A Comparative study on the Chemical and Biological Profiling of Acacia species growing in Egypt

Abstract

Three Acacia species: A. farnesiana, A. tortilis and A. longifolia, were investigated for seasonal variations of the phytochemical constituents and their influence on in-vitro anti-inflammatory activities. Samples of leaves and bark of the three species were collected in two different seasons and extracted using 50% and 70% ethanol. LC-MS analysis revealed the presence of rutin in the leaves of all three species, while catechin was commonly present in the bark. Other major components included vicenin 2, isoquercitrin, kaempferol 3-O-rutinoside and isorhamnetin 3-Orutinoside in A. farensiana leaves, while A. longifolia leaves contained myricetin 3-Orhamnoside, quercitrin and luteolin. The level of rutin varied according to the flowering period being highest in winter in A. tortilis (245.4 mg/mg) and A. longifolia (3.0 mg/mg). The content of total phenolics (TPC) showed a marked variation among the three species, which was reflected to some extent in the COX-1 and COX-2 enzymes inhibition. The anti-inflammatory activity of the 50% AF bark (s) extract was assessed at two different doses adopting the carrageenan induced rat hind paw edema method. The maximum inhibition of edema of the bark extract was 34% at 120min and 37.8% at 240min for doses of 100 and 200 mg/kg, respectively. Optimization modeling was performed for better visualization and utilization of the data showing a strong inverse correlation between TPC and the mean inhibition of COX-2 in case of the leaves (r2 0.783). Finally, cluster analysis of the data obtained from the leaf samples reflected on the taxonomical classification of the species; that of A. farnesiana and A. tortilis on one hand and that of A. longifolia in another class. This is in coherence with the grouping of the former speci in the Vachellia taxon while that of A. longifolia in the Acacia taxon