The anticancer, antioxidant and phytochemical screening of Philenoptera violacea and Xanthocercis zambesiaca leaf, flower & twig extracts

Published ArticleThe aim of this study was to investigate the antioxidant potential, anticancer activity, phytochemical constituents and total phenolic content of Philenoptera violacea and Xanthocercis zambesiaca leaves, flower & twig extracts. The anticancer activity of the extracts was tested in the 5-cell line panel consisting of MCF7 (breast cancer), HCT116 (colon cancer), TK10 (renal), UACC62 (melanoma) and PC3 (prostate cancer) by Sulforhodamine B (SRB) assay at the CSIR. The scavenging activities of the Xanthocercis zambesiaca extract and Philenoptera violacea was determined by 2, 2- diphenyl-1-picrylhydrazyl (DPPH) assay and was compared with standard antioxidant (ascorbic acid). Xanthocercis zambesiaca showed moderate (50%) free radical scavenging activity, while Philenoptera violacea extract had low free radical scavenging activity at the concentration of 2.5 mg/ml when compared to ascorbic acid. Qualitative phytochemical analysis of these plant extracts confirmed the presence of tannins, flavonoids, steroids, terpenoids, alkaloids and cardiac glycosides from Philenoptera violacea extract, while Xanthocercis zambesiaca extract showed the presence of flavonoids, saponnins, terpenoids and glycosides. Both extracts showed inactivity against all 5 cell lines with an IC50 of more than 100 μg/ml. Our results indicate that, Xanthocercis zambesiaca extract is a weak source of antioxidant and Philenoptera violacea extract has a number of phytochemical compounds. Future study will be done to isolate and identify the active compounds of both these plants

Self-Assembled Lipid Cubic Phase and Cubosomes for the Delivery of Aspirin as a Model Drug

Three-dimensionally organized lipid cubic self-assemblies and derived oil-in-water emulsions called “cubosomes” are attractive for various biotechnological applications due to their ability to be loaded with functional molecules and their associated sustained release properties. Here, we employed both of these lipid-based systems for the delivery of a model drug, aspirin, under comparable conditions. Studies were performed by varying drug-to-lipid ratio and the type of release medium, water and phosphate buffer saline (PBS). Release rates were determined using UV−vis spectroscopy, and small-angle X-ray scattering was used to confirm the type of self-assembled nanostructures formed in these lipid systems. The release from the bulk lipid cubic phase was sustained as compared to that of dispersed cubosomes, and the release in PBS was more efficient than in water. The tortuosity of the architecture, length of the diffusion pathway, type of nanostructure, and physicochemical interaction with the release media evidently contribute to these observations. This work is particularly important as it is the first report where both of these nanostructured lipid systems have been studied together under similar conditions. This work provides important insights into understanding and therefore controlling the release behavior of lipid-based drug nanocarriers

Isolation and characterisation of endocrine disruptor nonylphenol-using bacteria from South Africa

Published ArticleEndocrine disrupting chemicals (EDCs) are synthetic chemicals that alter the function of endocrine systems in animals including humans. EDCs are considered priority pollutants and worldwide research is ongoing to develop bioremediation strategies to remove EDCs from the environment. An understanding of indigenous microorganisms is important to design efficient bioremediation strategies. However, much of the information available on EDCs has been generated from developed regions. Recent studies have revealed the presence of different EDCs in South African natural resources, but, to date, studies analysing the capabilities of microorganisms to utilise/degrade EDCs have not been reported from South Africa. Here, we report for the first time on the isolation and enrichment of six bacterial strains from six different soil samples collected from the Mpumalanga Province, which are capable of utilising EDC nonylphenol as a carbon source. Furthermore, we performed a preliminary characterisation of isolates concerning their phylogenetic identification and capabilities to degrade nonylphenol. Phylogenetic analysis using 16S rRNA gene sequencing revealed that four isolates belonged to Pseudomonas and the remaining two belonged to Enterobacteria and Stenotrophomonas. All six bacterial species showed degradation of nonylphenol in broth cultures, as HPLC analysis revealed 41–46% degradation of nonylphenol 12 h after addition. The results of this study represent the beginning of identification of microorganisms capable of degrading nonylphenol, and pave the way for further exploration of EDC-degrading microorganisms from South Africa

