Preliminary study of the mechanism of Andrographis Paniculata in mitigating the toxic effects of Naja naja venom

Introduction: Snake venom is a modified digestive secretion consisting of a complex mixture of biologically active compounds including variety of enzymes, enzyme inhibitors, inorganic metal ions, growth factors, nucleosides and so on, each one playing an important role in its toxicity. The venomous bite of the Indian cobra i.e Najanaja accounts for 10,000 deaths annually in India. Treatment with antivenin is expensive. Poor accessibility to antivenin and anaphylactic reactions associated with 20% of the patients during treatment with antivenin, further complicate the situation. Andrographis paniculata (A.P) is a herb, commonly known as 'king of bitters', has been used in the treatment of envenomation due to Naja najaby traditional healers in India and south east Asia. The mechanism of its action in mitigating snake venom toxicity has not been explored in detail. Aims and Objectives: To study the effect of the methanolic extract of A.P on proteolytic activity, destruction of proteinase inhibitory activity of plasma and anticoagulant activity of Najanajavenom. Materials and Methods: Proteolytic activity of the venom and the effect of methanolic extract of A.P on proteolytic activity was measured using the case inolytic assay of Kunitz. Effect of synthetic proteinase inhibitors on proteolytic activity was measured in the presence of ethylene diamine tetraacetic acid (EDTA) and phenyl methyl sulfonyl fluoride (PMSF). Heparinized plasma was obtained from healthy volunteers (IEC 631/2015)to estimate antitryptic and antichymotrypticactivity in the presence of venom. Citrated plasma was used to study the effect of the venom and A.P extract on prothrombin time(PT) using Coag THREE kit. Results: Progressive increase in the inhibition (14 to 54%) of case inolytic activity of the venom (300 [micro]g)was observed in the presence of increasing concentrations of A.P (300 [micro]g to 18mg). EDTA ([10.sup.-3] mM)and PMSF ([10.sup.-5] mM) caused 89% and 78% inhibition of case inolytic activity of venom (300 [micro]g) respectively. Venom (10 [micro]g) did not cause a loss of antitryptic and antichymotryptic activity of the plasma when plasma was incubated with the venom for 16 hours at 37[degrees]C.PT of citrated plasma was prolonged by 36% (from 13.5 secs to 18.3 secs) by the venom(10 [micro]g). Addition of A.P did not reverse the change in PT. However, pre-incubation of the venom with A.P followed by its addition to the assay system, completely reversed-PT back to normal.