Papers by Hamisi Masanja Malebo
Journal of Biosciences and Medicines
One of the serious problems the world is facing today is the antimicrobial resistance on availabl... more One of the serious problems the world is facing today is the antimicrobial resistance on available antibiotics by most bacterial pathogens and the rising cost of finding effective antimicrobial agents. In recent years, efforts to find new drugs especially from natural sources have been boosted by the demand for an effective cure for infectious diseases. Only the antibacterial activity of apis mellifera honey and not stingless bee honey from western Kenya has been reported. This study was therefore carried out to determine the effect of Plebenia hylderbrandii and Meliponula bocandei honey samples on the growth of control; sensitive cases of Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923). Different honey concentrations (1.18%-17.65% v/v) of the two samples were tested against the two microorganisms. The samples were screened for their antibacterial potential against Escherichia coli and Staphylococcus aureus by agar well dilution method. The Partial inhibitory concentration (PIC), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were determined by in vitro method. The inhibitory effect of Plebenia hylderbrandii honey on E. coli and S. aureus growth was apparent at concentrations 3.53% and 1.76% (v/v) respectively. On the other hand, the inhibitory effect of Meliponula bocandei honey on S. aureus growth was at concentration 16.47% (v/v).
Chromatographic separation of Acridocarpus chloropterus extract led to the isolation and identifi... more Chromatographic separation of Acridocarpus chloropterus extract led to the isolation and identification of five triterpenes: β-sitosterol (1), stigmasterol (2), friedelin (3), oleanolic acid (4), ursolic acid (5); and five flavonoids: apigenin (6), luteolin (7), vitexin (8), kaempferol (9) and quercetin (10). Quercetin (10) exhibited moderate in vitro anti-plasmodial activity (IC 50 2.6+0.05 μg/ml) while the rest of compounds were inactive. Mild to weak in vitro anti-trypanosomal activity was observed in quercetin (10) (IC 50 3.60+0.1 μg/ml), ursolic acid (5) (IC 50 7.80+0.1 μg/ml) and apigenin (6) (IC 50 9.0+0.1 μg/ml). Ursolic acid (5) exhibited strong in vitro anti-leishmanial activity (IC50 0.80+0.001 μg/ml) while oleanolic acid (4), apigenin (6), kaempferol (9) and quercetin (10) showed moderate to mild activity (2.10+0.1, 2.20+0.1, 5.90+ 0.1 and 3.5+0.2 μg/ml, respectively) whereas favorable selectivity was observed with all flavonoids. Structure-activity-relationship (SAR) co...
objectives To assess the microbiological effectiveness of several household water treatment and s... more objectives To assess the microbiological effectiveness of several household water treatment and safe storage (HWTS) options in situ in Tanzania, before consideration for national scale-up of HWTS. methods Participating households received supplies and instructions for practicing six HWTS methods on a rotating 5-week basis. We analysed 1202 paired samples (source and treated) of drinking water from 390 households, across all technologies. Samples were analysed for thermotolerant (TTC) coliforms, an indicator of faecal contamination, to measure effectiveness of treatment in situ. results All HWTS methods improved microbial water quality, with reductions in TTC of 99.3% for boiling, 99.4% for Waterguard TM brand sodium hypochlorite solution, 99.5% for a ceramic pot filter, 99.5% for Aquatab â sodium dichloroisocyanurate (NaDCC) tablets, 99.6% for P&G Purifier of Water TM flocculent/disinfectant sachets, and 99.7% for a ceramic siphon filter. Microbiological performance was relatively h...
Social Science & Medicine, 2017
at Berkeley, for their support during the data analysis and writing phases of this project.
Malaria journal, Jan 18, 2006
The current malaria control strategy of WHO centres on early diagnosis and prompt treatment using... more The current malaria control strategy of WHO centres on early diagnosis and prompt treatment using effective drugs. Children with severe malaria are often brought late to health facilities and traditional health practitioners are said to be the main cause of treatment delay. In the context of the Rectal Artesunate Project in Tanzania, the role of traditional healers in the management of severe malaria in children was studied. A community cross-sectional study was conducted in Kilosa and Handeni Districts, involving four villages selected on the basis of existing statistics on the number of traditional health practitioners involved in the management of severe malaria. A total of 41 traditional health practitioners were selected using the snowballing technique, whereby in-depth interviews were used to collect information. Eight Focus Group Discussions (FGDs) involving traditional health practitioners, caregivers and community leaders were carried out in each district. Home management o...
