Paper Status Tracking
Contact us
[email protected]
Click here to send a message to me 3275638434
Paper Publishing WeChat

Article
Affiliation(s)

ABSTRACT

Guava leaf tea has been used as a folk medicine for treating hyperglycemic conditions in Asia and Africa. The hypoglycemic efficacy of guava leaf has been documented by many scientists in these regions, but the hypoglycemic mechanism is poorly understood. Guava leaves were extracted with methanol and the crude extract was partitioned against hexane, ethyl acetate, and butanol in sequence. The leftover in water is defined as the aqueous partition. A second smaller batch was extracted with hot water directly. Oral glucose tolerance test was carried out on healthy mice instead of diabetic mice that lack endogenous insulin. Glucose uptake was examined with 3T3-L1 adipocytes. Oxidative effect on PTP1B (protein tyrosine phosphatase 1b) was carried out with real-time PTP1B enzymatic assay. The aqueous partition of guava leaf extract possesses a potent inhibitory effect on PTP1B enzymatic activity and this PTP1B inhibition is through a slow oxidative but reversible inactivation on the enzyme. The reversible inactivation would suggest guava leaf extract may augment PTP1B inhibition alongside the endogenous H2O2 which itself is induced by insulin. In addition, our study confirmed the hypoglycemic efficacy being associated with guava leaf and found the most effective molecules reside in the aqueous partition which is also less cytotoxic to Chinese hamster ovary cells when compared to other less polar partitions. The guava leaf extract can modulate insulin activity through a redox regulation on PP1B enzymatic activity. It is speculated that a compound similar to gallocatechin in the aqueous partition can reduce an oxygen molecule to hydrogen peroxide which in turn oxidizes the catalytic residue Cys in PTP1B. Therefore, the guava leaf tea can serve as a functional hypoglycemic drink that is suitable for either healthy or diabetic subjects.

KEYWORDS

Guava leaf extract, hypoglycemic, oxidative, protein tyrosine phosphatase 1b, slow inactivation.

Cite this paper

Wu, W-J., et al. 2018. “Inactivation of Protein Tyrosine Phosphatase 1B (PTP1B) Activity by the Aqueous Partition of Guava Leaf Extract.” Journal of Pharmacy and Pharmacology 6 (10): 890-906.

References

About | Terms & Conditions | Issue | Privacy | Contact us
Copyright © 2001 - David Publishing Company All rights reserved, www.davidpublisher.com
3 Germay Dr., Unit 4 #4651, Wilmington DE 19804; Tel: 1-323-984-7526; Email: [email protected]