Browsing by Author "Makangara, John J."

Now showing 1 - 12 of 12
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    Antiplasmodial, antimicrobial and cytotoxic activities of extracts from selected medicinal plants growing in Tanzania
    (Taylor & Francis, 2019) Begum, Sartaz; Nyandoro, Stephen S.; Munissi, Joan J. E.; Buriyo, Amelia S.; Makangara, John J.; Lucantoni, Leonardo; Avery, Vicky M.; Erdelyi, Mate
    This paper reports on the evaluation of antiplasmodial, antimicrobial and cytotoxic activities of extracts from eleven plant species traditionally used by some Tanzanian coastal communities for treatment of malaria, microbial infections and related ailments. Crude extracts from selected plant species namely Acacia zanzibarica, Danais xanthorrhoea, Diospyros loureiriana ssp. rufescens, Erythrina sacleuxii, Newtonia paucijuga, Pentas lanceolata, Scorodophloeus fischeri, Stuhlmannia moavi, Tarenna pavettoides, Tessmannia burttii and Toussaintia orientalis growing in Tanzania were investigated using an imaging-based assay (antiplasmodial), well diffusion and microplate dilution methods (antimicrobial) and human embryonic kidney cells (HEK 293) and brine shrimp larvae assays (toxicity). The extracts exhibited activities of varying potencies and cytotoxicity with IC50 values ranging from 0.45 ± 0.09 to 75.70 ± 24.19 μg/mL against Plasmodium falciparum (3D7 strain), MIC ranging from 0.25 to 2.0 mg/mL (against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans and Cryptococcus neoformans), LC50 ranging from 0.75 to 1000 μg/mL against brine shrimp larvae (Artemia salina) and IC50 ranging from 4.02 ± 1.05 to more than 289 μg/mL against HEK 293 cells. The observed bioactivities of some of the investigated plant extracts validate their ethnomedicinal use and are indicative of the presence of bioactive ingredients for further phytochemical investigations.
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    Changes in drug availability patterns on Tanzanian mainland: The effects of the surge operations deterrent strategy
    (Elsevier, 2022) Makangara, John J.
    This study investigated the recent changes in illegal substances availability on the Tanzanian mainland as a result of the government’s surge operations as a deterrent approach against illicit drug production, trafficking and usage from 2017 to 2020, as well as the consequences of the COVID-19 pandemic on the drug market. Overall, 247467 seizures of illegal substances weighing 25357.9 kg were tested at The Government Chemist Laboratory Authority (GCLA), an average of 6339.5 kg annually. According to the findings, cannabis was the most frequently encountered substance, accounting for 80.6%, 88.2%, and 83% of all incidents, samples, and weight, respectively. Heroin came in second with 12.6% of the total incidents and 7.4% of the total number of samples, while khat came in second with 15.2% of the weight of the seized illegal substances during the period under study. Apart from a 202 and 4709 decline in heroin incidents and samples, the weight jumped from 15.3 kg in 2017 to 303.5 kg in 2020. Generally, the overall weight of the seizures decreased by 67.3% from 13036.4 kg in 2017–3890.7 kg in 2020. The results were particularly noticeable in the case of cannabis, which plunged by 76.5% from 11771.1 kg in 2017–2727 kg in 2020. Despite the eruption of the COVID-19 pandemic and associated lockdowns and travel limitations, heroin seizures increased by 67.4% in 2020 compared to the preceding three years combined.
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    Ethnomedicinal uses, phytochemistry and pharmacological study of Ocimum americanum L.: A review
    (Elsevier, 2023) Luanda, Amos; Ripanda, Asha; Sahini, Mtabazi G.; Makangara, John J.
    Background: Ocimum americanum L., commonly known as Hoary basil, is a wild aromatic shrub traditionally used to treat different ailments. Its leaves, flowers and aerial parts have been widely studied to evaluate its medicinal potential such as lowering blood pressure, treatment of microbial infections, malaria, cold, liver and eye problems. Purpose: This study aims to provide an in-depth review of ethnomedicinal uses, phytochemistry, and pharmacological activities of O. americanum, to evaluate its benefits, challenges and potential future prospects. Methods: All the information about O. americanum was collected from various platforms, including google scholar, PubMed, ScienceDirect, plants of the world online and Research4Life. The acceptance criteria of the collected information based on the PICOS model. The GRADE approach was used to analyze and evaluate the quality of the collected information. Results: This study showed that O. americanum has tremendous therapeutic potential to be integrated into mainstream medical practice to manage various medical conditions. The inconsistence of the phytoconstituents among the plant parts resulted in a significant variation of pharmacological activities. Plant originality, genetic variability and extraction techniques are among the factors contributing to the variation of phytoconstituents that are responsible for pharmacological activities. Conclusion: This study revealed that O. americanum is a potential medicinal plant for mitigating various medical conditions. However, future study should continue to focus on the bioactive compounds and their mechanisms of action. Additionally, the utilization of the O. americanum for the development of drugs as well as quality evaluation in clinical settings are highly recommended.
