Plants In South Africa Research Articles

Occurrence and risk assessment of azole antifungal drugs in water and wastewater

The occurrence of azole antifungals in the environment presents one of the emerging concerns due to their ecotoxicological threat as well as their potential contribution to the evolution of drug resistant fungi in the environment. In this study, the occurrence of eight commonly prescribed azole antifungal drugs was seasonally determined in influent and effluent water samples from three wastewater treatment plants and a drinking water treatment plant in South Africa. In addition, the risk quotient (RQ) method was employed to investigate the potential ecological and human health risks associated with their presence in the wastewater and/or drinking water. Clotrimazole, econazole, fluconazole, itraconazole, ketoconazole and miconazole were detected at least once in the water samples, while posaconazole and voriconazole were not detected in any of the samples for all seasons at which the samples were collected. Fluconazole was detected at higher frequency (about 96%) with a concentration up to 9959.0 ng L−1. Clotrimazole had the second highest frequency of detection (about 33%) with a concentration up to 143.3 ng L−1. Statistically significant temporal variation in clotrimazole (p < 0.05) and spatial variation in fluconazole (p < 0.05) were observed. In general, the preliminary ecological risk assessment based on risk quotient (RQ) calculation indicated that there is currently no high risk against aquatic organisms (Algae, Daphnia and Fish) related to the azole antifungals. Meanwhile, human health risk assessment demonstrated that fluconazole represented high risk in drinking water. Furthermore, risk estimates showed a potential for the detected concentrations of fluconazole and itraconazole in water samples to pose moderate to high risk for development of antifungal drug resistance. Some of the azole antifungal drugs are ubiquitous in the wastewater and future monitoring and validation studies should be conducted for those drugs that seem to pose human health and ecological risks.

Value Chain Analysis of Medicinal Plants in South Africa

Value Chain Analysis of Medicinal Plants in South Africa

Bulbine frutescens phytochemical inhibits notch signaling pathway and induces apoptosis in triple negative and luminal breast cancer cells

Breast cancer (BCa) is the most commonly diagnosed lethal cancer in women worldwide. Notch signaling pathway is directly linked to BCa recurrence and aggressiveness. Natural remedies are becoming a prime choice to overcome against cancer due to lesser side effect and cost-effectiveness. Bulbine frutescens (Asphodelaceae), a traditional medicinal plant in South Africa possess bioactive flavonoids and terpenoids. Polar (methanol) and non-polar (hexane) B. frutescens plant extracts were prepared. GC–MS analysis revealed the differential presence of secondary metabolites in both methanolic and hexane extracts. We hereby first time evaluated the anticancer potential of B. frutescens methanolic and hexane extract in triple-negative and luminal BCa cells. B. frutescens extracts significantly decreased cell viability (IC50 4.8–28.4 μg/ml) and induced cell cycle arrest at G1 phase in MDA-MB-231 and T47D cells as confirmed by spectrophotometry and flow cytometry technique. RT-PCR analysis of cell cycle (cyclin D1, CDK4, and p21) and apoptosis modulating genes (caspase 3, Bcl2 and survivin) revealed upexpression of p21, and caspase 3, and down expression of cyclin D1, CDK4, Bcl2 and survivin genes in extract-treated BCa cells. Fluorescence spectrophotometry and confocal microscopy showed B. frutescens induced nuclear morphology and mitochondrial integrity disruption, and increased reactive oxygen species production in MDA-MB-231 and T47D cells. Flow cytometric apoptosis analysis of B. frutescens extracts treated MDA-MB-231 cells showed ≈13% increase in early apoptotic population in comparison to non-treated cells. Dual-Luciferase Reporter assay confirmed notch promoter inhibitory activity of B. frutescens extracts. Moreover, RTPCR analysis showed down regulation of notch responsive genes (Hes1 and Hey1) at transcription levels in extract-treated BCa cells. Western Blot analysis showed increased procaspase 3 protein expression in extract-treated BCa cells. In all the assays methanolic extract showed better anti-cancer properties. Literature-based identification of methanol soluble phytochemicals in B. frutescens and in silico docking study revealed Bulbineloneside D as a potent ϒ-secretase enzyme inhibitor. In comparison to standard notch inhibitor, lead phytochemical showed two additional hydrophobic interactions with Ala80 and Leu81 amino acids. In conclusion, B. frutescens phytochemicals have cell cycle arrest, ROS production, apoptosis induction, and mitochondria membrane potential disruption efficacy in breast cancer cells. B. frutescens phytochemicals have the ability to downregulate the notch signaling pathway in triple-negative and luminal breast cancer cells.

