Phytochemical characterization and valorization of Quercus ilex (west of Algeria)

ABSTRACT

This project is part of the promotion of natural resources such as Non-Timber Forest Products (NTFP). In order to assess the economic value of NTFP, this research focuses on the phytochemical analysis of holm oak (Quercus ilex L.) from the Terni region (Western Algeria). It focused on bioactive substances, particularly polyphenols. The method used consists of extracting the phenolic compounds by two methods which are maceration and ultrasound from the leaves and bark of this species. The quantity of these compounds is assessed spectrometrically and the antioxidant activity of the extracts in vitro using free radical scavenging and total antioxidant capacity assays. The results obtained indicate that maceration offers the best yield for extracting phenolic compounds from the leaves, with a yield of 10.74%. These results also showed that the extracts of holm oak leaves and bark are rich in phenolic compounds and have a content of total phenols (103,014±1,393 and 813.462±1.675 mg EAG/g DM), flavonoids (87.078±6.220 and 949.936±36.394 mg EC/g DM) and condensed tannins (57.194±12.447 and 940.195±20.417 mg EC/g DM). Regarding the antioxidant power, it is evident that all extracts have significant antioxidant capacity, and all have high free radical scavenging activity. The highest inhibition percents are 84.98±7.45% for the leaf extract and 83.15±9.27% for the bark extract. According to these results, holm oak contains a large quantity of polyphenols and antioxidant molecules. This information represents a natural source of antioxidants which remains to be exploited for future use in the agri-food and health sectors, within the broader framework of promoting the biodiversity of Algerian plants (NTFP).