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    Geranylbenzoquinonoids from Lettowianthus stellatus fruits
    (Taylor & Francis, 2010) Makangara, John J.; Nkunya, Mayunga H.H.; Jonker, Stephan S.
    The geranylbenzoquinonoids 7-(3,7-dimethylocta-2,6-dienyl)-5-hydroxy-3H-benzofuran-2-one (lettowienolide), dimethyl 2,3-bis-[5-(3,7-dimethylocta-2,6-dienyl)-3,6-dioxocyclohexa-1,4-dienyl]-succinate (lettowiquinone), 2-(3,7-dimethylocta-2,6-dienyl)-6-[7-(3,7-dimethylocta-2,6-dienyl)-5-hydroxybenzofuran-2-yl]-[1,4]benzoquinone (lettowifuraquinone), methyl [3-(3,7-dimethylocta-2,6-dienyl)-6-methyl-5-(3-methylbut-2-enyl)-1,4-dioxo-1,5, 8,8a-tetrahydro-4H-nathphalen-4a-yl)]-acetate (lettowinone) and methyl [6-hydroxy-2-methyl-2-(4-methylpent-3-enyl)-2H-chromen-8-yl]-acetate (lettowipyraquinol) were isolated from fruits of Lettowianthus stellatus Diels, together with juvenile hormone III and 7-octadecen-9-ynoic acid. Lettowienolide and lettowiquinone exhibited mild in vitro activity against the Plasmodium falciparum malaria parasite (each IC50 ∼ 20 µg mL−1). Structural determination was achieved based on extensive analysis of spectroscopic data.
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    Post-harvest practices associated with aflatoxins contamination of complementary flours in Bahi district, Dodoma, Tanzania
    (Global Society of Scientific Research and Researchers (GSSRR), 2017) Aron, Lilian; Makangara, John J.; Kassim, Neema; Ngoma, Selestin Joseph
    Aflatoxins are secondary metabolites produced by several species of Aspergillus fungi, which occur in food crops due to exposure of pre-harvest and post-harvest conditions. Complementary foods are considered an important source of energy, protein and fat for children aged between 6-24 months. The study was carried out to explore the association between post-harvest handling practices and aflatoxins contamination in maize-based complementary foods. Complementary flour samples were collected from randomly selected household and analyzed by using HPLC. The presence and concentration of aflatoxins B1, B2, G1, G2 and total AFs was detected. About 48.95% of all samples were found to be contaminated with aflatoxins. A stepwise linear regression in generalized linear model was used to identify factors that significantly affected contamination of complementary food with aflatoxins. The analyzed sample was found to be less contaminated with aflatoxins B1 across all six villages with range of 0.24-1.39 µg/kg, with mean value of 0.67µg/kg and total mean aflatoxins were found to be 4.79µg/kg. Results indicated that some of the post-harvest handling practices used by parents/caregivers to agricultural produce used to prepare complimentary food are highly associated with aflatoxins contamination (p<0.05). The occurrence of total aflatoxin levels in complimentary flour composite across the six villages was significantly associated with insect infestation, maize/cereals stored for more than 12 months, drying on bare ground, uses of pesticides to protect stored maize/cereals (p<0.05). Estimate from the linear regression model indicated that, insect infestation (0.3870), and drying on bare ground (0.0856) were positively associated with aflatoxins contamination. This study recommends education and awareness campaign are needed to inform farmers, traders, processors about the risk of fungal growth and toxins contamination.
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    Prenylindoles from Tanzanian Monodora and Isolona Species
    (Taylor & Francis, 2004) Nkunya, Mayunga H.H.; Makangara, John J.; Jonker, Stephan A.
