Volume 24, Issue 1, January 2016, Pages 179–188
Open Access
Original Article
- Open Access funded by Taiwan Food and Drug Administration
- Under a Creative Commons license
Abstract
In the present study, 2,2-diphenyl-1-picrylhydrazyl radical scavenging, α-amylase and α-glucosidase inhibition activities, and total phenolic contents of n-hexane, ethyl acetate, and methanol extracts of various parts of Allium paradoxum, Buxus hyrcana, Convolvulus persicus, Eryngium caucasicum, Heracleum persicum, Pimpinella affinis, Parrotia persica, Primula heterochroma, Pyrus boissieriana, Ruscus hyrcanus, and Smilax excelsa
were investigated. These plants, which mostly serve as food flavoring,
were collected from Hyrcania region, Sari, Iran. Some extracts of H. persicum, S. excels, P. boissieriana, P. persica, and P. heterochroma exhibited significant antidiabetic activities in α-amylase and α-glucosidase assays, more effective than acarbose (concentrations that cause 50% inhibition = 75.7 μg/mL and 6.1 μg/mL against α-amylase and α-glucosidase, respectively). Also, C. persicus, P. boissieriana, and P. heterochroma
showed strong antioxidant activities, compared with butylated
hydroxytoluene (concentration that causes 50% inhibition = 16.7 μg/mL).
In conclusion, this study can recommend these plants as good candidates
for further investigations to find potent antidiabetic natural products
or probable lead compounds. Statistical analysis showed significant
correlation between the 2,2-diphenyl-1-picrylhydrazyl scavenging
activity and total phenolic contents (r = 0.711, p < 0.001).
Keywords
- 2,2-diphenyl-1-picrylhydrazyl;
- α-amylase;
- α-glucosidase;
- antidiabetics;
- phenolic content
1. Introduction
Plants
have developed an array of defense strategies (antioxidant systems) to
manage oxidative stress. In these systems, there is a wide variety of
antioxidants [e.g., ascorbic acid, gluthione, uric acid, tocopherol,
carotenoids, and (poly)phenols], which are different in their
composition, mechanism, and site of action [1].
Antioxidants have significant inhibition roles, not only on undesirable
changes in the flavor and nutritional quality of food, but also on
tissue damage in various human diseases such as inflammation, cancer,
and atherosclerosis [2].
Moreover, having antioxidant activity in addition to pharmaceutical
properties, such as antidiabetic, anticarcinogenic, and antialzheimeric
activities, can be a special function to obtain multifunctional drugs.
Recently, there has been an increased interest globally to discover
natural antioxidants with low or no side effects for use in preventive
medicine and the food industry [3].
Noninsulin-dependent
diabetes mellitus or type-II diabetes mellitus is one of the most
common and serious metabolic disorders with abnormally high blood
glucose levels (hyperglycaemia) due to defects in insulin secretion, or
action, or both [4]. Hydrolysis of dietary carbohydrates such as starch is the major source of glucose in the blood. Because α-glucosidase and pancreatic α-amylase
play a critical role in carbohydrate digestion and glycoprotein
processing, inhibitors of these enzymes might be used to treat diabetes,
human immunodeficiency virus, Gaucher's disease, cancers, and
Alzheimer's disease [5], [6] and [7].
Some inhibitors, such as acarbose, miglitol (a deoxynojirimycin
derivative), and voglibose, are widely used clinically in combination
with diet to control blood glucose levels of patients [8] and [9].
To prevent or decline the side effects of these drugs and also to
provide more candidates of drug choices, it is still essential to seek
new α-glucosidase inhibitors for further drug development. In
recent years, many efforts have been made to approach glucosidase
inhibitors from natural sources for antidiabetes treatment [10] and [11].
One
of the major hypotheses proposed to explain the hyperglycaemia-induced
onset of diabetic complications is that it is a result of the impairment
in the equilibrium between reactive oxygen species capacity and
antioxidant defence capacity [12], [13] and [14].
Accordingly, using antioxidant agents can be helpful for scavenging
various reactive oxygen species and prevention of diabetes mellitus.
In this work, antioxidant and antidiabetic activities of different extracts of Allium paradoxum (M.B.) G.Don (Liliaceae), Buxus hyrcana Pojark. (Buxaceae), Convolvulus persicus L. (Convolvulaceae), Eryngium caucasicum Trautv. (Apiaceae), Heracleum persicum Desf. ex Fischer (Apiaceae), Pimpinella affinis Ledeb. (Apiaceae), Parrotia persica C.A. Mey (Hamamelidaceae), Primula heterochroma Stapf (Primulaceae), Pyrus boissieriana Buhse (Rosaceae), Ruscus hyrcanus Woron. (Asparagaceae), and Smilax excelsa
L. (Smilacaceae) were investigated. These plants were collected in
Sari, Hyrcania region, Iran. The Hyrcania (Caspian) region, that covers
an area of 1,925,125 ha, extends throughout the south coast of the
Caspian Sea in the northern part of Iran [15].
In this region, people use these plants as food flavoring, and
antiflatulence, antimicrobial, antifever, and antidiabetic natural
sources (Table 1).
