Mitochondrial targeting of wild-type and mutant human protoporphyrinogen oxidase (PPOX)

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Rooibos (Aspalathus linearis) and its Major Flavonoids — Potential Against Oxidative Stress-Induced Conditions

Reactive species are products of normal cellular metabolism and may be deleterious or beneficial. At low/moderate concentrations, reactive species are involved in physiological roles including cell signalling, defense against infectious agents and mitogenic responses. However, unbalanced defense mechanism of antioxidants, overproduction of reactive species or incorporation of free radicals into the living system from the environment may result in oxidative stress, a deleterious process that can lead to damage of important cell structures, including lipids and membranes, proteins and nucleic acids. The role of oxidative stress as a contributing factor in the pathophysiology of various diseases is increasingly being recognized, and augmenting the oxidative defense capacity of the cell through the intake of antioxidants as a way of preventing free radical-mediated cellular injuries is becoming a popular strategy. Much attention is being focused on the health beneficial role of phenolic phytochemicals derived from plants. They are considered to play an important role as physiologically functional foods and for the prevention of clinical conditions related to oxidative stress, even though their modes of action may still not be fully understood. Rooibos (Aspalathus linearis) is a popular South African tisane enjoyed for its taste and aroma. Rooibos has been made in the Cederberg mountain region of South Africa for generations and has been used medicinally for alleviation of allergies, asthma, infantile colic and skin problems. The potential antioxidative, immune-modulating, chemopreventive and chemotherapeutic actions of rooibos have been reported in several studies. This review provides a comprehensive data on the current knowledge of the biological and chemotherapeutic activity of rooibos and its major flavonoids. Most recent in vitro and in vivo (animal and human) studies were conducted with special attention paid to clinical conditions in which oxidative stress has been implicated. The conclusion described directions for future rooibos research to establish its activity and utility as a human chemopreventive and therapeutic agent

St John's Wort (Hypericum perforatum L.) photomedicine: hypericin-photodynamic therapy induces metastatic melanoma cell death

Hypericin, an extract from St John's Wort ( Hypericum perforatum L. ), is a promising photosensitizer in the context of clinical photodynamic therapy due to its excellent photosensitizing properties and tumoritropic characteristics. Hypericin-PDT induced cytotoxicity elicits tumor cell death by various mechanisms including apoptosis, necrosis and autophagy-related cell death. However, limited reports on the efficacy of this photomedicine for the treatment of melanoma have been published. Melanoma is a highly aggressive tumor due to its metastasizing potential and resistance to conventional cancer therapies. The aim of this study was to investigate the response mechanisms of melanoma cells to hypericin-PDT in an in vitro tissue culture model. Hypericin was taken up by all melanoma cells and partially co-localized to the endoplasmic reticulum, mitochondria, lysosomes and melanosomes, but not the nucleus. Light activation of hypericin induced a rapid, extensive modification of the tubular mitochondrial network into a beaded appearance, loss of structural details of the endoplasmic reticulum and concomitant loss of hypericin co-localization. Surprisingly the opposite was found for lysosomal-related organelles, suggesting that the melanoma cells may be using these intracellular organelles for hypericin-PDT resistance. In line with this speculation we found an increase in cellular granularity, suggesting an increase in pigmentation levels in response to hypericin-PDT. Pigmentation in melanoma is related to a melanocyte-specific organelle, the melanosome, which has recently been implicated in drug trapping, chemotherapy and hypericin-PDT resistance. However, hypericin-PDT was effective in killing both unpigmented (A375 and 501mel) and pigmented (UCT Mel-1) melanoma cells by specific mechanisms involving the externalization of phosphatidylserines, cell shrinkage and loss of cell membrane integrity. In addition, this treatment resulted in extrinsic (A375) and intrinsic (UCT Mel-1) caspase-dependent apoptotic modes of cell death, as well as a caspase-independent apoptotic mode that did not involve apoptosis-inducing factor (501 mel). Further research is needed to shed more light on these mechanisms

The anti-proliferative and anti-bacterial activity of argan oil and crude saponin extract from Argania spinosa (L.) skeels

INTRODUCTION: Argan oil is a well-known cosmeceutical that is commercially available. It is traditionally used for the treatment of acne and skin inflammation among others. The objective of this study was to assess the anti-proliferative and antibacterial activities of argan oil and a crude saponin extract from the argan tree (Argania spinosa (L.) Skeels) that is endemic to Morocco. MATERIALS AND METHODS: The anti-proliferative activity of argan oil and the crude saponin extract was assessed by the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay on A431; HaCat; HeLa; MCF-7 and UCT-Mel 1 cells. The antibacterial activity was evaluated by the broth microdilution method against two species of bacteria: Cutibacterium acnes and Prevotella intermedia. RESULTS: The results of this study indicated that the argan oil sample did not inhibit the cell growth of the specified cell lines up to 1000µg/ml, while the crude saponin extract had low anti-proliferative activity. The minimal inhibitory concentration (MIC) values for both the argan oil and the crude saponin extract were found to be 500µg/ml against Cutibacterium acnes. No antibacterial activity from the argan oil or the crude saponin extract was evident against Prevotella intermedia up to a concentration of 12.5mg/ml. CONCLUSION: The results of this study indicated that argan oil and the crude saponin extract might have direct inhibitory effects on the growth and proliferation of Cutibacterium acnes. This finding supports the use argan oil as a treatment for acne vulgaris.National Research Foundationhttp://www.phcogfirst.com/content/pharmacognosy-journalpm2020Plant Production and Soil Scienc

The phenomenon of skin lightening: Is it right to be light?

AbstractChemicals capable of lightening the skin – variously known as skin-bleaching, skin-lightening, depigmenting, skin-evening and skin-brightening agents – are among the most commonly used skin preparations in the world. Globally, Africa reportedly exhibits a high prevalence of skin lightener use. In this review, we provide both clinical and social perspectives on skin lightener use in Africa, with particular emphasis on South Africa. We narratively explore the timeline associated with skin lightener use in South Africa and attempt to interweave the social rhetoric of this specific paradigm. Despite the risks associated with exposing the skin to known constituents of these formulations, such as hydroquinone and mercury, chronic use continues. In spite of legislation banning hydroquinone and mercury in cosmetics in South Africa, these ingredients are present in widely available products. We recommend better implementation of policies and greater ethical responsibility of multinational cosmetic companies in addition to the initiation of a system of random product testing and penalties that could improve industry compliance

Diesel exhaust particles and endothelial cells dysfunction: An update

Epidemiological studies have shown a consistent positive correlation between exposure to particulate matter (PM) and increased mortality largely due to increased rates of cardiovascular morbidity and mortality. Diesel exhaust particles (DEPs) are major constituents of atmospheric PM and have been shown to cause disruption of the endothelial cell monolayer integrity, thereby affecting organ functions. Endothelial cells are very active metabolic components of biological tissue that performs a number of important physiological functions. Therefore, anything that compromises the integrity and functions of the endothelium will lead to organ dysfunction and disease. This review focuses on scientific evidence that link DEP exposure to endothelial cell dysfunction in various pathophysiological conditions affecting the cardiovascular system. The various mechanisms involved in the DEP-induced endothelial cell dysfunction are also addressed together with the preventive and therapeutic approaches to overcoming these challenges

Solar ultraviolet radiation exposure and human health in South Africa: Finding a balance

In considering the likelihood of South Africa (SA) attaining the 2015 Millennium Development Goals, many health issues require urgent attention. The adverse effect of insufficient or excessive exposure to solar ultraviolet radiation (UVR) may exacerbate an already stressed public health service. These concerns become important when considering climate variability and patterns of behaviour