Epicatechin 3 gallate

All reagents used for analytical determinations, (water, acetonitrile, methanol, formic acid and hydrochloric acid) were from VWR International (Fontenay-sous-Bois, France).
Hyperoside (purity > 98%), kaempferol-3-O-glucoside (purity > 99%), procyanidin B1 (purity ≥ 80%), procyanidin B2 (purity ≥ 90%), and catechin (purity ≥ 99%) were purchased from Extrasynthese (Genay, France); rutin (purity > 97%), quercetin-3-O-glucoside (purity ≥ 98%), quercetin-3-O-glucuronide (purity > 98%), epicatechin (purity > 90%), epicatechin-3-gallate (purity > 98%), epigallocatechin-3-gallate (purity > 95%), Gallic acid, sodium carbonate, and Folin–Ciocalteu’s reagent were from Sigma-Aldrich (St. Louis, MO, USA); caftaric acid (purity ≥ 95%) and procyanidin C1 (purity ≥ 80%) were from Phytolab GMBH & Co. (Vestenbergsgreuth, Germany); and procyanidin B3 (purity > 98%) was from Carbosynth Limited (Compton, Berkshire, UK).

HPLC-grade acetonitrile and methanol were purchased from Fisher Chemicals (NJ, USA). HPLC grade formic acid was purchased from Tedia (Lake Forest, CA, USA). Ultrapure water was produced by a Milli-Q Plus water purification system (Millipore, Bedford, MA). Commercial standards including caffeine, theanine, (+)-catechin (C), (−)-epicatechin (EC), (+)-gallocatechin (GC), (−)-epigallocatechin (EGC), (−)-catechin- 3-gallate (CG), (−)-epicatechin-3-gallate (ECG), (−)-gallocatechin-3-gallate (GCG), (−)-epigallocatechin-3-gallate (EGCG) were purchased from Sigma (Sigma-Aldrich, USA) and used to construct standard curves for quantitative analysis in the tea leaves.

Formic acid and HPLC grade methanol were purchased from VWR Prolabo (Fontenay-sous-Bois, France). Deionized water was obtained from a Milli-Q purification system (Millipore, Molsheim, France). Standard of trans-piceid was purchased from Selleckchem (Houston, TX, USA). Standards of caffeic acid, vanillic acid, gallic acid and ferulic acid were purchased from Fluka (Buchs, Switzerland). Standards of syringic acid, p-coumaric acid, protocatechuic acid, ethyl protocatechuate, tyrosol, tryptophol, tryptophan, trans-resveratrol, quercetin, catechin, epicatechin, epicatechin 3-gallate, taxifolin, oxidized and reduced glutathione were purchased from Sigma-Aldrich (St. Louis, MO, USA), as well as hydrochloric acid, phloroglucinol, L-ascorbic acid, and ammonium formiate. Standards of ethyl gallate, ethyl caffeate, tyrosine, hydroxytyrosol, epigallocatechin, malvidin 3-O-glucoside chloride, and malvidin 3,5-diglucoside chloride were purchased from Extrasynthese (Geney, France). Standards of trans-caftaric acid, quercetin glucoside and procyanidin dimers B1, B2, B3, B4, and trimer C1 were purchased from Phytolab (Vestenbergsgreuth, Germany).

H. camelliae WT00C and WT00F were isolated from the tea plant in Wuhan City, China [5 ] and stored in our laboratory. H. rubrisubalbicans Os34 [32 (link)] was given by Zhejiang University as a gift, and H. seropedicae Z67 [33 (link)] (#ATCC35892) was purchased from ATCC (American Type Culture and Collection). Other bacterial strains (e.g., E. coli DH5α and BL21(ED3) pLysS) used in this study were stored in our laboratory. These bacterial strains were usually cultured in LB medium at 37℃. Methyl gallate (MG), tannic acid, gallic acid (GA), (–)–epicatechin-3-gallate (ECG), and (–)–epigallocatechin-3-gallate (EGCG) were purchased from Sigma-Aldrich, USA. Inorganic and organic reagents, as well as culture media, were purchased from Zhong Ke (Shanghai, China).