Tanzania Journal of Health Research, 2010
The antiplasmodial, anti-trypanosomal and anti-leishmanial activity of 25 plant extracts obtained... more The antiplasmodial, anti-trypanosomal and anti-leishmanial activity of 25 plant extracts obtained from seven Tanzanian medicinal plants: Anncka (Enanta) kummerae (Annonaceae), Artemsa annua (Asteraceae), Pseudospondas mcrocarpa (Anacardiaceae), Drypetes natalenss (Euphorbiaceae), Acrdocarpus chloropterus (Malpighiaceae), Maytenus senegalenss (Celastraceae) and Neurautanena mts (Papilonaceae), were evaluated n vtro against Plasmodum falcparum K1, Trypanosoma bruce rhodesense STIB 900 and axenic Leshmana donovan MHOM-ET-67/82. Out of the 25 extracts tested, 17 showed good antiplasmodial activity (IC 50 0.04-5.0 µg/ml), 7 exhibited moderate anti-trypanosomal activity (IC 50 2.3-2.8 µg/ml), while 5 displayed mild anti-leishmanial activity (IC 50 8.8-9.79 µg/ml). A. kummerae, A. annua, P. mcrocarpa, D. natalenss, M. senegalenss and N. mts extracts had good antiplasmodial activity (IC 50 0.04-2.1 µg/ml) and selectivity indices (29.2-2,250 µg/ml). The high antiplasmodial, moderate anti-trypanosomal and mild anti-leishmanial activity make these plants good candidates for bioassay-guided isolation of anti-protozoal compounds which could serve as new lead structures for drug development.
Drug Design, Development and Therapy
Continuous efforts into the discovery and development of new antimalarials are required to face t... more Continuous efforts into the discovery and development of new antimalarials are required to face the emerging resistance of the parasite to available treatments. Thus, new effective drugs, ideally able to inhibit the Plasmodium life-cycle stages that cause the disease as well as those responsible for its transmission, are needed. Eight compounds from the Medicines for Malaria Venture (MMV) Malaria Box, potentially interfering with the parasite polyamine biosynthesis were selected and assessed in vitro for activity against malaria transmissible stages, namely mature gametocytes and early sporogonic stages. Methods: Compound activity against asexual blood stages of chloroquine-sensitive 3D7 and chloroquine-resistant W2 strains of Plasmodium falciparum was tested measuring the parasite lactate dehydrogenase activity. The gametocytocidal effect was determined against the P. falciparum 3D7elo1-pfs16-CBG99 strain with a luminescent method. The murine P. berghei CTRP.GFP strain was employed to assess compounds activities against early sporogonic stage development in an in vitro assay simulating mosquito midgut conditions. Results: Among the eight tested molecules, MMV000642, MMV000662 and MMV006429, containing a 1,2,3,4-tetrahydroisoquinoline-4-carboxamide chemical skeleton substituted at N-2, C-3 and C-4, displayed multi-stage activity. Activity against asexual blood stages of both strains was confirmed with values of IC 50 (50% inhibitory concentration) in the range of 0.07-0.13 µM. They were also active against mature stage V gametocytes with IC 50 values below 5 µM (range: 3.43-4.42 µM). These molecules exhibited moderate effects on early sporogonic stage development, displaying IC 50 values between 20 and 40 µM. Conclusion: Given the multi-stage, transmission-blocking profiles of MMV000642, MMV000662, MMV006429, and their chemical characteristics, these compounds can be considered worthy for further optimisation toward a TCP5 or TCP6 target product profile proposed by MMV for transmission-blocking antimalarials.
International Journal of Environmental Research and Public Health
We report on the management of infant feces in a rural village in Geita region, Tanzania. Finding... more We report on the management of infant feces in a rural village in Geita region, Tanzania. Findings discussed here emerged incidentally from a qualitative study aimed at investigating vulnerability and resilience to health challenges in rural settings. Data was gathered through semi-structured focus group discussions (FDGs) with women (n = 4; 32 participants), men (n = 2; 16 participants), and community leaders (n = 1; 8 participants). All FDGs were audio recorded, transcribed verbatim and thematically analyzed using Atlas.ti. Respondents reported feces of a child under the age of six months were considered pure compared to those of older children. Infant feces were seen as transitioning to harmful at the point when the child began to eat solid food, resulting in their stool visually changing in appearance. Caregivers reportedly used soft implements to handle infant feces due to the belief that tools with hard surfaces would physically harm the child. Infant feces were disposed in en...
