) on morphine tolerance in sham and ovariectomized (OVX) female mice was investigated. Methods: Forty mice were divided into sham and OVX groups. On the first day, a hot plate test ((55±0.2) °C; cut-off 30 s) was carried out as a base record 15 min before injection of morphine (10 mg/kg, subcutaneously (s.c.)) and was repeated every 15 min after injection. The sham group was then divided into two subgroups: sham-tolerance-L-arginine (Sham-Tol-LA) and sham-tolerance-saline (Sham-Tol-Sal) which received either L-arginine 50 mg/kg (intraperitoneally (i.p.)) or saline 10 ml/kg (i.p.), respectively, three times in a day for three consecutive days. Morphine tolerance was induced in animals by injecting 30 mg/kg morphine (s.c.) three times/day for three days. This treatment was also used for OVX subgroups. On the fifth day, the hot plate test was repeated. The analgesic effect of morphine was calculated as the maximal percent effect (MPE). The results were compared using repeated measure analysis of variance (ANOVA). Results: There was no significant difference in MPE between the OVX and sham groups. The MPEs in both the Sham-Tol-Sal and OVX-Tol-Sal groups were lower than those in both the sham and OVX groups (P<0.01). The MPE in the OVX-Tol-Sal group was greater than that in the Sham-Tol-Sal group (P<0.01). The MPE in the Sham-Tol-LA group was higher than that in the Sham-Tol-Sal group (P<0.01). However, there was no significant difference between the Sham-Tol-LA and sham groups or between the OVX-Tol-LA and OVX-Tol-Sal groups. Conclusions: The results of the present study showed that repeated administration of morphine causes tolerance to the analgesic effect of morphine. L-Arginine could prevent tolerance to morphine but its effect was different in the presence of ovarian hormones