Etude biologique de Ceratonia siliqua L. dans la région de El Oued

Abstract

This study aimed to valorize the carob tree " C. siliqua " in the Oued Souf region (Algeria), where carob cultivation in the Algerian desert is recent. We evaluated the phytochemical and biological properties of the plant parts (leaves, bark, fruit, and seed gum). Polyphenols were extracted by maceration in 80% ethanol, while seed gum (LBG) was extracted in crude form. We also developed environmentally and biologically nanometric materials using carbon quantum dots (CQDs) from carob leaf powder through two methods: simple prolysis and the hydrothermal method, obtaining two samples (CDM1 and CDM2), whose properties were analyzed using XRD and FTIR techniques. The selected samples were studied for their quantitative phenolic compound content, and their antioxidant, antibacterial, and anti-inflammatory activities were evaluated both in vivo and in vitro. The highest polyphenol contents were recorded in the bark and leaves (19,51 ± 0,64 and 19,02 ± 0,88 mg EAG/g respectively), while the highest flavonoid content was found in the leaves (5,05 ± 0,35 mg QE/g). Bark and leaf extracts contained the highest value of condensed tannins (0,053 ± 0.008 and 0,034 ± 0,003 mg EC/g respectively). Antioxidant activity was assessed using the FRAP and DPPH methods, and the results revealed a strong response, with a good correlation between activity and polyphenol and flavonoid contents. The studied extracts demonstrated antibacterial activity against four types of bacteria. The leaves demonstrated higher inhibitory activity against Gram-negative bacteria, while the fruits showed greater effectiveness against Gram-positive bacteria. Toxicity tests showed that the extracts (leaves, fruit, CDM1, CDM2) were non-toxic even at a concentration of 4500 mg/kg. In the edema test, leaves showed the highest inhibition rate, while the CDM1 extract achieved the highest protection rate (93,95%) in the egg albumin denaturation protection test. We also studied the effect of seed gum as a preservative at 20% and 10% ratios on fresh cheese, and the results showed positive effects on coliformes fécaux et totaux, FTAM, Salmonella et Staphylococcus aureus.