Is lead in Nagabhasma toxic to liver? - A histological evaluation

Ayurvedic medicines is known to use heavy metals in their preparation. Nagabhasma is one such form of a lead-based medicine. Even though lead is known to be toxic to several systems of the human body, according to Ayurveda, the metallic toxicity of the lead gets nullified and thereby imbibes medicinal property when it is prepared using many herbs and stringent traditional methods. Therefore, the present study is designed to evaluate the effect of such detoxified lead in various stages of authentically prepared Nagabhasma on the histopatholo-gy of liver in comparison with lead acetate and commercially available Nagabhasma-administered animals. Less than the human-equivalent doses of Nagabhasma at four intermittent stages of its preparation were administered orally for 30 days and 60 days (short term and long term exposure) to Wistar rats. In another set of experiment, test-material-administered animals were kept under observation for an additional period of two months to record the residual effect. Immediately after the administration and after the observation period, the animals were sacrificed to collect the liver for histopathological examination. The histopathological results of the immediate and residual effects showed varying alterations in the microarchitecture of the liver as the stages of Nagabhasma preparation advanced. The final product (stage 4 bhasma), showed very less toxic effect in comparison with other stages. In conclusion, the results state that, by following the traditional procedures while preparing Nagabhasma, the metallic lead gets converted into non-toxic organometallic compound.