Schistosomicidal effects of Pavetta owariensis and Harrisonia abyssinica in mice infected with Schistosoma mansoni.

The schistosomicidal properties of ethanol and acetone extracts of Pavetta owariensis and an ethanol extract of Harrisonia abyssinica were assessed in mice infected with Schistosoma mansoni. Spleen weight, number of adult worms and eggs and size of liver granulomas were the main parameters studied. All P. owariensis extracts containing proanthocyanins were shown to cause a reduction in size of periovular granuloma formation in the liver. This effect was most pronounced with ethanol extracts of both "white bark" and "red bark" varieties of the plant. Acetone extracts of P. owariensis "red bark" variety, containing the highest concentration of proanthocyanins, caused a marked reduction of egg numbers in the liver and intestine whereas the ethanol extract of H. abyssinica proved to be inactive.