Class of 2017 Abstract / Objectives: Evaluate thymoquinone (TQ) and thymol (THY) inhibitory activities against α-glucosidase enzyme by using an in vitro assay and determine the IC50 (concentration of TQ/THY to inhibit 50% of maximum enzyme activity).
Methods: Various concentrations of thymoquinone and thymol were incubated, separately, with one concentration of the substrate - p-nitrophenol-α-D-glucopyranoside (PNPG) (<<Km) in presence of α-glucosidase enzyme. A positive and a negative control consisting of acarbose, and buffer, respectively, were included in the incubation as well. The incubation time was set at 30 min in a 37 °C controlled water bath. The enzyme activity was determined by detecting and quantitating the levels of p-nitrophenol using a spectrophotometer set at 405 nm. The percent inhibition exhibited by any studied drug was calculated as shown in equation 1.
% inhibition = Absorbance Substrate Alone – Absorbance of Substrate + Inhibitor
Absorbance Substrate Alone
Results: Results of the in vitro incubation of thymoquinone, thymol and acarbose revealed “statistically” significant inhibition of -glucosidase (p<0.05). At 400 g/ml, thymoquinone inhibited the enzyme activity by ~52 % whereas
the enzyme inhibition by thymol and acarbose were calculated to be ~84% and 57%, respectively.
IC50 were tentatively determined although the maxima inhibitions of the inhibitors were not reached fully. IC50s were calculated as 234 μg/ml, 304 μg/ml and 157 μg/ml for each of thymoquinone, thymol and acarbose, respectively.
Conclusions: Thymoquinone and thymol do exhibit antagonistic pharmacological activity against α-glucosidase.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/624026 |
| Date | January 2017 |
| Creators | Maher, Noureddine, Begijian, Argam |
| Contributors | Nix, David, College of Pharmacy, The University of Arizona |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Electronic Report |
| Rights | Copyright © is held by the author. |
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