Charles Awortwe

• PhD in Pharmacology
• Stellenbosch University

Introduction: With a five-year survival rate of 6.8%, glioblastoma multiforme (GBM) is one of the most malignant brain tumors. Chemotherapy using alkylating agents, e.g. temozolomide and the nitrosoureas lomustine and carmustine is the main pillar of therapy. Nevertheless, therapy success still is often limited. One restraining factor is drug resis...

Glioblastoma multiforme (GBM) is the most common malignant brain tumor with limited therapeutic options. Besides surgery, chemotherapy using temozolomide, carmustine or lomustine is the main pillar of therapy. However, therapy success is limited and prognosis still is very poor. One restraining factor is drug resistance caused by drug transporters...

Rooibos ( Aspalathus linearis ), an indigenous South African plant and its major flavonoid, aspalathin, exhibited positive effects on glycemia and dyslipidemia in animal studies. Limited evidence exists on the effects of rooibos extract taken in combination with oral hypoglycemic and lipid-lowering medications. This study investigated the combined...

Oral therapeutics used to treat type 2 diabetes and cardiovascular disease often fail to prevent the progression of disease and their comorbidities. Rooibos (Aspalathus linearis), an endemic South African plant used as an herbal tea, has demonstrated positive effects on glycemia and hypercholesterolemia. However, the treatment efficacy of rooibos e...

Preparations of Echinacea purpurea (E. purpurea) are widely used for the management of upper respiratory infections, influenza, and common cold, often in combination with other conventional drugs. However, the potential of phytochemical constituents of E. purpurea to cause herb-drug interactions via ABCB1 and ABCG2 efflux transporters remains elusi...

Drug-drug interactions (DDI) potentially occurring between medications used in the course of COVID-19 infection and medications prescribed for the management of underlying comorbidities may cause adverse drug reactions (ADRs) contributing to worsening of the clinical outcome in affected patients. First, we conducted a meta-analysis to determine com...

What would it take in terms of the structural reforms in science, technology, and culture to cultivate sustainable therapeutic and preventive medicine innovations against zoonotic infections such as coronavirus disease 2019 (COVID-19) in the 21st century? In May 2019, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Servi...

The increased use of herbal supplements as complementary or alternative medicines has become a clinical conundrum due to the potential for herb-drug interactions. This is exacerbated by an increased supply of new herbal supplements in the market claiming various health advantages. These herbal supplements are available as over-the-counter self-medi...

An aspalathin-rich green rooibos extract (Afriplex GRT™) has demonstrated anti-diabetic and hypolipidemic properties, while also moderately inhibiting CYP3A4 activity, suggesting a potential for herb–drug interaction. The present study, therefore, evaluated the effects of orally administered GRT on the pharmacokinetics of atorvastatin and metformin...

Although several studies on pharmacokinetic and/or pharmacodynamic herb–drug interactions (HDI) have been conducted in healthy volunteers, there is large uncertainty on the validity of these studies. A qualitative review and a meta-analysis were performed to establish the clinical evidence of these interaction studies. Out of 4026 screened abstract...

Aim: The aim of this review was to assess the severity of adverse drug reactions (ADRs) due to herb-drug interactions in patients taking herbs and prescribed medications based on published evidence. Method: Electronic databases of PubMed, the Cochrane Library, Medline and Scopus were searched for randomized or non-randomized clinical studies, ca...

The aim of this study was to investigate the regulatory effect of Echinacea purpurea (EP) on efflux transporters ABCB1 and ABCG2 and to identify specific microRNAs contributing to their post-transcriptional regulation. ABCB1 and ABCG2 levels were assessed in human hepatoblastoma HepG2 cells treated with 50 µg/mL methanolic extract of commercial EP...

Rooibos extract, due to its glucose and lipid lowering effects, has potential as a nutraceutical for improvement of metabolic dysfunction. Potential herb-drug interactions as a result of the use of natural products are of increasing concern. Cytochrome P450 enzymes, CYP2C8, CYP2C9, and CYP3A4, are important in the metabolism of hypoglycemic drugs,...

Highly active antiretroviral therapy (HAART) has greatly improved health parameters of HIV infected individuals. However, there are several challenges associated with the chronic nature of HAART administration. For populations in health transition, dual use of medicinal plant extracts and conventional medicine poses a significant challenge. There i...

Polyhexamethylene biguanide (PHMB) is an antiseptic with antiviral and antibacterial properties used in a variety of products including wound care dressings, contact lens cleaning solutions, perioperative cleansing products, and swimming pool cleaners. There are regulatory concerns with regard to its safety in humans for water treatment. We decided...

