Phytochemical Characterics and its Effect on Protein Tyrosine Phosphatase 1B of Guava Leaf Extract

ASIA unversity > 醫學暨健康學院 > 食品營養與保健生技學系 > 博碩士論文 > Item 310904400/107588

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题名:	Phytochemical Characterics and its Effect on Protein Tyrosine Phosphatase 1B of Guava Leaf Extract
作者:	Yu, Shiou-Cherng
贡献者:	保健營養生技學系
关键词:	Diabetes;Guava Leaf Extract;Protein Tyrosine Phosphatase 1B;Inhibitors;Chromatography
日期:	2017
上传时间:	2017-09-15
出版者:	亞洲大學
摘要:	The hypoglycemic potency of guava leaf extract has been reported repeatedly by many research groups. This research was carried out with a focus on purifying the hypoglycemic compounds that reside in the aqueous partition of guava leaf extract, since our laboratory has identified the aqueous partition possesses the most potent hypoglycemic properties in in vivo. The chemical properties, phenol/flavonoid contents and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability, of those partitions were similar to other reports. The aqueous partition has the lowest contents in phenolic and DPPH scavenging contents, while its flavonoid content is among the lower groups along with butanol and hot water extracts. 　　The hypoglycemic compounds in the aqueous partition were further purified by LH -20 (hydroxypropyl dextran) columns with PTP1B inhibition as the screening method. The most potent PTP1B inhibitory fraction comes out after the main peak that suggests the hypoglycemic compound is a small molecule. 　　The HPLC can further purified the compound to near homogeneity but the acetonitrile inactivate the active compounds. The LC/MS method identified one major species in each of the electron spray, a 428 Da in the negative spray and a 516 Da in the positive spray. 　　A time course study reveals the aqueous partition has a unique slow inactivation property on PTP 1B enzyme activity. This slow inactivation is much less significant with hot water extract and not observed in other organic partitions. Therefore, it is suggested the inactivation of PTP 1B enzymatic activity is probably through a covalent bond inactivation, such as oxidation of cysteine reside.
显示于类别:	[食品營養與保健生技學系] 博碩士論文

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