Pharmacognosy Communications
Introduction: Plants of the genus Garcinia are traditionally used treat a range of infectious and... more Introduction: Plants of the genus Garcinia are traditionally used treat a range of infectious and non-infectious diseases. Garcinia species are reported to have been shown to have a range of biological activities including cytotoxicity antimicrobial, antifungal, antioxidant, antimalarial and HIV-1 protease inhibitory activity among others. Methods: Solvent extraction was done using CH 2 Cl 2 : MeOH (1:1). Isolation was done using column chromatography with silica gel as the stationery phase and ethyl acetate and n-hexane used as mobile phase in increasing polarity. Thin layer chromatography was used to monitor the isolation. Structure elucidation was done using nuclear magnetic resonance and mass spectroscopic techniques. Chloroquine resistant (W2) and chloroquine sensitive (D6) P. falciparum strains were used for antiplasmodial assay. Results: Further bioassay guided fractionation of a CH 2 Cl 2 : MeOH (1:1) extract of Garcinia buchananii led to the isolation of two already reported biflavanones, isogarcinol (1) and guttiferone (2) with promising antiplasmodial activity against a chloroquine resistant (W2) Plasmodium falciparum strain with an IC 50 of 2.8 ± 0.90 µg/mL for compound 1 and IC 50 of 3.94 ± 0.38 µg/mL for compound 2. Compounds 1 and 2 also exhibited moderate activity against the chloroquine sensitive (D6) Plasmodium falciparum strain with IC 50 of 7.03±0.60 and 10.64±4.50 µg/mL, respectively. Conclusion: The results provide proof to support the use of G. buchananii by the indigenous community for antimalarial therapy.
Antimicrobial resistance and infection control, 2018
Data about the burden of extended-spectrum beta-lactamase (ESBL)-producing microorganisms in Afri... more Data about the burden of extended-spectrum beta-lactamase (ESBL)-producing microorganisms in Africa are limited. Our study aimed to estimate the prevalence of human faecal ESBL carriage in the community of an informal urban settlement in Dar es Salaam (Tanzania, East Africa) by using environmental contamination of household latrines with ESBL as a surrogate marker. Within the context of a large survey in February 2014 assessing 636 randomly selected household latrines for faecal contamination by the detection of growth of and total faecal coliform bacteria, a randomly selected subset of the samples were screened for ESBL. Seventy latrines were screened for ESBL. An average of 11.4 persons (SD ±6.5) were sharing one latrine. Only three (4.3%) latrines had hand-washing facilities and 50 showed faeces on the floor. ESBL-producing were confirmed in 17 (24.3%) of the 70 latrine samples: 16 and 1 Five ESBL strains were detected on door handles. The most prevalent ESBL type was CTX-M-1 gro...
International Journal of TROPICAL DISEASE & Health, 2015
ABSTRACT Essential oil was extracted from Ocimum suave Willd leaves by water distillation and tes... more ABSTRACT Essential oil was extracted from Ocimum suave Willd leaves by water distillation and tested for repellency effectiveness against Anopheles gambiae adult mosquitoes. The percentage yield of the essential oil was 0.2%. Six concentrations of O. suave essential oil were applied on human skin of four volunteers, and the repellency effectiveness which was analyzed by PoloPlus (LeOra software version 1.0, 2002-2014), revealed promising RC50, RC75, RC90 and RC99 with their confidence limits as 0.1161 mg/cm2 (0.02067 - 0.1767 mg/cm2), 0.2823 mg/cm2 (0.22328 - 0.3654 mg/cm2), 0.4319 mg/cm2 (0.35226 - 0.58862 mg/cm2) and 0.98934 mg/cm2 (0.54731 - 0.99972 mg/cm2), respectively. O. suave essential oil exhibited high Anopheles mosquitos’ repellency effectiveness which merits further scientific attention for the development of natural repellents for the control of malaria and other mosquito borne diseases. These findings provides a scientific evidence and base for formulation for further mosquito repellency semi-field and field trials for the development of cheaper and affordable new mosquito repellent product(s) to meet human healthcare needs in the prevention and control of malaria and other mosquito transmitted infections. - See more at: http://www.sciencedomain.org/abstract.php?iid=912&amp;amp;id=19&amp;amp;aid=7651#sthash.Hdn1XaCZ.dpuf
International Journal of TROPICAL DISEASE & Health, 2015
This work was carried out in collaboration between all authors. Author CSMK conceived the study, ... more This work was carried out in collaboration between all authors. Author CSMK conceived the study, wrote the protocol, corrected and analyzed data and drafted the manuscript. Author HMM reviewed the study design and protocol and supervised data collection and analysis. Authors LY and JAS did the analysis and literature searches. All authors read and approved the final manuscript.
BMC Research Notes, 2015
Background: Condoms are scientifically recommended as potential products for preventing infection... more 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 Regionbetween 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.
