ABSTRACT
PURPOSE: Sprouts of evening primrose (Oenothera laciniata, OL) were reported to have high contents of flavonoids and potent antioxidant activity. This study examined the antioxidant and antiobesity activities of OL sprouts to determine if they could be a natural health-beneficial resource preventing obesity and oxidative stress.METHODS: OL sprouts were extracted with 50% ethanol, evaporated, and lyophilized (OLE). The in vitro antioxidant activity of OLE was examined using four different tests. The antiobesity activity and in vivo antioxidant activity from OLE consumption were examined using high fat diet-induced obese (DIO) C57BL/6 mice.RESULTS: The IC₅₀ for the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging and superoxide dismutase (SOD)-like activities of OLE were 26.2 µg/mL and 327.6 µg/mL, respectively. OLE exhibited the ferric reducing antioxidant power (FRAP) activity of 56.7 µg ascorbic acid eq./mL at 100 µg/mL, and an increased glutathione level by 65.1% at 200 µg/mL compared to the control in the hUC-MSC stem cells. In an animal study, oral treatment with 50 mg or 100 mg of OLE/kg body weight for 14 weeks reduced the body weight gain, visceral fat content, fat cell size, blood leptin, and triglyceride levels, as well as the atherogenic index compared to the high fat diet control group (HFC) (p < 0.05). The blood malondialdehyde (MDA) level and the catalase and SOD-1 activities in adipose tissue were reduced significantly by the OLE treatment compared to HFC as well (p < 0.05). In epididymal adipose tissue, the OLE treatment reduced the mRNA expression of leptin, PPAR-γ and FAS significantly (p < 0.05) compared to HFC while it increased adiponectin expression (p < 0.05).CONCLUSION: OLE consumption has potent antioxidant and antiobesity activities via the suppression of oxidative stress and lipogenesis in DIO mice. Therefore, OLE could be a good candidate as a natural resource to develop functional food products that prevent obesity and oxidative stress.