Browsing by Author "Ndhlala, Ashwell Rungano."

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Assessment of spatial and temporal variation in water quality of the Pienaars River, Limpopo water management area.
(2018) Mlotshwa, Lungile Wendy.; Tsvuura, Zivanai.; Ndhlala, Ashwell Rungano.; Ncube, Bhekumthetho.
Abstract available in pdf.
Effects of pruning and fertilizer on growth, phytochemistry and biological activity of Sutherlandia frutescens (L.) R.Br.
(2017) Raselabe, Maanda Benjamin.; Van Staden, Johannes.; Finnie, Jeffrey Franklin.; Abdelgadir, Hafiz Ahmed.; Ndhlala, Ashwell Rungano.
Sutherlandia frutescens (L.) R.Br. (Fabaceae), commonly known as cancer bush, is a herb with a long history of traditional use by a variety of cultures. The plant mainly grows in the dry parts of southern Africa, mostly in the Western and Eastern Cape as well as the neighbouring countries like Lesotho, Botswana and Namibia. Cancer bush is traditionally used for the treatment of external wounds, internally for fevers, stomach problems, cancer, diabetes, influenza, HIV, depression, eye problems, TB, colds and asthma. The plant is famously known for the treatment of Type 2 diabetes, cancer and HIV. However, these claims remain inconclusive. Recent studies have shown S. frutescens to have antidiabetic, anti-HIV, anti-inflammatory, antibacterial, analgesic, anti-stress, anticonvulsant, antiproliferative and antithrombotic activities. Phytochemical investigations of S. frutescens leaves detected the presence of high levels of free amino acids and non-protein amino acids namely: canavanine, gamma aminobutyric acid (GABA) and pinitol. The presence of these compounds has been reported to be responsible for its reputed effectiveness in a wide range of illnesses. In view of its importance as a multipurpose medicinal crop, it is important to bring this plant under cultivation and determine agronomic requirements for its successful cultivation. Several factors can be investigated to enhance the growth and increase the level of active ingredients. The current study was aimed at evaluating the effect of pruning and fertilizer levels on the growth, phytochemistry and biological activity of Sutherlandia frutescens. Seeds were sown in seedling trays to produce seedlings. One-month-old seedlings were then transplanted on a prepared field. The study trial was carried out at the Agricultural Research Council-Vegetable and Ornamental Plants Research Station (ARC-VOP). The experiment was conducted in a randomized complete block design (RCBD) with three pruning levels, three fertilizer levels and four replicates. There were 9 treatments, namely; no pruning (P0), tip-pruning (P1) and heading back (P2) in combination with levels of fertilizers as follows: 200 kg/ha NPK (F1), 100 kg/ha NPK (F2) and 0 kg/ha NPK (F0). Plants without treatments were considered as controls. Growth parameters taken were plant height, stem diameter, chlorophyll and Leaf Area Index (LAI). Dried leaf samples were analysed for the presence of secondary metabolites and antidiabetic activities. There was no significant interaction effect between pruning and fertilizer levels amongst all parameters measured in this study. Pruning treatments had a significant effect on the LAI at week one and week two but did not affect the plant height, stem diameter and chlorophyll content. Different levels of fertilizers had a significant effect on the LAI, where 100 kg/ha NPK significantly increased LAI at week one and week two. In an investigation which was conducted from January to May 2015, plants showed yellowing, stunting, and high levels of infestation expressed as extensive galling on the roots which led to the nematode infestation study. Nematodes were extracted from the roots of a healthy living, a wilted and a dead plant, as well as from the rhizosphere soil. A small population of Scutellonema, Pratylenchus, Helicotylenchus and Tylenchorhynchus were identified. Examination of the root of an infected plant revealed the presence of root-knot nematodes (Meloidogyne javanica) in large numbers. Juveniles, eggs and females were isolated, and the species were identified on the basis of morphological characteristics. Symptoms usually associated with root-knot nematodes were observed on the roots of the wilted plant and the soil in which the plant was growing. Extracts from all nine treatments showed stronger activity against α-glucosidase than the positive control acarbose. The highest α-glucosidase inhibitory activity was demonstrated by the treatment with no pruning (P0) while the heading back (P2) treatment exhibited the lowest inhibitory activity. Fertilizer levels at 200 kg/ha (F1) NPK resulted in a significantly higher α-glucosidase inhibitory activity compared to other fertilizer treatments. The presence of secondary metabolites (including total phenolics and flavonoids) was determined qualitatively. The total phenolic content was determined using the Folin-Ciocalteu method and flavonoids were determined using the vanillin HCL assay. The study showed that pruning and fertilizer increased the production of secondary metabolites in S. frutescens as compared to the control. Fertilizer at 200 kg/ha NPK (F1) did seem to improve phenolics and flavonoids with pruning but phenolic levels were actually quite low when treatment was P0F1. Total phenolics and flavonoids were significantly increased by the heading back (P2) treatment and decreased in the treatment with no pruning (P0). The application of fertilizer at 200 kg/ha NPK (F1) improved the production of secondary metabolites, and reduced production of secondary metabolites was recorded in plants that received no fertilizer. There was no direct correlation between the level of phytochemicals and the antidiabetic activity recorded. This study examined the effects of different levels of pruning and fertilizers on the growth of S. frutescens. The results showed that there was no significant difference. At this stage, no positive recommendations can be made for cultivating S. frutescens. Plant extracts showed good antidiabetic activities in response to different pruning and fertilizer treatments. This was further seen as an increase in the production for secondary metabolites. However, further investigation of plant cultivation practices and further screening for bioactivities is required. S. frutescens may offer a new source of drugs for diabetes mellitus and other related diseases.
