Potential toxicity of some traditional leafy vegetables consumed in Nyang’oma division, western Kenya

Traditional leafy vegetables are those plants whose leaves or aerial parts have been integrated in a community’s culture for use as food over a long span of time. These vegetables are highly recommended due to their relatively high nutritional value  compared to the introduced varieties, and are also important in food security. Qualitative phytochemical screening, using  standard laboratory procedure, was carried out for alkaloids, saponins, cardenolides, flavonoids and polyphenols on traditional  leafy vegetables consumed amongst the Luo, an agro-pastoral community living along the shores of lake Victoria, Western  Kenya. The vegetables were: Amaranthus hybridus L. (subsp.hybridus), Asystasia mysorensis T. Anderson, Coccinia grandis (L) Voigt, Crotalaria ochroleuca (Kotschy) Polhill, Cucurbita maxima Duchesne ex Lam, Portulaca quadrifida L., Sesamum calycimum Welw. var. angustifolium (Oliv.) Ihlenf. and Siedenst., Senna occidentalis L. and Sida acuta Burm. F. All the vegetables were found to contain polyphenols and flavanoids while other classes of phytochemicals varied from species to species Brine shrimp lethality tests  revealed that S. calycimum var. angustifolium (LC50 84.8 μg/ml), S. occidentalis (LC5099.5 μg/ml), S. acuta (LC50 99.4 μg/ml), C. grandis (LC50  100.6 μg/ml) and A. mysorensis (LC50 207.7 μg/ml) exhibited marked levels of toxicity. C. ochroleuca (Sunnhemp) contained all the five classes of  phytochemicals, but proved less toxic (LC50 4511.3 μg/ml). This vegetable is highly utilized in Nyang’oma, and seventy per cent of the respondents consume this species. A. hybridus (African spinach, or Amaranth) was found to be the least toxic (LC50 6233.6 μg/ml) and this vegetable is recommended for consumption. From the results, five vegetables contain possible agents that can cause acute or chronic toxicities when consumed in large quantities or over a long period of  time. Hence some vegetables should be consumed with great care. Though further studies are required to determine which of the phytochemicals are lethal to mammals.Key words: Traditional vegetables, phytochemicals, toxicity, Luo, Nyang’om

In vitro anti-viral activity of aqueous extracts of Kenyan Carissa edulis Prunus africana and Melia azedarach against human cytomegalovirus.

The aqueous extracts of three medicinal plants, Carissa edulis (Forssk.) Vahl (Apocynaceae), Prunus africana (Hook.f.) Kalkm (Rosaceae) and Melia azedarach L. (Meliaceae) have shown significant reduction in the replication of human cytomegalovirus (HCMV) in human embryonic lung (HEL) fibroblasts cells in vitro. Using the plaque inhibition assay for the determination of anti-viral activity, the HEL fibroblast cells cultured in 24 well plates were infected with 1 x 102 PFU 91S HCMV and treated with various concentrations of the extracts. The plaques formed were counted after 7 days incubation at 370C in 5% CO2 and the percent plaques inhibited were calculated against infected untreated control. The effective concentrations inhibiting plaque formation by 50% (EC50) was found between 40 to 80 μg/ml for all the extracts. The cell cytotoxic concentrations (CC50) for each of the three extracts, by the trypan blue exclusion test, gave a safe therapeutic index. These results have demonstrated the potential anti-viral activities of the extracts of the three medicinal plants at non-cytotoxic concentrations. African Journal of Health Sciences Vol. 14 (3-4) 2007: pp. 143-14

PEER REVIEWED ARTICLE No 9 - POTENTIAL TOXICITY OF SOME TRADITIONAL LEAFY VEGETABLES CONSUMED IN NYANG’OMA DIVISION, WESTERN KENYA

