Compound 15 exhibited a (+)-HRESIMS peak at 865.1960 [M + H] + , corresponding to a molecular formula of C45H36O18, which was consistent with its 13 C NMR data. Compound 15 was thus assigned as a trimeric PAC with one A-and one B-type IFL. Two major rotamers in a ~4:1 ratio were observed in the H and 13 C NMR spectra (Tables and) acquired at low temperature (255 K) for restricted rotation around the B-type linkage. The doubly linked interflavanyl bonds (2→O→7,4→8) between units II and III were verified by the HMBC correlations (Figure ) from both II-H-4 (H 4.33) and III-H-2 (H 4.95) to C-9 (C 152.23). Unit I was attached to unit II through a 4→6 bond as derived from the NOESY correlations from II-H-8/II-H-2′ and II-H-6′ (Figure ), as well as the downfield shifted II-C-6 carbons (avg. C 110.6). The ECD data (Figure ) showed a high-amplitude positive CE at 220-240 nm, which assigned a - Unit I was, thus, identified as epicatechin with a (2R, 3R)-absolute configuration. The 3,4-trans configuration in the C-ring was assigned based on the NOESY correlation between II-H-3 and III-H-6. Finally, the diagnostic C patterns were applied to determine the absolute configuration of the terminal unit III: it was identified as epicatechin as its C resonances were significantly closer to those of the corresponding carbons in 4 than to those in 6 (Table ). To further confirm this conclusion, phloroglucinolysis of 15 was performed. The reaction products were identified as 1 and 4 by MS and chiral phase HPLC (Figure ). Thus, compound 15 was unambiguously elucidated as epicatechin-(4→6)-[PAC 4]. While this structure has been reported previously, the prior NMR data did not match the present data set. This mismatch can be explained by the incorrect assignment of II-C-10 (C 104.9) in the previous report, which led to establishment of an incorrect 4→6 linkage through interpretation of HMBC correlations. The chemical shift previously reported for II-C-6 (C 108.9) better matches the corresponding carbons in 11 and 12. This indicated that the compound reported earlier in fact had a 4→8 IFL. Thus, its structure should be revised to epicatechin-(4→8)-epicatechin-(4→8,2→7)-epicatechin. However, considering the subtle substituent chemical shift (.s.c.s.)