Evaluation of amentoflavone isolated from Cnestis ferruginea Vahl ex DC (Connaraceae) on production of inflammatory mediators in LPS stimulated rat astrocytoma cell line (C6) and THP-1 cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Cnestisferruginea (CF) Vahl ex DC (Connaraceae) is a shrub widely used in traditional African medicine for the treatment of various psychiatric illness and inflammatory conditions.

AIM OF THE STUDY: This study was carried out to investigate the effect of amentoflavone isolated from methanolic root extract of CF on lipopolysaccharide (LPS)-induced neuroinflammatory cascade of events associated to the oxidative and nitrative stress, and TNF-α production in rat astrocytoma cell line (C6) and human monocytic leukemia cell line (THP-1), respectively.

MATERIALS AND METHODS: Rat astrocytoma cells (C6) were stimulated with LPS (10μg/ml) alone and in the presence of different concentrations of amentoflavone (0.1-3μg/ml) for 24h incubation period. Nitrite release, reactive oxygen species (ROS), malondialdehyde (MDA) and reduced-glutathione (GSH) in C6 cells were estimated; while the TNF-α level was estimated in THP-1 cell lysate. In vivo analgesic activity was evaluated using mouse writhing and hot plate tests while the anti-inflammatory effect was investigated using carrageenan-induced oedema test.

RESULTS: LPS (10μg/ml) significantly (P<0.05) stimulated C6 cells to release nitrite, ROS, MDA, and TNF-α generation while GSH was down regulated in comparison to control. However, amentoflavone significantly (P<0.05) attenuated nitrite, ROS, MDA and TNF-α generation and also up regulated the level of GSH. Amentoflavone per se did not have any significant effect on C6 and THP-1 cells. Amentoflavone (6.25-50mg/kg) significantly (P<0.05) reduced number of writhes and also increase pain threshold in hot plate test. It produced time course significant (P<0.05) decrease in oedema formation in rodents.

DISCUSSION AND CONCLUSION: Findings in this study demonstrate the anti-neuroinflammatory and antinoceptive effects of amentoflavone which may suggest its beneficial roles in neuroinflammation associated disorders.