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Drought stress is a serious threat which decreases crop production. The present investigation was taken up to study the effect of drought stress at vegetative and reproductive stages on potential biochemical and enzymatic responses were investigated in two rice cultivars Rashi (tolerant) and Swarna (sensitive). Here, we observed significant changes in the biochemical and enzymatic responses between control and treatments as well as between the genotypes. Activity of catalase, peroxidase and superoxide dismutase (SOD), and glutathione reductase were also found to be different among the rice cultivars. Moreover, phenol content and activity of superoxide dismutase, catalase and glutathione reductase were increased significantly under drought stress in Rashi compared to Swarna. Nitrogen assimilatory enzymes such as nitrate and nitrite reductase (NiR) were sensitive to drought stress and both the genotype showed decreased activity at reproductive stage. Catalase activity was significantly higher at controlled reproductive (11.72%) and vegetative stage (4.14%) compared to Swarna. Rashi also showed an elevated SOD activity in controlled reproductive (180.55%) and vegetative stage (7.67%) compared to Swarna. Similarly, highest NiR activity found in Swarna (17.03%) compared to Rashi. Highest nitrate reductase activity was found in Rashi (10.87%) compared to Swarna. Rashi showed significantly higher chlorophyll content in vegetative stage and decreased in reproductive stage (26.33%). The improved performance of drought tolerant genotype (Rashi) was associated with more efficient biochemical factors under conditions of stress compare to drought sensitive genotype (Swarna).

In vitro inhibitory activity of Carissa spinarum leaf extracts against Bungarus caeruleus and Vipera russelli toxic snake venom enzymes was determined. The leaf extracts in non-polar and polar solvents were concentrated and were used for inhibitory activity determination. Methanol extracts (100 μg.mL−1) inhibited acetylcholinesterase, phospholipase A2, hyaluronidase, phosphomonoesterase, phosphodiesterase, 5′ nucleotidase enzymes of B. caeruleus and V. russelli venoms.

Background: Snakebites are considered a neglected tropical disease that affects thousands of people worldwide. Although antivenom is the only treatment available, it is associated with several side effects. As an alternative, plants have been extensively studied in order to obtain an alternative treatment. In folk medicine, Azima tetracantha Lam. is usually used to treat snakebites. The present study aims to provide a scientific explanation for the use of this plant against snakebite. The extracts of shade dried leaves of A. tetracantha were tested for in vitro inhibitory activity on toxic venom enzymes like phosphomonoesterase, phosphodiesterase, acetylcholinesterase, hyaluronidase etc. from Bungarus caeruleus and Vipera russelli venoms. Results: The ethylacetate extract rendered a significant inhibitory effect on the phosphomonoesterase, phosphodiesterase, phospholipase A2 and acetylcholinesterase enzymes. Conclusions: The present study suggests that ethylacetate extract of A. tetracantha leaves possesses compounds that inhibit the activity of toxic enzymes from Bungarus caeruleus and Vipera russelli venom. Further pharmacological and in vivo studies would provide evidence that this substance may lead to a potential treatment against these venoms.

Bungarus caeruleus (Indian common krait) is a venomous snake that is responsible for most of the snakebites in India. In the present study, we report the isolation and purification of neurotoxin and the biochemical changes and pathological effects induced by injection of purified neurotoxin into rats. The purpose of this study was to compare the effects of crude krait venom and the purified toxin. Both the crude venom and a sublethal dose of 60 microg/kg B. caeruleus purified toxin significantly increased the serum levels of alkaline phosphatase, alanine aminotransferase, and urea (p < 0.05). The crude venom but not the purified toxin increased the levels of lactate dehydrogenase, aspartate aminotranseferase, creatine kinase, and glucose. The kidneys showed congestion of the vessels, hemorrhage, and necrosis in venom-injected but not in toxin treated animals. The results of this study indicate that although crude krait venom has severe lethal, hemorrhagic, nephrotoxic, and proteolytic activities, the purified neurotoxin shows only moderate toxic activity, manifested as prominent local and systemic effects.