The recently discovered myokines, irisin and fibroblast growth factor-21, have emerged beneficial for metabolic health due to their role in regulating browning. This study examined the effects of high-intensity circuit training on obesity indices, physical fitness, and irisin and fibroblast growth factor-21 levels in inactive female college students. Ten female college students performed high-intensity circuit training (jogging, stretching, squat jumps, arm walking and push-ups, lunge jumps, burpee test, mountain climbers, side steps, and crunches and side crunches exercises). The exercise program consisted of 40 min of circuit training at 60%-80% hear rate reserve and was conducted 3 times per week for 4 weeks. The body composition, physical fitness, and concentration of plasma irisin and fibroblast growth factor-21 were ana-lyzed before and after the exercise. The body weight (P= 0.001), waist circumference (P= 0.003), and body fat percentage (P= 0.003) decreased, while the muscular strength (handgrip strength test, P= 0.030; sit-ups test, P= 0.024) and cardiorespiratory fitness (P= 0.001) increased after the exercise program. However, there were no significant changes in the irisin and fibroblast growth factor-21 levels. These results suggest that high-intensity circuit training could be the ideal type of exercise in inactive female college students to induce a positive change in the obesity indices and physical fitness. Further studies are needed to determine the effects of exercise on the browning factors.

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We aimed to investigate the effects of nobiletin on hepatic lipogenesis in high glucose-induced lipid accumulation in HepG2 cells. Nobiletin, a citrus polymethoxyflavonoid with six methoxy groups, is present abundantly in the peels of citrus fruits. HepG2 cells were incubated in Dulbecco's modified Eagle's medium containing high glucose (25 mM) and subsequently treated with nobiletin at different concentrations (5, 25, and 50 μM). Results showed that nobiletin markedly inhibited high glucose-induced hepatic lipid accumulation in HepG2 cells. In addition, it reduced the protein expression of lipogenic factors, including sterol regulatory element-binding protein 1c (SREBP-1c) and fatty acid synthase (FAS). Nobiletin significantly increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase. Pretreatment with compound C, an AMPK inhibitor, abolished the inhibitory effects of nobiletin on SREBP-1c and FAS expression. These results suggested that nobiletin might attenuate high glucose-induced lipid accumulation in HepG2 hepatocytes via modulation of AMPK signaling pathway. Therefore, nobiletin might be useful for the prevention and treatment of nonalcoholic fatty liver diseases.

In this study, the protective effects of caffeic acid (CA) and sinapic acid (SA) on photoaging in human skin fibroblasts induced by UVB irradiation (30 mJ/cm2) were examined. The results revealed that exposure to UVB irradiation reduced cell viability by approximately 33% compared with the non‐UVB irradiated control. However, CA and SA blocked the UVB irradiation‐induced cytotoxicity greater than the other phenolic acids. CA and SA also significantly inhibited the release of matrix metalloproteinase 1 (MMP‐1) and reduced the expression of MMP‐1 mRNA in UVB‐irradiated Hs68 cells. Furthermore, CA and SA reduced UVB‐induced production of reactive oxygen species (ROS) and collagen degradation in Hs68 cells. Finally, CA and SA effectively downregulated activation of the UVB‐induced mitogen‐activated protein kinases (MAPKs) and nuclear factor κB (NFκB) signaling pathways. These results imply that hydroxylated cinnamate derivatives can be therapeutic agents against UVB‐induced skin photoaging. Practical applications Hydroxylated cinnamate derivatives such as CA and SA have a high cytoprotective effect against UV irradiation‐induced photoaging in human fibroblasts via the inactivation of the MAPKs/NFκB signaling pathway. The present study suggests that CA and SA may be useful in therapeutic and cosmetic applications for the treatment of skin photoaging.

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