<p>Inhibition of nitric oxide production and free radical scavenging activities of four South African medicinal plants</p>

Abstract

Introduction Traditional healing is often the preferred form of therapy especially in rural and resource-limited communities. The extracts of plants are used to treat many diseases such as arthritis and chronic pain. Four medicinal plant species, namely, Acokanthera oppositifolia, Plantago lanceolata, Conyza canadensis and Artemisia vulgaris used in Southern Africa to treat pain and inflammation-related diseases were selected for evaluation in laboratory-based experiments. Methods The selected plant species were evaluated for phytochemical content, antioxidant and anti-inflammatory activities, as well as cytotoxicity effects against mammalian cells in culture. Results The results indicated that the n -hexane and chloroform extracts of P. lanceolata had the best antioxidant activities with an IC 50 =0.41 μg/mL. Also, the acetone extracts of P. lanceolata had 93.76% nitric oxide (NO) inhibition. However, the chloroform and n -hexane extracts of C. canadensis produced NO inhibition of 98.53% and 99.2%, respectively, at 100 μg/mL with IC 50 =17.69 μg/mL. Furthermore, the ethyl acetate extracts also had promising NO inhibitory activity (96.33%), but the cytotoxicity results with cell viabilities of 5.31%, 5.7% and 5.89%, respectively, suggested that the observed activity was due to a cytotoxic effect. Acetone extracts of C. canadensis were also cytotoxic at 30 µg/mL with 6.07–6.67% cell viabilities compared with the acetone extracts of P. lanceolata (99.57%). Conclusion The results partially validate the ethnomedicinal uses of the selected plant species used for inflammation-related conditions. However, because some of the extracts had potential cytotoxic effects, caution is advised in their use, especially those consumed orally.

Ethanol leaf extract of Psychotria microphylla rich in quercetin restores heavy metal induced redox imbalance in rats

“…This is comparable to the IC 50 of ascorbic acid (43.43 ± 0.03759) and gallic acid (33.85 ± 0.03734), which were used as standards in the study. This inhibitory activity is slightly comparable to that of the plant extracts reported by Adebayo et al. (2019) and lower than the value reported by Suluvoy and Berlin Grace (2017) for Averrhoa bilimbi L. fruit extract.…”

Plants as Sources of Anti-Inflammatory Agents

“…The majority of free radicals observed are superoxide (O 2 − ), hydroxyl (OH − ), hydroperoxide (HO 2 − ), nitric oxide (NO • ), and nitrogen dioxide (NO 2 • ). Among these, the hydroxyl radical is the most reactive in the induction of cellular lesions and hydrogen peroxide can cross the nuclear membrane and induce damage in the DNA molecule [ 119 , 120 ].…”

Wound Healing Effect of Acokanthera schimperi Schweinf (Apocynaceae) Methanol Leaf Extract Ointment in Mice and Its in-vitro Antioxidant Activity

“…As evidence, the leaf extract of Acokanthera oppositifolia showed good antiinflammatory, antioxidant, and analgesic activities. 40,41 Likewise, the leaf extract of Acokanthera oblongifolia also displayed strong antimicrobial, antioxidant, and wound healing activities. 42 Moreover, the crude extract ointments of this plant revealed a statistically significant wound healing effect in S. aurous-infected mice, in an infected model.…”