A proposed simulation-based theoretical preconstruction process: The case of solar photovoltaic technology in South African shopping centres

At present, simulation processes for determining the yield of PV plants are fairly unstructured. This research proposes a structured pre-assessment process to increase the electricity yield of a PV plant in South Africa throughout its life cycle. Furthermore, enhanced electricity yield and increased accuracy in estimating the yield of such a plant will result in a higher degree of return on investment, and reduce the propability of legal disputes between the parties involved. A shopping centre, consuming approximately 5000 kVA under maximum load, in Johannesburg, Gauteng, was used as a case study to apply the proposed pre-assessment of a solar PV plant. The pre-assessment includes analysing the load demand of the shopping centre (without the presence of the solar PV plant), relating that to the seasonal change and the subsequent average ambient temperature variation and conducting simulations in PVSyst 6.7.9 by permuting various variables within the software. The variables include investigating the effect of PV module orientation adjustment, the effect of PV module degradation on electricity yield over its lifespan and the effect of increasing the array-to-inverter ratio (DCpower/ACpower). The research found that by implementing the process, the electricity yield and return on investment will be increased.

Antidiabetic, anti-inflammatory, anticholinesterase and cytotoxicity determination of two Carpobrotus species

Carpobrotus edulis (L.) N. E. Br., commonly grown in many parts of the world, and C. dimidiatus (Haw.) L. Bolus are highly used medicinal plants in South Africa for treating diabetes, wounds, inflammation and other closely-related diseases. This study was aimed at evaluating the antidiabetic, anti-inflammatory, and acetylcholinesterase inhibitory activities as well as cytotoxicity effects (using RAW 264.7, Vero kidney and HepG2 liver cells) of different solvent (water, 70% acetone, and 50% methanol) extracts obtained from the leaves of C. edulis and C. dimidiatus. Antidiabetic and anti-inflammatory activities were evaluated using alpha-glucosidase and 15-lipoxygenase (LOX) enzyme inhibition assays, respectively. In addition, the phenolic content of the two plant species was quantified. Water extract of C. edulis leaves exhibited noteworthy alpha-glucosidase inhibitory activity with an IC50 value of 5 μg/ml. Acetone and water extracts of C. edulis showed promising 15-LOX inhibition activity with IC50 values of 22.3 and 59.8 μg/ml, respectively. These same extracts demonstrated strong free radical scavenging activity as reflected by their EC50 values of 5.6 and 6.2 μg/ml, respectively. Carpobrotus edulis leaves had a significantly high total phenolic and flavonoid contents when compared to C. dimidiatus. Furthermore, all extracts exhibited very low cytotoxicity against all the tested cells. The current findings offer supporting evidence for the use of these plant species in the development of natural products to treat diabetes, among other ailments. These plant species can be used in the production of natural supplements or functional food for the management of pain, diabetes and free radical-induced disorders.

Risk assessment to interpret the physiological host range of Hydrellia egeriae, a biocontrol agent for Egeria densa

Egeria densa Planchon (Hydrocharitaceae) is a submerged macrophyte native to South America. It forms part of a new suite of invasive aquatic plants that has benefited from open nutrient-rich freshwater systems following the successful biological control of floating aquatic plants in South Africa. The specificity of the leaf-mining fly, Hydrellia egeriae Rodrigues (Diptera: Ephydridae) was tested, using traditional laboratory host-specificity testing (i.e., no-choice and paired choice). Only one non-target species, Lagarosiphon major Deeming (Hydrocharitaceae) supported larval development during pair-choice tests. In order to avoid the rejection of a safe and potentially effective agent, continuation (i.e., multiple generations) tests were conducted to measure the ability of the non-target species to nutritionally support a population indefinitely. None of these species could sustain a viable agent population for more than three generations. Laboratory host-specificity tests are limited as they exempt certain insect-host behaviours. To enhance the interpretation of host-specificity results, a risk assessment was conducted using agent preference (i.e., choice tests) and performance (i.e., choice and continuation tests) results. The feeding and reproductive risk that H. egeriae poses to non-target species is below 2%. Based on these findings, permission for its release in South Africa has been obtained.

