Etude phytochimique et évaluation de l’activité antioxydante des extraits brutes et de l’huile essentielle du Citrus aurantium

Abstract

Citrus fruits, such as oranges, which are widely consumed worldwide, represent rich sources of magnesium, potassium, calcium and antioxidants. However, the by-products of the bitter orange (bigarade, Citrus aurantium) used as an ornamental tree in Algeria, represent a rich source of phenolic compounds, and can be considered as a precious source of functional ingredients. In this perspective, our work consists in carrying out a phytochemical study, namely the dosage of total phenols and flavonoids as well as the evaluation of the antioxidant activity of the three crude extracts (peel, leaves and seeds) and oil essential of Citrus aurantium. First of all, phytochemical tests revealed the presence of different families of chemical compounds such as flavonoids, tannins and mucilages. Then, the quantitative evaluation of the phenolic compounds revealed that peel extract (12,415 ± 0,27 mg EAG/gMS) has the highest content compared to the other extracts, while the highest content of flavonoids is presented by the leaf extract (13,67 ± 1,96 mg EAG / g MS). On the other hand, the extraction of essential oil by hydrodistillation from the fresh peel of C. aurantium gave a yield of 1,43 ± 0,319% with a density of 0,705 ± 0,05 and an index of refraction of 1,473. The evaluation of the antioxidant power by the method of trapping the free radical DPPH of the three crude extracts and of the essential oil revealed that our extracts had a different antioxidant activity. However, seeds extract has better activity (IC50: 13,775 mg/ml) compared to the other extracts tested, but remains less active than ascorbic acid (IC50: 0,060 mg / ml).