Chemical Profiling and Vascular Effects of a Hydroalcoholic Extract of Calophyllum longifolium Willd: Role of Nitric Oxide and Potassium Channels

TL;DR

This study identifies the chemical makeup and vascular effects of Calophyllum longifolium, showing it can relax blood vessels through nitric oxide and potassium channels.

Contribution

First UHPLC-ESI-Q-TOF-MS chemical profile and vascular mechanism study of Calophyllum longifolium.

Findings

C. longifolium extract contains coumarins, xanthones, and other bioactive compounds.

The extract induces biphasic vascular effects, with relaxation at low concentrations and contraction at high concentrations.

Effects are mediated by nitric oxide and potassium channels in endothelium-dependent manner.

Abstract

Calophyllum spp. infusions are used to treat varicose veins, hemorrhoids, and hypertension. However, the chemical composition and mechanisms of action are poorly understood. Accordingly, the aim of this study was to investigate the phytochemical composition and vascular effects of hydroalcoholic extracts of Calophyllum longifolium. Phytochemical profiling was performed using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-ESI-Q-TOF-MS). Extract effects on rat aortic rings and aortic vascular smooth muscle cells (VSMCs) were evaluated using wire myography and photometric measurement of intracellular Ca2+, respectively. UHPLC-ESI-Q-TOF-MS revealed the presence of coumarins, xanthones, flavonoids, triterpenes, and phenolic acids. Coumarin–resveratrol hybrids, such as gut-70 derivatives, were also abundant. In aortic rings from normotensive rats, C. longifolium induced a biphasic vascular response whereby low concentrations (1 μg/mL) produced significant vascular relaxation, whereas high concentrations (100 μg/mL) produced contraction. Blockade of ATP-sensitive (KATP) or voltage-gated (KV) potassium channels attenuated these effects. Furthermore, effects were not observed in preparations preincubated with L-NG-Nitro-L-arginine methyl ester (L-NAME) or in endothelium-denuded rings. In aortic VSMCs, extracts (1 µg/mL) rapidly reduced sarcoplasmic reticulum (SR) Ca2+ content. This study provides the first UHPLC-ESI-Q-TOF-MS chemical profile of C. longifolium, revealing diverse bioactive metabolites. It is also the first to demonstrate that C. longifolium exerts an endothelium-dependent, nitric oxide- and Ca2+-mediated biphasic effect on vascular function. Taken together, these findings highlight C. longifolium as a potential novel source of vasculotropic phytopharmaceuticals.

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