A streamlined life cycle assessment of a coal-fired power plant: the South African case study.

Non-renewable energy sources have detrimental environmental effects, which directly and indirectly affect the biosphere as environmental deposits from their use for energy generation exceed a threshold. This study performs a streamlined life cycle assessment (LCA) of a coal-fired plant in South Africa. The cradle-to-grave LCA focuses on the coal cycle to determine hotspots with high environmental impacts in the process. Four impact categories were considered in this study: global warming potential, photochemical ozone creation potential, eutrophication potential, and acidification potential. Coal transportation, coal pulverization, water use, and ash management were identified as hotspots in the coal cycle. The coal process has 95% potential for global warming, 4% potential for eutrophication, 1% potential for acidification, and a negligible percentage for photochemical ozone creation. Susceptibility to climate change, eutrophication, acid rain, soil degradation, and water contamination among others are major concerns of the coal cycle. Outsourcing coal from nearby mines with train as medium of transportation reduces environmental impact. Similarly, the use of mitigation technologies like flue gas desulphurization, carbon capture storage, or selective catalytic reduction will reduce the concentration of the flue gas emitted. Ultimately, substituting the coal process with renewable energy sources will ensure environmental sustainability in South Africa. This study will serve as a good resource for further studies on LCA of coal power plants not only in other African countries but in other developing countries with similar situation.

The Color Line and the Assembly Line: Managing Race in the Ford Empire. By Elizabeth D. Esch (Berkeley, University of California Press, 2018) 257 pp. $85.00 cloth $29.95 paper and e-book

The Ford Motor Company was not only a leader in the adaptation of assembly-line technologies to auto production; it was also unusual in several dimensions of its approach to labor relations. Esch examines the interplay of Ford’s technological practices and its broader labor policies, giving particular attention to Ford’s approach to race, ethnicity, and immigrant status in forming its workforce. Although she provides a thorough discussion of Ford’s plants in Detroit, a major goal of this volume is to extend the Ford story by examining the company’s labor practices outside the United States, especially on its rubber plantations in Brazil and in its production facilities in South Africa.Esch makes much use of quantitative studies of Ford by economic historians, as well as archival material. Her discussion repeatedly calls back to Gramsci’s writing on Ford and on the interplay between technology, culture, and politics in getting workers to produce under Ford’s intense system.1Chapters 1, 2, and 3, which focus on Ford’s activities in the United States, are the most thoroughly developed. Esch begins with an examination of Ford’s use of immigrant workers, particularly at the Highland Park plant. Ford’s establishment of the $5.00 day wage, in part to stymie organizing efforts, was tied to a program of “Americanization” through Ford’s Sociological Department and English School. Esch’s discussion of this program is thorough and vivid, including a description of the graduation ceremonies at the English School in which immigrant workers emerged from an actual “melting pot” waving American flags.2As production moved from Highland Park to Rouge, Ford began to draw from different labor supplies, and the company’s methods of extracting effort also changed. Rather than focusing on “making [American] men” out of an immigrant workforce, this new approach established order through both the pace of the assembly line and the harsh, sometimes arbitrary, discipline meted out by supervisors. Esch emphasizes that the role of the foreman as a driver of labor was a constant in Ford’s modern production methods, and she connects this system of labor control to Ford’s expressions of support for emerging Fascist movements.Esch highlights the role of the “color line” in her extended discussion of the use of African-American labor at Rouge. She aptly applies the work of Whatley, Wright, and their co-authors in creating and analyzing data sets based on personnel records from Ford’s Detroit plants in the 1920s, 1930s, and 1940s.3 The main lesson is that Ford was effective in exploiting the limited outside options of African-American workers by concentrating them in difficult and dangerous jobs that white workers would not tolerate for long, particularly in the foundry.Chapters 4 and 5 deal with Ford’s rubber production facilities in the Amazon and auto plants in South Africa. In Brazil, Ford applied aspects of both its “making men” and foreman-driven methods of extracting effort at rubber-production facilities at Fordlandia and Belterra. In neither case was Ford able to adapt its established methods to this new context. Esch’s discussion of South Africa focuses on the 1920s and 1930s, well before the formal establishment of apartheid. She notes that “company records on Ford in South Africa are scarcely available” for this period (152). She instead highlights analysis and recommendations in the 1932 Carnegie Commission Report about the conditions of the white poor in South Africa. The Carnegie Report emphasized themes similar to those characterizing labor relations at Highland Park—the reform of the white poor through factory discipline and mass consumerism. Although these ideas apparently influenced government and business leaders in pre-apartheid South Africa, concrete evidence about Ford’s “specific impact” is, as Esch admits, “fragmentary” (181).In a substantive concluding chapter, Esch takes a look at the operation of new Ford facilities around the globe and the firm’s continuing practice of identifying vulnerable groups of workers that might be susceptible to intense production methods. Her discussion of the use of migrants from the countryside in urban auto plants in China, in particular, draws interesting and surprising parallels to Ford’s use of migrant black workers at Rouge.Esch’s discussion of Ford’s practices outside the United States is less detailed than her discussion of Detroit, but she provides a useful starting point for examining Ford’s adaptation of its labor practices to differing national contexts. Historians and historically minded social scientists will find this book to be an accessible, informative, and engaging contribution to the literature about Ford.

