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An in vitro investigation of the immunomodulatory effects of a traditional polyherbal traditional medicine product
Moloti, Tebatso Martin (University of Pretoria, 2018)
In South Africa, human immunodeficiency virus (HIV) remains one of the major public health concerns. HIV is a highly infectious lentivirus which causes a progressive degeneration of the immune system. When not treated, it leads to the development of acquired immunodeficiency syndrome (AIDS). AIDS is an immunosuppressive disease that results in opportunistic infections that can lead to death. Antiretroviral therapy (ART) is the most common and widely used treatment. Despite the availability of ART, HIV prevalence is on the rise. This has led to a surge in traditional herbal preparations that are purported as immune boosters for treatment in HIV patients. It is known that many patients switch from using ART to traditional herbal medicine due to side effects associated with ART. In South Africa and on the African continent, traditional medicine is not used only as an alternative and supplementary medicine, but also as a primary source of health care due to its ease of accessibility, affordability and also as it forms part of traditional and cultural practices. Safety and efficacy of many traditional medicines is not yet established and the pharmacological properties of the latter are based on anecdotal evidence with no scientific evidence. Prijap Health is a herbal traditional medicine preparation that is sold as an immune booster for immunocompromised patients. Prijap Health traditional herbal medicine is comprised of the following plants: Acorus calamus, Aloe arborescens, Artemisia afra, Drimia robusta, Elephantorrhiza elephantina, Erythrina lysistemon, Persea americana, Senecio serratuloides and Xysmalobium undulatum. It is claimed to have anti-viral, antioxidant, anti-inflammatory, blood cleansing and appetising properties. It is currently traded in select stores across South Africa. The aim of this study was to investigate the immune modulating properties of Prijap Health herbal concoction and the individual plant species that comprise the concoction. Water was used as a solvent to prepare plant extracts mimicking the traditional healer’s preparation technique. Phytochemical analysis was carried out using thin layer chromatography (TLC) and ultra-high-performance liquid chromatography coupled with mass spectrometry (UPLC-MS). Cytotoxicity of the extracts was evaluated by the sulphorhodamine B (SRB) protein staining assay using differentiated human acute leukaemia monocytic (THP-1) and human histiocytic lymphoma (U937) cell lines after incubation for 72 h. The free-radical scavenging activity of the extracts was evaluated against the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2’-azinobis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals to determine the antioxidant potential. Evaluation of prostaglandin E2 concentration in phorbol-12-myristate 13-acetate (PMA)-differentiated and lipopolysaccharide (LPS)-activated THP-1 and U937 was conducted using enzyme-linked immunosorbent assay (ELISA). Determination of Th1/Th2/Th17 (IL-2, IL-4, IL-6, IL-10, TNF-α, IFN-ᵞ and IL-17A) and human inflammatory (IL-8, IL-1β, IL-6, IL-10, TNF-α and IL-12p70) cytokines concentrations was done using BD cytometric bead array (CBA) kits. The TLC revealed the presence of flavonoids in the extracts of A. afra, E. elephantina, P. americana and S. serratuloides. Sterols were detected in the extracts of A. arborescens, E. elephantina, P. americana, X. undulatum. Saponins were present in the extracts of A. afra, A. calamus, D. robusta, E. elephantina and P. americana. Alkaloids were not detected in any of the extracts. Phytochemical markers were identified in the plant extracts using UPLC-MS. These include uzarin (X. undulatum), β-asarone (A. calamus), catechin (P. americana), (-)-epicatechin (E. elephantina), rutin (A. afra), D-saccharic acid (D. robusta), 3-caffeoylquinic acid (S. serratuloides) and aloesin (A. arborescens). From the SRB assay, it was evident that the hot water extracts of A. afra, A. arborescens, A. calamus, E. elephantina, E. lysistemon, P. americana and S. serratuloides had no cytotoxic effects in both cell lines at the highest concentration tested (IC50>100 µg/mL). The THP-1 cells were found to be more sensitive and indicated lower cell viability than the U937 cells. The D. robusta, X. undulatum extracts and Prijap Health traditional herbal medicine displayed a potential for toxicity in the THP-1 cell line with IC50 = 39.29±1.76, 76.05±1.21 and 74.52±1.31 µg/mL, respectively. The DPPH and ABTS radical scavenging activity was most potent for the E. elephantina extract (DPPH scavenging EC50= 6.98±1.04 µg/mL; ABTS scavenging EC50= 2.45±1.05 µg/mL) and was found to be comparable to that of Trolox, the positive control (DPPH EC50 = 7.39±1.04 µg/mL; ABTS EC50 = 1.79±1.04 µg/mL). Prijap Health traditional herbal medicine showed greater antioxidant activity than all the individual plant extracts with the exception of E. elephantina. Curcumin (positive control), Prijap, D. robusta and X. undulatum extracts decreased the extracellular and intracellular PGE2 concentration in THP-1 cells, but not in U937 cells. Cytokine concentration determination by flow cytometry revealed that curcumin (positive control), A. calamus, Prijap Health traditional herbal medicine, and E. elephantina significantly (p<0.05) reduced IL-1β concentration. Curcumin, A. calamus and Prijap significantly (p<0.05) reduced TNF-α concentration. E. elephantina, A. arborescens and P. americana increased IL-10 concentration whereas curcumin, A. afra and Prijap significantly (p<0.05) reduced IFN-ᵞ concentration in both THP-1 and U937 cells. These findings suggest that the above-mentioned extracts and Prijap Health traditional herbal medicine have the potential to be used as anti-inflammatory agents. In conclusion, the results of the present study provide evidence of the antioxidant, anti-inflammatory, immune modulatory potential as well as safety of use of Prijap Health traditional herbal medicine. With this said, E. elephantina as a single plant showed to contain better activity than Prijap Health traditional herbal medicine concoction. Further studies in drug-herb interaction and antiviral properties should be conducted to investigate all the pharmacological properties of Prijap Health traditional herbal medicine.
