Citotoxicidade, atividades antioxidante, anti-inflamatória e antitumoral de extratos de capim-elefante [Cenchrus purpureus (Schumach.) Morrone] com alta concentração de antocianinas

Abstract

The search for bioactive compounds of natural origin has driven research into promising sources, such as elephant grass [Cenchrus purpureus (Schumach.) Morrone], particularly the elite genotype T_44.1, which stands out for its high anthocyanin content. This study aimed to evaluate in vitro, the cytotoxicity and the antioxidant, anti-inflammatory, and antitumor activities of its extract, as well as its bioaccessibility after simulated digestion. The extracts were prepared by aqueous and hydroalcoholic extraction (ethanol:water, 70:30 v/v), followed by rotary evaporation at 30 °C and 40 °C, and subsequent lyophilization. Cyanidin-3-glucoside was identified and quantified by UPLC-MS/MS. Cytotoxicity was assessed in WI-38 fibroblasts and RAW 264.7 macrophages using the MTT cell viability assay. Antioxidant and antitumor activities (in MCF-7 breast cancer cells) were also investigated, along with the anti-inflammatory capacity in macrophages. In the MTT assay, the extract demonstrated cell viability ≥ 70% in WI-38 and RAW 264.7 cell lines up to a concentration of 1000 µg/mL in vitro, indicating potential safety. The extracts exhibited antioxidant activity in the performed assays, achieving 50% inhibition of free radicals and lipid peroxidation at doses ≤ 17.330 µg/mL and ≤ 11.170 µg/mL in the DPPH and β-carotene/linoleic acid assays, respectively. A significant maintenance of activity was observed after in vitro digestion, indicating high bioaccessibility of its bioactivity (>70%). Regarding anti-inflammatory activity, a dose-dependent reduction in TNF-α, IL-1β, and IL-6 levels was observed in LPSstimulated macrophages, with decreases ranging from 60% to 80%. In breast cancer cells (MCF-7), the antitumor activity was considered low to moderate, due to the high concentration required to induce cytotoxicity (IC₅₀ = 1,908.33 ± 135.06 µg/mL), when compared with data reported in the literature. The results suggest that elephant grass extracts possess significant functional properties, highlighting their potential for development as phytotherapeutic agents. However, further studies are necessary to elucidate their mechanisms of action and to evaluate their in vivo efficacy.