In Vitro Antibacterial, Antioxidant and Anti-Inflammatory Effects of Senecio Asperulus and Gunnera Perpensa from Mohale’s Hoek, Lesotho

Original ArticleBackground: Traditional medicinal plants have been widely used to treat or manage various ailments for centuries in Lesotho. With an increase in multi drug resistance and undesired adverse events to current drugs challenges, there is a need for alternative drugs. Aim: In this study we aimed at the investigation of antibacterial, antioxidant and anti-inflammatory effects of Senecio asperulus and Gunnera perpensa roots extracted in three solvents of different polarities. Materials and Methods: Antibacterial activity was determined using the disc diffusion method, while antioxidant activity was determined using free radical scavenging of 2,2-diphenyl-1-picrylhydrazyl and the ferric reducing antioxidant power assay. The Lipopolysaccharide (LPS) stimulated RAW 264.7 mouse macrophage in vitro model was used to evaluate the anti-inflammatory activity of both plants. Resveratrol was used as a positive control. Results: Methanol extracts of Senecio asperulus inhibited microbial growth even at the lowest concentration of 50 μg/ml. Senecio asperulus dichloromethane extract was active on most bacteria with MIC’s between 50 μg/ml and 500 μg/ml. However, the water and methanol extracts of Gunnera perpensa had no activity against all organisms tested. Aqueous extracts of Senecio asperulus and Gunnera perpensa showed free radical scavenging activity yielding EC50 values of 100 μg/ml and 25 μg/ml, respectively. The aqueous extracts of Senecio asperulus showed moderate anti-inflammatory activity from 50 to 200 μg/ml. while the methanol extract was at 200 μg/ml and with no cytotoxicity. No anti-inflammatory activity was observed from all Gunnera perpensa extracts using LPS-induced macrophages, this suggests that this species may be using other mechanisms for anti-inflammatory activity. Conclusion: The antibacterial, antioxidant and anti-inflammatory activities observed from water extracts of Senecio asperulus support its ethnomedicinal use for the management of inflammation related diseases

Natural compounds isolated from African mistletoes (loranthaceae) exert anti-inflammatory and acetylcholinesterase inhibitory potentials : in vitro and in silico studies

DATA AVAILABILITY STATEMENT: All data generated or analysed during this study are included in this published article.Please read abstract in article.The Central University of Technology operational expenses and the National Research Foundation (NRF) of South Africa.https://www.mdpi.com/journal/applsciParaclinical Science

Personal NO2 and volatile organic compounds exposure levels are associated with markers of cardiovascular risk in women in the Cape Town region of South Africa

CITATION: Everson, F., et al. 2019. Personal NO2 and volatile organic compounds exposure levels are associated with markers of cardiovascular risk in women in the Cape Town region of South Africa. International Journal of Environmental Research and Public Health, 16(13):2284, doi:10.3390/ijerph16132284.The original publication is available at http://www.mdpi.comENGLISH ABSTRACT: Exposure to ambient NO2 and benzene, toluene ethyl-benzene and m+p- and o-xylenes (BTEX) is associated with adverse cardiovascular effects, but limited information is available on the effects of personal exposure to these compounds in South African populations. This 6-month follow-up study aims to determine 7-day personal ambient NO2 and BTEX exposure levels via compact passive diffusion samplers in female participants from Cape Town, and investigate whether exposure levels are associated with cardiovascular risk markers. Overall, the measured air pollutant exposure levels were lower compared to international standards. NO2 was positively associated with systolic and diastolic blood pressure (SBP and DBP), and inversely associated with the central retinal venular equivalent (CRVE) and mean baseline brachial artery diameter. o-xylene was associated with DBP and benzene was strongly associated with carotid intima media thickness (cIMT). Our findings showed that personal air pollution exposure, even at relatively low levels, was associated with several markers of cardiovascular risk in women residing in the Cape Town region.https://www.mdpi.com/1660-4601/16/13/2284Publisher's versio