Post-synthesis physical and hydrothermal mixing of MnO2, SnO2, and rGO influence on ultracapacitor electrode performance
Anito, Solomon E.; Saliu, Oluwaseyi D.; Mamo, Messai; Ramontja, James; Mombeshora, Edwin Tonderai; Ndungu, Patrick Gathura (Wiley, 2025-11)
Please read abstract in the article.
Vegetative propagation of Pelargonium sidoides D.C. (Rabassam) using leaf-bud cuttings
Pholo, Mafamo Samuel (University of Pretoria, 2019-02)
Pelagonium sidoides (Rabassam) is an herbaceous plant of the Geraniaceae family used throughout history as a medicine for the people of South Africa which has and recently also been exported to other parts of the world. A number of studies have shown that the plant extracts have anti-microbial, anti-viral and immune boosting properties. Consequently, it has been harvested in the wild for these properties, exposing the species to possible extinction. This scenario can be addressed by artificially mass propagating and producing the species to satisfy demand. One method of propagating the plant is to use leaf-bud cuttings. Unfortunately, vegetative propagation of the species using leaf-bud cuttings is not documented. This study was therefore conducted to investigate the influence of rooting medium (sand and sand + coir), rooting hormone (0.1% indole-butyric acid (IBA), planting depth (1.5 and 3 cm) and season (summer, autumn, winter and spring) on rooting success of leaf-bud cuttings as well as impacts of these treatments on the survival and morphological characteristics of subsequent transplants. The experiments were conducted on a mist bed in a greenhouse located at the Experimental Farm of the University of Pretoria (25o45’S, 28o16’E). A 23 factorial experiment laid out in a randomized complete block design (RCBD) with 3 replicates was carried out. Root length, root number, planting depth, growth media and hormone application, were assessed by destructive sampling at 5 to 25 days after planting (DAP). Results of the study demonstrated that sand medium, compared to a mixture of sand + coir medium, resulted in higher rooting percentage and more roots. However, sand + coir medium produced longer roots on the cuttings. Planting depth of 3 cm resulted in higher rooting percentage and better establishment of cuttings as compared to a depth of 1.5 cm. Application of the rooting hormone 0.1% IBA improved the number of roots but not rooting percentage nor root length. Rooting of cuttings was improved when propagated in autumn (longer roots) and spring (higher number of roots) than in summer or winter. After one month transplanting of cuttings, significant differences (P < 0.05) were noted in survival percentage due to the media initially used. Cuttings initially propagated on sand showed a higher survival percentage (78.6%) and had a higher number of roots, which were longer, compared to cuttings initially propagated in a medium of sand + coir (61.2%). Cuttings initially propagated in sand and treated with hormone had significantly more roots after transplanting. Application of hormone also improved root and shoot length of transplants. Based on observations, cuttings taken from younger mother stock plants had a higher chance of survival than cuttings taken from mature stock plants. In general, leaf-bud cuttings of P. sidoides can be artificially propagated without rooting hormone but the success rate will be low. The ideal regime is to propagate cuttings treated with IBA in a sand medium.
