Metabolic syndrome (MS), which increases cardiovascular risk, is constituted by abdominal obesity, dyslipidemia, insulin resistance, and hypertension (HTN). Garambullo, the fruit of Myrtillocactus geometrizans, contains cardioprotective betalains and flavonoids, but its effect on vascular function has not been elucidated. This study evaluated the vasodilator effect of a freeze-dried garambullo juice concentrate (CJG_L) on the thoracic aortic rings of Wistar rats with MS and high-fat-diet-induced HTN (HFD, 41%).

The total betalains, polyphenol content, and antioxidant capacity of CJG_L were analyzed in vitro by ORAC and FRAP assays performed in triplicate. Secondary metabolites were profiled by high-performance liquid chromatography coupled with mass spectrometry. Ex vivo, rat thoracic aortic rings precontracted with phenylephrine (10 μM) were used to evaluate the vasoactive effect of CJG_L (1-75 mg/mL) in isometric stress studies (n=5). Twenty-nine rats were divided into two groups: standard diet (CG; n=10) and HFD (MS; n=19). Over 27 weeks, we measured body weight, abdominal circumference, adipose mass, oral glucose tolerance, HDL cholesterol (c-HDL), and blood pressure, and isometric stress studies were performed to evaluate the vasoactive effect of CJG_L. The trial was registered under reference number BGFMUASLP-13-22.

CJG_L contains polyphenols (521.4 mgGAE/L), flavonoids (143.8 mg catechin equivalents/L), and betalains (75.8 mg/L), which exhibited ~18- and ~16-fold higher antioxidant capacities in FRAP and ORAC assays, respectively. The identified metabolites included betacyanins, betaxanthins, and flavonoids. CJG_L demonstrates dose-dependent vasodilation, with an EC₅₀ of 10.68 mg/mL. Rats fed an HFD developed MS, with increased body metrics, glucose intolerance, and decreased c-HDL; 57% had HTN (MS+HTN). CJG_L at 10.5 mg/mL induced 62.6% endothelium-independent vasodilation in the aorta rings of MS+HTN rats, with no significant change compared to the control and MS groups without HTN (p>0.05; two-way ANOVA).

CJGL shows an endothelium-independent vasodilator effect related to its secondary metabolites, highlighting the ability of this functional food to alleviate vascular dysfunction in MS.