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 370C 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. African Journal of Health Sciences Vol. 14 (3-4) 2007: pp. 143-14

The use of Sorbarod biofilms to investigate some organisms involved in bacterial Vaginosis

Sorbarod biofilms were investigated for their suitability in establishing a continuous growth for the study of bacterial vaginosis. Important organisms in the condition, Gadnerella vaginalis, Mobiluncus curtisii and Lactobacillus acidophilus were studied. In contrast to growth in broth culture, L. acidophilus and G. vaginalis were maintained for at least 96 hours in steady state on the biofilms. The strict anaerobe M. curtisii was maintained in these biofilms for at least 48 hours an indication that anaerobic conditions do exist in these biofilms. The haemolytic activity of G. vaginalis was consistently maintained in the biofilms in contrast to the short-term activity in the broth culture, which matched the bacterial titre. Gram stains of thin sections of paraffin wax embedded Sorbarods showed the micro-colonies as distinct irregular aggregates of organisms adherent to the cellulose matrix for G. vaginalis while L. acidophilus appeared as large latticed networks that formed between the cellulose fibre matrix. The simple Sorbarod system appears to be suitable for studying the growth of bacteria in continuous culture and has a potential for investigating interactions between micro- organisms. Journal of Tropical Microbiology Vol.1(1) 2002: 36-4

The anti-viral effect of Acacia mellifera, Melia azedarach and Prunus Africana, extracts against herpes simplex virus type 1 infection in mice

Aqueous extracts from the stem barks of Prunus africana(Hook.f.) Kalkm, Acacia mellifera (Vahl.) Benth. and Melia azedarach L. were evaluated for in vivo antiviral activity in Balb/C mice following a cutaneous wild type strain 7401H herpes simplex virus type 1 (HSV-1) infection. A significant therapeutic effect was observed when the infected mice were orally treated with the extracts of Prunus africana and Acacia mellifera at a dose of 500 mg/kg. A delayed onset of skin lesions, slowed progression of infection and a prolonged mean survival time was expressed as opposed to the untreated infected control (p ≤0.05). Treatment with the Melia azedarach extract at a dose of 500 mg/kg was acutely toxic to mice, however a reasonable antiviral activity was exhibited at a lower dose of 250 mg/kg. No acute toxicity was presented in mice treated withP. africana and A. mellifera at the therapeutic dose. The results suggest the presence of anti-HSV agents in these medicinal plant extracts that can be exploited as possible antivirals. Keywords: Prunus africana, Acacia mellifera, Melia azedarach, HSV-1, antiviral activity, medicinal plants Journal of Tropical Microbiology and Biotechnology Vol. 2(1) 2006: 3-