Content area
Full Text
Article history
Received: 2July 2013
Received in revised form: 4 September 2013
Accepted: 5 September 2013
Keywords
Free radical scavenging activity
α-glucosidase inhibitory activity
Traditional medicinal plants
Abstract
The study was aimed to determine the antioxidant and α-glucosidase inhibition activities of the stem and leaf of five different traditional medicinal plants. The studied plants exhibited varied antioxidant and α-glucosidase inhibition activities. The antioxidant activities of the plants were determined through their free radical scavenging capabilities using DPPH assay. The most potent antioxidant activity was demonstrated by Neptunia oleracea with an IC50 of 35.45 and 29.72 μg/mL for leaf and stem, respectively. For α-glucosidase inhibition activity, Neptunia oleracea exhibited potential α-glucosidase inhibition activity with IC50 value of 19.09 and 19.74 μg/mL for leaf and stem, respectively. The highest total phenolic content (TPC) was also marked in Neptunia oleracea leaf and stem with value of 40.88 and 21.21 mg GAE/g dry weight, respectively. The results also showed that Strobilanthes crispus collected from two different locations possessed different levels of phenolic content, antioxidant and α-glucosidase inhibition activities. The study revealed that phenolic compounds could be the main contributors to the antioxidant and α-glucosidase inhibition activities with R values of 78.9 and 67.4%, respectively. In addition, antioxidant and α-glucosidase were positively correlated (R = 81.9%). Neptunia oleracea could be suggested as a potential natural source of antioxidant and antidiabetic compounds that can be used for the prevention or treatment of diabetes.
© All Rights Reserved
Introduction
Free radicals are the molecular species that possess a single unpaired electron in the outermost atomic orbit. In spite of different types of free radicals, those of most concern free radicals in biological system are the reactive oxygen species (ROS) which include hydroxyl radical, superoxide anion radical, hydrogen peroxide, oxygen singlet, hypochlorite, nitric oxide radical, and peroxynitrite (Valko et al., 2007). Human body has antioxidant defence system to cope with the activity of free radicals formed in the body. However, the imbalance between the free radical production and the antioxidant defence arises when the free radicals are overproduced in the body (Bahorun et al., 2006). This may result in the accumulation of oxidative stress in the body and cause damage to macromolecules, such as lipid, protein and nucleic acid. Oxidative damage to...