3,3′-O-dimethylquercetin: A bi-functional vasodilator isolated from green propolis of the Caatinga Mimosa tenuiflora

Author(s)

Son, Ninh The ; Gianibbi, Beatrice ; Panti, Alice ; Spiga, Ottavia ; Bastos, Jairo Kenupp ; Fusi, Fabio

• Document type: Journal article
• Source: European Journal of Pharmacology; v. 967, p. 13-pg., 2024-02-17.

Abstract

In the search for novel, bi-functional compounds acting as CaV1.2 channel blockers and K+ channel stimulators, which represent an effective therapy for hypertension, 3,3 '-O-dimethylquercetin was isolated for the first time from Brazilian Caatinga green propolis. Its effects were investigated through electrophysiological, functional, and computational approaches. In rat tail artery myocytes, 3,3 '-O-dimethylquercetin blocked Ba2+ currents through CaV1.2 channels (IBa1.2) in a concentration-dependent manner, with the inhibition being reversed upon washout. The compound also shifted the voltage dependence of the steady-state inactivation curve to more negative potentials without affecting the slope of the inactivation and activation curves. Furthermore, the flavonoid stimulated KCa1.1 channel currents (IKCa1.1). In silico simulations provided additional evidence for the binding of 3,3 '- O-dimethylquercetin to KCa1.1 and CaV1.2 channels and elucidated its mechanism of action. In depolarized rat tail artery rings, the flavonoid induced a concentration-dependent relaxation. Moreover, in rat aorta rings its antispasmodic effect was inversely related to the transmembrane K+ gradient. In conclusion, 3,3 '-O-dime- thylquercetin demonstrates effective in vitro vasodilatory properties, encouraging the exploration of its scaffold to develop novel derivatives for potential use in the treatment of hypertension. (AU)

• FAPESP's process: 21/01411-0 - Chemical study of the Caatinga propolis produced by Apis mellifera and re-isolation of red propolis compounds to perform biological tests and develop analytical methods.
• Grantee: Ninh The Son
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/04138-8 - Attainment of chemical, analytical, biological, pharmacological and technological studies to fill the gaps on the development of Brazilian propolis sector
• Grantee: Jairo Kenupp Bastos
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/08386-6 - Phytochemical study, development of analytical method and biological evaluation of brown propolis produced by Apis mellifera from Morus Alba
• Grantee: Victor Pena Ribeiro
• Support Opportunities: Scholarships in Brazil - Doctorate