Evaluation of medicinal plant extracts against blood-sucking parasites.

The present study was based on assessments of the antiparasitic activities to determine the efficacies of acetone, chloroform, ethyl acetate, hexane, and methanol dried leaf, flower, and seed extracts of Cassia auriculata L., Rhinacanthus nasutus KURZ., Solanum torvum Swartz, Terminalia chebula Retz., and Vitex negundo Linn. were tested against larvae of cattle tick Rhipicephalus (Boophilus) microplus Canestrini, 1887 (Acari: Ixodidae), adult of Haemaphysalis bispinosa Neumann, 1897 (Acarina: Ixodidae), hematophagous fly Hippobosca maculata Leach (Diptera: Hippoboscidae), nymph of goat-lice Damalinia caprae Gurlt (Trichodectidae), and adult sheep parasite Paramphistomum cervi Zeder, 1790 (Digenea: Paramphistomatidae). All plant extracts showed moderate parasitic effects after 24 h of exposure at 3,000 ppm; however, the highest parasite mortality was found in leaf ethyl acetate, flower methanol of C. auriculata, leaf and seed methanol of S. torvum, seed acetone of T. chebula, and leaf hexane extracts of V. negundo against the larvae of R. microplus (LC(50) = 335.48, 309.21, 297.43, 414.99, 167.20, and 611.67 ppm; LC(90) = 1571.58, 1111.82, 950.98, 1243.64, 595.31, and 1875.50 ppm), the leaf and flower methanol of R. nasutus, leaf and seed methanol of S. torvum, and seed methanol extracts of T. chebula against the nymph of D. caprae (LC(50) = 119.26,143.10,164.93,140.47, and 155.98 ppm; LC(90) = 356.77, 224.08, 546.20, 479.72, and 496.06 ppm), the leaf methanol of R. nasutus, leaf and seed methanol of S.torvum, and seed acetone of T. chebula against the adult of H. bispinosa (LC(50) = 333.15, 328.98, 312.28, and 186.46 ppm; LC(90) = 1056.07, 955.39, 946.63, and 590.76 ppm), the leaf methanol of C. auriculata, the leaf and flower methanol of R. nasutus, the leaf ethyl acetate of S. torvum against the H. maculata (LC(50) = 303.36, 177.21, 204.58, and 211.41 ppm; LC(90) = 939.90, 539.39, 599.43, and 651.90 ppm), and the leaf acetone of C. auriculata, the flower methanol of R. nasutus, the seed methanol of S. torvum, and the seed acetone of T. chebula were tested against the adult of P. cervi (LC(50) = 180.54, 168.59, 200.89, and 87.08 ppm; LC(90) = 597.51, 558.65, 690.37, and 433.85 ppm), respectively. Therefore, this study provides first report on the veterinary parasitic activity of plant extracts from Southern India.