Inhibitory Effects of Usnic and Carnosic Acid on Some Metabolic Enzymes: An In vitro Study

Related Experiment Video

Updated: Jan 28, 2026

Author Spotlight: Characterizing Novel Enzymes from Extremophiles and Common Pathogens to Understand DNA Repair and Replication

Author Spotlight: Characterizing Novel Enzymes from Extremophiles and Common Pathogens to Understand DNA Repair and Replication

Published on: July 5, 2024

Hamid Ceylan¹, Yeliz Demir², Şükrü Beydemir³

¹Department of Molecular Biology and Genetics, Faculty of Science, Ataturk University, Erzurum, Turkey.

Protein and Peptide Letters

|March 5, 2019

Abstract

Background:

Natural products are produced via primary and secondary metabolism in different organisms. The compounds obtained via secondary metabolism are not essential for the survival of the organism, but they can have a different value for humans.

Objective:

The objective of this study was to examine inhibitory effects of Usnic Acid (UA), a well-known lichen secondary metabolite, and Carnosic Acid (CA), the primary antioxidant compound of Rosmarinus officinalis L., on purified Human Paraoxonase, (PON1), Glutathione Reductase (GR) and Glutathione S-Transferase (GST). These enzymes have antioxidant properties and a protective effect on the oxidation of free radicals. Hence, deficiencies of such enzymes inside cells can result in a buildup of toxic substances and cause some metabolic disorders.

Methods:

UA and CA were tested in various concentrations against human GST, PON1, and GR activity in vitro and they reduced human GST, PON1, and GR activity.

Results:

UA Ki constants were calculated as 0.012±0.0019, 0.107±0.06 and 0.21±0.1 mM for GST, PON1, and GR enzymes. CA Ki constants were determined as 0.028±0.009, 0.094±0.03 and 0.79±0.33 mM, for GST, PON1, and GR enzymes. UA and CA showed competitive inhibition for GR and GST enzymes, while they exhibited non-competitive inhibition for PON1.

Conclusion:

These findings indicate that UA and CA could be useful in drug development studies.

Keywords:

Carnosic acid glutathione S-transferase glutathione reductase metabolic disorders paraoxonase usnic acid.

More Related Videos

A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s

A General Method for Detecting Nitrosamide Formation in the In Vitro Metabolism of Nitrosamines by Cytochrome P450s

Published on: September 25, 2017

Metabolic Glycoengineering of Sialic Acid Using N-acyl-modified Mannosamines

Metabolic Glycoengineering of Sialic Acid Using N-acyl-modified Mannosamines

Published on: November 25, 2017

Related Concept Videos

Excitatory and Inhibitory Effects of Neurotransmitters

Excitatory and Inhibitory Effects of Neurotransmitters

When an action potential reaches the presynaptic axon terminal, it releases neurotransmitters from the neuron into the synaptic cleft at a chemical synapse. The released neurotransmitter can be excitatory or inhibitory. The critical criteria commonly used to determine whether a molecule is a neurotransmitter at a chemical synapse are the molecule's presence in the presynaptic neuron. Second, its release is in response to strong presynaptic depolarization. And lastly, the presence of...

Substituent Effects on Acidity of Carboxylic Acids

Substituent Effects on Acidity of Carboxylic Acids

The acidity of carboxylic acids is influenced by the nature of the substituents bounded to the functional group. The acid strength is determined by the stability of the carboxylate anion—the conjugate base formed by dissociating the corresponding carboxylic acid.

Overview of Fatty Acid Metabolism

Overview of Fatty Acid Metabolism

Lipids also are sources of energy that power cellular processes. Like carbohydrates, lipids are composed of carbon, hydrogen, and oxygen, but these atoms are arranged differently. Most lipids are nonpolar and hydrophobic. Major types include fats and oils, waxes, phospholipids, and steroids.
Fatty acids are catabolized in a process called beta-oxidation, which takes place in the matrix of the mitochondria and converts their fatty acid chains into two-carbon units of acetyl groups. The acetyl...

Enzymes

Enzymes

Inside living organisms, enzymes act as catalysts for many biochemical reactions involved in cellular metabolism. The role of enzymes is to reduce the activation energies of biochemical reactions by forming complexes with its substrates. The lowering of activation energies favor an increase in the rates of biochemical reactions.
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...

What is Metabolism?

What is Metabolism?

Enzyme Kinetics

Enzyme Kinetics

Enzymes speed up reactions by lowering the activation energy of the reactants. The speed at which the enzyme turns reactants into products is called the rate of reaction. Several factors impact the rate of reaction, including the number of available reactants. Enzyme kinetics is the study of how an enzyme changes the rate of a reaction.
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...

Articles linked to this work by shared authors, journal, and citation graph.

Design and Synthesis of New Thiazole Derivatives for Alzheimer's Disease Therapy as a Potential Cholinesterase Inhibitor; Toxicity Prediction and Molecular Docking Studies and Biological Evaluation.

Molecules (Basel, Switzerland)·2026

Probing novel azole-sulfonamide urea/thiourea conjugates as multitarget inhibitors of AChE and hCAs (I and II): synthesis, in vitro, and in silico studies.

Medicinal chemistry research : an international journal for rapid communications on design and mechanisms of action of biologically active agents·2026

Clinical utility of in-ear EEG electrodes in hospitalized patients: comparison with standard scalp EEG.

Clinical neurophysiology practice·2026

Design, synthesis, biological evaluation, and in silico studies of novel pyrrolidine based hybrids bearing indole, chromone, and benzoylthiourea pharmacophores as multitarget hCA and AChE inhibitors.

Computational biology and chemistry·2026

Design, Synthesis, In Silico ADME, Toxicity Prediction and Molecular Docking Studies of Benzimidazole-Oxadiazole Derivatives for α-Glucosidase and Aldose Reductase Pathways as Potent Anti-Diabetic Agents.

Molecules (Basel, Switzerland)·2026

Development of novel diaryl ether-phenolic Mannich Base derivatives with potent cholinesterase inhibition and low neuronal toxicity.

Bioorganic chemistry·2026

See all related articles