Variation in Phenolic Composition, Antioxidant Activity and Cyclic Voltammetry Study of Juncus rigidus Desf. (Juncaceae) Root Extracts according Flowering and Ripening Period

In this study, two solvents with different polarity were used in the extraction of the dried powdered roots of the plant Juncus rigidus; ethanol, acetone, during two different growth stages : ripening period (November) and flowering period (April). Total phenolics, total flavonoids, and total flavanols contents were evaluated using the colorimetric assays. The obtained results were very significant and showed that polarity of solvents and growth stage affects the composition of the plant. The highest content in total phenolic (87,249 ± 0.005 mg GAE/g), total flavonoid (28,109 ± 0.041 mg QE/g) and total flavonol (33,195 ± 0,013 mg GAE/g) contents was obtained in acetone extract during flowering period witch decrease during ripening period. The best result for the evaluation of the antioxidant activity indicated that highest value in DPPH free radical scavenging activity (0,014 ± 0,0003 mg/mL-1), phosphomolybdenum assay (425,168 ± 0,006 mL/mg), ferric reducing antioxidant power (1217,914 ± 0,022 mgFeSO4/g) and cyclic voltammetry (47,07 ± 0,04 mg/g) was unregistered during ripening stage using acetone solvent.