Traditional leafy vegetables are those plants whose leaves or aerial parts have been integrated in a community's culture for use as food over a long span of time. These vegetables are highly recommended due to their relatively high nutritional value compared to the introduced varieties, and are also important in food security. Qualitative phytochemical screening, using standard laboratory procedure, was carried out for alkaloids, saponins, cardenolides, flavonoids and polyphenols on traditional leafy vegetables consumed amongst the Luo, an agro-pastoral community living along the shores of lake Victoria, Western Kenya. The vegetables were: Amaranthus hybridus L. (subsp.hybridus), Asystasia mysorensis T. Anderson, Coccinia grandis (L) Voigt, Crotalaria ochroleuca (Kotschy) Polhill, Cucurbita maxima Duchesne ex Lam, Portulaca quadrifida L., Sesamum calycimum Welw. var. angustifolium (Oliv.) Ihlenf. and Siedenst., Senna occidentalis L. and Sida acuta Burm. F. All the vegetables were found to contain polyphenols and flavanoids while other classes of phytochemicals varied from species to species Brine shrimp lethality tests revealed that S. calycimum var. angustifolium (LC50 84.8 μg/ml), S. occidentalis (LC50 99.5 μg/ml), S. acuta (LC50 99.4 μg/ml), C. grandis (LC50 100.6 μg/ml) and A. mysorensis (LC50 207.7 μg/ml) exhibited marked levels of toxicity. C. ochroleuca (Sunnhemp) contained all the five classes of phytochemicals, but proved less toxic (LC50 4511.3 μg/ml). This vegetable is highly utilized in Nyang'oma, and seventy per cent of the respondents consume this species. A. hybridus (African spinach, or Amaranth) was found to be the least toxic (LC50 6233.6 μg/ml) and this vegetable is recommended for consumption. From the results, five vegetables contain possible agents that can cause acute or chronic toxicities when consumed in large quantities or over a long period of time. Hence some vegetables should be consumed with great care. Though further studies are required to determine which of the phytochemicals are lethal to mammals

The anti-viral effect of Acacia mellifera, Melia azedarach and Prunus Africana, extracts against herpes simplex virus type 1 infection in mice

Aqueous extracts from the stem barks of Prunus africana(Hook.f.) Kalkm, Acacia mellifera (Vahl.) Benth. and Melia azedarach L. were evaluated for in vivo antiviral activity in Balb/C mice following a cutaneous wild type strain 7401H herpes simplex virus type 1 (HSV-1) infection. A significant therapeutic effect was observed when the infected mice were orally treated with the extracts of Prunus africana and Acacia mellifera at a dose of 500 mg/kg. A delayed onset of skin lesions, slowed progression of infection and a prolonged mean survival time was expressed as opposed to the untreated infected control (p ≤0.05). Treatment with the Melia azedarach extract at a dose of 500 mg/kg was acutely toxic to mice, however a reasonable antiviral activity was exhibited at a lower dose of 250 mg/kg. No acute toxicity was presented in mice treated withP. africana and A. mellifera at the therapeutic dose. The results suggest the presence of anti-HSV agents in these medicinal plant extracts that can be exploited as possible antivirals. Keywords: Prunus africana, Acacia mellifera, Melia azedarach, HSV-1, antiviral activity, medicinal plants Journal of Tropical Microbiology and Biotechnology Vol. 2(1) 2006: 3-

Diversity of alternative hosts of maize stemborers in Trans-Nzoia district of Kenya

Genetically-engineered (GE) crops such as those expressing insecticidal Bacillus thuringiensis (Bt) toxin genes have the potential to greatly reduce the use of broad spectrum insecticides and increase crop productivity. However, development of resistance by the target insect species is an important consideration in the deployment of this strategy. In areas where GE crops are deployed on a large scale, current resistance management strategies rely on a ‘refuge strategy’, comprising the incorporation of a certain proportion of non-GE plants in the agro-ecosystems, to conserve susceptible individuals of the target pests. In the USA, simulation models indicate that at least 20% of the crop should be non-Bt plants. In Africa, the target lepidopteran stemborers attack a wide range of wild grass species as well as cultivated cereal crops. Wild grasses generally occur in the vicinity of maize and other cereal fields, and may provide a refuge if GE crops are in the farming systems. To assess the quality of these grasses as refuges, it is critical to obtain information about their size and spatial distribution. In this study, we have assessed the abundance and diversity of alternative refuge of stemborers, mainly wild grasses occurring in the proximity of maize fields, in Trans-Nzoia district, one of the most important maize growing areas in Kenya. The proportion of wild host plants relative to maize was found to decline from 100% during the non-cropping season to <8% during the maize-growing season. The Shannon-Weaver diversity index indicated high variation in the diversity of wild hosts of stemborers between agro-ecological zones in the district. The results of this study are discussed in light of the possible role that wild host plant species might play in stemborer resistance management following the introduction of Bt maize