Geographic-based metabolomic variation and toxicity analysis of Sutherlandia frutescens L. R.Br. – An emerging medicinal crop in South Africa

Sutherlandia frutescens (syn. Lessertia frutescens), an indigenous southern African species, is important for the local and global phytomedicine's industry. As farming of medicinal plants in South Africa is not extensive, wild populations are also used as a source of material to bulk available cultivated yields prior to industrial processing. This may cause inconsistency in the quality of medicinal products derived from this species, inducing discrepancies in the plant’s therapeutic profile. The current study aimed to elucidate the phytochemical variations among S. frutescens plants growing in different geographical localities, especially in areas which have not been studied before. One set of extracts were generated using a 50% acetonitrile and formic acid solution (0.1%) (v/v). By using a targeted metabolomics approach, two major phytochemical groups, sutherlandins and sutherlandiosides were used to display metabolite-based clusters after LC–MS/MS analysis. Plants from different geographical locations grouped into separate chemical lineages. Another set of ethanol and aqueous extracts of pooled leaf materials were screened for their toxicity effect on the hatching rate of zebrafish embryos and mortality of larvae at different concentrations, ranging from 5 to 300 μg ml−1. We also calculated the LC50 values using a zebrafish microplate bioassay and this value was 297.57 μg ml−1 for the water extract. The aqueous extracts were relatively less toxic compared to ethanol extracts (LC50 value of 40.54 μg ml−1). Both the hatching rate and mortality were negatively affected by increasing extract dosages. The highest concentrations, between 200 to 300 μg ml−1, caused acute lethal effects for both extract types. This study adds additional evidence of the cytotoxicity reported by others in this species and will further aid in the domestication of S. frutescens.

A new leafhopper genus Discolopeus and nine new species (Hemiptera, Cicadellidae, Deltocephalinae) associated with shrubs, trees and poisonous plants in South Africa.

Nine new species in a new genus, Discolopeus gen. n. are described from south-western South Africa, with some species associated with plants that are medicinal or toxic or harmful to ungulates, such as Antizoma miersiana (Menispermaceae), Galenia africana (Aizoaceae), Hyaenanche globosa (Euphorbiaceae) and Zygophyllum foetidum (Zygophyllaceae). New species are as follows: Discolopeus arctus, D. colopeus, D. copeus, D. diacaenus, D. lissus, D. tetracaenus, D. thigmacaenus, D. triacaenus and D. viraktamathi. This new genus is allied to the Bonaspeiini, and distinguished by a paired aedeagal, preatrial process. Cladistic analyses of morphology with parsimony, Bayesian inference and maximum likelihood examined species relationships and showed the monophyly of Discolopeus. Historical biogeographic analyses examined hypotheses of dispersal and vicariance to explain distributions. Niche modelling showed narrow distribution in south-western parts of South Africa.

