## 4 Discussion
In the present study, TJ increased cAMP activity and decreased the protein levels of CREB, C/EBP\(\beta\), C/EBPa, and PPAR\(\gamma\) compared to the differentiation induction group. Due to this, the protein levels of FABP4, leptin, and G6 Pase were also regulated. In the lipogenesis mechanism, SREBP1c with various functions plays a crucial role. It stimulates ligands for nuclear receptors and PPAR\(\gamma\) and regulates FA synthesis by activating lipogenesis-related factors, including ACC and FAS [37; 38; 39]. ACC is the rate-limiting enzyme in de novo FA synthesis and has been reported to be the enzyme responsible for the production of malonyl-CoA [40; 41]. It has been reported that AMPK acts as an energy sensor that regulates lipid metabolism in cells, and the active form suppresses adipogenesis by down-regulating the expression of SREBP1c [42; 43]. In addition, LPL is also an important factor in lipogenesis metabolism because it is also involved in FA synthesis and lipoprotein metabolism [44]. In the present study, TJ decreased the expression of SREBP1c by activating AMPK compared to the control group. In addition, it induced the activity of ACC and decreased the protein expression of FAS and LPL, thereby reducing the intracellular FA level. These results also affected the reduction in lipid accumulation, leading to a decrease in TG. In the lipolysis mechanism, cAMP levels are regulated by the expression of PDE3B, and the PDE3 gene forms encode the PDE3A and 3B forms that act in the process of decomposing cAMP to 5\({}^{\prime}\)AMP. PDE3B is expressed in insulin-sensitive cells, such as hepatocytes, pancreatic \(\beta\)-cells, while adipocytes play a key role in glycogenolysis and lipolysis mechanisms. Lipolysis is mainly stimulated by the activation of the cAMP-PKA pathway, and since a decrease in the expression of PDE3B is related to a decrease in the hydrolysis of cAMP, the cAMP-PKA pathway can be stimulated [12; 45]. In the next step, HSL and perilipin are phosphorylated by activation of PKA. This step is related to the efficiency of lipolysis: HSL migrates from the cytoplasm to the lipid droplets and activates this step, which ultimately affects the hydrolysis of TG [11; 13; 46]. Perilipin exists in the form of surrounding lipid droplets and can protect TG from several lipolytic enzymes [13; 47]. It has been reported that an absence or decrease in the level of perilipin promotes basal lipolysis [46; 47]. As a result of confirming the effect of TJ on the lipolysis mechanism using our established experimental model, TJ treatment increased cAMP levels and decreased the expression of PDE3B compared to the differentiation control group. In addition, TJ reduced the expression of ATGL, increased the expression levels of PKA, activated AMPK and HSL phosphorylation, and decreased the perilipin in the adipocytes. Furthermore, TJ reduced the intracellular FA content compared to that of the differentiation control group. This led to the reduction in TG content, and glycerol release was finally induced to promote lipolysis. In our study, we evaluated the anti-obesity effect of Chinese TJ (extracted with 20% ethyl alcohol), which had not been attempted before, by various mechanisms. Although there have been reports of previously known adipogenesis inhibitory effects of TJ [15], we expected that the efficacy would be different depending on the country of origin and extraction process, and in order to open the possibility of future development as a health functional food, we evaluated the maximum effective dose within the range of non-toxicity. Although there were limitations to the markers showing effects at high concentrations, we differentiated them by identifying various factors of the mechanism extending to the previously unreported lipogenesis inhibitory activity and lipolysis activity of TJ.