Résumé:
Quercus spp or oak, belonging to the fagaceae family, is an important tree in the
Algerian forest, but its biological properties and interest in phytotherapy are little known. In
order to contribute to the improvement of the Algerian flora, The objective of this study was to
prepare alcoholic and aqueous extracts of both oak leaves and fruits using two different
extraction methods. The phytoconstituents present in the oak extracts were then detected and
spectrophotometrically measured, with a focus on secondary metabolites such as polyphenols
and flavonoids. Finally, the biological activities of the extracts were evaluated.
Extraction by maceration and ultrasound was carried out using 2 solvents of different
polarities (ethanol, distilled water). A quantitative analysis was carried out to determine the
polyphenols contained in the extracts using the Folin Ciocalteu reagent, as well as the
flavonoids present in the extracts using the aluminium chloride (AlCl3) method.
The results of the various assays show that the highest content of phenolic compounds
was obtained in the leaf extracts. In terms of flavonoid content, the aqueous acorn extract had
the highest flavonoid content. Phytochemical screening of Quercus acorn and leaf extracts
revealed the presence of tannins, gall tannins, catechetic tannins, saponins, favonoids,
polyphenols, terpenes and carbohydrates.
The results of the DPPH test demonstrated that Quercus extracts exhibited significant
antioxidant activity. As the in vitro investigation indicated that the extracts, when subjected to
the protein denaturation method and haemolysis test, exhibited good anti-inflammatory
properties.
This study has demonstrated that the ethanolic and aqueous extracts of this plant have
the potential to act as a potent antioxidant and anti-inflammatory agent, with significant
biological and therapeutic implications.
