Polyphenolic Composition and Hypotensive Effects of Parastrephia quadrangularis (Meyen) Cabrera in Rat

Abstract

Parastrephia quadrangularis (Pq), commonly called “Tola”, is widely used in folk medicine in the Andes, including for altitude sickness. In this study, polyphenolic composition was determined, and hypotensive effects were measured; the ethnopharmacological use as hypotensive was related to the presence of phenolic compounds. For this purpose, male Sprague-Dawley rats (6 to 8 weeks of age, 160 to 190 g) were fed Pq extract (10 to 40 mg/kg) for 10 days through gavage. Blood pressures and heart rate were significantly (p < 0.01) reduced in normotensive rats receiving Pq extract (40 mg/kg body weight). Pq extract induced a negative inotropic effect, and endothelium-dependent vasodilation mediated by nitric oxide (NO). Furthermore, preincubation with Pq extract significantly decreased the cytosolic calcium on vascular smooth muscle cells A7r5 in response to L-phenylephrine (PE). Seven metabolites were isolated from the Pq extract, but three flavonoids (10−4 M) showed similar vasodilation to the extract in intact rat aorta as follows: 5,3′,4′-trihydroxy-7-methoxyflavanone (2); 3,5,4′-trihydroxy-7,8,3′-trimethoxyflavone (6); and 5,4′-dihydroxy-3,7,8,3′-tetramethoxyflavone (7). The Pq extract and compounds 2 and 7 significantly (p < 0.05) reduced the contraction to Bay K8644 (10 nM, an agonist of CaV1.2 channels). Administration of Pq decreased cardiac contractility and increased endothelium-dependent and -independent vasodilation.

Fast Isolation of Flavonoids from the Endemic Species Nolana ramosissima I.M. Johnst and Its Endothelium-Independent Relaxation Effect in Rat Aorta

“…Interestingly, the blockage of L-type voltage-gated Ca 2+ channels (Cav1.2) with 10 -6 M nimodipine decreased the contractile response to KCl (5 ± 2%) and PE (57 ± 7%) in a similar way than N. ramosissima ( Figure 8B). Therefore, this comparison with nimodipine suggests that extract-induced vascular effect is major by blocking of Ca 2+ influx through the plasmatic membrane [24].…”

“…Five major flavones were quickly isolated by HSCCC from a methanol extract of the endemic species N. ramosissima, and four of them showed relaxation activity. Besides, some 61 compounds were detected in both N. ramosissima polar extracts by UHPLC-MS. Of those, four were coumarins (peaks 2, 3, 6 and 18), 15 flavanones (peaks 4, 7, 9, 11, 15, 17, 21, 22, 32, 38, 46-49 and 56), 12 flavones (peaks 12, 13, 19, 23, 30, 39, 40-44 and 50), 3 phenolic acids (peaks 5,8 and 10) and 22 oxylipins/fatty acids (peaks 1,14,16,20,24,29,31,[33][34][35][36][37], 51-55, 57-61). Compound 2 presented higher relaxation effects than N. ramosissima extract.…”

“…The procedure of these experiments was realized in accordance to described by Cifuentes et al [24]. Rats were sacrificed through cervical dislocation.…”

“…HPLC hyphenated with high resolution mass spectrometry with the help of diode array UV detection such as PDA Q-TOF-MS or PDA-HESI-Q-orbitrap HR-MS are outstanding techniques for the fast and accurate untargeted small metabolite analysis of plant samples [19,20]. This technique has been successfully used in the last few years by our group to analyze several endemic Chilean species [21][22][23][24].…”

UHPLC-ESI-OT-MS Phenolics Profiling, Free Radical Scavenging, Antibacterial and Nematicidal Activities of “Yellow-Brown Resins” from Larrea spp.

“…In previous reports, several medicinal plants and native fruits growing in Argentina and Chile have been analyzed combining full mass spectra and MSn experiments from quadrupole orbitrap spectrometry (Q-OT-MS), significantly updating the chemical composition and their biological activities, in most of the species investigated. A considerable number of these previous reports have given scientific support to the use or consumption in traditional medicine in both countries [ 19 , 20 , 21 , 22 , 23 , 24 , 25 ].…”