Anti-inflammatory Activity of the Phenolic-rich Extract of Schotia brachypetalea Sond. Fam. Fabaceae, Cultivated in Egypt

Aim: The current study evaluates the anti-inflammatory activity of the methanolic leaf extract of Schotia brachypetalea, isolates and identifies the phenolic content and standardizes the crude leaf extract using HPLC.

Place and Duration of study: This study was conducted in the Departments of Pharmacognosy and Pharmacology, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt during the period between July 2013 and December 2014.

Methodology: The anti-inflammatory activity was assessed using 2 models viz. carrageenan induced rat paw edema and croton oil induced ear edema. Column and paper chromatography were used to fractionate and isolate the phenolic compounds. The isolated compounds were analyzed using UV and1H-NMR spectroscopy. The methanolic leaf extract was standardized using gallic acid as a reference by HPLC analysis. Total phenolic and flavonoidal contents were determined using Folin-Ciocalteu and Aluminium chloride colorimetric assays, respectively.

Results: Significant dose dependent edema inhibition was observed in the carrageenan model at a dose 200 mg/kg (79.31%, 2hrs) and (85.19%, 3hrs). Also, levels of PGE2 had decreased significantly at this dose at the corresponding time intervals. In the croton oil model, the methanolic leaf extract of S. brachypetalea (50 mg/kg) decreased the edema to about 39.56% while 100 and 200 mg/kg doses decreased the edema to about 23 and 15.8%, respectively. Myloperoxidase (MPO) levels were reduced by 38, 45 and 63% in doses 50, 100 and 200 mg/kg, respectively. TNF-α level was reduced similarly. The anti-inflammatory activity was confirmed by the histopathological examination of the ear tissue revealing that the 200 mg/kg dose of the methanolic leaf extract of S. brachypetalea had normal dermal structure with no histopathological changes. The total phenolic content of S. brachypetala leaf extract was calculated as 376 mg of caffeic acid equivalents (CAE) per one gram extract while the total flavonoid content was 67.87 mg in one gram extract calculated as quercetin equivalent (QE). Three phenolic constituents were isolated, namely 1 Gallic acid, 2 Myrecitin-3-O-α-L-1C4-rhamnoside and 3 Quercetin-3-O-α-L-1C4-rhamnoside.

Conclusion: The study showed the potent anti-inflammatory activity of the methanolic leaf extract of S. brachypetalea; this might be attributed to its phenolic content.