| Summary: | 碩士 === 國立中興大學 === 食品暨應用生物科技學系所 === 102 === Obesity has become a global epidemic and an important health problem in recent years. It is also a risk factor of many chronic diseases. Maitake (Grifola frondosa) is a popular study material with good therapeutic effect and contains various bioactive substances and nutrients. Many studies have shown that Maitake mushroom exhibits anti-cancer activity, and it can improve ascites from cirrhosis, diabetes, hypertension, high cholesterol, etc. Moreover, the studies related to maitake are mainly focusing on physiological activities of polysaccharide and submerged culture condition of obtaining mycelium recently. In this study, Maitake fruiting body powders irradiated by pulsed light were extracted by 70% ethanol. There are four kinds of extracts from Maitake fruiting body powders irradiated by pulsed light, including aqueous layer (NW: non-irradiated; IW: irradiated) and ethyl acetate layer (NEA: non-irradiated; IEA: irradiated). We investigated the impact of NW and IW on cell cycle related protein expression and the anti-lipogenesis effect of extracts from Grifola frondosa on 3T3-L1 preadipocytes before and during differentiation.
The results showed that the suppressive effect of NW, IW, NEA and IEA (at concentration 0~2.00 mg/mL) on cell viability of 3T3-L1 preadipocyte was dose- and time-dependent. In addition, that NW and IW could arrest cell cycle at G2 / M phase significantly in cell cycle analysis. After 3T3-L1 preadipocyte reached confluent, we added fresh medium with different extracts to incubate for 8 days. We found that all extracts could significantly reduce the formation of intracellular oil droplets, and NW and IW inhibited oil droplets formation to 81.45% and 81.55%, respectively. According to the results of western blotting, NW and IW significantly inhibited the expression of Cdc25C, which further regulate the protein expression of Cdc2 and p-Cdc2 (Thr161). Besides, p53 protein significantly activated by extracts, which revealed that 3T3-L1 preadipocyte would proceed to apoptosis after the inhibition of cell proliferation.
In conclusion, we demonstrated that aqueous layer extracts (NW and IW) had the effect of anti-proliferation and the inhibition of oil droplets formation on 3T3-L1 preadipocyte. The mechanism of anti-proliferation of Maitake may be mainly regulated by inhibition of Cdc25C expression and activation of p53 protein. The high contains higher contents of total phenolic substances in the aqueous layer extracts may be associated with the effect of cell anti-proliferation in Maitake.
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