Tropical medicine & international health : TM & IH, Jan 27, 2015
To assess the microbiological effectiveness of several household water treatment and safe storage... more To assess the microbiological effectiveness of several household water treatment and safe storage (HWTS) options in situ in Tanzania, before consideration for national scale-up of HWTS. Participating households received supplies and instructions for practicing six HWTS methods on a rotating five-week basis. We analysed 1202 paired samples (source and treated) of drinking water from 390 households, across all technologies. Samples were analysed for thermotolerant (TTC) coliforms, an indicator of faecal contamination, to measure effectiveness of treatment in situ. All HWTS methods improved microbial water quality, with reductions in TTC of 99.3% for boiling, 99.4% for Waterguard(™) brand sodium hypochlorite solution, 99.5% for a ceramic pot filter, 99.5% for Aquatab(®) sodium dichloroisocyanurate (NaDCC) tablets, 99.6% for P&G Purifier of Water(™) flocculent/ disinfectant sachets, and 99.7% for a ceramic siphon filter. Microbiological performance was relatively high compared with othe...
Chromatographic separation of the leaves of Teclea trichocarpa (Engl.) Engl. (Rutaceae) used trad... more Chromatographic separation of the leaves of Teclea trichocarpa (Engl.) Engl. (Rutaceae) used traditionally by Akamba tribe in Kenya yielded three acridone alkaloids, a furoquinoline alkaloid and two triterpenoids. The total extract (methanol) of the leaves of this plant and the isolated compounds were screened for in vitro for cytotoxicity and against parasitic protozoa, Plasmodium falciparum, Trypanosoma brucei rhodesiense, Trypanosoma cruzi and Leishmania donovani. Among the compounds a-amyrin had the best anti-plasmodial activity (IC50 = 0.96 μg/ml), normelicopicine and skimmianine had the best anti-trypanosomal activity against T. b. rhodesiense (IC50 = 5.24 μg/ml) and T. cruzi (IC50 = 14.50 μg/ml), respectively. Normelicopicine also exhibited best anti-leishmanial activity (IC50 = 1.08 μg/ml). Arborinine exhibited moderate cytotoxicity (IC50 = 12.2 μg/ml) against L-6 cells. The compounds with low anti-protozoal and high cytotoxicity IC50 values are potential source of template ...
BACKGROUND The Participatory Hygiene and Sanitation Transformation (PHAST) was implemented in Tan... more BACKGROUND The Participatory Hygiene and Sanitation Transformation (PHAST) was implemented in Tanzania in 1997 and after 8 years, an evaluation was carried out by the National Institute for Medical Research (NIMR) to monitor the progress. NIMR identified a number of shortfalls and put forward a number of recommendations. On this background, WaterAid Tanzania and her partners convened in September, 2007 at MTUMBA village in Dodoma to review different participatory approaches used in the promotion of hygiene and sanitation in the country. The meeting deliberated and ironed out strengths and weaknesses of various participatory approaches implemented in the country and finally used the strengths to form an approach that would be effective with particular emphasis to Tanzanian context. The meeting finally came up with MTUMBA Sanitation and Hygiene Participatory Approach, named after the MTUMBA village in Dodoma region in Tanzania. MTUMBA Sanitation and Hygiene Participatory Approach is b...
Phytochemical investigation of the stem and bark of Steganotaenia araliacea led to the isolation ... more Phytochemical investigation of the stem and bark of Steganotaenia araliacea led to the isolation of two flavonoids. The structures of these compounds were identified as apigenin 4′-glucoside 1 and sophoraflavone B 2 using spectroscopic analysis including 1D (1H, 13C and DEPT), 2D (COSY, HMQC and HMBC), Mass Spectrometer (EI-MS and HRMS), Infrared (IR) and Specific rotation. These compounds have not been previously reported from Steganotaenia species and are reported from this plant for the first time. Steganotaenia araliacea is one of four medicinal plants for more than twenty years used by traditional healers to treat various ailments including HIV in Tanga, Tanzania.
The main purpose of this study was to optimize extraction conditions for ferrous (iron II) and L-... more The main purpose of this study was to optimize extraction conditions for ferrous (iron II) and L-ascorbic acid from dried calyces of Hibiscus sabdariffa L grown in Dodoma in Tanzania by using Response Surface Methodology (RSM). Plant materials were taxonomically identified and authenticated by a plant taxonomist whereby a voucher specimen number 4992 was deposited at the herbarium in the Department of Botany at the University of Dar es Salaam. RSM with five level three-factor central composite rotatable design (CCRD) was employed to determine optimal combination of independent factors- soaking time, extraction temperature and solid-solvent ratio. Both single and multiple factor experiments were conducted. In single factor experiment (SFE) each independent factor was assessed to give experimental range. Ferrous was estimated by atomic absorption spectrophotometric method (AAS) while L-ascorbic acid was measured by iodometric titration technique. Data were analyzed using SPSS Version ...
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Papers by Hamisi Masanja Malebo