No abstract

In order to characterize the structures, biological activity, and mechanisms of action for walnut constituents, the key phytochemicals must be isolated in sufficient quantities. The objective of this research was to establish a method for rapid separation of walnut polyphenols which preserves structural integrity and yields high quantities and purities. A robust HSCCC method was developed to fractionate ethyl acetate and butanol extracts. This method efficiently yielded gallic acid, catechin, ellagic acid, casuarictin, pedunculagin, tellimagrindin I, 2,3‐O‐hexahydroxydiphenoyl‐ glucopyranoside (2,3‐HHDP‐glc), strictinin, and α‐hydrojuglone 4‐glucoside in 1 to 2 runs, and allowed us to test the ability of these walnut components to inhibit LPS‐induced ROS in human neuroblastoma (SH‐SY5Y) cells and reduce lipid accumulation in mouse adipocytes (3T3‐L1). The ethyl acetate and butanol extracts, as well as isolated ellagitannins, decreased ROS generation in SH‐SY5Y cells. Additionally, the 2,3‐HHDP‐glc decreased lipid accumulation in a dose‐dependent manner, resulting in 14% reduction of intracellular fat at 90 μM after 24 h of treatment. Treatment with 2,3‐HHDP‐glc increased basal oxygen consumption rate by 24.9% but had no effect on extracellular acidification rate, suggesting that it decreased lipid content of adipocytes by stimulating mitochondrial respiration. (Support from California Walnut Commission)