The In Vitro Multifaceted Biological Activity of Catechins in Relation to Their Oxidation Potentials

Area of Science:

• Biochemistry
• Pharmacology
• Natural Products Chemistry

Background:

• Catechins are polyphenolic compounds found in tea with diverse biological activities.
• Understanding the structure-activity relationships of catechins is crucial for their therapeutic applications.
• Existing research highlights catechin's antioxidant potential, but comprehensive profiling of their multifaceted activities is needed.

Purpose of the Study:

• To rank the multifaceted activities of five major catechins: catechin (C), epicatechin (EC), epigallocatechin (EGC), epicatechin-3-gallate (ECG), and epigallocatechin-3-gallate (EGCG).
• To evaluate their antioxidant capacity, angiotensin-converting enzyme (ACE) inhibitory activity, acetylcholinesterase (AChE) inhibitory activity, and ability to inhibit advanced glycation end-product (AGE) formation.
• To correlate these activities and explore their potential against hypertension, Alzheimer's-type dementia, and diabetic complications.

Main Methods:

• Differential pulse voltammetry (DPV) was employed to determine antioxidant activity.
• In vitro model systems were used to assess ACE inhibitory activity, AChE inhibitory activity, and AGE formation inhibition.
• Structure-activity relationships were analyzed by comparing the inhibitory potencies and correlating them with electrochemical properties.

Main Results:

• The ranking for antioxidant potential was EGCG > ECG > EC > EGC ≈ C > gallic acid (GA).
• ACE inhibitory activity followed the order EGCG > ECG > EGC > EC > C.
• AChE inhibitory activity was ranked EGCG ≈ EGC > ECG > EC > C, and anti-AGE formation activity was EGCG ≈ ECG > EGC > EC > C.
• Significant correlations were observed between antioxidant activity, electrochemical properties, and inhibitory effects against ACE, AChE, and AGE formation.

Conclusions:

• Epigallocatechin-3-gallate (EGCG) and epicatechin-3-gallate (ECG) exhibit the most potent multifaceted activities among the tested catechins.
• These findings underscore the importance of catechin structure in determining their biological effects.
• The study provides valuable insights into the potential of EGCG and ECG as therapeutic agents for conditions like hypertension, Alzheimer's disease, and diabetes.