N-Ethyl-2-pyrrolidinone-substituted flavanols (EPSF) are marker compounds for long-term stored white teas. However, due to their low contents and diasteromeric configuration, EPSF compounds are challenging to isolate. In this study, two representative epimeric EPSF compounds, 5′′′
R- and 5′′′
S-epigallocatechin gallate-8-C
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N-Ethyl-2-pyrrolidinone-substituted flavanols (EPSF) are marker compounds for long-term stored white teas. However, due to their low contents and diasteromeric configuration, EPSF compounds are challenging to isolate. In this study, two representative epimeric EPSF compounds, 5′′′
R- and 5′′′
S-epigallocatechin gallate-8-C
N-ethyl-2-pyrrolidinone (
R-EGCG-cThea and
S-EGCG-cThea), were isolated from white tea using centrifugal partition chromatography (CPC). Two different biphasic solvent systems composed of 1.
N-hexane-ethyl acetate-methanol-water (1:5:1:5,
v/
v/
v/
v) and 2.
N-hexane-ethyl acetate-acetonitrile-water (0.7:3.0:1.3:5.0,
v/
v/
v/
v) were used for independent pre-fractionation experiments; 500 mg in each separation of white tea ethyl acetate partition were fractionated. The suitability of the two solvent systems was pre-evaluated by electrospray mass-spectrometry (ESI-MS/MS) analysis for metabolite distribution and compared to the results of the CPC experimental data using specific metabolite
partition ratio KD values,
selectivity factors α, and
resolution factors RS. After size-exclusion and semi-preparative reversed-phase liquid chromatography, 6.4 mg of
R-EGCG-cThea and 2.9 mg of
S-EGCG-cThea were recovered with purities over 95%. Further bioactivity evaluation showed that
R- and
S-EGCG-cThea possessed in vitro inhibition effects on
α-glucosidase with IC
50 of 70.3 and 161.7 μM, respectively.
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