Assessment of Sterculia setigera and Lantana camara Extracts as Schistosomicidal and Molluscicidal Agents

Abstract

This study was planned to evaluate the prophylactic and curative activities of the methanol extract of two medicinal plants; Sterculia setigera bark and Lantana camara leaves and their combination against Schistosoma mansoni in white albino mice and to evaluate their effects on the major enzyme activities involved in liver metabolism during the course of infection. Liver function tests, total proteins, albumins, globulins, alanine aminotransferase (ALT) and aspratate aminotransferase (AST) were also measured. It also covered the in vitro activity of S.setigera against S. mansoni. The molluscicidal activities of the methanol extracts of S. setigera bark and L.camara leaves were also tested against Bulinus truncatus and Biomphalaria pfeifferi. For the snails, LC95 and LC50 were the measure for the toxicity. A group of 35 adult normal CD-1 Swiss albino mice, each weighing 20 gms, were divided into five groups and infected each with 80 S.mamsoni cercariae (Egyptian strain). Groups, one, two and three of the infected mice were treated orally with the extract in a dose rate of III IV Please purchase PDFcamp Printer on http://www.verypdf.com/ to remove this watermark. a ͹ a 500 mg /kg b.wt for five consecutive days; seven days before infection with S.mamsoni cercariae (Prophylactic), as well as four and seven weeks post- infection (curative). Group four was treated with praziquantel (PZQ) at a dose of 500 mg/kg b.wt for two consecutive days seven weeks post -infection (treated control), while in group five the mice were left untreated after infection (infected untreated control). Nine weeks post infection (constant period), the animals were sacrified, perfused to evaluate the efficacy of the plant extracts in the treatment of the infection. Treatment with curative dose of praziquantel (500 mg/kg body/ weight) for two consecutive days, as a reference of anti-schistosomal drug reduced the total number of mature ova and complete absence of immature ova and increased the percentage of dead ova. Also, the drug tended to normalize all the changed biochemical parameters and improved the histopathological features of the liver. When compared with the standard treatment, the results obtained showed that S. setigera bark extract did not show anti- schistosomal activity on worms in culture in vitro (100μg/ml), but it had a significant anti-schistosomal activity (29% worm reduction) and promising prophylactic activity (40% worm reduction) in vivo. A significant reduction of ova output from S. mansoni infected mice (treated group) , was recorded compared with a slight reduction in the prophylactic group. The number of ova from the liver and intestine was significantly reduced. The result also indicated that administration of L. camara leaves extract produced significant reduction in worm burden (29%) and ova count and a decrease in the percentage of mature ova stages. Please purchase PDFcamp Printer on http://www.verypdf.com/ to remove this watermark. a ͺ a Administration of a combined dose of both extracts improved their effects on the parasitological parameters; with significant reduction in worm burden (40%) and ova count and a decrease in the percentage of mature and immature stages. S .mansoni infection elevated serum ALT, AST levels. Administration of S.setigera bark or L.camara leaves extracts significantly diminished serum ALT and AST and restored albumin, globulins and total protein to the normal levels in both treated and prophylactic groups and improved A/G ratio. Combination of the extracts of S.setigera bark and L. camara leaves improved their effect on the serum enzymes related to liver functions. On the other hand, 7 series of descending double successive dilutions, were prepared starting from 1000 ppm of the extracts of S.setigera bark and L. camara leaves. Ten snails from each group were used in each replicate and control , the exposure and recovery periods were 24 hours. The toxicity measures indicated that the methanol extract of S. setigera bark was more toxic to B. pfeifferi snails (LC50 = 296ppm) than B. truncatus (LC50 = 482ppm), meanwhile the methanol extract of L. camara leaves was more toxic to B. truncatus (LC50 = 48ppm) than B. pfeifferi (LC50 = 111ppm) . In conclusion; S. setigera bark and L. camera leaves showed an indication that they possess anti schistosomal, prophylactic and hepatoprotective activities during the course of infection with S.mansoni, as well as molluscicidal activity against B. truncatus and B. pfeifferi. These plants open the way for further investigations as prospective schistosomal and molluscicidal Agents.