Anti-inflammatory and analgesic effects of methanol extract of red cultivar Allium cepa bulbs in rats and mice.

OBJECTIVES: Several cultivars of Allium cepa L. have been studied for anti-inflammatory and analgesic activities but there is inadequate information on such biological activities of the concentrated extracts of the Nigerian grown red cultivar A. cepa bulb. METHODS: The anti-inflammatory models used in this study were Carrageenan-induced paw oedema and formalin-induced paw lick in rats, while acetic acid-induced abdominal writhing, hot plate reaction, hot water tail flick tests in mice were the analgesic models. RESULTS: At 30 min post-induction (pi), the inhibition of paw oedema (62.50%) by 200 mg/kg of methanol extract of red cultivar A. cepa bulb (MERCACB) was significantly (p<0.001) higher than that of indomethacin (15.63%) at 10 mg/kg. The paw oedema inhibition at 60 min pi by MERCACB (76.92%) was significantly higher than that of indomethacin (41.03%). At the early phase of formalin paw-lick test, the pain reaction time (PRT) of rat treated with MERCACB (400 mg/kg) was significantly lower than that of indomethacin and the control groups. The hotplate test revealed that PRT of mice treated with 800 mg/kg of MERCACB were significantly (p<0.01) longer in comparism to indomethacin and control groups. The PRT of mice subjected to thermal pain due to hot water and treated with 800 mg/kg of MERCACB was significantly (p<0.05) longer than that of the control group. CONCLUSIONS: These findings indicate that MERCACB possesses potent anti-inflammatory and analgesic properties which confirm the traditional use of the plant for the treatment of inflammatory diseases and may be useful as a future therapeutic agent.

Effect of the methanol extract of the red cultivar Allium cepa L. on the serum biochemistry and electrolytes of rats following sub-chronic oral administration.

Background In traditional medicine, Allium cepa Linnaeus is used for the treatment of several disease conditions. Whilst reports abound on the effects of several cultivars of A. cepa L on biochemical parameters, similar information on the red cultivar is scarce. This study examines the effects of the methanol extract of the red cultivar A. cepa L on some serum biochemical parameters in experimental Wistar rats. Materials and methods Fifty-five Wistar rats were divided into three groups (A, B and C), which include 25, 25 and 5 rats, respectively. The rats in Groups A and B were sub-divided into 5 groups of 5 rats. Each rat was administered a certain dose of methanol extract of the red cultivar A. cepa L for 14 days (Group A) or 28 days (Group B). Group C rats served as the control and were administered with distilled water (10 mL/kg). Results A. cepa L administration resulted in dyslipidaemia, hyponatremia, hypokalaemia and hyperchloraemia; a significant (p < 0.05) decrease in hepatic enzymes and a significant (p < 0.05) increase in serum bicarbonate, bilirubin and its fractions. Conclusions These biochemical results indicate that the excessive and prolonged medicinal consumption of A. cepa L products beyond 7 days may induce moderate hepatic injury and mild renal dysfunction and may complicate disease conditions, such as hypertension and diabetes. Thus, in order to minimize its toxic effects, it is recommended that A. cepa L products should not be used for more than seven consecutive days or beyond a dosage of 90 mg/kg.