Quercetin based derivatives as sirtuin inhibitors.

Area of Science:

• Biochemistry
• Pharmacology
• Molecular Biology

Background:

• Polyphenols exhibit diverse pharmacological effects and modulate sirtuins, enzymes crucial for aging, metabolism, and disease.
• Sirtuin 6 (SIRT6) is vital for genomic stability and glucose metabolism, making it a key target for therapeutic intervention.
• Quercetin and its derivatives are known to interact with sirtuins and offer protection against chronic illnesses.

Purpose of the Study:

• To identify and characterize novel SIRT6 inhibitors from quercetin derivatives.
• To elucidate the mechanism of inhibition for identified compounds using in vitro and molecular modeling approaches.
• To explore the therapeutic potential of these polyphenolic compounds in age-related diseases.

Main Methods:

• In vitro enzyme inhibition assays to determine IC50 values against SIRT6 and SIRT2.
• Kinetic analysis to understand the mode of inhibition (e.g., competitive, non-competitive).
• Molecular docking simulations to predict binding interactions within the SIRT6 catalytic site.

Main Results:

• Diquercetin and 2-chloro-1,4-naphtoquinone-quercetin were identified as SIRT6 inhibitors with IC50 values of 130 μM and 55 μM, respectively.
• 2-Chloro-1,4-naphtoquinone-quercetin also inhibited SIRT2 (IC50 = 14 μM).
• Kinetic studies revealed diquercetin competes with NAD+, while 2-chloro-1,4-naphtoquinone-quercetin competes with the acetylated substrate, suggesting distinct binding mechanisms.

Conclusions:

• Diquercetin and 2-chloro-1,4-naphtoquinone-quercetin are effective SIRT6 inhibitors with different modes of action.
• These findings highlight the potential of natural polyphenols as a novel therapeutic strategy for age-related conditions.
• Further research into these compounds could lead to the development of new treatments targeting sirtuin pathways.