الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
We aimed in this research to exploit the advantages of natural compounds with their wide ranges of activities and investigate their potential to modulate multiple tar-gets simultaneously. Indeed, the results are promising. Three metabolism-related enzymes were selected based on their activities and their significance as target for management of many ailment and ailment-related bio-logical processes. The three assayed enzymes, α-amylase, tyrosinase and hyaluronidase, were selected on the basis explained in detail in the previous chapters.
To achieve the aims of the study, 27 plants were ex-tracted using methanol and assayed for their inhibitory in vitro activities for the mentioned enzymes. Five ex-tracts with the most promising results were further fractionated into four fractions which also investigated for the same activities. Phytochemical screening and antioxidant activity assays were conducted using the same fractions to determine the most abundant active constituents in the respective fractions revealing many compounds classes in each fraction.
Building on these results, 7 natural compounds with different organic nuclei were chosen for further inves-tigations. The compounds were assayed to determine their inhibitory potentials against the three investigated enzymes, determine their kinetic inhibition mechanisms and IC50¬. Using computer aided docking, the binding mode of some of these ligands were determined. Furthermore, the binding modes of some of these ligands were predicted with human respective enzymes.
Quercetin and quinol showed inhibition against the three investigated enzymes with different inhibition mechanisms. Other compounds exhibited dual inhibi-tion against two of the investigated enzymes. They in-clude, quinalizarin and arbutin that inhibited both am-ylase and hyaluronidase activities, and ellagic acid that inhibited both tyrosinase and hyaluronidase activities. The compounds could inhibit the respective enzymes under the same assaying conditions but with different potentials. Glycyrrhizin and 4-hydroxycoumarin were found to be potent competitive inhibitors for tyrosinase and hyaluronidase, respectively