Bioactive compounds and bioactivity of the heads of wild artichokes

Abstract

Wild artichokes (Cyanara algarbiensis, C. baetica, C. cardunculus, and C. humilis) heads are globally consumed, although some taxa remain understudied, constituting natural reservoirs of bioactive phytochemicals. This study was focused on four Cyanara taxa collected in diverse locations in the SE of the Iberian Peninsula in comparison with cultivated C. scolymus. Analyses of vitamin C was effected by HPLC-DAD, and the methanol:water (80:20, v/v) extracts were analyzed for: i) phenolic compounds by HPLC-DAD and LC-MS; ii) phenolic acids and flavonoid using the Folin-Ciocalteu and aluminum chloride methods; iii) the antioxidant activity through the DPPH and ABTS•+ methods; iv) the in vitro antiproliferative activity against HT-29 cells using the MTT assay; and v) caspase-3 activity, which was performed to verify induced apoptosis. Vitamin C highlighted in C. humilis (59.9 mg/100 g fw), and total phenolics (by chromatography quantitation) reached 645.9 mg/100 g fw in C. baetica. The antioxidant activity stood out in C. baetica, with 0.50 (DPPH) and 0.52 (ABTS•+) mmol TE/100 g fw. Chlorogenic acid, apigenin-7-O-glucoronide, and apigenin-7-O-rutinoside highlighted in C. baetica (159.5, 274.5, and 50.3 mg/100 g fw); and quercetin-3-O-glucoside and 1,5-di-O-caffeoylquinic acid stood out in C. algarbiensis (61.5 and 93.5 mg/100 g fw). Artichoke extracts inhibited HT-29 colorectal cancer cells proliferation, particularly the ones from C. algarbiensis and C. baetica (GI50 of 975 and 650 μg/mL for 72-h exposed cells). This work constitutes a whole approach to the knowledge of phytochemicals and bioactivities of wild artichoke taxa to discern their use as functional foods.