Life cycle cost profitability of biomass power plants in South Africa within the international context

South Africa's renewable energy programme has been widely considered a success. Biomass is one of the selected technologies, on which capacity and tariff caps are set in place. It is unclear whether the price caps allow for sufficient profits for private role-players. The aim of the study is to investigate the potential profit margins for biomass power plant companies entering the programme. Costs throughout the lifespan of the power purchase agreement were determined by using the Levelised Cost of Electricity (LCOE) metric. The method used cost inputs which were determined using a mixture of local and international indicators for three scenarios, the worst case (WC) scenario representing highest input costs, the most likely case (MLC) scenario representing median costs, and best case (BC) scenario representing lowest input costs. The results show that the WC, MLC and BC LCOE for biomass power plants in South Africa are 3.53 ZAR/kWh (0.235 USD/kWh), 1.30 ZAR/kWh (0.086 USD/kWh) and 0.78 ZAR/kWh (0.052 USD/kWh), respectively. In all three scenarios, the bulk of the cost constitute delivered fuel costs. Considering sales tariffs at ZAR1.475/kWh, profit margins for WC, MLC and BC scenarios were determined as −139%, 12% and 47%, respectively. These figures compare favourably with China, the United States of America, and Europe in general, opposed to Canada, where higher profit margins are achievable.

Manager-Employee Relationships during Turbulent Times at a Gold Mine in South Africa

This article aims to provide new conceptual insights into the responsibilities of an engineer who acts as a plant manager and who has to deal with employee relations during a turbulent time at a gold mining plant in South Africa. A qualitative research approach was used to gather the data in this study. Trustworthiness of the research was ensured by applying various reasoning strategies, such as content analysis, inductive reasoning, blending, bracketing and understanding in order to interpret the data. The first group interview comprised managers as well as engineers who were appointed as managers, the second, administrative employees from the service departments, and the third, artisans and foremen employed at the mine. Qualitative content analysis was used to analyse the transcripts. The recurring themes from the group interviews were ‘employee empowerment’, ‘trust building’, ‘employee voice’ and ‘development of skills’. A conceptual framework for manager-employee relations during troubled times was developed from the findings. The essential responsibilities of a gold mining plant manager during periods of turbulence were described.

Power quality grid code compliance for renewable power plants in South Africa

The introduction of renewable generation to South Africa's grid has introduced challenges to the management and regulation of power quality (PQ). These have been addressed by establishing PQ compliance criteria in line with local circumstances and by the introduction of a Power Quality Guideline for renewable power plants (RPPs). A key challenge to RPPs has been meeting emission limits for harmonics. This has been addressed in South Africa's RPP Guideline by the development and introduction of a Group Harmonic Distortion limit which provides some flexibility to RPPs in making individual harmonic emission limits. The use of 95th percentile harmonic impedance envelopes is discussed and recommendations for impedance envelopes are made for different voltage levels within the South African Grid, based on actual network data. A lesson learnt is that using international standards and guidelines provides a starting point for compliance rules when introducing renewable generation. Developing countries that share economic and electricity network characteristics with South Africa should tailor the PQ rules and guidelines for RPPs to meet local conditions.

Geochemical scaling potential simulations of natural organic matter complexation with metal ions in cooling water at Eskom power generation plants in South Africa

The modified database in the pH, redox equilibrium calculations code (PHREEQC) with a Tipping and Hurley database (T_H.DAT) coupled with the Windermere’s humic acid model (WHAM) was used to simulate scale formation potential in cooling water circuitry, at Eskom power generating stations in South Africa. This study reports a semi-empirical simulative approach in which organic matter fractions, metals and anions in raw and cooling water were used as modelling experimental inputs. By using the saturation index profiles of Ca2+/ Mg2+ with fulvic acid in a modified Tipping and Hurley (T_H.DAT) database, fulvate complex species such as CaFulvate, MgFulvate, and geochemical modelling predictions, mineral phases that potentially precipitate are discussed. Speciation calculations showed that the increase in fulvic acid levels decreased saturation indices of scaling metal phases due to reduced levels of Ca2+ and Mg2+ in the water. Furthermore, if the concentrations of fulvic acid are known, semi-empirical calculations using the geochemical PHREEQC code with a modified T_H.DAT arepossible. Consequently, mineral phase equilibria outputs may give an indication of how the pH and temperature is to be manipulated to optimally predict and control the incidence of scaling.

