| Summary: | 碩士 === 東海大學 === 食品科學系 === 106 === Gjuava leaves extracts (GLE) were prepared by ultrasound-assisted extraction
with 0, 25, 50, and 75% ethanol and denoted as GLE0, GLE25, GLE50 and GLE75,
respectively. At first, antioxidant activity and glycolytic activity inhibition of the extracts were compared. The results showed that GLE50 had the highest total flavonoid content (TFC) up to 35.1 mg QE/g extract among four extracts, where as GLE25 had the highest total phenolic content (TPC) up to 254.3 mg GAE /g extract. However there were no significant difference in the TFC and TPC between GLE25 and GLE50 (p > 0.01). The free radical scavenging capacity was expressed as trolox equivalent (TE).TE is proportional to total antioxidant capacity (TEAC). GLE25 showed the hightest TEAC, reaching 59.1 μg TE/mL, followed by GLE50 with 49.2 μg TE/mL. GLE25 also had the highest reducing power reaching 113.1 μg ascorbic acid equivalent/mL, followed by GLE50 with 110.5 μg AAE/mL. Furthermore, GLE25 and GLE50 also showed the highest inhibitory effect of α-glucosidase and α- amylase. According to the above resules, GLE25 was selected to study regulation mechanism of blood glucose in C2C12 cells. Based on cytotoxicity test, GLE25 less than 300 μg/mL was no toxicity to C2C12 cells. Finally, the effect of 200 μg/mL GLE25 on glucose regulation in palmitate-induced insulin resistance C2C12 cells was investigated. The results indicated that GLE25 could activate the increase of IRS1/PI3K/Akt resuled in glucose uptake in the insulin delivery pathway. GLE25 also activated AMPK to inhibit ACC, thereby promoting the oxidation of free fatty acids, releasing a large amount of energy to provide cells for use, reducing the storage of fatty acids, and improving the insulin resistance induced by free fatty acids.
|
|---|
