Antidiabetic, anti-inflammatory, anticholinesterase and cytotoxicity determination of two Carpobrotus species

Abstract

Carpobrotus edulis (L.) N. E. Br., commonly grown in many parts of the world, and C. dimidiatus (Haw.) L. Bolus are highly used medicinal plants in South Africa for treating diabetes, wounds, inflammation and other closely-related diseases. This study was aimed at evaluating the antidiabetic, anti-inflammatory, and acetylcholinesterase inhibitory activities as well as cytotoxicity effects (using RAW 264.7, Vero kidney and HepG2 liver cells) of different solvent (water, 70% acetone, and 50% methanol) extracts obtained from the leaves of C. edulis and C. dimidiatus. Antidiabetic and anti-inflammatory activities were evaluated using alpha-glucosidase and 15-lipoxygenase (LOX) enzyme inhibition assays, respectively. In addition, the phenolic content of the two plant species was quantified. Water extract of C. edulis leaves exhibited noteworthy alpha-glucosidase inhibitory activity with an IC50 value of 5 μg/ml. Acetone and water extracts of C. edulis showed promising 15-LOX inhibition activity with IC50 values of 22.3 and 59.8 μg/ml, respectively. These same extracts demonstrated strong free radical scavenging activity as reflected by their EC50 values of 5.6 and 6.2 μg/ml, respectively. Carpobrotus edulis leaves had a significantly high total phenolic and flavonoid contents when compared to C. dimidiatus. Furthermore, all extracts exhibited very low cytotoxicity against all the tested cells. The current findings offer supporting evidence for the use of these plant species in the development of natural products to treat diabetes, among other ailments. These plant species can be used in the production of natural supplements or functional food for the management of pain, diabetes and free radical-induced disorders.