Festus Tolo

Anticytomegalovirus activity of pristimerin, a triterpenoid quinone methide isolated from Maytenus heterophylla (Eckl. & Zeyh.)

We examined the anticytomegalovirus properties of four compounds: pristimerin, the pristimerin analogue, lupeol and 2-acetylphenol-1-β-D-glucopyranosyl (1→6)-β-D-xylpyranoside (acetophenol glycoside), isolated from Maytenus heterophylla, a Kenyan medicinal plant. The effects were studied on human cytomegalovirus (HCMV) replication in the human embryonic fibroblast cell line, MRC-5. In a viral plaque-reduction assay, pristimerin showed dose-dependent inhibitory properties with a 50% inhibitory concentration of 0.53 µg/ml (selective index=27.9). The cells treated with pristimerin inhibited the cytopathic effects in HCMV-infected cells. Moreover, pristimerin suppressed viral replication without affecting the cell growth. Pristimerin inhibited the synthesis of viral DNA but had no virucidal effect on cell-free HCMV. Furthermore, Western blot analysis demonstrated that pristimerin decreased the amount of immediate early (IE) antigen (especially IE2) expression in the infected cells. These results suggest that pristimerin is a unique compound with potential anti-HCMV activity.

Secondary bacterial infections and antibiotic resistance among tungiasis patients in Western, Kenya

Tungiasis or jigger infestation is a parasitic disease caused by the female sand flea Tunga penetrans. Secondary infection of the lesions caused by this flea is common in endemic communities. This study sought to shed light on the bacterial pathogens causing secondary infections in tungiasis lesions and their susceptibility profiles to commonly prescribed antibiotics. Participants were recruited with the help of Community Health Workers. Swabs were taken from lesions which showed signs of secondary infection. Identification of suspected bacteria colonies was done by colony morphology, Gram staining, and biochemical tests. The Kirby Bauer disc diffusion test was used to determine the drug susceptibility profiles. Out of 37 participants, from whom swabs were collected, specimen were positive in 29 and 8 had no growth. From these, 10 different strains of bacteria were isolated. Two were Gram positive bacteria and they were, Staphylococcus epidermidis (38.3%) and Staphylococcus aureus (21.3%). Eight were Gram negative namely Enterobacter cloacae (8.5%), Proteus species (8.5%), Klebsiellla species (6.4%), Aeromonas sobria (4.3%), Citrobacter species (4.3%), Proteus mirabillis(4.3%), Enterobacter amnigenus (2.1%) and Klebsiella pneumoniae (2.1%). The methicillin resistant S. aureus (MRSA) isolated were also resistant to clindamycin, kanamycin, erythromycin, nalidixic acid, trimethorprim sulfamethoxazole and tetracycline. All the Gram negative and Gram positive bacteria isolates were sensitive to gentamicin and norfloxacin drugs. Results from this study confirms the presence of resistant bacteria in tungiasis lesions hence highlighting the significance of secondary infection of the lesions in endemic communties. This therefore suggests that antimicrobial susceptibility testing may be considered to guide in identification of appropriate antibiotics and treatment therapy among tungiasis patients.

In vitro Anti-Herpes simplex Type-1 Virus Evaluation of Extracts from Kenya Grown Pyrethrum (Chrysanthemum cinerariaefolium)

Objective: To evaluate in vitro anti-Herpes simplex type 1 activity of methanol and aqueous crude extracts of pyrethrum (Chrysanthemum cinerariaefolium) plant grown in Kenya. Methods: Cytotoxic effect of methanol and aqueous extracts was determined on vero cells (African green monkey kidney cells) by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-DiphenylTetrazolium Bromide) reduction colorimetric assay. Antiviral effect of pyrethrum extracts was evaluated; before (posttreatment infection) virus infection to the cells and after (pre-treatment infection) virus infection to cells. Original Research Article Alem et al.; EJMP, 17(2): xxx-xxx, 2016; Article no.EJMP.28967 2 Results: Methanol extract exhibited higher cytotoxicity of CC50 = 42.23 ± 0.320 μg/ml compared to aqueous extract of CC50 = 249 ± 8.4 μg/ml. Methanol extract exhibited a higher anti HSV-1 potency of IC50 = 1.69 μg/ml (TI = 24.99) than the aqueous extract of IC50 = 38.13 μg/ml (TI = 6.53) in the post-treatment infection evaluations. This might be due to its effect on cellular receptors preventing virus entry, while the aqueous extract exhibited higher virus inhibitory potency in the pre-treatment infection, of IC50 = 23.21 μg/ml (TI=10.73) compared to the methanol extract of IC50 = 11.18 μg/ml (TI =3.78), this effect could be due to its effect on some stage during HSV virus replication process. Conclusions: Crude methanol and aqueous extracts from Kenyan grown pyrethrum exhibited inhibition potency against HSV-1 in vitro on Vero cells.

P2.180 TMR5 (ZedupexTM) as a Management Therapy For Herpes Infections: Results of Preclinical Evaluations

TMR5 (ZedupexTM) is a product of a Kenyan medicinal plant, prepared as a lyophilized extract and a cream. The products have been evaluated for preclinical safety and efficacy in suitable in vitro and in vivo systems of herpes infections. Herpes is a viral infection affecting over 60% of the sub-Saharan Africa young adult population. It is caused by two similar viruses, HSV-1 and HSV-2 which share 50% gene sequence homology. The infection in a major cause of genital ulcer disease, associated with increased risks of HIV acquisition and transmission. The aim is to develop TMR5 as an alternative anti-herpes agent, this being necessitated by increased resistance to available drugs and the cost of the drug of choice, acyclovir, in the region. Using the trypan blue exclusion test, plaque inhibition and viral yield reduction assays for assessment of cytotoxicity (CC50) and efficacy (EC50), and Mice and guinea pig cutaneous and genital HSV infection models respectively following oral and topical treatments, TMR5 exhibited no cytotoxicity in mammalian cell lines with a wide therapeutic index (CC50 ≥ 58.5 ± 4.6µg/ml). An EC50 of ≤ 14.7 ± 3.7µg/ml for both wild type and resistant strains of HSV was realised in plaque and viral yield assays. Oral (250 mg/kg) and topical (10% cream) administrations exhibited significant delay in onset of infections, hindered progression of infection to lethal forms with increased mean survival times and low mortality in both mice and guinea pig models. No acute toxicity has been realised at the therapeutic concentrations. TMR5 has demonstrated a high potential as an anti-herpes agent and arrangements are presently underway to evaluate its efficacy and safety in human clinical trials. A pilot production scheme supported by the National Commission for Science, Technology and Innovation (NCSTI) of Kenya has been undertaken as means of developing TMR5 as an alternative management therapy for herpes infections.