Heavy metal contamination in South African medicinal plants: A cause for concern

AbstractThe quality and safety of herbal medicines is becoming a major concern worldwide particularly due to contamination by heavy metals. The present study quantified the levels of heavy metals in frequently used South African medicinal plants and determined the variations in certain biological activities and phytochemical compositions. Eleven plant species were obtained from both muthi shops (MS) (commercial outlets) and from open street markets (OSM) for comparison. Samples were dried, powdered and digested using microwave acid-assisted digestion. The digested solutions were analysed for heavy metals using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Plants were classified based on their elemental composition using chemometric techniques. Powdered plant samples were extracted using 70% acetone and screened for antibacterial activity against E. coli and S. aureus. Phytochemical analyses were carried out to determine total phenolic and flavonoid content. Of the 22 samples analysed, Bulbine natalensis obtained from OSM and Alepidea amatymbica obtained from MS exhibited high levels of Al [5559 and 4392mg/kg dry weight (DW)] and Fe (4164 and 4465mg/kg DW) respectively. Levels of As and Hg were above the World Health Organization permissible limits in most of the samples analysed. Hierarchical cluster analysis classified the samples into four groups based on their metallic analyte concentrations. Group one having low metal content and group four having a high metal content. In general, plant samples with high levels of metals yielded greater antibacterial activity. However, antibacterial activity recorded in this study is not an indicator of high levels of heavy metal contamination as some samples despite the high levels of metal exhibited low antibacterial activity. The variations in the amounts of phenolics and flavonoids in the evaluated samples could have probably been that some of the plant samples may have been harvested from different localities or at different times of the year, perhaps plant age or degree of storage. The results highlighted the need for in-depth risk and quality assessments

Does the unification of health financing affect the distribution pattern of out‐of‐pocket health expenses in Turkey?

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149529/1/ijsw12389_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149529/2/ijsw12389.pd

Impacts of 1.5°C Global Warming on Natural and Human Systems

An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate povert

Micropropagation and secondary metabolites in Agathosma betulina (Berg.)

ArticleThe global demand for medicinal plant products has increased in the last two decades leading to overexploitation and sometimes extinction of indigenous medicinal plants. Plant biotechnology offers an efficient approach to enhanced biosynthesis of essential and/or bioactive compounds in plants. This study was aimed at developing a micropropagation protocol for Agathosma betulina Berg. (Buchu), one of the most highly utilized aromatic medicinal plants in South Africa. The study also aimed to develop a technique that will enhance the biosynthesis of some bioactive compounds by manipulating the media composition. Seeds and nodal explants from Buchu were decontaminated, germinated and sub-cultured on Murashige and Skoog (1962) (MS) media adjusted with different concentrations of N6-Benzyladenine (BA), 1-naphthaleneacetic acid (NAA) and dichlorophenoxy acetic acid (2,4-D). Dried samples from in vitro cultures were extracted using dichloromethane and analyzed for phytochemical compositions using GC–MS. In vitro seed germination produced healthy seedlings that can be transplanted ex vitro. Significantly higher shoot proliferation was recorded in nodal explants grown in 1/2 strength MS supplemented with 2,4-D and a combination of NAA and BA. Phytochemical analysis revealed significantly higher amounts of limonene accumulated in callus compared to other plant parts. The most abundant phytochemicals were recorded in plants grown on media supplemented with NAA 2.7 μM; these include limonene, pulegone and isomenthone (68, 39 and 33 μg kg− 1 DW respectively). Biosynthesis of certain compounds in in vitro culture of Buchu was induced by plant growth regulator application compared to the control. The plants possess a number of pharmacological properties including anticancer, antimicrobial and antioxidant. These activities are linked to inherent phytochemical contents. Hence, the use of micropropagation techniques that will enhance the biosynthesis of some bioactive compounds in Buchu will be an efficient means to meet the high demands for this plant.Cape Peninsula University of TechnologyNational Research FoundationStellenbosch Universit

Effects of drip irrigation on growth, physiological parameters, and yield in hydroponically cultivated cucumis sativus

The effect of drip irrigation regimen on growth, physiological parameters, and crop yield in Cucumis sativus L. was investigated using a drip irrigation system. The experimental design comprised eight various water regimens (2, 4, 6, 8, 10, 12, 14, and 16 L·h−1). Plants received water five times a day, making a total of 10, 20, 30, 40, 50, 60, 70, and 80 L per day. Growth and photosynthetic parameters were analyzed on a weekly base for a period of 8 weeks. Crop yield was measured at the end of the experiment. In general, photosynthetic rate (A), intercellular CO2 concentration (Ci), stomatal conductance (gS) and the transpiration rate (E) of the cucumber plants were enhanced by increasing water quantities compared with the control. Overall, the total chlorophyll content was significantly enhanced between week 7 and 8 in plants treated with high irrigation volume. Significant improvements were recorded in plant height and number of leave from week 3 to 8 in plants supplied with high irrigation volume. The observed increase in photosynthetic parameters, chlorophyll contents, and plant growths perhaps accounted for the significant increase in the number of marketable fruits in cucumber grown in higher water regimen. The optimal yield of cucumber in the present study was attained in plants irrigated with water regimen ranging from 40 to 80 L per day. The results of this study present valuable information that cucumber growers in South Africa should adopt the use of drip irrigation technique to save water considering the high drought condition in the country