Molecular and pharmacokinetic properties of the histidine decarboxylase inhibitors from clove

Abstract

Introduction: Histidine decarboxylase is widely distributed in the gastrointestinal mucosa, mast cells,
cerebrospinal fluid, bone marrow, and certain actively growing tumors. This enzyme has been studied till date
of various organisms, but the mechanism of action had not been understood. In the present study, the inhibitory
activity of flavonoids on purified histidine decarboxylase enzyme from bacterial source using a methanolic extract
of clove was examined. Materials and Methods: Phytochemical screening of methanolic extract of clove was
performed for the presence of various bioactive constituents. Further, the purification of flavonoids present in the
spice extract was carried out by thin-layer chromatography (TLC) and high-performance liquid chromatography
(HPLC) to isolate and identify the different flavonoids present in methanolic extract of clove. The inhibition
of the enzyme was studied by checking the activity of an enzyme in the presence of varying concentrations of
inhibitor. Dixon plot was plotted to determine the concentration of the inhibitor at which it inhibits the enzyme.
Results and Discussion: Phytochemical screening of the clove extract revealed the presence of flavonoids
in maximum in comparison to the other constituents. TLC and HPLC were carried out, which indicated the
presence of ellagic acid, gallic acid, kaempferol, and quercetin in the methanolic extracts of the clove sample. The
concentration of the clove extract in inhibiting the enzyme was found to be 0.9 μmoles from Dixon plot. All the
components identified in HPLC quantification were subjected to software’s like Molinspiration and SwissADME
to study the molecular properties, drug-likeness, and pharmacokinetics. Conclusion: In the present study, histidine
decarboxylase and the various medical aspects in which the enzyme plays a role and where the function of the
enzyme can be altered to treat the disease is highlighted to dictate their ability to be a promising lead compound.