Total Phenolic and Flavonoid Content and Biological Activities of Extracts and Isolated Compounds of Cytisus villosus Pourr.

The aim of this study was to evaluate the total phenolic and flavonoid content, and the in vitro antioxidant, anti-inflammatory, antibacterial, antifungal, antimalarial, cytotoxicity, and antiprotozoal activities of the Algerian plant Cytisus villosus Pourr. (Syn. Cytisus triflorus L'Hérit.). Additionally, the radioligand displacement affinity on opioid and cannabinoid receptors was assessed for the extracts and isolated pure compounds. The hydro alcoholic extract of the aerial part of C. villosus was partitioned with chloroform (CHCl₃), ethyl acetate (EtOAc), and n-butanol (n-BuOH). The phenolic content of the C. villosus extracts was evaluated using a modified Folin-Ciocalteau method. The total flavonoid content was measured spectrometrically using the aluminum chloride colorimetric assay. The known flavonoids genistein (1), chrysin (2), chrysin-7-O-β-d-glucopyranoside (3), and 2″-O-α-l-rhamnosylorientin (4) were isolated. The antioxidant activities of the extracts and isolated compounds were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DDPH) and cellular antioxidant activity (CAA) assays. The plant extracts showed moderate antioxidant activity. EtOAc and n-BuOH extracts showed moderate anti-inflammatory activity through the inhibition of induced nitric oxide synthase (iNOS) with IC₅₀ values of 48 and 90 µg/mL, respectively. The isolated pure compounds 1 and 3 showed good inhibition of Inducible nitric oxide synthase (iNOS) with IC₅₀ values of 9 and 20 µg/mL, respectively. Compounds 1 and 2 exhibited lower inhibition of Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB) with IC₅₀ values of 28 and 38 µg/mL, respectively. Furthermore, the extracts and isolated pure compounds have been shown to exhibit low affinity for cannabinoid and opioid receptors. Finally, n-BuOH extract was a potent inhibitor of Trypanosoma brucei with IC₅₀ value of 7.99 µg/mL and IC₉₀ value of 12.61 µg/mL. The extracts and isolated compounds showed no antimicrobial, antimalarial nor antileishmanial activities. No cytotoxic effect was observed on cancer cell lines. The results highlight this species as a promising source of anti-inflammatory and antitrypanosomal agents.