Related Experiment Video
Updated: Sep 26, 2026

Analytical Techniques for Assaying Nitric Oxide Bioactivity
Published on: June 18, 2012
Structural requirements of flavonoids for nitric oxide production inhibitory activity and mechanism of action
Hisashi Matsuda1, Toshio Morikawa, Shin Ando
1Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto 607-8412, Japan.
Abstract:
To clarify the structure-activity relationships of flavonoids for nitric oxide (NO) production inhibitory activity, we examined the inhibitory effects of 73 flavonoids on NO production in lipopolysaccharide-activated mouse peritoneal macrophages. Among those flavonoids, apigenin (IC(50)=7.7 microM), diosmetin (8.9 microM), and tetra-O-methylluteolin (2.4 microM), and hexa-O-methylmyricetin (7.4 microM) were found to show potent inhibitory activity, and the results suggested the following structural requirements of flavonoids: (1) the activities of flavones were stronger than those of corresponding flavonols; (2) the glycoside moiety reduced the activity; (3) the activities of flavones were stronger than those of corresponding flavanones; (4) the flavones and flavonols having the 4'-hydroxyl group showed stronger activities than those lacking the hydroxyl group at the B ring and having the 3',4'-dihydroxyl group; (5) the flavonols having the 3',4'-dihydroxyl group (catechol type) showed stronger activities than those having the 3',4',5'-trihydroxyl group (pyrogallol type); (6) the 5-hydroxyl group tended to enhance the activity; (7) methylation of the 3-, 5-, or 4'-hydroxyl group enhanced the activity; (8) the activities of isoflavones were weaker than those of corresponding flavones; (9) methylation of the 3-hydroxyl group reduced the cytotoxicity. In addition, potent NO production inhibitors were found to inhibit induction of inducible nitric oxide synthase (iNOS) without iNOS enzymatic inhibitory activity.
More Related Videos
08:32Application of Genetically Encoded Fluorescent Nitric Oxide (NO•) Probes, the geNOps, for Real-time Imaging of NO• Signals in Single Cells
Published on: March 16, 2017
08:23Chemiluminescence-based Assays for Detection of Nitric Oxide and its Derivatives from Autoxidation and Nitrosated Compounds
Published on: February 16, 2022
Related Concept Videos
Nitric Oxide Signaling Pathway
Antianginal Drugs: Nitrates and β-Blockers
Organic nitrates, such as nitroglycerin, play a pivotal role. Once metabolized, they liberate nitric oxide, a molecular marvel. Nitric oxide triggers guanylyl cyclase and augments cGMP production. This biochemical cascade orchestrates the relaxation of vascular smooth muscles, ushering in vasodilation and enhancing coronary blood flow. Administered...
Oxidation of Phenols to Quinones
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
Indirect-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
Reversible inhibitors display short to medium durations of action. Short-acting agents include simple alcohols with...
2° Amines to N-Nitrosamines: Reaction with NaNO2
Cholinergic Antagonists: Chemistry and Structure-Activity Relationship