Occurrence of Aflatoxins in Maize and Maize Products from Selected Locations of Tanzania and the Effects of Cooking Preparation Processes on Toxin Levels

The production and storage of food crops in different countries is affected by aflatoxins contamination, which are known to be carcinogenic and mutagenic to human beings and domestic animals. This study investigated on the occurrence of aflatoxins in maize products and the effects of cooking preparation processes on their concentrations. The maize samples were collected from fields, farmers' stores and markets of selected locations in Tanzania (i.e., Kongwa and Njombe districts). Extracted samples were analyzed for aflatoxins using high performance liquid chromatography. The concentrations of aflatoxins in maize and maize products ranged from below detection limit to 9.99 ± 1.43 μg/kg and 9.99 ± 0.14 μg/kg for Njombe and Uwemba wards, respectively. Whereas those collected from Kibaigwa ward in Kongwa district ranged from 2.87 ± 0.02 μg/kg to 10.26 ± 0.46 μg/kg. The levels in cooked maize products were lower than the uncooked maize products. The mean concentrations of total aflatoxins in cooked maize products were 0.45 ± 0.05 μg/kg for stiff porridge prepared from dehulled maize flour, 1.39 ± 0.02 μg/kg for stiff porridge prepared from undehulled maize flour, and 0.584 ± 0.06 μg/kg for maize meal (kande). Generally, the levels of aflatoxins were below the maximum acceptable limits set by WHO except for some samples from Kibaigwa market which were slightly above the set limits. Keywords: Aflatoxins; High Performance Liquid Chromatography; Maize; Fung

Phylogenetic diversity of Actinobacteria from Momela soda lakes, Arusha National Park, Tanzania

The Momela soda lakes consist of seven small, hypersaline, alkaline lakes, situated in the East African rift valley at Arusha National Park, Tanzania. The lakes are fed by separate underground water sources with slightly varying mineral contents resulting in colour variation and supporting different kinds of prokaryotic and eukaryotic species. In this study, the diversity of Actinobacteria in surface water and sediments of five Lakes were investigated using culture-dependent and culture-independent molecular techniques. A total of 34 out of 112, and 13 out of 85, representatives of Actinobacteria isolates and clones, respectively, were selected for gene sequencing using the CD-HIT program. Analysis of their 16S rRNA gene sequences displayed the presence of species affiliated to 15 different genera, namely Mycobacterium, Rhodococcus, Microbacterium, Isoptericola, Dietzia, Leucobacter, Jonesia, Nesterenkonia, Micrococcus, Streptomyces, Hoyosella, Norcadiopsis, Cellulomonas, Bogoriella, and Agromyces. The results showed 5 and 12 putative new Actinobacteria isolates and clones, respectively. This is the first report of isolation of bacteria from the genus Mycobacterium from a soda lake globally, as well as the genera Hoyosella, Isoptericola, Jonesia, Micrococcus, Leucobacter and Agromyces from a soda lake in East Africa. Because Actinobacteria are known as a source of biotechnologically important compounds, the species revealed set a platform to search for novel bioactive compounds

Flavonoids from <i>Erythrina schliebenii</i>

Prenylated and <i>O</i>-methylflavonoids including one new pterocarpan (<b>1</b>), three new isoflavones (<b>2</b>–<b>4</b>), and nineteen known natural products (<b>5</b>–<b>23</b>) were isolated and identified from the root, stem bark, and leaf extracts of <i>Erythrina schliebenii</i>. The crude extracts and their constituents were evaluated for antitubercular activity against <i>Mycobacterium tuberculosis</i> (H37Rv strain), showing MICs of 32–64 μg mL^–1 and 36.9–101.8 μM, respectively. Evaluation of their toxicity against the aggressive human breast cancer cell line MDA-MB-231 indicated EC₅₀ values of 13.0–290.6 μM (pure compounds) and 38.3 to >100 μg mL^–1 (crude extracts)

Flavonoids from <i>Erythrina schliebenii</i>

Prenylated and <i>O</i>-methylflavonoids including one new pterocarpan (<b>1</b>), three new isoflavones (<b>2</b>–<b>4</b>), and nineteen known natural products (<b>5</b>–<b>23</b>) were isolated and identified from the root, stem bark, and leaf extracts of <i>Erythrina schliebenii</i>. The crude extracts and their constituents were evaluated for antitubercular activity against <i>Mycobacterium tuberculosis</i> (H37Rv strain), showing MICs of 32–64 μg mL^–1 and 36.9–101.8 μM, respectively. Evaluation of their toxicity against the aggressive human breast cancer cell line MDA-MB-231 indicated EC₅₀ values of 13.0–290.6 μM (pure compounds) and 38.3 to >100 μg mL^–1 (crude extracts)

Flavonoids from <i>Erythrina schliebenii</i>

Prenylated and <i>O</i>-methylflavonoids including one new pterocarpan (<b>1</b>), three new isoflavones (<b>2</b>–<b>4</b>), and nineteen known natural products (<b>5</b>–<b>23</b>) were isolated and identified from the root, stem bark, and leaf extracts of <i>Erythrina schliebenii</i>. The crude extracts and their constituents were evaluated for antitubercular activity against <i>Mycobacterium tuberculosis</i> (H37Rv strain), showing MICs of 32–64 μg mL^–1 and 36.9–101.8 μM, respectively. Evaluation of their toxicity against the aggressive human breast cancer cell line MDA-MB-231 indicated EC₅₀ values of 13.0–290.6 μM (pure compounds) and 38.3 to >100 μg mL^–1 (crude extracts)