Protective efficacy of semi purified fraction of high altitude podophyllum hexandrum rhizomes in lethally irradiated Swiss albino mice.

A fraction of high altitude Podophyllum hexandrum rhizome, REC-2006, was evaluated for its radioprotective efficacy against lethal gamma-irradiation (10 Gy, whole body) in Swiss albino mice. The maximum tolerated dose (MTD) and LD50 of this fraction were found to be 45 mg/kg b.w. and 74 mg/kg b.w. respectively. Pre-irradiation (- 2 h, ) administration (i.p.) of 6 or 8 mg/kg b.w. of REC-2006 rendered > 90% survival in lethally irradiated mice. The dose reduction factor was calculated to be 1.62 considering survival as the end point. REC-2006 treatment marked in significant increase in endogenous spleen colony forming units. In REC-2006 treated group, super oxide dismutase activity was increased significantly compared to the radiation control group (Liver, p = 0.00, Jejunum p = 0.00). The extract also inhibited radiation induced lipid peroxidation in liver (p = 0.00) at 24 h. REC-2006 administration (100-200 microg/ml) significantly reduced the halo diameter in mice thymocytes. Nearly 10 fold difference between the effective dose (6 mg/kg b.w.) and LD50 and the high degree of whole body survival (> 90% against 10 Gy irradiation) indicates REC-2006 to be safe and highly promising to achieve significant radioprotection against lethal radiation. Further purification and identification of active molecules and their efficacy studies in higher animals therefore demand attention.