Historicising perceptions and the national management framework for invasive alien plants in South Africa

This article offers a historical framework for understanding changes to human perceptions and efforts to manage invasive alien plants and weeds in South Africa from the mid-nineteenth century until the present. The article argues that South African legislation and policy for managing invasive alien plants and weeds has historically been limited because people have held contradictory values about plants, many private land owners have lacked resources and have not been compelled to follow government legislation and because policy has reflected the interests of a small group of farmers or scientific experts who have had limited influence on most private land owners and traditional land users. Successful control efforts often relied on technical expertise that was applied controversially or could be implemented on government land without extensive public consultation or social conflict. The creation of a national framework for invasive alien plants through the Working for Water Programme in 1995 and National Environmental Management of Biodiversity Act (no. 10) of 2004 (NEMBA) has increased public awareness, but the Programme and NEMBA remain limited by many of the same institutional and social constraints that experts and institutions faced in the past. In conclusion, the article draws on history to provide insights to contemporary challenges.

Characterization of Ralstonia strains infecting tomato plants in South Africa

Ralstonia spp., the causal agents of bacterial wilt, cause severe yield losses of Solanaceous crops, including tomato. The disease is difficult to control due to the pathogen's ability to survive in soil and to cause latent infections. Therefore, characterizing Ralstonia strains is important in developing effective strategies for diagnoses, quarantine and selection of biocontrol agents. In this study, 50 Ralstonia strains previously isolated from wilted tomato plants in different locations in South Africa were obtained from the culture collection of the Agricultural Research Council, Pretoria, and private seed companies. A phylogenetic analysis of the endoglucanase gene sequences revealed that 49 strains were R. pseudosolanacearum and only one was R. solanacearum. R. pseudosolanacearum strains grouped into two sequevars, 18 and 31, while the single R. solanacearum strain grouped into the cold-adapted sequevar 1, also known as race 3 biovar 2. The pathogenicity results revealed that the selected strains were pathogenic on tomato seedlings. This study thus revealed that bacterial wilt of tomato is caused primarily by R. pseudosolanacearum, but R. solanacearum IIB-1 is also present in South Africa. This information is relevant in terms of the implementation of quarantine measures, notably to put into place measures that will prevent the introduction of strain IIB-1 into other provinces of South Africa.

Bioprospecting of South African Plants as a Unique Resource for Bioactive Endophytic Microbes.

South Africa has a long history and strong belief in traditional herbal medicines. Using ethnobotanical knowledge as a lead, a large number of South African medicinal plants have been discovered to possess a wide spectrum of pharmacological properties. In this review, bioprospecting of endophytes is highlighted by following the advantages of the ethnomedicinal approach together with identifying unique medicinal plants where biological activity may be due to endophytes. This review focuses on the current status of South African medicinal plants to motivate the research community to harness the benefits of ethnobotanical knowledge to investigate the presence of endophytic microbes from the most potent South African medicinal plants. The potential chemical diversity and subsequent putative medicinal value of endophytes is deserving of further research. A timely and comprehensive review of literature on recently isolated endophytes and their metabolites was conducted. Worldwide literature from the last 2 years demonstrating the importance of ethnobotanical knowledge as a useful approach to discover endophytic microbes was documented. Information was obtained from scientific databases such as Pubmed, Scopus, Scirus, Google Scholar, Dictionary of Natural Products, Chemical s Services, official websites, and scientific databases on ethnomedicines. Primary sources such as books, reports, dissertations, and thesises were accessed where available. Recently published information on isolated endophytes with promising bioactivity and their bioactive natural products worldwide (2015-2017) was summarized. The potential value of South African medicinal plants as sources of endophytes is discussed. The insights provided through this study indicate that medicinal plants in South Africa are highly under-investigated sources of potentially useful endophytic microbes. New approaches may be used by medicinal plant scientists for further exploration of natural products from endophytic fungi and bacteria in southern Africa.

