Identification and Characterization of Tocotrienols in Muscadine Grape Seed Oil and their Inhibitory Effects on Adipogenesis and Inflammation

Abstract

Tocotrienols are unsaturated forms of vitamin E that accumulate in adipose tissue where they exert potent anti‐adipogenic and anti‐inflammatory effects compared to saturated vitamin E, tocopherols. Tocotrienols have been known to exist in a limited variety of vegetable oils such as rice bran and red palm oil. However, we have recently found that muscadine grape seed oils (MGSOs), byproducts of wine making, contain high levels of α‐ and γ‐tocotrienol. The aim of this study is to determine the efficacy of MGSOs in reducing adipogenesis and inflammation by using primary human adipose‐derived stem cells (hASCs). Differentiating hASCs were treated with MGSOs in comparison with rice bran and olive oil. TG accumulation was significantly lower in MGSOs‐treated hASCs than the other edible oils. A tocotrienols rich fraction (TRF) from MGSOs was prepared by solid phase extraction and used to treat hASCs. The MGSOs‐derived TRF significantly reduced the mRNA and protein expression of genes that are crucial to adipogenesis (e.g., PPARg and aP2). Furthermore, TRF from MGSOs markedly reduced LPS‐induced proinflammatory gene expression and cytokine secretion to the media (IL‐6 and IL‐8). Taken together, our results demonstrated that MGSOs are a significant source for tocotrienols that may attenuate hyperplastic obesity and obesity‐induced adipose inflammation.