Modulatory effect of some citrus (Citrus limon, Citrus reticulata, Citrus maxima) peels on monoamine oxidase, phosphodiesterase-5 and angiotensin-1 converting enzyme activities in rat heart homogenate

Ayokunle O. Ademosun 1 , Adeniyi A. Adebayo 1  and Ganiyu Oboh 1
  • 1 Department of Biochemistry, Functional Foods and Nutraceutical Unit, Federal University of Technology, P.M.B. 704, Akure, Nigeria
Ayokunle O. Ademosun
  • Department of Biochemistry, Functional Foods and Nutraceutical Unit, Federal University of Technology, P.M.B. 704, Akure, 340001, Nigeria
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, Adeniyi A. Adebayo
  • Department of Biochemistry, Functional Foods and Nutraceutical Unit, Federal University of Technology, P.M.B. 704, Akure, 340001, Nigeria
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and Ganiyu Oboh
  • Corresponding author
  • Department of Biochemistry, Functional Foods and Nutraceutical Unit, Federal University of Technology, P.M.B. 704, Akure, 340001, Nigeria
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Citrus peels have been reported useful in folk medicine for the management of cardiovascular diseases, but there is dearth of information on the possible mechanisms for their therapeutic action. The aim of this study was to investigate the effect of methanolic extracts from some citrus [lime (Citrus limon), tangerine (Citrus reticulata), shaddock (Citrus maxima)] peels on some enzymes relevant to the management of cardiovascular diseases [monoamine oxidase (MAO), phosphodiesterase-5 (PDE-5) and angiotensin-1-converting enzyme (ACE)].


Effect of methanolic extracts of lime, tangerine and shaddock peels on MAO, PDE-5 and ACE were carried out using standard methods. In addition, the ability of the extracts to prevent oxidative damage in rat heart homogenates was also investigated. Finally, the total polyphenol content of extracts was determined.


The results revealed that methanolic extracts of lime, tangerine and shaddock peels inhibited MAO, PDE-5, ACE and pro-oxidants induced lipid peroxidation in rat heart homogenate in a concentration-dependent manner.


Findings in this study revealed citrus peel methanolic extracts as natural inhibitor of enzymes (MAO, PDE-5 and ACE) implicated in cardiovascular diseases. Therefore, citrus peels could help in the management of cardiovascular diseases possibly through inhibition of these enzymes.

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The Journal of Complementary and Integrative Medicine focuses on evidence concerning the efficacy and safety of complementary and alternative medical (CAM) whole systems, practices, interventions and natural health products, including herbal medicines.