Vaginal microbiome topic modeling of laboring Ugandan women with and without fever

The composition of the maternal vaginal microbiome influences the duration of pregnancy, onset of labor, and even neonatal outcomes. Maternal microbiome research in sub-Saharan Africa has focused on non-pregnant and postpartum composition of the vaginal microbiome. Here we aimed to illustrate the relationship between the vaginal microbiome of 99 laboring Ugandan women and intrapartum fever using routine microbiology and 16S ribosomal RNA gene sequencing from two hypervariable regions (V1–V2 and V3–V4). To describe the vaginal microbes associated with vaginal microbial communities, we pursued two approaches: hierarchical clustering methods and a novel Grades of Membership (GoM) modeling approach for vaginal microbiome characterization. Leveraging GoM models, we created a basis composed of a preassigned number of microbial topics whose linear combination optimally represents each patient yielding more comprehensive associations and characterization between maternal clinical features and the microbial communities. Using a random forest model, we showed that by including microbial topic models we improved upon clinical variables to predict maternal fever. Overall, we found a higher prevalence of Granulicatella, Streptococcus, Fusobacterium, Anaerococcus, Sneathia, Clostridium, Gemella, Mobiluncus, and Veillonella genera in febrile mothers, and higher prevalence of Lactobacillus genera (in particular L. crispatus and L. jensenii), Acinobacter, Aerococcus, and Prevotella species in afebrile mothers. By including clinical variables with microbial topics in this model, we observed young maternal age, fever reported earlier in the pregnancy, longer labor duration, and microbial communities with reduced Lactobacillus diversity were associated with intrapartum fever. These results better defined relationships between the presence or absence of intrapartum fever, demographics, peripartum course, and vaginal microbial topics, and expanded our understanding of the impact of the microbiome on maternal and potentially neonatal outcome risk

Cytomegalovirus Infections in Ugandan Infants:Newborn-Mother Pairs, Neonates with Sepsis, and Infants with Hydrocephalus

Objective To estimate the prevalence of cytomegalovirus (CMV) infections in newborn-mother pairs, neonates with sepsis, and infants with hydrocephalus in Uganda. Design and Methods Three populations: (1) newborn-mother pairs, (2) neonates with sepsis, and (3) infants (≤ 3 months) with non-postinfectious (NPIH) or postinfectious (PIH) hydrocephalus, were evaluated for CMV infection at three medical centers in Uganda. Quantitative PCR (qPCR) was used to characterize the prevalence of CMV. Results The overall CMV prevalence in 2498 samples in duplicate across all groups was 9%. In newborn-mother pairs, there was a 3% prevalence of cord blood CMV positivity and 33% prevalence of maternal vaginal shedding. In neonates with clinical sepsis there was a 2% CMV prevalence. Maternal HIV seropositivity (aOR, 25.20; 95% CI, 4.43-134.26; p= 0.0001), residence in Eastern Uganda (aOR, 11.06; 95% CI, 2.30-76.18; p=0.003), maternal age < 25 years (aOR, 4.54; 95% CI, 1.40-19.29; p=0.02), and increasing neonatal age (aOR, 1.08 for each day older; 95% CI, 1.00-1.16; p= 0.05), were associated risk factors for CMV in neonates with clinical sepsis. We found a two-fold higher maternal vaginal shedding in Eastern (45%) vs Western (22%) Uganda during parturition (n=22/49 vs. 11/50, Fisher's exact test, p=0.02). In infants with PIH, the prevalence in blood was 24% and in infants with NPIH it was 20%. CMV was present in the CSF of 13% of infants with PIH compared to 0.5% of infants with NPIH (n=26/205 vs. 1/194, p<0.0001). Conclusion Our findings highlight that congenital and postnatal CMV prevalence is substantial in this African setting and the long-term consequences are uncharacterized