A Comprehensive Review On Zinc(Ii) Complexes As Anti-Diabetic Agents: The Advances, Scientific Gaps And Prospects

ArticleZinc has gained notable attention in the development of potent anti-diabetic agents, due to its role in insulin storage and secretion, as well as its reported insulin mimetic properties. Consequently, zinc(II) has been complexed with numerous organic ligands as an adjuvant to develop anti-diabetic agents with improved and/or broader scope of pharmacological properties. This review focuses on the research advances thus far to identify the major scientific gaps and prospects. Peer-reviewed published data on the anti-diabetic effects of zinc(II) complexes were sourced from different scientific search engines, including, but not limited to “PubMed”, “Google Scholar”, “Scopus” and ScienceDirect to identify potent anti-diabetic zinc(II) complexes. The complexes were subcategorized according to their precursor ligands. A critical analysis of the outcomes from published studies shows promising leads, with Zn(II) complexes having a “tri-facet” mode of exerting pharmacological effects. However, the promising leads have been flawed by some major scientific gaps. While zinc(II) complexes of synthetic ligands with little or no anti-diabetic pharmacological history remain the most studied (about 72 %), their toxicity profile was not reported, which raises safety concerns for clinical relevance. The zinc(II) complexes of plant polyphenols; natural ligands, such as maltol and hinokitiol; and supplements, such as ascorbic acid (a natural antioxidant), L-threonine and L-carnitine, showed promising insulin mimetic and glycemic control properties but remain understudied and lack clinical validation, in spite of their minimal safety concerns and health benefits. A paradigm shift toward probing (including clinical studies) supplements, plant polyphenol and natural ligands as anti-diabetic zinc(II) complex is, therefore, recommended. Also, promising anti-diabetic Zn(II) complexes of synthetic ligands should undergo critical toxicity evaluation to address possible safety concerns

In vitro antiproliferative, anti-inflammatory effects and molecular docking studies of natural compounds isolated from Sarcocephalus pobeguinii (Hua ex Pobég)

DATA AVAILABILITY STATEMENT : The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding authors.BACKGROUND : Sarcocephalus pobeguinii (Hua ex Pobég) is used in folk medicine to treat oxidative-stress related diseases, thereby warranting the investigation of its anticancer and anti-inflammatory properties. In our previous study, the leaf extract of S. pobeguinii induced significant cytotoxic effect against several cancerous cells with high selectivity indexes towards non-cancerous cells. AIM : The current study aims to isolate natural compounds from S. pobeguinii, and to evaluate their cytotoxicity, selectivity and anti-inflammatory effects as well as searching for potential target proteins of bioactive compounds. METHODS : Natural compounds were isolated from leaf, fruit and bark extracts of S. pobeguinii and their chemical structures were elucidated using appropriate spectroscopic methods. The antiproliferative effect of isolated compounds was determined on four human cancerous cells (MCF-7, HepG2, Caco-2 and A549 cells) and non-cancerous Vero cells. Additionally, the anti-inflammatory activity of these compounds was determined by evaluating the nitric oxide (NO) production inhibitory potential and the 15-lipoxygenase (15-LOX) inhibitory activity. Furthermore, molecular docking studies were carried out on six putative target proteins found in common signaling pathways of inflammation and cancer. RESULTS : Hederagenin (2), quinovic acid 3-O-[α-D-quinovopyranoside] (6) and quinovic acid 3-O-[β-D-quinovopyranoside] (9) exhibited significant cytotoxic effect against all cancerous cells, and they induced apoptosis in MCF-7 cells by increasing caspase-3/-7 activity. (6) showed the highest efficacy against all cancerous cells with poor selectivity (except for A549 cells) towards noncancerous Vero cells; while (2) showed the highest selectivity warranting its potential safety as a chemotherapeutic agent. Moreover, (6) and (9) significantly inhibited NO production in LPS-stimulated RAW 264.7 cells which could mainly be attributed to their high cytotoxic effect. Besides, the mixture nauclealatifoline G and naucleofficine D (1), hederagenin (2) and chletric acid (3) were active against 15-LOX as compared to quercetin. Docking results showed that JAK2 and COX-2, with the highest binding scores, are the potential molecular targets involved in the antiproliferative and anti-inflammatory effects of bioactive compounds. CONCLUSION : Overall, hederagenin (2), which selectively killed cancer cells with additional anti-inflammatory effect, is the most prominent lead compound which may be further investigated as a drug candidate to tackle cancer progression.The Central University of Technology operational expenses and the National Research Foundation (NRF), South Africa. The APC was funded by the Central University of Technology research expenses (TM).http://www.frontiersin.org/Pharmacologyam2024Paraclinical SciencesSDG-03:Good heatlh and well-bein

