Purple Sweet Potato Leaf Extract Induces Apoptosis and Reduces Inflammatory Adipokine Expression in 3T3-L1 Differentiated Adipocytes

Abstract EN

Background.

Purple sweet potato leaves (PSPL) are widely grown and are considered a healthy vegetable in Taiwan.

PSPL contain a high content of flavonoids, and the boiling water-extracted PSPL (PSPLE) is believed to prevent metabolic syndrome.

However, its efficacy has not yet been verified.

Therefore, we investigated the effect of PSPLE on adipocytes.

Methods.

The differentiated 3T3-L1 cells used in this study were derived from preadipocytes that were differentiated into adipocytes using an adipogenic agent (insulin, dexamethasone, and 3-isobutyl-1-methylxanthine); approximately 90% of the cells were differentiated using this method.

Results.

Treating the differentiated 3T3-L1 cells with PSPLE caused a dose-dependent decrease in the number of adipocytes rather than preadipocytes.

In addition, treatment with PSPLE resulted in apoptosis of the differentiated 3T3-L1 cells as determined by DAPI analysis and flow cytometry.

PSPLE also increased the expression of cleaved caspase-3 and poly ADP-ribose polymerase (PARP).

Furthermore, PSPLE induced downregulation of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) gene expression in the differentiated 3T3-L1 cells.

Conclusions.

These results suggest that PSPLE not only induced apoptosis but also downregulated inflammation-associated genes in the differentiated 3T3-L1 cells.