Abstract:
ETHNOPHARMAOLOGICAL RELEVANCE :Oxidative stress and inflammatory conditions are among the pathological features associated
with the central nervous system in Alzheimer’s disease. Traditionally, medicinal plants have
been used to alleviate inflammation, pains and also other symptoms possibly associated with
Alzheimer’s disease. Therefore, the present study was designed to determine the in vitro antiinflammatory,
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 Ellman’s 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 100 μg/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 25 μg/mL. In addition, both Leucaena leucocephala and Englerophytum
magaliesmontanum had strong activity against acetylcholinesterase with IC50 values of 118
μg/mL and 160 μg/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.
