St. John's wort (SJW), or Hypericum perforatum, is a perennial herb that has been used in the treatment of depression in several countries. Though its therapeutic effect on depression has been extensively studied, its influence on metabolic syndrome is yet to be fully characterized. Therefore, we investigated the effect of SJW extract on adipocyte differentiation and its anti-inflammatory effects by using 3T3-L1 preadipocytes. Oil Red O staining indicated that SJW promotes adipocyte differentiation, while immunoblots indicated that SJW increases the expression of peroxisome proliferator activated receptor γ (PPARγ), a nuclear receptor regulating adipocyte differentiation, and adiponectin, an anti-inflammatory adipokine. Furthermore, the anti-inflammatory activity of SJW was demonstrated by its inhibition of the activation of nuclear factor-κB (NF-κB), an inflammatory transcription factor. Stimulation of mature 3T3-L1 adipocytes by tumor necrosis factor-α (TNF-α) decreased the expression of the NF-κB inhibitor IκBα, and increased its phosphorylation. Treatment with SJW further decreased the TNF-α-induced perturbation in IκBα expression and phosphorylation, which indicated that SJW mediated the inhibition of NF-κB activation. In addition, SJW decreased the TNF-α-induced increase in the mRNA levels of pro-inflammatory adipokines, interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1). Collectively, our results indicate that SJW treatment could promote adipocyte differentiation probably through its anti-inflammatory activity, which in turn suggests that SJW has the potential to minimize the risk factors of metabolic syndrome.

Nowadays, a lot of food ingredients are marketed as dietary supplements for health. Because the eŠectiveness and mechanisms of these compounds have not been fully characterized, they might have unknown functions. Therefore, we investigated the eŠect of several food ingredients (Bergamottin, Chrysin, L-Citrulline and b-Carotene) known as health foods on adipocyte diŠerentiation by using 3T3-L1 preadipocytes. In this study, we found that Bergamottin, a furanocoumarin isolated from grapefruit juice, promotes adipocyte diŠerentiation. In addition, Bergamottin increases the expression of adiponectin, an anti-in‰ammatory adipokine, and peroxisome proliferator activated receptor g (PPARg), a nuclear receptor regulating adipocyte diŠerentiation. Furthermore, the anti-in‰ammatory activity of Bergamottin was demonstrated by its inhibition of the activation of nuclear factor-kB (NF-kB), an in‰ammatory transcription factor. Stimulation of mature 3T3-L1 adipocytes by tumor necrosis factor-a (TNF-a) decreased the expression of the endogeneous NF-kB inhibitor, IkBa. Treatment with Bergamottin further decreased the TNF-a-induced change in IkBa expression, suggesting that Bergamottin mediated the inhibition of NF-kB activation. In addition, Bergamottin decreased the TNF-a-induced increase in the mRNA levels of pro-in‰ammatory adipokines, monocyte chemoattractant protein-1 and interleukin-6. Taken together, our results show that Bergamottin treatment could inhibit in‰ammatory activity through promoting adipocyte diŠerentiation, which in turn suggests that Bergamottin has the potential to minimize the risk factors of metabolic syndrome.

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