المساهمة في دراسة فيتوكيميائية وبيولوجية لبذور الدرع

Abstract

In the context of efforts to valorize the use of local plant resources, we conducted this study to evaluate the nutritional content, phytochemical composition, and biological activity of pearl millet (Pennisetum glaucum L.) seeds cultivated in the Mih Athia region (El-Ragouba, El-Oued). Mature seeds were collected during the fruiting stage and prepared according to standardized protocols. Nutritionally, quantitative analysis revealed a total mineral content of 17.539 g/100 g. The concentrations of essential mineral elements (Mg, Ca, and Fe) were determined using flame atomic absorption spectroscopy, with results indicating 39 mg/kg of Ca, 131.4 mg/kg of Mg, and 6.670 mg/kg of Fe. Regarding organic compounds, the seeds exhibited a high carbohydrate content of 71.275 g/100 g, while containing a relatively low fat content of 5.150 g/100 g. Phytochemically, two different extracts were prepared: aqueous and methanolic. The methanolic extract demonstrated higher levels of total polyphenols and flavonoids compounds, with values of 7.809 ± 0.383 mg GAE/g extract and 2.974 ± 0.399 mg QE/g extract, respectively, as determined by colorimetric methods using the Folin-Ciocalteu reagent and AlCl3 assay. The biological activity of the extracts was assessed through three antioxidant tests: DPPH• radical scavenging, β-carotene bleaching inhibition, and inhibition of erythrocyte hemolysis. The methanolic extract exhibited superior efficacy in DPPH• inhibition (IC50 = 0.430 ± 0.0015 mg/mL) and erythrocyte hemolysis inhibition (66.985 ± 0.0284%), while the aqueous extract showed better activity in protecting β-carotene from bleaching (51.935 ± 0.833%). Although this activity was lower than that of reference antioxidants, the results confirm that pearl millet seeds represent a promising source of bioactive compounds, supporting their cultivation as a sustainable food with potential nutritional and pharmaceutical value.