Non-Effectiveness of Azadirachta indica (Neem Tree) Leaf Extract against the Larvae of Angiostrongylus cantonensis and Trichinella spiralis.

The effectiveness of the leaf extracts of Azadirachta indica (neem tree) against two nematodes, Angiostrongylus cantonensis and Trichinella spiralis was investigated in mice. Laboratory mice were inoculated with the nematodes followed by the oral administration of the leaf extracts. Two standard drugs, flubendazole and mebendazole were compared with the plant extract in the study. No significant effects of the leaf extract against the nematodes were observed. Thus, although the extract has been shown by other investigators to be animalarial, antibacterial and antifungal, no activity was observed against the two nematodes in this study

In vitro anti-viral activity of aqueous extracts of Kenyan Carissa edulis , Prunus africana and Melia azedarach against human cytomegalovirus

The aqueous extracts of three medicinal plants, Carissa edulis (Forssk.) Vahl (Apocynaceae), Prunus africana (Hook.f.) Kalkm (Rosaceae) and Melia azedarach L. (Meliaceae) have shown significant reduction in the replication of human cytomegalovirus (HCMV) in human embryonic lung (HEL) fibroblasts cells in vitro. Using the plaque inhibition assay for the determination of anti-viral activity, the HEL fibroblast cells cultured in 24 well plates were infected with 1 x 102 PFU 91S HCMV and treated with various concentrations of the extracts. The plaques formed were counted after 7 days incubation at 37\ub0C in 5% CO2 and the percent plaques inhibited were calculated against infected untreated control. The effective concentrations inhibiting plaque formation by 50% (EC50) was found between 40 to 80 \u3bcg/ml for all the extracts. The cell cytotoxic concentrations (CC50) for each of the three extracts, by the trypan blue exclusion test, gave a safe therapeutic index. These results have demonstrated the potential anti-viral activities of the extracts of the three medicinal plants at non-cytotoxic concentrations

In vitro anti-viral activity of aqueous extracts of Kenyan Carissa edulis , Prunus africana and Melia azedarach against human cytomegalovirus

The aqueous extracts of three medicinal plants, Carissa edulis (Forssk.) Vahl (Apocynaceae), Prunus africana (Hook.f.) Kalkm (Rosaceae) and Melia azedarach L. (Meliaceae) have shown significant reduction in the replication of human cytomegalovirus (HCMV) in human embryonic lung (HEL) fibroblasts cells in vitro. Using the plaque inhibition assay for the determination of anti-viral activity, the HEL fibroblast cells cultured in 24 well plates were infected with 1 x 102 PFU 91S HCMV and treated with various concentrations of the extracts. The plaques formed were counted after 7 days incubation at 37°C in 5% CO2 and the percent plaques inhibited were calculated against infected untreated control. The effective concentrations inhibiting plaque formation by 50% (EC50) was found between 40 to 80 μg/ml for all the extracts. The cell cytotoxic concentrations (CC50) for each of the three extracts, by the trypan blue exclusion test, gave a safe therapeutic index. These results have demonstrated the potential anti-viral activities of the extracts of the three medicinal plants at non-cytotoxic concentrations

Evaluation of the HIV-1 reverse transcriptase inhibitory properties of extracts from some medicinal plants in Kenya

Extracts from twenty two medicinal plants popularly used in preparing traditional remedies in Kenya were screened for activity against the HIV-1 reverse transcriptase. The screening procedure involved the use of tritium labeled thymidine triphosphate as the enzyme substrate and polyadenylic acid.oligodeoxythymidylic acid [poly(rA).p(dT)12-18] as the template primer dimer. Foscarnet was used as a positive control in these experiments. At a concentration of 100µg/ml, extracts from eight of these plants showed at least 50 per cent reverse transcriptase inhibition. This activity was abitrarily considered as significant. This indicates that there is the probability that some antiretroviral compounds could be identified and isolated from materials from these plants. [Afr. J. Health Sci. 2002; 9:81-90