Tea(Camellia sinensis)is rich in flavan-3-ols(catechins),especially epicatechin(EC),which is the predominant extension unit of polymeric proanthocyanidins(PAs).However,studies assessing ECs stereochemistry are scarce.Here,a high performance liquid chromatography column using amylose tris-(3,5-dimethylphenylcarbamate)immobilized on silica-gel as chiral stationary phases(CSPs)was applied to explore its stereochemistry and biosynthetic pathway in tea plants.The results revealed(-)-epicatechin [(-)-EC] was the predominant di-hyroxy-non-galloylated-catechins,while(+)-epicatechin [(+)-EC] was not detected.Interestingly,(-)-EC was the only product obtained from cyanidin using the preliminarily purified native Camellia sinensis anthocyanidin reductase(CsANR)in the presence of reduction nicotinamide adenine dinucleotide phosphate(NADPH); meanwhile,(+)-EC was the main product using recombinant CsANR in the same conditions.In addition,(-)-EC could be obtained from(+)-catechin [(+)-C] using recombinant CsANR,which displayed C3-epimerase activity in the presence of oxidation nicotinamide adenine dinucleotide phosphate(NADP+).But the preliminarily purified native CsANR did not possess this function.Finally,(-)-EC could result from the de-gallate acid reaction of epicatechin gallate(ECG)catalyzed by a novel preliminarily purified native galloylated catechins hydrolase(GCH)from tea leaves.In summary,(-)-EC is likely the product of native protein from the tea plants,and(+)-EC is only produced in a reaction catalyzed by recombinant CsANR in vitro.