Drinking Thunbergia laurifolia Lindl. Leaf Extract Helps Prevent Renal Toxicity Induced by Cadmium in Rats

Abstract

Thunbergia laurifolia Lindl. (TL) or “Rang Jerd” is a Thai herbal medicine used as an antidote for several poisonous agents. Cadmium (Cd) is an environmental pollutant in Mae Sot district, Tak province, Thailand. Chronic exposure to Cd causes renal and bone dysfunction in exposed human populations. In order to investigate whether TL leaf extract could prevent Cd induced renal toxicity, two groups of male Wistar rats, six rats each were injected with cadmium chloride solution (CdCl2) at the concentration of 1.0 mg/kg BW for 20 days. Group 1 was serving as control and fed distilled water for 20 days before Cd administration while group 2 was administered TL leaf extract at 0.1 mg/ml in drinking water for 20 days before and during injection of CdCl2 at the same concentration as in group 1. The body weight of rats pretreated with TL leaf extract before Cd exposure in group 2 was significantly (p<0.05) greater than that of rats given with Cd alone. However, TL leaf extract did not reduce the levels of Cd in blood and urine of the Cd exposed rats. The rats in group 2 did not show histopathological changes in the kidney that were observed in the control group which given Cd alone. Therefore, this study demonstrated that TL leaf extract can protect against Cd induced structural damage in rat kidney and also reduce other systemic toxicity. TL leaf extract may be useful for reducing Cd toxicity in human populations exposed to Cd in food and drinking water.