Evaluation of lipid accumulation inhibitory activity in vitro of theaflavins in black tea using ¹H NMR spectral data and multivariate analysis

抄録

Black tea contains unique polyphenolic pigments, known as theaflavins, which are formed during the enzymatic oxidation of tea leaves and are believed to contribute to various health benefits. We previously confirmed the antioxidant properties of black tea. Therefore, we combined compositional analysis with functional evaluation to clarify the lipid accumulation inhibitory activity of black tea. Samples from different regions worldwide were analysed using ¹H NMR spectral data and multivariate analysis. In parallel, the effects were assessed by measuring lipid accumulation in 3T3-L1 preadipocyte cells. While crude extracts exhibited the activity without clear correlations to NMR-derived components, analysis of theaflavin-rich fractions revealed that samples containing high levels of gallated theaflavins suppressed lipid accumulation. Positive correlations were observed between their quantified contents, principal component loadings, and lipid accumulation inhibitory activity. These findings demonstrate that ¹H NMR spectral data, when integrated with functional assays, provide an approach for screening and evaluating tea constituents.