Genetic diversity of some Moringa oleifera Lam. cultivars available in South Africa.
(2020) Makgolane, Thandy Ramathetje.; Tsvuura, Zivanai.; Zishiri, Oliver Tendayi.; Ndhlala, Ashwell Rungano.
Moringa oleifera Lam. (Moringaceae) is a nutritious and high medicinal value tree. The species is native to India but grown globally due to its properties. The nutritional content of the species includes high levels of vitamins, minerals, calcium, magnesium and iron. It is now known that different cultivars of M. oleifera are grown throughout the world depending on the intended products. However, in South Africa, there is limited knowledge on the genetic variation of the cultivars most farmers and researchers are growing. In this study, a partial sequence of chloroplast atpB gene was used to determine genetic diversity of M. oleifera cultivars from different regions across the world but grown for research at the Agricultural Research Council, Vegetable and Ornamental Plants campus in Roodeplaat, Gauteng Province, South Africa. Thirteen cultivars were collected, of which three were domesticated cultivars from South Africa, eight were from Thailand, and one cultivar each was from Taiwan and the United States of America. Each cultivar consisted of six replicates. DNA extraction, PCR and gel electrophoresis were performed at the University of KwaZulu-Natal whereas DNA sequencing was done at Inqaba Biotec laboratory. DNA sequence analysis was done using BioEdit, MegaX, POPArT and DnaSP softwares. Based on the phylogenetic analysis, the average total length of the sequences was 404 nucleotides with the number of polymorphic segregating sites and mutation of 21 and 24, respectively. From the maximum likelihood tree and neighbour-joining tree, South African domesticated cultivars SH and Limpopo were more related to each other than to the domesticated cultivar, CHM (South African). The cluster which was well supported with 84% bootstrap value was between cultivars TOT 5077 (Thailand) and TOT 4100 (Taiwan). The polymorphic data indicated a nucleotide diversity of 0.01654 and average number of nucleotide difference (k) of 6.58095. The haplotype network also showed less genetic differences between the cultivars with some cultivars recorded as similar. The low genetic diversity observed in these cultivars suggests that the cultivars might have originated from a common ancestor. However, further study is necessary by collecting more cultivars of M. oleifera South Africa and other parts of the world to get a clear view on the genetic diversity. The results from this study will be an addition to the already existing knowledge of M. oleifera available in the world and new knowledge on genetic variation among South African cultivars, which may be relevant in cultivar development and conservation.
Investigating the effectiveness of a simple water-purifying gadget made of Moringa oleifera seeds as the active beads.
(2023) Raphasha, Dineo Gladys.; Tsvuura, Zivanai.; Ndhlala, Ashwell Rungano.; Mbendana, Dambudzo.
Abstract available in PDF.
Pharmacological, phytochemical and safety evaluation of commercial herbal preparations common in South Africa.
(2009) Ndhlala, Ashwell Rungano.
Herbal formulations claimed to cure several medical conditions including skin eruptions, chest pains, wounds, gout, menstrual pains, stress, nervous disorders, microbial and viral infections as well as stomach ailments have recently appeared as part of South African traditional medicine. The formulations consist of mixtures of extracts of different plant parts from several different plant species packaged in labelled bottles or boxes. The mixtures are available for sale in herbal shops and public places. While there has been widespread use of these herbal mixtures, there has been no scientific evidence to support their use. This project was aimed at documenting, validating claimed efficacy and testing the safety of fourteen unregistered commercial herbal preparations commonly sold in Pietermaritzburg. A detailed investigation of the pharmacological effects and safety of the plant components of one of the mixtures, Imbiza ephuzwato was also carried out.
The potential of Moringa oleifera (Lam.) leaves for use in complementary foods to combat child food and nutrition insecurity among South African rural and peri-urban communities.