Cardiovascular risk and endothelial function in people living with HIV/AIDS: design of the multi-site, longitudinal EndoAfrica study in the Western Cape Province of South Africa

CITATION: Strijdom, H., et al. 2017. Cardiovascular risk and endothelial function in people living with HIV/AIDS: design of the multi-site, longitudinal EndoAfrica study in the Western Cape Province of South Africa. BMC Infectious Diseases, 17:41, doi:10.1186/s12879-016-2158-y.The original publication is available at http://bmcinfectdis.biomedcentral.comBackground: There is growing evidence of an interaction between HIV-infection, anti-retroviral therapy (ART) and cardiovascular diseases (CVD). Epidemiological studies in Europe and North America have been observing a shift towards an increased incidence of coronary heart disease and acute myocardial infarctions in HIV-infected populations compared to the general population even after adjusting for traditional cardiovascular risk factors. Despite South Africa (and sub-Saharan Africa, SSA) being regarded as the epicentre of the global HIV epidemic, very little is known about the prevalence of cardiovascular risk factors and precursors of vascular disease in HIV-infected populations in this region. The knowledge gap is further widened by the paucity of data from prospective studies. We present the rationale, objectives and key methodological features of the EndoAfrica study, which aims to determine whether HIVinfection and ART are associated with altered cardiovascular risk and changes in vascular endothelial structure and function in adults living in the Western Cape Province of South Africa. Methods: In this longitudinal study, comprehensive cardiovascular assessments of HIV-negative and HIV-positive (with and without ART) study participants are performed by clinical and biochemical screening for traditional cardiovascular risk factors and biomarkers of CVD. Vascular and endothelial function is determined by brachial artery flow-mediated dilatation (FMD), carotid-intima-thickness (IMT) measurements and quantitative retinal blood vessel analyses, complemented by vascular endothelial biomarker assays. Finally, we aim to statistically determine whether HIVinfection and/or ART are associated with increased cardiovascular risk and vascular endothelial dysfunction, and determine whether there is progression/regression in these endpoints 18 months after the baseline assessments. Discussion: The EndoAfrica study provides a unique opportunity to recruit a cohort of HIV-infected patients and HIVnegative controls who will be comprehensively and longitudinally assessed for cardiovascular risk and disease profile with vascular endothelial function as a potentially important intermediate cardiovascular phenotype. To our knowledge, it is the first time that such a systematic study has been established in the context of SSA and South Africa.http://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-016-2158-yPublisher's versio

Lack of human-assisted dispersal means Pueraria montana var. lobata (kudzu vine) could still be eradicated from South Africa

The legume, Pueraria montana var. lobata (kudzu vine) is one of the worst plant invaders globally. Here we present the first study of P. montana in South Africa. We found only seven P. montana populations covering an estimated condensed area of 74 hectares during the height of the growing season. Based on a species distribution model, it appears that large parts of the globe are suitable, including parts of the eastern escarpment of South Africa (where most populations occur). South African populations of P. montana appear to have a similar ecology to populations in the USA: high growth rates, low seed germination, no natural long-distance dispersal, little herbivory and vigorous post-fire resprouting. In contrast to the USA, most South African populations do flower and flowers are capable of producing seed in the absence of pollinators. However, P. montana appears to have never been widely planted in South Africa, and the incursion was for many years restricted to a single introduction site. The comparison between the invasions of P. montana in the USA and South Africa highlights the often overriding importance of human assisted dispersal and cultivation in creating widespread invasions, and should serve as a warning to people who have proposed to utilize the species in Africa