Dzoyem_2015_J.Ethnopharmacol_160_194

ETHNOPHARMACOLOGICAL RELEVANCE: Oxidative stress and inflammatory conditions are among the pathological features associated with the central nervous system in Alzheimers disease. Traditionally, medicinal plants have been used to alleviate inflammation, pains and also other symptoms possibly associated with Alzheimers disease. Therefore, the present study was designed to determine the in vitro anti-inflammatory, antioxidant and anticholinesterase activity of twelve South African medicinal plants traditionally used to alleviate pain and inflammation. MATERIALS AND
METHODS: Nitric oxide (NO) production in LPS-activated RAW 264.7 macrophages and 15-lipoxygenase (LOX) inhibitory assay were used to evaluate the anti-inflammatory activity. Acetylcholinesterase inhibition was assessed by using a modification of the Ellmans method. Antioxidant activity, total phenolic and total flavonoids contents were determined using standard in vitro methods.
RESULTS: The extract of Burkea africana had the highest anti-15-lipoxygenase activity with 85.92% inhibition at 100microg/mL. All the extracts tested inhibited nitric oxide (NO) production in a dose dependant manner in LPS-stimulated RAW 264.7 macrophages. However, extracts from Leucaena leucocephala, Lippia javanica inhibited the production of NO by 97% at a concentration of 25microg/mL. In addition, both Leucaena leucocephala and Englerophytum magaliesmontanum had strong activity against acetylcholinesterase with IC50 values of 118microg/mL and 160microg/mL respectively. Hight levels of phenolics and flavonoids were found in Leucaena leucocephala, Lippia javanica and Burkea africana. The correlation with antioxidant activities was not strong indicating that other metabolites may also be involved in antioxidant activity.
CONCLUSIONS: The results obtained in this study validate the use of leaf extracts of these plants in South African traditional medicine against inflammation. Extracts of these plants species might be of value in the management of various diseases emerging from oxidative stress and related degenerative disorders.