Investigation of alternative molecular approaches for enhanced traceability of illegally traded Temminck's Ground Pangolins (Smutsia temminckii)
Heighton, Sean Paul (University of Pretoria, 2018-12)
Conservation regulatory bodies created to limit the overexploitation of wildlife are reliant on regulatory adherence. This over-reliance on regulation means that complementary approaches to assist with enforcement are often required. Wildlife forensics is one such approach that can be used to address the illegal trade in wildlife and pangolins in particular. With estimates from the legal trade being that over one million pangolins were trafficked in a ten-year period, it is clear that alternative approaches to curb illegal trade, which represents >98% of pangolin trade, are needed. Geographic traceability uses a range of markers and georeferenced samples for tracking the origins of trafficked pangolins and their derivatives. In this study, the applicability of two molecular profiling approaches (stable isotopes and host microbes) were evaluated for their traceability potential, for three pangolin populations sampled from two sites in the Kalahari (xeric savanna) and one site in the Lowveld (mesic savanna). The feasibility of carbon and nitrogen stable isotope traceability using pangolin scales was evaluated through mass spectrometry (Chapter 2). Results revealed that intra-scale and inter-individual variation are important considerations for traceability, whilst inter-scale variation and scale harvesting methods (boiling or direct flaming of carcasses) are not. Given the high levels of intra-scale variation, development of a time and cost-effective sampling protocol suitable for forensic investigations was attempted. It was found that the use of duplicate samples of homogenised scales provides an averaged effect on scale variability. However, scale tips are comparatively isotopically enriched and should be taken into consideration during forensic analyses. Although preliminary results indicate that geographic separation based on isotopic ratios between Lowveld and Kalahari regions may be possible, geographic partitioning through use of stable isotopes could not be conclusively demonstrated due to the small sample size. Baseline estimates of microbial diversity were established using two metagenomics approaches (cloning versus next generation sequencing (NGS)) targeting the 16S rRNA gene of bacteria and two taxonomic assignment methods (phylogeny testing versus a heuristic search tool; Chapter 3). These differed significantly with respect to microbial community composition with results suggesting that phylogeny testing in combination with NGS holds potential for pangolin traceability. Although whole microbial communities differed by 70.3% between the two Kalahari sites, constraints with respect to the number of localities sampled and the number of cloning colonies characterised are duly noted. The results also revealed that Clostridium sordellii and genospecies C. novyi sensu lato appear to be key site-specific taxa for presence/absence and topotype traceability methods, respectively.Using a primer-set developed to target the phylogenetically-informative phospholipase C gene, the potential health risks and geographic traceability efficacy of the C. novyi sensu lato pathogenic genospecies group was investigated (Chapter 4). Although the prevalence was moderate at 17.65% and thus not feasible for traceability purposes, the potential public and animal health risks that the genospecies group poses, particularly for the illicit trade of pangolins, is of concern. Expanded studies using high throughput metagenomics and additional stable isotopes hold promise for enhanced traceability of illegally traded pangolins, particularly when used together.
Unravelling the role of Aurora kinases in cell cycle regulation of malaria parasites
Abrie, Clarissa (University of Pretoria, 2018-11)
The P. falciparum parasite’s life cycle, and implied cell cycle, is strictly controlled allowing the parasite to rapidly develop during the intraerythrocytic stages alternating DNA synthesis and mitosis during endocyclic schizogony. This results in asynchronous nuclear divisions to form multinucleated schizonts during mitosis. However, mitotic nuclear division in P. falciparum parasites remain poorly understood. Several mitotic kinases of the P. falciparum kinome, such as aurora related kinases (ARKs), have been suggested to be cell cycle regulators. The PfARKs are essential for intraerythrocytic stages of the Plasmodium parasite of which PfARK-1 are highly conserved and associated with spindle pole bodies (SPB) during schizogony. The role of PfARK associated with SPB in cell cycle regulation of P. falciparum parasites has been understudied, despite the close link to centrosome and bipolar microtubule dynamics, chromosome segregation and cytokinesis of Aurora kinases in various other organisms. Knowledge gaps regarding the parasite’s cell cycle regulatory mechanisms is mostly due to the complexity associated with cell cycle compartment synchronisation of the parasite under in vitro conditions. In this dissertation, an innovative approach is used for cell cycle compartmentalisation of parasites as a tool to interrogate the importance of PfARK in cell cycle regulation during the intraerythrocytic stages of the parasite through hesperadin-induced PfARK inhibition. Collectively, this dissertation provides extensive insight to PfARK cell cycle regulation during parasite asynchronous nuclear division associated with M-phase progression, chromosomal segregation and spindle formation. The data demonstrate that novel cell cycle regulatory mechanisms of mitotic kinases, such as PfARKs and their involved pathways, serve as attractive future drug targets in Plasmodium parasites.