    6-(3-Methyl-but-2-enyl)-1,3-dihydro-indol-2-one, annonidine F [3-[6-(3-methyl-but-2-enyl)-1H-indolyl]-6-(3-methyl-but-2-enyl)-1H-indole], 1H-indole-5-carbaldehyde, 6-(3-methyl-2-butenyl)-1H-indole, 6-(3-methylbuta-1,3-dienyl)-1H-indole, 6-(4-oxo-but-2-enyl)-1H-indole and 3-geranylindole were isolated from Monodora angolensis (Annonaceae) while 3-(1,1-dimethyl-but-2-enyl)-5-(3-methyl-but-2-enyl)-1H-indole (caulidine A), 4-[3-(1,1-dimethyl-but-2-enyl)-1H-indol-5-yl]-but-3-en-2-one (caulidine B), 5-(3-methyl-2-butenyl)-1H-indole and 5-(3-methylbuta-1,3-dienyl)-1H-indole were obtained from Isolona cauliflora (Annonaceae); structural determination by spectroscopic analysis. Some of the prenylindoles had antifungal and antimalarial activities.
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    A review of the newly identified impurity profiles in methamphetamine seizures
    (Elsevier, 2020) Onoka, Isaac; Banyika, Andrew Toyi; Banerjee, Protibha Nath; Makangara, John J.; Dujourdy, Laurence
    Forensic intelligence of synthetic illicit drugs suffers a problem of continuous introduction of new synthetic methods, modification of the existing routes of manufacture, and adulterations practiced by criminal networks. Impurity profiling has been indispensable in methamphetamine intelligence based on precursors, synthetic routes, and chemical modifications during trafficking. Law enforcement authorities maintain the credibility and integrity of intelligence information through constant monitoring of the chemical signatures in the illicit drug market. Changes in the synthetic pattern result in new impurity profiles that are important in keeping valuable intelligence information on clandestine laboratories, new synthetic routes, trafficking patterns, and geographical sources of illicit Methamphetamine. This review presents a critical analysis of the methamphetamine impurity profiles and more specifically, profiling based on impurity profiles from Leuckart, Reductive amination, Moscow, Emde, Nagai, Birch, Moscow route; a recent nitrostyrene route and stable isotope signatures. It also highlights the discrimination of ephedrine from pseudoephedrine sources and the emerging methamphetamine profiling based on stable isotopes.
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    Review on the secondary metabolites, biological properties, and ethnomedicinal uses of the component species of the buheri wa afya formula used to treat COVID-19 in Tanzania
    (Elsevier BV, 2024) Makangara, John J.; Mshandete, Anthony M.; Mbega, Ernest R.; Nyika, John R.; Mbago, Frank; Ndilanha, Edward G.; Nyika, Raphael J.; Nyika, Joseph J.
    It has proven difficult to treat viral infections like SARS-CoV, MERS-CoV, and SARS-CoV-2 that cause severe respiratory disorders with the currently available medications. Alternative strategies for combating viral infections are required to adequately treat infectious diseases like COVID-19. The most potent of them all may be plant-based products or herbal remedies. Following the advent of the COVID-19 epidemic, a number of alternative medicine practitioners in Tanzania developed herbal medicine formulations, claiming that they were effective in treating COVID-19 patients. One among the formulations is Buheri wa Afya, meaning "good health". The rationale for choosing Buheri wa Afya over the other formulations was justified by its efficacy in treating COVID-19 patients at different stages of the illness.
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    Theoretical and conceptual framework to design D-π-A type organic dyes for application dye-sensitized solar cells
    (Elsevier BV, 2024) Makangara, John J.; Sahini, Mtabazi G.; Babu, Numbury Surendra
    The optimized structures and absorption spectra of five D-A-type organic dyes (M1, M2, M3, M4, and M5) were investigated using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT). These dyes contain the same electron acceptors and -spacers but distinct 3,6- and 2,7-carbazole electron-donating groups. The results showed coplanar geometries for the dyes, which implied strong conjugation. When intramolecular charge transfer was investigated, it was discovered that 3,6-carbazole had a better capacity to give electrons than 2,7-carbazole. These dyes' projected orbital energy levels indicate that excited dyes might successfully decrease by electrolyte while oxidized dyes could successfully inject electrons into semiconductor conduction bands. The study investigated the suitability of different dyes for use in dye-sensitized solar cells (DSSCs) and found that the M2 dye, which contains a thio group as the terminal electron donor, exhibited the most promising optoelectronic properties. In particular, M2 had a narrow energy gap, superior optical qualities, optimal FMO energy levels, the lowest total value, and greater GInject and GReg values compared to the other dyes tested. These factors contributed to M2's superior photosensitizing performance, suggesting that using M2 in DSSCs may lead to higher optoelectronic characteristics and total energy conversion efficiency compared to using other dyes.
