The anti-inflammatory and anti-nociceptive activities of some medicinal plant species used to treat inflammatory pain conditions in Southern Africa

The biological activities of 4 medicinal plants (Acokanthera oppositifolia, Plantago lanceolata, Artemisia vulgaris and Conyza canadensis) were investigated. These plant extracts were subjected to screening for their possible effects as analgesic, and anti-inflammatory agents. The plant materials (only leaves were used in this study) were used in 4 solvents (acetone, ethyl acetate, chloroform and hexane). Plantago lanceolata hexane leaf extract inhibited cyclooxygenase-2 (COX-2) activity with an IC50 value of 0.41 μg/mL. Quercetin, positive control in this study inhibited COX-2 with a recorded IC50 = 8.39 μg/mL. However, the COX-1 inhibition by same extract indicated an IC50 of 68.99 μg/mL compared to the positive control (quercetin), whose activity was represented with an IC50 value of 4.6 μg/mL. The lipoxygenase assay indicated that Plantago lanceolata hexane extract and Acokanthera oppositifolia acetone extract were the most active samples with an IC50 of 4.75 μg/mL and 7.73 μg/mL. Plantago lanceolata hexane extract was the most active in all enzyme inhibitions, revealing the great potential it presents as a source of new anti-oxidative, analgesic and anti-inflammatory drugs, with less adverse effects.www.ijppr.comam2016Paraclinical Science

Inhibition of nitric oxide production and free radical scavenging activities of four South African medicinal plants

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 IC50=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 IC50=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.The University of South Africa (UNISA) and the National Research Foundation.http://www.dovepress.com/journal-of-inflammation-research-journalam2020Paraclinical Science