Effect of Pueraria tuberosa tuber extract on chronic foot shock stress in Wistar rats.

The present study was undertaken to explore the protective effects of tuberous root extract of Pueraria tuberosa on chronic foot shock stress (CS) induced physiological, neurobehavioral and neuropathological alterations. Male Wistar rats (120-150 g) were divided into seven groups, consisting of ten animals in each. Group I served as normal, group II as positive control, while group III-VII as test drug treated. P tuberosa tuber extract (PTE) was given to rats of groups III-VI at the doses of 50, 100, 200 and 400 mg/kg respectively, while group VII treated with Withania somnifera rhizome extract (WSE) (100 mg/kg) as reference drug. Group II (stress control) received only equivalent volume of distilled water (0.5 ml/100 g) orally. All the drugs were given orally once/day for 14 consecutive days. The last dose was given 1 h before study. Simultaneously, all the animals (except group I) were subjected to 1 h of foot-shock (2 mA) through a grid floor for those 14 days in a standard conditioning chamber with the escape route closed [Chronic stress (CS)]. Thereafter, the rats were placed on open-field and plus maze apparatus for studying the behavioral patterns of them, and the anxiolytic effects of the putative drug. Sexual activities of the animals were also studied. Finally, the animals were sacrificed and their ulcer formation in gastric mucosa was noted. Weights of adrenals and spleen were also taken. Further, plasma corticosterone levels were estimated spectroflurometrically. Results indicated that, CS significantly altered the behavioral patterns, decreased the sexual urge and activities, damaged the gastric mucosal layers, enhanced plasma corticosterone levels and increased adrenal glands and spleen weights. PTE and WSE showed significant anxiolytic activity, protected the gastric mucosa, lowered plasma corticosterone level (indicating HPA axis inhibition) and negated the hypertrophy of adrenals and spleen. PTE also enhanced the sexual urge and activities in animals exposed to chronic stress. The findings suggest significant anxiolytic and anti-stress properties of PTE, confirming the clinical efficacy of the plant mentioned in Ayurveda (Indian system of traditional medicine).