Purple coloured
tea shoot clones have gained interest due to high content of
anthocyanins in addition to catechins. Transcript expression of genes encoding
anthocyanidin reductase (ANR),
dihydroflavonol-4-reductase (DFR),
anthocyanidin synthase (ANS),
flavonol synthase (FLS) and leucoantho
cyanidin reductase (LAR)
enzymes in three new purple shoot
tea clones compared with normal
tea clone showed higher expression of CsDFR, CsANR, CsANS and lower expression of CsFLS and CsLAR in purple shoot clones compared to normal clone. Expression pattern supported high content of
anthocyanins in purple
tea. Four
anthocyanins (AN1-4) were isolated and characterized by UPLC-ESI-QToF-MS/MS from IHBT 269 clone which recorded highest total
anthocyanins content. Cyanidin-3-O-β-d-(6-(E)-coumaroyl) glucopyranoside (AN2) showed highest in vitro
antioxidant activity (IC50 DPPH = 25.27 ± 0.02 μg/mL and IC50 ABTS = 10.71 ± 0.01 μg/mL). Anticancer and immunostimulatory activities of
cyanidin-3-glucoside (AN1), cyanidin-3-O-β-d-(6-(E)-coumaroyl) glucopyranoside (AN2), delphinidin-3-O-β-d-(6-(E)-coumaroyl) glucopyranoside (AN3), cyanidin-3-O-(2-O-β-xylopyranosyl-6-O-acetyl)-β-glucopyranoside (AN4) and crude
anthocyanin extract (
AN5) showed high therapeutic perspective.
Anthocyanins AN1-4 and
crude extract AN5 showed cytotoxicity on C-6
cancer cells and high relative fluorescence units (RFU) at 200 μg/mL suggesting promising apoptosis induction activity as well as influential immunostimulatory potential. Observations demonstrate potential of purple
anthocyanins enriched
tea clone for exploitation as a nutraceutical product.