Evaluation of extracts of South African plant species for the treatment of venous thromboembolism

Abstract

Venous thromboembolism (VTE) is a collective term for the cardiovascular diseases, deep vein thrombosis and pulmonary embolism. Many of those who live in developing countries rely on herbal medicinal products as a primary source of healthcare. Thrombosis causes the progression of VTE; thus, the study investigated the antithrombotic properties of selected plant extracts. Thirty-three (33) plant extracts were prepared from 11 South African medicinal plants using ethanol, dichloromethane and water. The extracts were tested for liver antiproliferative effects as well as antioxidant, anti-FXa (activated coagulation factor X) and cyclooxygenase-1 (COX-1) inhibitory activity. The phytochemistry of the plant extract with note-worthy activity, was also determined. The ethanolic extract of Hypoestes forskaolii had the most potent antiproliferative activity at a IC50 (50 percent inhibitory concentration) lower than 3.13μg/mL. The most potent antioxidant was the aqueous extract of Heteropyxis natalensis (IC50 = 2.71μg/mL), which also displayed potent anti-FXa activity with a IC50 value of 2.64μg/mL. The same extract inhibited COX-1 at a IC50 value of 25.32μg/mL. The presence of β-carotene was confirmed in the aqueous extract of H. natalensis. Amongst the 33 extracts tested, the aqueous extract of H. natalensis was the best candidate for future antithrombotic studies for VTE.