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Identification of flavonoids with trypsin inhibitory activity extracted from orange peel and green tea leaves

Authors

  • Durre Shahwar,

    Corresponding author
    • Research Lab II, Department of Chemistry, Government College University, Lahore, Pakistan
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  • Muhammad A Raza,

    1. Research Lab II, Department of Chemistry, Government College University, Lahore, Pakistan
    2. Department of Chemistry, Hafiz Hayat Campus, University of Gujrat, Gujrat, Pakistan
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  • Atta-Ur-Rahman

    1. HEJ Research Institute of Chemistry, International Center for Chemical Sciences, University of Karachi, Karachi, Pakistan
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Correspondence to: Durre Shahwar, Research Lab II, Department of Chemistry, Government College University, Lahore 54000, Pakistan. E-mail: drdshahwar@yahoo.com

Abstract

Background

Orange peel (Citrus sinensis) and green tea (Camellia sinensis) leaves, rich sources of food flavonoids, were analyzed for their trypsin inhibitory potential. Hesperetin, rutin and hesperidin from orange peel, and catechin from green tea leaves, were isolated and their chemical structures were analyzed. All four compounds were evaluated for their trypsin inhibitory potential.

Results

Among all the isolated compounds, rutin exhibited the highest protease inhibition activity (75.4 ± 0.9%) with IC50 = 16 ± 2 µmol L−1, followed by catechin (65.3 ± 1.4%; IC50 = 83 ± 9 µmol L−1), hesperetin (62.1 ± 1.3%; IC50 = 104 ± 12 µmol L−1) and hesperidin (59.7 ± 1.1%; IC50 = 127 ± 14 µmol L−1). Lineweaver–Burk and Dixon plots and their secondary replots indicated that all four compounds possessed non-competitive inhibition. The Ki values of hesperetin, rutin, hesperidin and catechin were calculated as 90.2 ± 1.1, 17.5 ± 0.6, 84.2 ± 1.5 and 65.1 ± 1.5 µmol L−1 respectively.

Conclusion

The present results suggest that the four isolated flavonoids can be used as a supplement in food for the treatment of pathologies associated with the degradation of a specific protein. © 2012 Society of Chemical Industry

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