Oleanolic acid, a triterpenoid known for its anti-inflammatory properties, is commonly present in several medicinal plants. The present study evaluated the effect of oleanolic acid on sPLA (2), a key enzyme in inflammatory reactions. Oleanolic acid inhibited sPLA (2) activities of human synovial fluid (HSF), human pleural fluid (HPF) and VIPERA RUSSELLI (VRV-PL-V) and NAJA NAJA (NN-PL-I) snake venoms in a concentration-dependent manner. The IC (50) values of sPLA (2) from these sources ranged from 3.08 to 7.78 muM. Increasing calcium (Ca (2+)) concentrations from 2.5 to 15 mM and substrate concentration up to 180 nM did not affect the level of inhibition. Oleanolic acid enhanced the relative intrinsic fluorescence intensity of sPLA (2) (VRV-PL-V). In the presence of oleanolic acid, an apparent shift in the far UV-CD spectrum of sPLA (2) was observed. These studies indicate direct interaction with the enzyme and formation of an sPLA (2)-oleanolic acid complex. The complex formed resulted in irreversible inhibition of sPLA (2). Oleanolic acid inhibited indirect hemolytic activity and mouse paw edema induced by sPLA (2). Inhibition of IN VITRO and IN VIVO sPLA (2) activity by oleanolic acid explains the observed anti-inflammatory properties of several oleanolic acid-containing medicinal plants.
In the present study we evaluated the presence of cysteine protease from the latex of four plants Asclepias curassavica L., Calotropis gigantea R.Br., Pergularia extensa R.Br. and Cynanchum puciflorum R.Br. belongs to the family Asclepiadaceae. Cysteine proteases from these plants latex exhibited both thrombin and plasmin like activities. Latex enzyme fraction in a concentration dependent manner induced the formation of clot in citrated blood plasma. Direct incubation of fibrinogen with latex enzyme fraction resulted in the formation of fibrin clot similar to thrombin enzyme. However prolonged incubation resulted in degradation of the formed fibrin clot suggesting plasmin like activity. Latex enzyme fraction preferentially hydrolyzed Aalpha and Bbeta chains of fibrinogen to form fibrin clot. Latex enzyme fraction also hydrolyzed the subunits of fully cross linked fibrin efficiently, the order of hydrolysis was alpha-polymer > alpha-chains > beta-chain and gamma-gamma dimer. Cysteine proteases from all the four Asclepiadaceae plants latex exhibited similar action on fibrinogen and fibrin. This study scientifically validate the use of plant latex in stop bleeding and wound healing by traditional healers all over the world.
A major myonecrotic zinc containing metalloprotease 'malabarin' with thrombin like activity was purified by the combination of gel permeation and anion exchange chromatography from T. malabaricus snake venom. MALDI-TOF analysis of malabarin indicated a molecular mass of 45.76 kDa and its N-terminal sequence was found to be Ile-Ile-Leu- Pro(Leu)-Ile-Gly-Val-Ile-Leu(Glu)-Thr-Thr. Atomic absorption spectral analysis of malabarin raveled the association of zinc metal ion. Malabarin is not lethal when injected i.p. or i.m. but causes extensive hemorrhage and degradation of muscle tissue within 24 hours. Sections of muscle tissue under light microscope revealed hemorrhage and congestion of blood vessel during initial stage followed by extensive muscle fiber necrosis with elevated levels of serum creatine kinase and lactate dehydrogenase activity. Malabarin also exhibited strong procoagulant action and its procoagulant action is due to thrombin like activity; it hydrolyzes fibrinogen to form fibrin clot. The enzyme preferentially hydrolyzes Aα followed by B subunits of fibrinogen from the N-terminal region and the released products were identified as fibrinopeptide A and fibrinopeptide B by MALDI. The myonecrotic, fibrinogenolytic and subsequent procoagulant activities of malabarin was neutralized by specific metalloprotease inhibitors such as EDTA, EGTA and 1, 10-phenanthroline but not by PMSF a specific serine protease inhibitor. Since there is no antivenom available to neutralize local toxicity caused by T. malabaricus snakebite, EDTA chelation therapy may have more clinical relevance over conventional treatment.
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