Kalanchoe crenata popularly known as "dog's liver" is used in most African countries for the treatment of chronic diseases such as diabetes, asthma and HIV/AIDS related infections. The evaluation of K. crenata for herb-drug interactions has not been reported. This study therefore aims to evaluate the risk of K. crenata for herb-drug interaction in...

1. This study investigated the mechanism underlying Echinacea-mediated induction of CYP1A2, CYP3A4 and MDR1 in terms of human pregnane X receptor (PXR) activation. 2. Crude extracts and fractions of Echinacea purpurea were tested for PXR activation in HepG2 cells by a reporter gene assay. Quantitative real-time PCR was carried out to determine thei...

Polyhexamethylene guanidine hydrochloride (PHMGH) is used worldwide as an antimicrobial agent with broad spectra of activity and also for treating pool water. This non-GLP preliminary study aims at investigating in a subchronic toxicity study possible effects at supra-optimal doses of this biocide. Both acute and subchronic toxicity studies were co...

Labisia pumila (Kacip Fatimah) is a popular herb in Malaysia that has been traditionally used in a number of women’s health applications such as to improve libido, relieve postmenopausal symptoms, and to facilitate or hasten delivery in childbirth. In addition, the constituents of this plant have been reported to possess anticancer, antioxidant, an...

Moringa oleifera is a multipurpose plant used in Ghana and most parts of Africa. Its high mineral, protein, and vitamins content has enabled its use as a nutraceutical and panacea for various diseases. This study aimed at measuring the micro- and macroelements content of dried Moringa oleifera leaves using energy dispersive X-ray fluorescence spect...

Lessertia frutescens is a popular medicinal product used in sub-Saharan Africa by patients with HIV-infection, malignancies or other diseases. Non-nucleotide reverse transcriptase inhibitors (NNRTIs) (nevirapine and efavirenz) and protease inhibitors (PIs) (ritonavir) are mainly biotransformed by CYP3A4. Consequences of CYP3A4 inhibition by Lessert...

Unsweetened natural cocoa powder is enriched with nutraceutical abundance of anti-asthmatic compounds theobromine and theophylline. Cocoa powder, which is prepared after removal of the cocoa butter, contains about 1.9% theobromine and 0.21% caffeine. Anecdotal reports indicate that regular consumption of unsweetened natural cocoa powder (UNCP), a c...

The purpose of this study was to evaluate the potential risk of common herbal medicines used by HIV-infected patients in Africa for herb-drug interactions (HDI). High throughput screening assays consisting of recombinant Cytochrome P450 enzymes (CYPs) and fluorescent probes, and parallel artificial membrane permeability assays (PAMPA) were used. Th...

Objective: Kalanchoe integra is known to possess antihistaminic and mast cell stabilizing effect. Inflammatory mediators, such as histamine and eicosanoids have been implicated in the pathophysiology of allergen-induced asthma including bronchospasm, vasodilation, increased vascular permeability, perivascular and peribronchial oedema, acute functio...

p>The Caco-2 model is employed in pre-clinical investigations to predict the likely gastrointestinal permeability of drugs because it expresses cytochrome P450 enzymes, transporters, microvilli and enterocytes of identical characteristics to the human small intestine. The FDA recommends this model as integral component of the Biopharmaceutics Class...

Background: Kalanchoe integra is widely used in folklore medicine as an antiasthmatic agent. Previous studies have shown the ameliorating effect of Kalanchoe integra leaf extract [KILE] on bronchial hyperesponsiveness and inflammation. Further, the stabilizing effect of Kalanchoe sp on mast cell degranulation, suggests that Kalanchoe species are su...

Background of Study: The Kalanchoe genus is a succulent perennial plant belonging to the class Bryophyllum. It thrives at temperate areas of the world. In Africa, over 200 species have being identified and many of these species have been used medicinally especially Kalanchoe pinnata and Kalanchoe integra in Ghana for the treatment of various ailmen...

Objective: Inflammatory mediators, such as histamine and eicosanoids have been implicated in the pathophysiology of allergen-induced asthma including bronchospasm, vasodilation, increased vascular permeability, perivascular and peribronchial oedema, acute functional changes in the lungs and diarrhoea due to increase intestinal motility. This study...

Kalanchoe integra is used in folklore medicine for hypertension and to prevent and treat cerebrovascular disorders like stroke etc. lesser degrees of ischemia possibly may contribute to the initiation of apoptosis and low CBF, and cerebral oxygen delivery has been associated with risk of later death, cerebral atrophy, or neurodevelopmental deficit....