Bombax costatum enhances piroxicam's efficacy: Possible involvement of alpha-2 adrenergic receptor, opioidergic and arachidonic pathways.

BACKGROUND

With increasing drug-herb combination and widespread use of Bombax costatum as analgesic in Africa, this research studies effects of Bombax costatum on piroxicam's efficacy and possible mechanisms of antinociception.

MATERIALS AND

METHODS

In efficacy studies, four groups of mice were respectively treated with 1mL/kg distilled water, 400mg/kg Bombax costatum, 20mg/kg piroxicam and a combination of both. Acetic acid and hot plate were used to induce pain in mice while prostaglandin-E2 and formalin were used to induce inflammation in rats. For mechanistic studies, different groups of mice were treated intraperitoneally with 2mg/kg naloxone, 1mg/kg yohimbine, 20mg/kg propranolol, 5mg/kg glibenclamide and 1mg/kg prazosin respectively. Two other groups were treated orally with 1mL/kg of the vehicle and 400mg/kg Bombax costatum respectively. 60minutes later, 10mL/kg of 0.6% acetic acid was administered via the intraperitoneal route and number of writhes were observed for 10minutes.

RESULTS

Concurrent administration of Bombax costatum and piroxicam decreased the number of writhes significantly (P≤0.001), increased reaction time with decreased paw diameter in comparison to control. Additionally, this drug-herb combination showed enhanced anti-nocipective efficacy than when administered singly. Also, pre-treatment with yohimbine and naloxone significantly (P≤0.01) inhibited the antinociceptive activities of Bombax costatum.

CONCLUSION

Bombax costatum posses antinociceptive and anti-inflammatory activities and may involve α-2 adrenergic receptor, opioidergic and arachidonic pathways. In addition, Bombax costaum augments the efficacy of piroxicam and could be of clinical benefits if studied on man.