(2017) Ntila, Sithandiwe Linda.; Siwela, Muthulisi.; Kolanisi, Unathi.; Abdelgadir, Hafiz Ahmed.; Ndhlala, Ashwell Rungano.
The inadequate nutritional quality of complementary foods is a major public health problem in developing countries such as South Africa, and contributes towards the reported high rates of child malnutrition. Consequently, there is an urgent need to investigate interventions aimed at improving the nutritional quality of complementary foods. The aim of this study was to assess the potential of Moringa oleifera (Lam.) leaves for use in complementary foods to combat food and nutrition insecurity amongst children in South African communities. Mothers from Lebowakgomo village in Limpopo province (n=106) and Hammanskraal Township in Gauteng province (n=106), were recruited on a voluntary basis to participate in the survey which assessed the food and nutrition security status of their children, aged 7-12 months old. Additionally, six focus group discussions were conducted per study area to assess mothers’ perceptions about children’s food access and to further establish a recipe for a popular traditional cereal-based complementary food. The Children’s Food Insecurity Access Scale (CFIAS) was used to assess the food security status (access) of the children. The Individual Dietary Diversity Score (IDDS) together with the unquantified food consumption frequency survey were used as a proxy measure of the nutritional quality of the children’s diets. The age and weight of the children were obtained from the children’s clinic health cards and were used to calculate Weight-for-Age Z scores (WAZ). These values were interpreted to determine the prevalence of underweight children. The popular cereal-based traditional complementary food recipe (white maize soft porridge) used by mothers from the studied communities was modified by substituting maize meal with MLP at 1, 2 and 3% (w/w) levels. The nutritional, phytochemical and antioxidant analysis of the popular traditional complementary soft porridge (control) and Moringa-added porridges (test samples) were determined using standard methods. The sensory acceptability of the porridges was evaluated by the mothers who were recruited on a voluntary basis (n= 60 per study area) and six focus group discussions were conducted per study area to assess mothers’ perceptions on the inclusion of Moringa in complementary foods. The findings of the survey showed that a large percentage of children were severely food-insecure, 87% and 78%, at Lebowakgomo and Hammanskraal, respectively. Additionally, children from Lebowakgomo (23.6%) and Hammanskraal (17.9%) were severely underweight. Overall, children’s diets in both study areas were characterized by nutrient-deficient complementary foods. Cheaper foods with a higher satiety value such as white maize meal (WMM) and sugar were the most commonly purchased and used. Hence, the children consumed very limited amounts of foods rich in proteins, minerals, and vitamins, which significantly increased the risk of malnutrition. As the MLP was increased from 0 to 3% in the Lebowakgomo white maize soft porridge, a corresponding significant increase in nutrient content was observed: ash (from 0.52 to 0.87 g/100 g), calcium (0.01 to 0.09 mg/100 g), potassium (0.10 to 0.14 mg/100 g), protein (8.70 to 9.68 g/100 g), threonine (0.14 to 0.66 g/100 g), glutamine (1.28 to 1.56 g/100 g), provitamin A (0.81-1.16 μg/g), lutein (0.04-0.30 μg/g), zeaxanthin (0.21-2.18 μg/g), β-cryptoxanthin (0.11-0.14 μg/g), β-carotene (0.25-0.50 μg/g) and 9-cis-β-cryptoxanthin (0.25-0.31 μg/g). Increasing the MLP from 0 to 3% in the soft porridge at Hammanskraal, caused a significant increase in the levels of iron (from 52.50 to 101.0 mg/100 g), manganese (1.00 to 4.00 mg/100 g), phenylalanine (0.35 to 0.47 g/100 g), provitamin A (0.87-1.01 μg/g), lutein (0.05-0.22 μg/g), zeaxanthin (0.22-1.29 μg/g) and β-carotene (0.27-0.39 μg/g). Additionally, the antioxidant activity, total phenolic and flavonoid contents of Hammanskraal and Lebowakgomo white maize soft porridges increased as the concentration of MLP was increased. The sensory evaluation results showed that the acceptance of each of the two traditional complementary foods decreased as the level of MLP increased. Mother’s indicated in the focus group discussions that Moringa-added soft porridges had a bitter taste, which would not be suitable for children. Only the Moringa-added soft porridge from Lebowakgomo containing 1% of Moringa was rated similar in overall acceptability as the corresponding white maize soft porridge (control). Nevertheless, all mothers expressed willingness to use Moringa in complementary foods if they would be trained on how to process it into foods suitable for children. There is a need to vary product formulation and processing methods, which may contribute to increased acceptance of Moringa-based foods. Additionally, the safety of using MLP in complementary foods should be investigated.