# Conifer Bark Extracts as Modulators of Endothelial Function: Evidence from Abies alba and Cedrus brevifolia

## TL;DR

This study shows that extracts from the bark of two conifer species can improve endothelial function by boosting nitric oxide and reducing oxidative stress.

## Contribution

The novel contribution is the comparative evaluation of Abies alba and Cedrus brevifolia bark extracts for their endothelial benefits and vasorelaxant effects.

## Key findings

- Abies alba extract significantly enhances nitric oxide production and reduces oxidative stress in endothelial cells.
- Both conifer bark extracts demonstrate strong vasorelaxant activity, primarily through endothelial nitric oxide synthase.
- Cedrus brevifolia extract shows greater vasorelaxant activity compared to Abies alba.

## Abstract

Conifer bark extracts have attracted growing interest for their potential to protect and support endothelial function. The objective of this study was to evaluate the effects of Abies alba Mill. and Cedrus brevifolia (Hook. f.) Henry bark extracts on vascular endothelial function. The bark extracts were characterized by liquid chromatography coupled to high-resolution mass spectrometry. Bioactivity studies were first conducted in EA.hy926 endothelial cells to investigate the effects of bark extracts on cell viability and proliferation, nitric oxide production, oxidative stress, and angiogenesis. The vasorelaxant effects of bark extracts in rat aortic rings, as well as their impact on in vitro arginase activity, were further assessed. Abies alba bark extract was more effective in enhancing nitric oxide production (8.8-fold vs. 7.4-fold at 0.1 mg/mL), reducing oxidative stress (by 33% vs. 26% at 0.1 mg/mL), and inhibiting angiogenesis in EA.hy926 endothelial cells. It also exhibited stronger arginase inhibitory activity (IC50 = 68.30 µg/mL vs. 115.31 µg/mL). Both bark extracts showed marked vasorelaxant activity (EC50 < 15 µg/mL), mainly mediated by an endothelial nitric oxide synthase-related mechanism, with the Cedrus brevifolia bark extract being more active. Overall, our findings indicate that both bark extracts are promising candidates for supporting endothelial function.