Studies of methanolic extract of Amaranthus paniculatus L. on Mice Liver against

India has a rich heritage of medicinal plants, many of which have been explored for the various bioactivities since ages, but the radioprotective potential of the plants have been hardly explored. Since Amaranthus, a common weed and very often caten as vegetable by rural population, has been used as emollient, astringent, diuretic, blood purifier, hemorrhagic diathesis and biliousness from time immemorial. Hence the present study aims to judge whether Amaranthus paniculatus (Linn) has the antiradiation efficacy against radiation induced histopathological and biochemical alterations in mice liver. Amaranthus paniculatus (Linn) belongs to family Amaranthaceae and commonly called as Amaranth, has good natural sources of carotenoids (beta carotene-1490 μg/100 gm of edible portion), vitamin C and high level of critical lysine and methionine, protein content (22 gm/100 gm of edible portion). Swiss albino mice of 6-8 weeks weighing 22 ± 3 gm were selected from an inbred colony and divided into four groups. One group served as normal and two groups were administered with alcoholic extract at a dose of 600 mg/Kg-body weight/day dissolved in distilled water for fifteen days. Fourth group was given distilled water, orally and ad libitum. Then two groups, one with drug treated and another with distilled water treated, were exposed to 5 Gy of gamma radiation at the dose rate of 1.07 Gy/min with a source to surface distance (SSD) of 77.5 cm. The animals were autopsied at 1, 3, 7, 15 and 30 days post exposure. the optimum dose was calculated to be 600mg/kg b.wt/day after treating mice with AE for fifteen consecutive days prior to irradiation (9 Gy) to get maximum protection against radiation injury. By the survival assay, DRF 1.43 was calculated with different doses of gammas radiation (6, 9, 12 Gy). The radiation induced augmentation in MDA, protein, glycogen, alkaline and acid phosphatase content of liver is significantly ameliorated by the drug. The radiation induced depletion in cholesterol and glutathione is also significantly checked. It is suggestive that radiation induced alteration in the histology and biochemistry of liver can be ameliorated or checked by Amaranthus paniculatus. Mechanisms of radioprotection may be by reducing the radiation induced augmentation in lipid peroxidation or by reduced depletion of glutathione after irradiation, by decreasing acid phosphatase activity in mice liver. The histopathological studies reveal that the increase in abnormal cell and biphasic changes in binucleated cell was not evident in Amaranthus pretreated irradiated group instead the greater number of normal hepatocytes was recorded. After irradiation the distortion in hepatic architecture, wider sinusoids, increase in number of Kupffer's cells, giant hepatocytes (mononucleated and multinucleated) were observed in only irradiated group which were either absent or lesser degree in Amaranthus pretreated groups. The present studies show that extract exerts its radioprotective effect in two ways: (i) it is able to curb the initial damage caused due to radiation (by antioxidant activity), and (ii) it stimulates the cellular regeneration in the post-irradiation period (particularly hematopoietic regeneration, liver recovery, gastrointestinal system recovery). The protection may be attributed to the synergistic effects of its constituents rather than any single factor, as all the constituents present in Amaranthus are well known antioxidants. Amaranthus thus showing protection in liver may also prove promising rich source of antioxidants for common people. (Author) 36 refs