Dihydroquercetin

All solvents and reagents were of analytical grade. Methanol, acetonitrile, phosphoric acid, and acetic acid (HPLC grade) were purchased from ThermoFisher Scientific (Shanghai, China). Authentic standards of apigenin, luteolin, naringenin, eriodictyol, dihydrokaempferol, and dihydroquercetin were purchased from Shanghai Yuanye Biotechnology Co., Ltd. (Shanghai, China).

E. coli DH5α and C41(DE3) were used as hosts for DNA cloning and whole-cell biotransformation, respectively. Primer STAR HS DNA polymerase and restriction endonucleases were obtained from Takara (Dalian, China). DNA and genomic DNA Extraction Kits were obtained from Thermo Scientific (Waltham, United States) and TIANGEN (Beijing, China), respectively. The plasmid miniprep purification kit was purchased from Sangon Biotech (Shanghai, China). Oligonucleotide synthesis and sequence analysis were achieved by Sangon Biotech (Shanghai, China). ALA and hemin were purchased from Sigma-Aldrich (St. Louis, MO, United States). Naringenin, eriodictyol, dihydrokaempferol, dihydroquercetin, kaempferol, quercetin, apigenin, luteolin, daidzein, and 7,3′,4′-trihydroxyisoflavone were purchased from Yuanye Bio-Technology (Shanghai, China). Other chemicals were purchased from Sangon Biotech (Shanghai, China) and were of the highest commercial grade available.

Naringenin, eriodictyol, apigenin, luteolin, liquiritigenin, butin, sakuranetin, kaempferol, quercetin, dihydrokaempferol, dihydroquercetin, eriocitrin, pinocembrin, narirutin, naringin, chrysin, genkwanin, baicalein, scutellarein, norwogonin, wogonin, and neoeriocitrin were purchased from Shanghai Yuanye Bio-Technology Co., Ltd (Shanghai, China). Hesperidin, neoHesperidin, sinensetin, isosinensetin, and nobiletin were obtained from Sigma-Aldrich (St Louis, MO, USA). 7-O-methyleriodictyol, isosakuranetin, and 5-HPMF were purchased from BioBioPha Co., Ltd (Kunming, China).