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

Analgesic effects of the methylene chloride/methanol extract of the leaves of Laportea ovalifolia (Urticaceae)

In the present work, the analgesic effects of methylene chloride/methanol (1:1) (CH2Cl2/CH3OH) extract of Laportea ovalifolia (Urticaceae) were evaluated using acetic acid and formalin test. The anticonvulsant effects of the same extract were also investigated on seizures induced by pentylenetetrazol (PTZ) and picrotoxin. CH2Cl2/CH3OH extract (100 -1000 mg/kg) exhibited protective effect reaching 59% of inhibition at a dose of 1000 mg/kg on the pain induced by acetic acid. The CH2Cl2/CH3OH extract significantly reduced the first phase and second phase of pain induced by formalin reaching a maximum of 98.7% of inhibition (in the late phase). The extract at the doses of 100 -2000mg/kg did not exert anti-convulsant effect neither against PTZ or PIC induced seizures. Keywords: Laportea ovalifolia, Urticaceae; analgesic activity; steroids; writhing test; formalin test.Cameroon Journal of Experimental Biology Vol. 4 (1) 2008: pp. 52-5

Synergistic activity of extracts of three South African alien invasive weeds combined with conventional antibiotics against selected opportunistic pathogens

Plants are known to play a major role in the treatment of microbial infections, as they contain important bioactive components that may act in synergism with conventional antibiotics, which are presently under threat of microbial resistance. Synergistic activity between dichloromethane, acetone, 70% ethanol, 50% methanol and hot water extracts of three southern African alien invasive plant species, namely Chromolaena odorata, Gomphrena celosioides and Tithonia rotundifolia and gentamicin, streptomycin, rifampicin and amphotericin B was studied using the checkerboard method. Antioxidant activity of the extracts was determined using the quantitative 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) decolourisation methods. The anti-inflammatory activity was determined with the 15-lipoxygenase enzyme assay. Synergistic to additive effects were observed among all tested extracts in combination with the conventional antibiotics against most of the tested strains. This was evident when the extracts were combined with gentamicin or amphotericin B against Klebsiella pneumoniae, Enterococcus faecalis, Salmonella Typhimurium, Cryptococcus neoformans and Candida albicans. The extracts of C. odorata had the best antioxidant activity in the ABTS assay with the 70% ethanol extract showing a minimum inhibitory concentration (IC50) of 1.960 μg/mL, better than that of vitamin C (IC50 = 2.027 μg/mL). The dichloromethane extract of T. rotundifolia displayed promising radical scavenging activity in the DPPH assay with an IC50 of 16.231 μg/mL. Most of the extracts of C. odorata (except the acetone extract) had anti-inflammatory activity better than that of the positive control quercetin (IC50 = 24.601 μg/mL). Results from this study indicate that extracts of these weedy plant species contain bioactive compounds that may act in synergy with conventional antibiotics in the fight against resistant microbial strains. Additionally they may reduce oxidative stress and inflammation.The National Research Foundationhttp://www.elsevier.com/locate/sajb2020-08-01hj2020Paraclinical Science