Evaluation of Antimycobacterial Activity of Higenamine Using Galleria mellonella as an In Vivo Infection Model.

The Phytochemical investigation on MeOH extract on the bark of Aristolochia brasiliensis Mart. & Zucc (Aristolochiaceae) led to the isolation of major compound (1) as light brown grainy crystals. The compound was identified as 1-(4-hydroxybenzyl)-1,2,3,4-tetrahydroisoquinoline-6,7-diol (higenamine) on the basis of spectroscopic analysis, including 1D and 2D NMR spectroscopy. The compound was evaluated for its antimycobacterial activity against Mycobacterium indicus pranii (MIP), using Galleria mellonella larva as an in vivo infection model. The survival of MIP infected larvae after a single dose treatment of 100 mg/kg body weight of higenamine was 80% after 24 h. Quantitatively the compound exhibited a dose dependent activity, as evidenced by the reduction of colony density from 105 to 103 CFU for test concentrations of 50, 100, 150 and 200 mg/kg body weight respectively. The IC50 value for higenamine was 161.6 mg/kg body weight as calculated from a calibration curve. Further analysis showed that, a complete inhibition of MIP in the G. mellonella could be achieved at 334 mg/kg body weight. Despite the fact that MIP has been found to be highly resistant against isoniazid (INH) in an in vitro assay model, in this study the microbe was highly susceptible to this standard anti-TB drug. The isolation of higenamine from the genus Aristolochia and the method used to evaluate its in vivo antimycobacterial activity in G. mellonella are herein reported for the first time.

Determinants of demand for condoms to prevent HIV infections among barmaids and guesthouse workers in two districts, Tanzania.

BACKGROUND: Condoms are scientifically recommended as potential products for preventing infections attributable to human immuno-deficiency viruses (HIV). However, evidence on factors leading to their inadequate use in developing countries is still scanty. This paper reports an exploratory study of factors constraining condoms use in Tanzania from the perspectives of barmaids, guest-house workers and retailers. METHODS: Data were collected in two districts-Mpwapwa in Dodoma Region and Mbeya Rural in Mbeya Region-between October and December 2011, using structured interviews with 238 individuals including barmaids, guesthouse workers and 145 retailers. Data analysis was performed using STATA 11 software. RESULTS: Awareness about condoms was high among all study groups. Male condoms were more popular and available than female ones. A considerable proportion of the barmaids and guesthouses were disappointed with condoms being promoted and distributed to young children and disliked condom use during sexual intercourse. Accessibility of condoms was reported as being lowered by condom prices, shortage of information concerning their availability; short supply of condoms; some people shying away to be watched by children or adult people while purchasing condoms; retailers' using bad languages to condom customers; occasionally condom shops/kiosks found closed when they are urgently needed; and prevailing social perception of condoms to have low/no protective efficacy. Regression analysis of data from barmaids and guesthouse-workers indicated variations in the degree of condom acceptability and methods used to promote condoms among respondents with different demographic characteristics. CONCLUSION: A combination of psychosocial and economic factors was found contributing to lower the demand for and actual use of condoms in study communities. Concerted measures for promoting condom use need to address the demand challenges and making operational research an integral element of monitoring and evaluation of the launched interventions, hence widening the evidence for informed policy decisions.

In vivo antiplasmodial and toxicological effect of Maytenus senegalensis traditionally used in the treatment of malaria in Tanzania.

BACKGROUND: In Tanzania and elsewhere, medicinal plants, including Maytenus senegalensis, are still widely used in the treatment of malaria and other ailments. The aim of the present study was to investigate the in vivo antiplasmodial and toxic effects in mice. METHODS: Oral antiplasmodial and acute toxicity of the ethanolic root extract of M. senegalensis was evaluated in mice. The Peters 4-day in vivo antiplasmodial effect against early rodent malaria infection in chloroquine-sensitive Plasmodium berghei NK 65 strain in mice. RESULTS: The M. senegalensis extract was found non-toxic and the oral median lethal dose in mice was determined to be greater than 1,600 mg/kg body weight. The findings revealed a significant (P = 0.001) daily increase in the level of parasitaemia in the parasitized untreated groups and a significant (P < 0.001) dose dependent decrease in parasitaemia in the parasitized groups treated with varying doses ranging from 25 to 100 mg/kg body weight of M. senegalensis extract and the standard drug sulphadoxine/pyrimethamine at 25/1.25 mg/kg body weight. Overall, the dose dependent parasitaemia suppression effects were in the order of: 25/1.25 mg/kg body weight of sulphadoxine/pyrimethamine > 100 mg/kg > 75 mg/kg > 50 mg/kg > 25 mg/kg body weight of M. senegalensis extract. CONCLUSION: The implications of these findings is that M. senegalensis ethanolic root bark extract possess potent antiplasmodial effect and may, therefore, serve as potential sources of safe, effective and affordable anti-malarial drugs. The displayed high in vivo antiplasmodial activity and lack of toxic effect render M. senegalensis a candidate for the bioassay-guided isolation of compounds which could develop into new lead structures and candidates for drug development programmes against human malaria.

Acceptability of condom promotion and distribution among 10-19 year-old adolescents in Mpwapwa and Mbeya rural districts, Tanzania.

BACKGROUND: The HIV/AIDS pandemic remains a leading challenge for global health. Although condoms are acknowledged for their key role on preventing HIV transmission, low and inappropriate use of condoms persists in Tanzania and elsewhere in Africa. This study assesses factors affecting acceptability of condom promotion and distribution among adolescents in Mpwapwa and Mbeya rural districts of Tanzania. METHODS: Data were collected in 2011 as part of a larger cross-sectional survey on condom use among 10-19 year-olds in Mpwapwa and Mbeya rural districts of Tanzania using a structured questionnaire. Associations between acceptability of condom promotion and distribution and each of the explanatory variables were tested using Chi Square. Multivariate logistic regression model was used to examine independent predictors of the acceptability of condom promotion and distribution using STATA (11) statistical software at 5% significance level. RESULTS: Mean age of the 1,327 adolescent participants (50.5% being males) was 13.5 years (SD = 1.4). Acceptance of condom promotion and distribution was found among 37% (35% in Mpwapwa and 39% in Mbeya rural) of the adolescents. Being sexually active and aged 15-19 was the strongest predictor of the acceptability of condom promotion and distribution (OR = 7.78, 95% CI 4.65-12.99). Others were; not agreeing that a condom is effective in preventing transmissions of STIs including HIV (OR = 0.34, 95% CI 0.20-0.56), being a resident of Mbeya rural district (OR = 1.67, 95% CI 1.28-2.19), feeling comfortable being seen by parents/guardians holding/buying condoms (OR = 2.20, 95% CI 1.40-3.46) and living with a guardian (OR = 1.48, 95% CI 1.08-2.04). CONCLUSION: Acceptability of condom promotion and distribution among adolescents in Mpwapwa and Mbeya rural is low. Effect of sexual activity on the acceptability of condom promotion and distribution is age-dependent and was the strongest. Feeling comfortable being seen by parents/guardians buying or holding condoms, perceived ability of condoms to offer protection against HIV/AIDS infections, district of residence and living arrangements also offered significant predictive effect. Knowledge of these factors is vital in designing successful and sustainable condom promotion and distribution programs in Tanzania.