TY - JOUR
T1 - Anthocyanin-rich extract from purple tea
T2 - Chemical stability, cellular antioxidant activity, and protection of human erythrocytes and plasma
AU - de Moura, Cristiane
AU - Vieira do Carmo, Mariana Araújo
AU - Xu, Yong Quan
AU - Azevedo, Luciana
AU - Granato, Daniel
N1 - Publisher Copyright:
© 2024 The Authors
PY - 2024/1
Y1 - 2024/1
N2 - This study aimed to obtain an anthocyanin extract from the purple leaves of Camellia sinensis cv. Zijuan using a sustainable, non-toxic, and low-cost solid-liquid extraction, employing an aqueous citric acid solution (0.2 mol/L) as the extracting solvent, and to evaluate its chemical stability at different pH values, as well as its in vitro antioxidant properties in chemical and biological terms. The phenolic composition, in vitro antioxidant activity, and the stability of anthocyanins against pH, temperature, and light of the crude extract (CE) were evaluated, as well as the phenolic composition and bioactivity in the crude lyophilised extract (CLE). In the direct/reverse spectrophotometric titration, anthocyanins showed structural changes between pH 2 and 10, and reversibility of 80%. The antioxidant activity against the DPPH radical showed inhibition percentages of 73% (pH 4.5) to 39% (pH 10). Thermal stability was observed at 60 °C, and prolonged exposure of the extract to light caused photodegradation of the anthocyanins. Thirty-three phenolic compounds, including anthocyanins and catechins, were quantified in the CLE by UPLC-ESI-MS and HPLC, totalling 40.18 mg/g. CLE reduced cell viability (IC50 from 18.1 to 52.5 μg GAE/mL), exerted antiproliferative (GI50 from 0.0006 to 17.0 μg GAE/mL) and cytotoxic (LC50 from 33.2 to 89.9 μg GAE/mL) effects against A549 (human lung adenocarcinoma epithelial cells), HepG2 (hepatocellular carcinoma), HCT8 (ileocecal colorectal adenocarcinoma), and Eahy926 (somatic cell hybrid cells); and showed protection against oxidation of human plasma (635 ± 30 mg AAE/g). The results showed the diversity of compounds in the extracts and their potential for technological applications; however, temperature, pH, and light must be considered to avoid diminishing their bioactivity.
AB - This study aimed to obtain an anthocyanin extract from the purple leaves of Camellia sinensis cv. Zijuan using a sustainable, non-toxic, and low-cost solid-liquid extraction, employing an aqueous citric acid solution (0.2 mol/L) as the extracting solvent, and to evaluate its chemical stability at different pH values, as well as its in vitro antioxidant properties in chemical and biological terms. The phenolic composition, in vitro antioxidant activity, and the stability of anthocyanins against pH, temperature, and light of the crude extract (CE) were evaluated, as well as the phenolic composition and bioactivity in the crude lyophilised extract (CLE). In the direct/reverse spectrophotometric titration, anthocyanins showed structural changes between pH 2 and 10, and reversibility of 80%. The antioxidant activity against the DPPH radical showed inhibition percentages of 73% (pH 4.5) to 39% (pH 10). Thermal stability was observed at 60 °C, and prolonged exposure of the extract to light caused photodegradation of the anthocyanins. Thirty-three phenolic compounds, including anthocyanins and catechins, were quantified in the CLE by UPLC-ESI-MS and HPLC, totalling 40.18 mg/g. CLE reduced cell viability (IC50 from 18.1 to 52.5 μg GAE/mL), exerted antiproliferative (GI50 from 0.0006 to 17.0 μg GAE/mL) and cytotoxic (LC50 from 33.2 to 89.9 μg GAE/mL) effects against A549 (human lung adenocarcinoma epithelial cells), HepG2 (hepatocellular carcinoma), HCT8 (ileocecal colorectal adenocarcinoma), and Eahy926 (somatic cell hybrid cells); and showed protection against oxidation of human plasma (635 ± 30 mg AAE/g). The results showed the diversity of compounds in the extracts and their potential for technological applications; however, temperature, pH, and light must be considered to avoid diminishing their bioactivity.
KW - Bioactivity
KW - Cell culture
KW - Functional foods
KW - Natural colourants
KW - Oxidative stress
KW - Phenolic compounds
UR - http://www.scopus.com/inward/record.url?scp=85185809515&partnerID=8YFLogxK
U2 - 10.1016/j.crfs.2024.100701
DO - 10.1016/j.crfs.2024.100701
M3 - Article
AN - SCOPUS:85185809515
SN - 2665-9271
VL - 8
JO - Current Research in Food Science
JF - Current Research in Food Science
M1 - 100701
ER -