Noxious to ecosystems, but relevant to pharmacology: Four South African alien invasive plants with pharmacological potential

Alien invasive plants pose a huge threat to natural and semi-natural ecosystems in their introduced ranges thereby compromising ecosystem integrity. However, anecdotal and empirical evidence suggests that some invasive alien plants are used in traditional medicine due to their pharmacological activities. Here, we evaluated the antimicrobial activity of 70% ethanol, dichloromethane, acetone and hot water extracts of four invasive alien plants in South Africa viz. Dolichandra unguis-cati, Cardiospermum grandiflorum, Chromolaena odorata and Gomphrena celosioides against pathogenic and non-pathogenic microbes. The test organisms included Staphylococcus aureus, Salmonella enterica serovar Typhimurium (S. Typhimurium), Salmonella Dublin, Klebsiella pneumoniae, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Mycobacterium aurum, M. fortuitum, M. smegmatis, Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans. Phytochemicals that may be responsible for antimicrobial activity were determined using standard phytochemical methods. A further objective was to investigate the safety of these plants by conducting cytotoxicity and genotoxicity tests. All solvent extracts of plants investigated exhibited a broad spectrum of antibacterial activity with minimum inhibitory concentration (MIC) values ranging from 0.039 to 2.5 mg/ml, with the acetone and dichloromethane extracts showing better activity against E. coli, K. pneumoniae and E. faecalis (MIC between 0.039 and 0.078 mg/ml). Of all extracts tested, only the ethanol extracts of C. grandiflorum showed good antimycobacterial activity with MIC of 0.078 mg/ml against M. smegmatis. In contrast, C. grandiflorum only showed moderate antifungal activity, while dichloromethane and acetone extracts of the other three plants were very effective against C. neoformans and A. fumigatus with MIC values ranging from 0.019 to 0.078 mg/ml. All four plants moderately inhibited C. albicans at MIC of 0.156 mg/ml. The plant species were rich in phenolics, flavonoids and tannins in varying amounts and had relatively low levels of cytotoxicity and none was mutagenic. Promising selectivity index values (between 10 and 50) highlight the potential of these plant species as sources of antimicrobial remedies. Despite the ecological noxiousness of these alien invasive plants, our findings suggest that they possess some antimicrobial properties that are too pharmacologically relevant to ignore.

Russian Projects and Energy Cooperation in South Africa

The article discusses the problems and prospects for the development of a Russian nuclear power plants in South Africa, as well as other innovative energy projects in this country. Acute energy shortages in South Africa give Russia a unique chance to enter the African market and create a technological link between African countries and Russian innovations. An analysis of the political and economic situation in South Africa, as well as an assessment of the prospects for Russian business participation in the development of the South African energy sector were carried out using research conducted by the authors in South Africa in 2016, and interviews with Russian and South African civil servants and businesmen.

Biological Activities of Heteropyxis natalensis Against Micro-Organisms Involved in Oral Infections.

The use of complementary and alternative medicine from plants in South Africa, as in the rest of the world, continues to increase. Heteropyxis natalensis, known as the Lavender tree, is indigenous to South Africa and is traditionally used for oral care. The ethanolic extract, of the leaves and twigs, of H. natalensis was investigated for antimicrobial activity against selected oral microorganisms. Actinomyces israelii was found to be the most sensitive oral microorganism to the extract, with a minimum inhibitory concentration (MIC) of 0.88 mg/ml and an MIC of 2.6 mg/ml against Streptococcus mutans. Five known compounds were identified from the ethanolic extract of H. natalensis. The compounds were identified as aurentiacin A (1), cardamomin (2), 5-hydroxy-7-methoxy-6-methylflavanone (3), quercetin (4) and 3,5,7-trihydroxyflavan (5). The MICs of the compounds 1 and 4 were found to be 0.06 mg/ml and 1 mg/ml, respectively, against A. israelii. The cytotoxicity, acute and sub-acute toxicity in pre-clinical studies were also determined for H. natalensis. The extract showed moderate cytotoxicity (35.56 ± 0.16 μg/ml) on human monocyte cells. The acute and sub-acute toxicity analysis of H. natalensis indicated the NOEL (no-observed-effect level) at 200 mg/kg. Interleukin-8 (IL-8) is a chemokine that stimulates the recruitment of leukocytes. A significant reduction of IL-8 production by macrophage cells was observed when exposed to the extract of H. natalensis. It is possible that H. natalensis can prevent excessive tissue damage in periodontal diseases through its reduction of inflammation. Enzymatic bioanalysis of lactic and acetic acid production from Streptococcus mutans and Lactobacillus paracasei was done. A reduction in the acid production from each bacterium was observed on exposure to the extract of H. natalensis. Consequently, this increased the pH, which could possibly reduce the demineralization of enamel which may help prevent the formation of dental caries. In addition the extract may be considered for preventing periodontal diseases.