# Elucidating the effects of blue light and NaCl on flavonoid biosynthesis in detached Lycium ruthenicum leaves by UPLC-MS/MS and chemometrics

## TL;DR

This study shows how blue light and salt together boost the production of healthful compounds in Lycium ruthenicum leaves.

## Contribution

The study reveals specific flavonoid biosynthesis pathways activated by blue light and NaCl in L. ruthenicum.

## Key findings

- Blue light and NaCl together increased anthocyanin content to 3.40 units·g−1 FW.
- Metabolomic analysis identified 495 flavonoids and treatment-specific biosynthesis pathways.
- Combined treatments enhanced dihydrokaempferol to dihydromyricetin conversion.

## Abstract

Lycium ruthenicum is rich in health-promoting anthocyanins and other flavonoids, however the effects of blue light (BL) and NaCl on their biosynthesis remained poorly understood. UPLC-MS/MS and chemometrics were utilized to investigate individual and combined effects of BL and NaCl treatments on flavonoids in detached L. ruthenicum leaves. BL significantly increased total anthocyanin content to 1.35 units·g−1 FW, 150 mM NaCl raised it to 2.64, and their combination further enhanced anthocyanin accumulation to 3.40. Comprehensive metabolomic profiling identified 495 flavonoids across different treatments. PCA and OPLS-DA revealed that BL and NaCl activated specific flavonoid biosynthesis pathways. BL preferentially enhanced quercetin derivatives and cyanidin 3-O-(6-p-coumaroyl)glucoside accumulation, whereas WL-NaCl markedly promoted the conversion of naringenin to eriodictyol, leading to dihydromyricetin biosynthesis. Combined treatments significantly stimulated the transformation of dihydrokaempferol into dihydromyricetin, and further boosted petunidins accumulation. These findings offered valuable strategies to enhance bioactive compounds production in L. ruthenicum for nutraceutical applications.

•BL and NaCl synergistically enhance anthocyanin accumulation in L. ruthenicum leaves.•Metabolomics identified 495 flavonoids, indicating pathway-specific induction by treatments.•BL promoted dihydrokaempferol conversion to dihydroquercetin, boosting quercetin production.•NaCl facilitated naringenin conversion to eriodictyol, enhancing dihydromyricetin biosynthesis.•BL and NaCl combined stimulated dihydrokaempferol transformation to dihydromyricetin.

BL and NaCl synergistically enhance anthocyanin accumulation in L. ruthenicum leaves.

Metabolomics identified 495 flavonoids, indicating pathway-specific induction by treatments.

BL promoted dihydrokaempferol conversion to dihydroquercetin, boosting quercetin production.

NaCl facilitated naringenin conversion to eriodictyol, enhancing dihydromyricetin biosynthesis.

BL and NaCl combined stimulated dihydrokaempferol transformation to dihydromyricetin.