Antioxidant and free radical scavenging activities of wild bitter melon (Momordica charantia Linn. var. abbreviata Ser.) in Taiwan
Journal
LWT
Journal Volume
41
Journal Volume
41
Journal Issue
2
Journal Issue
2
Pages
323-330
Start Page
323
End Page
330
ISSN
00236438
Date Issued
2008-03
Author(s)
Wu, Shu-Jing
Abstract
Momordica charantia Linn. var. abbreviata Ser. (Cucurbitaceae), also known as "Shan Ku Gua", is a wild variety of bitter melon (BM) in Taiwan. The size of its fruits is only about one-fifth of the commonly seen BM. It is commonly consumed as vegetable and also used as a popular folk medicine. In this study, the antioxidant and free radical scavenging activities of BM aqueous (BM-H2O) and ethanol (BM-EtOH) extracts were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), metal chelation, cytochrome c and xanthine oxidase inhibition (XOI) assays, as well as FeCl2-ascorbic acid induced lipid peroxidation (thiobarbituric acid reactive substances, TBARS) assay in rat liver homogenates in vitro. Total flavonoid and phenol contents of BM extracts were also analyzed. Results showed that both BM-H2O (IC50=129.94 μg/ml) and BM-EtOH (IC50=156.78 μg/ml) possess potent DPPH radical scavenging activity, which was better than vitamin E (IC50=172.21 μg/ml). These extracts also showed better iron chelating activity than vitamin E. However, they were weaker than vitamin E in free radical scavenging, xanthine oxidase inhibitory and anti-lipid peroxidation activities. With the exception of XOI activity [IC50=7.90 μg/ml (BM-H2O) vs. 7.69 μg/ml (BM-EtOH)], BM-H2O showed a lower IC50 value in free radical scavenging [IC50=6.15 μg/ml (BM-H2O) vs. 7.08 μg/ml (BM-EtOH)] and anti-lipid peroxidation [IC50=53.72 μg/ml (BM-H2O) vs. 88.51 μg/ml (BM-EtOH) for liver; 82.53 μg/ml (BM-H2O) vs. 91.83 μg/ml (BM-EtOH) for brain] activities than BM-EtOH. Both BM extracts showed a weak anti-lipid peroxidation activity in plasma. BM-H2O (62.0 mg/g) possessed a significant higher concentration of total flavonoids than BM-EtOH (44.0 mg/g), but was lower in the total phenol content (BM-H2O: 51.6 mg/g vs. BM-EtOH: 68.8 mg/g). In conclusion, BM extracts possess potent antioxidant and free radical scavenging activities. These antioxidant activities could have contributed, at least partly, to the therapeutic benefits of the certain traditional claims of wild BM.
Subjects
Antioxidant
Free radical scavenging
Momordica charantia
Wild bitter melon
Publisher
Academic Press
Type
journal article