Abstract
Wheat germ (WG) is a by-product of wheat milling and comprises many bioactive compounds. This study aimed to compare the antioxidant and antilipidemic effects of different WG extracts (WGEs) by analyzing candidate bioactive compounds such as carotenoids, tocopherols, γ-oryzanol, and biogenic amines by reversed-phase high-performance liquid chromatography. Antioxidant activity was determined using the ABTS, DPPH, and FRAP assays. The antilipidemic effect was evaluated in palmitic acid-induced steatosis in HepG2 hepatocytes and 3T3-L1 adipocytes. Cellular lipid accumulation was assessed by Oil Red O staining and a cellular triglyceride content assay. All analyzed WGEs showed significant antioxidant potential, although some bioactive compounds, such as carotenoids, tocopherols, and γ-oryzanol, were the highest in the ethanol extract. Correlation analysis revealed the antioxidant potential of all identified biogenic amines except for spermidine. Ethanol and n-hexane extracts significantly inhibited cellular lipid accumulation in cell models. These results suggest that WGEs exhibit promising antioxidant potential, with a variety of bioactive compounds. Collectively, the findings of this study suggest that bioactive compounds in WGEs attenuate plasma lipid and oxidation levels. In conclusion, WG can be used as a natural antioxidant and nutraceutical using appropriate solvents and extraction methods.
Highlights
Many physiological systems of the human body are damaged by reactive oxygen species (ROS)
The total flavonoid contents in all samples extracted with different extraction methods were highly proportional to the total polyphenolic contents, meaning that when there was a higher content of total polyphenols, there was a higher content of total flavonoids
The total polyphenol (128.62 mg) and flavonoid (21.29 mg) contents were the highest in the subcritical water extract (SWE) and the lowest in the ultrasonic water extract (UWE) (67.60 and 9.38 mg, respectively) (Table 2). These findings indicate that the antioxidant potential of SWE, with higher total polyphenol and flavonoid contents, could be higher than that of the other WG extracts (WGEs)
Summary
Many physiological systems of the human body are damaged by reactive oxygen species (ROS). These ROS are generated due to several internal (mitochondrial respiratory chain, NADPH oxidase, and xanthine oxidase) and external (stress, smoke, air pollutants, radiation, etc.) factors [1]. Excessive ROS levels lead to oxidative stress, which causes various cellular dysfunctions. Non-alcoholic fatty liver disease (NAFLD) is an emerging chronic liver disease, which interferes with lipid metabolism, resulting in increased lipid synthesis and excessive fat accumulation in the liver (hepatic steatosis), leading to a wide variety of hepatic dysfunctions [3]. Obesity is a well-known metabolic disease caused by the excessive accumulation of fat in adipocytes, and adipogenesis, the process of differentiation of the preadipocytes to mature adipocytes, is involved in intracellular lipid accumulation [6]. Reducing oxidative stress and inhibiting adipogenesis have been suggested to help treat and prevent obesity [9,10]
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