The spasmolytic effect of Aloysia citriodora, Palau (South American cedrón) is partially due to its vitexin but not isovitexin on rat duodenums

Antispasmodic effects of Aloysia polystachya and A. gratissima tinctures and extracts are due to non-competitive inhibition of intestinal contractility induced by acethylcholine and calcium

“…From the DRC it was calculated the affinity of (-)-carvone on its own cellular site, which was estimated by the pD´2. It resulted 4.002±0.117 (n=20) from the DRC of ACh and 3.86±0.19 (n=18) from the DRC of Ca Contrarily to what was described for Aloysia citriodora (Ragone et al, 2007) the HPLC chromatograms showed no presence of vitexin or isovitexin in the AE of Aloysia polystachya and Aloysia gratissima (Figure 7). Retention times of the standard drugs were Rt 11.51 min for vitexin and 16.85 min for isovitexin, with a good separation profile comparable to that previously described.…”

“…It was applied the previously developed method of high performance liquid chromatography (HPLC) contrasted with standards of both flavonoids (Ragone et al, 2007). It was used a 322-H2 series pump, a 155/156 UV/Vis detector and a work station equipped with the UniPoint LC, 3.3 version software (Gilson SAS, Villiers-Le-Bel, France).…”

“…In a previous work it was described for the first time the antispasmodic effect of Aloysia citriodora Ortega ex Pers., which is known as "cedrón" or "hierba luisa". Its pharmacological mechanism of action was related to activation of the guanylil-cyclase and the potassium channels (Ragone et al, 2007). In this work, the antispasmodic properties of two other species of Aloysia were validated and the pharmacological basis of the popular use was evaluated, as well as the correlation with its chemical composition.…”

The Occurrence, Fate and Biological Activities ofC-glycosyl Flavonoids in the Human Diet

“…The frequency of muscular contraction was also attenuated in a dose-dependent manner (Afifi et al, 1999). Ragone et al (2007) provided greater mechanistic evidence for effect of the dietary Cglycosyl flavone vitexin, but not its isomer isovitexin, isolated from the herbal plant Aloysia citriodora on attenuating induced rat duodenum contraction. Both acetylcholine and Ca 2+ dose-response curves were employed to potentiate contraction of the smooth muscle within this tissue.…”

“…However isovitexin, the 6-Cglycosylated isomer of vitexin, had no significant activity on the effect of acetylcholine at 69 µM (81.4 ± 9.5% of E max of acetylcholine,) indicating that the position of C-glycosylation may be crucial in producing this effect. Interestingly, despite the crude extract of Aloysia citriodora from which these compounds were isolated being capable of so doing, neither compound had a significant effect on the tissue response to increasing extracellular Ca 2+ concentrations at 46.3 µM (Ragone et al, 2007). Vitexin therefore has been shown to noncompetitively inhibit the activity of acetylcholine in potentiating smooth muscle contraction in rat duodenum, thus demonstrating its capability to produce a significant antispasmodic effect in the gastrointestinal tract at a high but lumenally relevant concentration (69.4 µM).…”