Luteolin-Rich Fraction from Dracocephalum lindbergii: Promising Agent for Hypertension Treatment.

Background: High blood pressure is one of the most critical issues in maintaining health; it requires prevention and management methods. In traditional medicine, the combination of medicinal plants was usually used to control high blood pressure. One of these plants is Dracocephalum lindbergii. Therefore, this article examines the vasodilating effects of the flavonoid fractions of this plant and deals with this extract as a new suggestion for the prevention and control of high blood pressure.

Methods: This research evaluates the hemodynamic properties of flavonoid-rich fractions extracted from this plant in a rat model under conditions of blood pressure induction. First, the phytochemistry laboratory prepared flavonoid fractions by using a chromatography column. Then, after surgical preparation, the arterial pressure of the rats was controlled until stabilization, and it was possible to record basal systolic pressures (SYS), diastolic pressures (DBP), and mean arterial pressures (MAP). Hypertension was maintained by continuous phenylephrine infusion at 0.1 mg/kg per minute, while the vascular responses were monitored during the infusion. After the animal tests, polyamide and Sephadex columns were used to analyze the most bioactive fractions, which led to the isolation of several flavones identified by regular one- and two-dimensional NMR spectra.

Results: In this model, administration of nifedipine led to an 8% decrease in SYS and a 9% decrease in DBP. Meanwhile, treatment with flavonoid-rich fractions 3, 4, 5, and 6 reduced SYS from 15% to 42% and DBP blood pressure from 6% to 30%. Among these samples, fraction number 6, followed by fraction number 4, showed more effects. Phytochemical studies of these fractions led to the identification of their major components probably responsible for observer effects, including apigenin (1) and apigenin-7-O-β-D-glucopyranoside (2), isolated from fraction number 4, as well as luteolin-4'-O-β-D-glucopyranoside (3) and luteolin-7-O-β-D-glucopyranoside (4) isolated from fraction 6. However, other minor components in fraction 6 are still possible with blood-pressure-lowering effects.

Conclusions: Flavonoid fractions, especially fraction number 6, rich in luteolin derivatives, can provide promising results in reducing blood pressure based on traditional medicine and complementary intervention in a model of acute phenylephrine-induced blood pressure. This study highlights the importance and potency of luteolin-rich fractions of D. lindbergii to serve as a complementary intervention in essential blood pressure control.