Phenolic compound profiles and antioxidant activity of Ruta chalepensis L. leaves, a spontaneous medicinal herb: influence of harvest zone (Western Algeria)

Abstract

Natural plant extracts contain a variety of phenolic compounds, to which various biological activities are attributed. Ruta chalepensis, known as “Fidjel”, is widespread in the Algerian territory, which was selected in order to estimate its content of secondary metabolites (phenolic compounds, flavonoids, tannins), and its antioxidant activity (DPPH, FRAP). For this purpose, two methanolic extracts were prepared from the leaves of this plant, harvested from two different areas: Tessala mountains (Sidi-Bel-Abbes town) and Taougrite mountains (Chlef town), which crude extract yields are around of 12.4% and 20.1% respectively. The quantitative estimation of the different secondary metabolites showed that the methanolic extract of Tessala mountains (MER) is the richest in polyphenols TES (10.65±0.67 mg GAE/g), flavonoids (31.16 ± 0.55 mg CE/g), hydrolyzable tannins (0.78 ± 0.02 mg CE / g), and in condensed tannins (2.75 ± 0.10 mg CE/g). However, an antioxidant activity evaluation of the two extracts showed that, both fractions are active with a maximum IC50 of 68.41±9.98 µg/ml in (MER). On the other hand, the TES extract from that of the Taougrite Mountains (MER) shows a stronger reducing activity than (MER); the TAO TES difference remains not significant. In conclusion, the plant harvesting area, and the bioclimatic conditions might influence the Rutaceae leaf extracts content and quality of the same family.