Phytochemical analysis and antioxidant properties of organic extracts obtained from Cynoglossum cheirifolium L.

The valorization of the local flora is the goal of the laboratory of Natural Products from the University of Tlemcen (Algeria). In this work, we report the scientific study of a medicinal plant Cynoglossum cheirifolium L. The crude methanol and tannin extracts of C. cheirifolium were preliminary analyzed for their phenolic contents (total phenolics, total flavonoids and total tannins). These extracts were evaluated for their antioxidant properties using different methods. The results showed that crude methanolic extract of the leaves part revealed high phenolic (134.93 ± 9.76 mg Gallic Acid Equivalent/g Dry Weigth), flavonoid (99.99 ± 0.72 mg Catechin Equivalent/g Dry Weigth) and condensed tannin contents (1.65 ± 0.05 mg Catechin Equivalent/g Dry Weigth). Furthermore, the results obtained from the study of the antioxidant activity showed that tannin extract of stems displayed the highest DPPH• scavenging ability with the inhibition concentration of 50% (IC50) value of 70 ± 1 μg/mL, it was comparable to the Vitamin E with an IC50 value of 60 ± 1 μg/mL. The vitamin E concentration required to reduce the ferric iron was lower (242 ± 6 μg/mL) than tannins extracted from leaves (214 ± 4 μg/mL). Hence, using an RP-HPLC-PDA (Reverse Phase-High Pressure Liquid Chromatography-PhotoDiode Array Detector) analysis, it was possible to identify phenolic acids and flavonoid like rutin; naringenin; rosmarinic acid; sinapic acid; p-coumaric acid; ferulic acid; caffeic acid and syringic acid.