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    Theoretical and conceptual framework to design D-π-A type organic dyes for application dye-sensitized solar cells
    (Elsevier BV, 2024) Makangara, John J.; Sahini, Mtabazi G.; babu, Numbury Surendra
    The optimized structures and absorption spectra of five D-A-type organic dyes (M1, M2, M3, M4, and M5) were investigated using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT). These dyes contain the same electron acceptors and -spacers but distinct 3,6- and 2,7-carbazole electron-donating groups. The results showed coplanar geometries for the dyes, which implied strong conjugation. When intramolecular charge transfer was investigated, it was discovered that 3,6-carbazole had a better capacity to give electrons than 2,7-carbazole. These dyes' projected orbital energy levels indicate that excited dyes might successfully decrease by electrolyte while oxidized dyes could successfully inject electrons into semiconductor conduction bands. The study investigated the suitability of different dyes for use in dye-sensitized solar cells (DSSCs) and found that the M2 dye, which contains a thio group as the terminal electron donor, exhibited the most promising optoelectronic properties. In particular, M2 had a narrow energy gap, superior optical qualities, optimal FMO energy levels, the lowest total value, and greater GInject and GReg values compared to the other dyes tested. These factors contributed to M2's superior photosensitizing performance, suggesting that using M2 in DSSCs may lead to higher optoelectronic characteristics and total energy conversion efficiency compared to using other dyes.
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    Theoretical studies of electronic and optical properties for some new azo disperse dyes for dye-sensitized solar cells by using TD and TD DFT method
    (East African Nature and Science Organization, 2018) Onoka, Isaac; Babu, Numbury Surendra; Makangara, John J.
    The ground states geometries, absorption wavelengths, oscillation strengths of new azo disperse dyes such as 3-aminopyrazoleazo -4- thiol-2,3,5-thiadiazole (D1),3-amino-4-methylpyrazoleazo-4-thiol-2,3, 5-thiadiazol (D2),2, 4-dihydroxybenzeneazo-4-thiol 1-2, 3,5- thiadiazole (D3),4-amino-3-benzonitrileazo-4-thiol-2,3,5-thiadiazole (D4), 2-hydroxylnaphtholazo-4-thiol-2,3,5-thiadiazole (D5) and 2-amino-5-ethylcarbazoleazo-4-thiol-2,3,5-Thiadiazole (D6) have been optimized by using density functional theory (DFT) at B3LYP level of theory with 6-31G(d) basis set. The excitation energies have been computed by using time dependent density functional theory (TDDFT). The study of structural, electronic and optical properties for these dyes could help to design more efficient functional photovoltaic organic materials. The electron injection (ΔGinject), electron coupling constants (|VRP|) and light harvesting efficiencies (LHE) of studied dyes and have been discussed with esteem to DSSCs. This theoretical designing will the pave way for experimentalists to synthesize the efficient sensitizers for solar cells
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    Therapeutic potential of Equisetum arvense L. for management of medical conditions
    (Elsevier, 2023) Luanda, Amos; Ripanda, Asha; Makangara, John J.
    Background: Equisetum arvense L. has a long history of use in traditional medicines for treating ailments like digestive, inflammatory, respiratory and urinary disorders. Researchers have been focused on developing drugs from natural sources particularly the medicinal plants for global mitigation of medical conditions while protecting the environment. The use of natural products is one of the strategies that the WHO recommended to manage global medical conditions. The interest to use natural remedies as alternative medicines for management of medical conditions is increasing considerably. Purpose: This review intended to discuss the therapeutic potential of E. arvense for the mitigation of various diseases by providing up-to-date information on its benefits, challenges and potential future opportunities. Methods: The information is collected and systematically analysed from various online databases including Google scholar, ScienceDirect, Springer, Web of Science, PubMed and Plant of the World Online. Results: This study demonstrated the enormous therapeutic potential of E. arvense for the management of various ailments. The significant changes in the phytoconstituents amongst the plant parts have been observed, which correspond to the variation in its pharmacological properties. Several pharmacological activities of E. arvense such as anticancer, anti-inflammatory, antibacterial, antifungal and antidiabetics support its traditional uses. Conclusion: E. arvense has a lot of therapeutic promises for treating a number of health disorders. The extension of its clinical study requires further identification of the bioactive compounds, their modes of action as well as toxicological study. The existing therapeutic potential of E. arvense, suggesting that it is a suitable medicinal plant for management of medical conditions.