Prophylactic effect of Mucuna pruriens Linn (velvet bean) seed extract against experimental Naja sputatrix envenomation: Gene expression studies.

Mucuna pruriens is widely used in traditional medicine for treatments of various diseases. In certain region of Nigeria, the seed is used as oral prophylactics for snakebite. Rats pretreated with the aqueous extract from M. pruriens seed (MPE) were protected against the lethal effects of Naja sputatrix (Javan spitting cobra) venom [Tan et al., J Ethnopharmacol, 123 (2009) 356]. The pretreatment also protected against venom-induced histopathological changes in rat heart. To contribute to the understanding of the mechanism of cardio-protective action, the present study examined the effects of MPE-pretreatment on gene expression profile of rat heart as well as effect of MPE-pretreatment on N. sputatrix venom-induced gene expression alterations in rat heart. The gene expression profiles were examined by microarray analysis and verified by real time PCR. The results showed that pretreatment with MPE caused 50 genes in the rat heart substantially up-regulated of which 19 were related to immune responses, 7 were related to energy production and metabolism. The up-regulation of genes related to energy metabolism probably plays a role in maintaining the viability of the heart. Four other genes that were up-regulated (alpha synuclein, natriuretic peptide precursor, calsequestrin and triadin) were involved in the maintenance of homeostasis of the heart or maintaining its viability, thereby contributing to the direct protective action. The results demonstrated that protective effect of MPE pretreatment against snake venom poisoning may involve a direct action on the heart.

Extraction of bioactive principles from Mucuna pruriens seeds.

Mucuna pruriens (L.) DC. Syn. M. prurita Hook. (Papilionaceae) is used in male impotency, as aphrodisiac, in sexual debility, and as nervine tonic. It also possesses anti-parkinson property, possibly due to the presence of L-DOPA. In the present study, attempts were made to develop the suitable method(s) for extraction of L-DOPA/other active components from the seeds using different solvents. The various extracts were also screened for their neuroprotective and antioxidant activities. In addition, TLC and HPLC fingerprinting of the extracts for amino acid components were also developed for preliminary and sophisticated analysis. The L-DOPA could be obtained in good yield on extraction with EtOH-H2O mixture (1:1) using ascorbic acid as protector. Interestingly, n-propanol extract, which contained negligible amount of L-DOPA, had shown significant neuroprotective activity, suggesting that some components, other than L-DOPA, might also be responsible for anti-Parkinson property of seeds. The extract (MW-0100) containing mainly amino acids and water-ethanol extract (1:1) (MWEL-1299) showed promising antioxidant activity (EC50 = 2.5 microg) against DPPH radicals. MWEL-1299 also exhibited encouraging results against 1-methyl-4-phenylpyridinium ion (MPP+) toxicity. The TLC fingerprinting may be used to authenticate the plant material in herbal industry.