Antihypertensive and vasorelaxant mode of action of the ethanol-soluble extract from Tagetes lucida Cav. aerial parts and its main bioactive metabolites

Ethnopharmacological relevance: Tagetes lucida Cav. commonly known as yauhtli or peric ' on is used in Mexican traditional medicine for the treatment of anxiety, depressant diseases, pain, hypertension, among others. Aim: To evaluate the antihypertensive and vasorelaxant modes of action of a crude ethanolic extract from T. lucida aerial parts and to isolate the bioactive compounds. Materials and methods: Ethanolic extract was tested in an in vivo assay in SHR rats by intragastric administration at 10 and 100 mg/kg dosages, to measure and to compare hemodynamic parameters like diastolic and systolic blood pressure and heart rate. Also, extract (3.03-1000 mu g/ml), fractions (3.03-1000 mu g/ml) and pure isolated compounds (1.75-550 mu M) were evaluated on isolated aortic rings contracted with noradrenaline (0.1 mu M) to determine their vasorelaxant effect and extract-mode of action. Results: Ethanolic extract of T. lucida lowered systolic and diastolic blood pressure on SHR rats without heart rate modification (P 0.05). Moreover, the extract showed concentration-dependent relaxant effect in a partially endothelium-dependent manner (P < 0.05), through NO/cGMP system activation and calcium channel blockade. 6,7,8-trimethoxycoumarin (1), 6,7-dimethoxycoumarin (2), and 7-methoxycoumarin (3) from T. lucida are the main bioactive compounds of the extract and showed significant vasorelaxant activity. Conclusions: Results provide evidence and endorsed the antihypertensive properties attributed to T. lucida in traditional medicine, which is produced by vasorelaxant effect mainly through multitarget NO/cGMP system activation and calcium channel blockade. Coumarin derivatives 1, 2 and 3 are the responsible of the vasorelaxant activity.

Automated summary

The study on the extract of Tagetes lucida Cav. confirms its antihypertensive properties, mainly achieved through vasorelaxant effect by activating the NO/cGMP system and calcium channel blockade. Additionally, active compounds like 6,7,8-trimethoxycoumarin also significantly contribute to vasorelaxation.