Vasodilator activity of methanol extract obtained from <i>Crataegus rosei</i> leaves and the chemical characterization of its main constituents

Persistent arterial hypertension (AHT) plays a very important role in the development of cardiovascular diseases (CVD). The present study assessed the vasodilator activities of the methanol extract (ME) and its fractions obtained from leaves of a Mexican <i>Crataegus rosei</i> plant. The fat- and tannin-free ME fraction (FTFME) produced the most potent vasodilator effect [EC₅₀ 8.253 (4.672 to 14.58 μg/mL)], that was 6.7-fold higher than that of the ME [EC₅₀ = 55.49 (29.78 to 68.69) μg/mL], which was similar to that of ACh used as a positive control. This effect was dependent on the nitric oxide/cGMP pathway. Six triterpene acids (ursolic, oleanolic, euscaphic, maslinic, corosolic, and alphitolic) were identified as the main constituents of this fraction. In contrast to the commercially available <i>Crataegus</i> extracts, these compounds must be the most suitable chemical and pharmacological markers for this methanol extract in research into obtaining a standardised antihypertensive extract.