Abstract:The spectrum-activity relationship between HPLC fingerprints and lipid-lowering effects of an ethanol extract, and its liquid-liquid extract and purified product (by macroporous resin), from the defatted walnut meal was studied, to provide a basis for determining the foundation material of their lipid-lowering effects. The HPLC fingerprints (S1~S9) of these extracts and purified products of defatted walnut meal were acquired; A free fatty acid (FFA) was added to HepG2 cells at 1 mM/L and treated for 24 h, to establish a model of steatosis. After the model was successfully established, the lipid-lowering effects of S1~S9 samples on steatosis in HepG2 cells were examined; The gray correlation method was used to analyze the spectrum-activity relationship between the common spectral peaks and the lipid-lowering effects of the active ingredient group. Results showed that among the 15 common peaks screened from the similarity range of 0.31~0.96 in the HPLC spectra of S1~S9, the ethyl acetate extract (S5) and the purified product of macroporous resin (S8) had the greatest lipid-lowering effects (p<0.001). The first 6 peaks corresponding to the fractions that made a relatively high contribution to the lipid-lowering effect were peak 14, 6, 12, 10, 13, and 11, respectively. The correlation coefficient of peak 14 was the highest (higher than 0.9), with those of the remaining 5 peaks all higher than 0.85. The lipid-lowering effect of the extract from walnut meal resulted from the combined action of multiple constituents. The substances corresponding to glansreginin A, (4S)-4-hydroxy-α-tetralone-4-O-β-D-(6′-O-4″-hydroxylbenzoyl)-glucopyranoside, (2E,4E)-8-hydroxy-2,7-dimethyl-2,4-decadiene-1,10-dioic acid 6'-O-β-d-glucopiranosyl ester, glansreginin B, rutin, and quercetin 3-arabinoside or quercetin 3-xyloside were identified a the main lipid-lowering active components in the extracts from the defatted walnut meal.
