Original Article
Copyright ©2014 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Diabetes. Apr 15, 2014; 5(2): 209-218
Published online Apr 15, 2014. doi: 10.4239/wjd.v5.i2.209
Exploration of natural enzyme inhibitors with hypoglycemic potentials amongst Eucalyptus Spp. by in vitro assays
Baishakhi Dey, Analava Mitra, Prakash Katakam, Rajeev K Singla
Baishakhi Dey, Analava Mitra, School of Medical Science and Technology, IIT Kharaghpur 721302, India
Prakash Katakam, Faculty of Pharmacy, University of Zawiya, Az-Zawiya 999054, Libya
Rajeev K Singla, Division of Biotechnology, Netaji Subhas Institute of Technology, Sector-3, Dwarka, New Delhi 110078, India
Author contributions: The central theme of the work was developed under the joint discussions of Dey B, Mitra A and Katakam P; lab work, data collections and preparation of the manuscript was done by Dey B under the valuable suggestions of Mitra A and Katakam P; and Singla RK took care of the statistical part and provided his valuable opinions about the work methodology.
Correspondence to: Analava Mitra, MBBS, PhD, School of Medical Science and Technology, Paschim Medinipur, West Bengal, IIT Kharaghpur 721302, India. analavamitra@gmail.com
Telephone: +91-9475258298 Fax: +91-32-22279970
Received: November 2, 2013
Revised: December 27, 2013
Accepted: January 17, 2014
Published online: April 15, 2014
Processing time: 147 Days and 16.7 Hours
Abstract

AIM: To investigate the presence and potency of natural enzyme inhibitors with hypoglycemic potentials amongst Eucalyptus Spp. by in vitro assays.

METHODS: The leaf extracts of the three different Eucalyptus species [E. globulus (EG), E. citriodora (EC), E. camaldulensis (ECA)] were subjected to in vitro assay procedures to explore the prevalence of natural enzyme inhibitors (NEIs) after preliminary qualitative and quantitative phytochemical evaluations, to study their inhibitory actions against the enzymes like α-amylase, α-glucosidase, aldose reductase, angiotensin converting enzyme and dipeptidyl peptidase 4 playing pathogenic roles in type 2 diabetes. The antioxidant potential and total antioxidant capacity of the species were also evaluated.

RESULTS: Major bioactive compounds like polyphenols (341.75 ± 3.63 to 496.85 ± 3.98) and flavonoids (4.89 ± 0.01 to 7.15 ± 0.02) were found in appreciable quantity in three species. Based on the IC50 values of the extracts under investigation, in all assays the effectivity was in the order of EG > ECA > EC. The results of the ferric reducing antioxidant power assay showed that the reducing ability of the species was also in the order of EG > ECA > EC. A strong correlation (R2 = 0.81-0.99) was found between the phenolic contents and the inhibitory potentials of the extracts against the targeted enzymes.

CONCLUSION: These results show immense hypoglycemic potentiality of the Eucalyptus Spp. and a remarkable source of NEIs for a future phytotherapeutic approach in Type 2 diabetes.

Keywords: Natural enzyme inhibitors; Hypoglycemic; Eucalyptus; In vitro assays; Pathogenic; Polyphenols; Flavonoids

Core tip: Enzymes play an essential role in mediating important biochemical processes of life but hyper or hypo activity of such enzymes leads to malfunctions of the processes. Etiopathogenesis of diseases at molecular level has shown that enzyme inhibitors can serve as effective therapeutic bullets for several diseases. The plant kingdom is a giant hub of phytomolecules with variant pharmacology, largely unexplored. Volatile and non-volatile fractions of Eucalyptus include bioactive compounds like terpenes, triterpenoids, flavonoids, polyphenols, etc. The exploration of enzyme inhibitors amongst Eucalyptus species by in vitro assays will help in bioactivity guided isolations of such inhibitors to be targeted as natural hypoglycemics.