Current research status of alkaloids against breast cancer.

Breast cancer is one of the most common malignant tumors in women worldwide. Surgery, chemotherapy, and targeted drugs are the main methods currently used in clinical treatment of breast cancer. Although they can improve the symptoms of patients, they are also accompanied by a large number of side effects. Because of its multiple targets, traditional Chinese medicine can improve the quality of life of breast cancer patients and reduce the side effects associated with chemotherapy, which plays an important role in the treatment of breast cancer. To a certain extent, traditional Chinese medicine has advantages that modern medicine does not have in the treatment of breast cancer. Alkaloids are active ingredients widely distributed in traditional Chinese medicine, which have a variety of pharmacological effects including anti-inflammatory, analgesic, and antitumor effects. The author reviewed the literature on the treatment of breast cancer with alkaloids extracted from traditional Chinese medicine in recent years, and discussed the unique advantages of alkaloids in the treatment of breast cancer.

Vasodilatory effects of betaine on isolated rat pulmonary artery rings.

The aim of this study was to investigate the vasodilatory effects of betaine, an alkaloid isolated from Lycium barbarum, on isolated pulmonary artery rings in rats and its possible mechanisms. Pulmonary vessels of normal Sprague-Dawley rats were isolated and pre-contracted using norepinephrine. Then, betaine was cumulatively added in differing concentrations (0.02-0.14 mg/mL), and the tension curve was observed and recorded. Changes in the tension of the pulmonary artery rings with an intact endothelium and a dissected endothelium were recorded. The interactions among betaine and NG-nitro-L-arginine methyl ester, indomethacin, 4-aminopyridine, barium chloride, and glibenclamide were evaluated. The experimental results show that betaine can relax the pulmonary artery rings pre-contracted by norepinephrine. Furthermore, pre-incubation with NG-nitro-L-arginine methyl ester and indomethacin did not inhibit betaine vasodilation, demonstrating that vasodilation by betaine is endothelium-dependent. Additionally, pretreatment of pulmonary artery rings with 4-aminopyridine and glibenclamide had no effect on betaine. However, pretreatment of pulmonary artery rings with barium chloride attenuated the effects of betaine. In conclusion, the vasodilatory effects of betaine on pulmonary artery rings is associated with inward rectifier potassium channels.

Vasorelaxation effect of oxysophoridine on isolated thoracicc aorta rings of rats.

Oxysophoridine (OSR) is a main active alkaloid extracted from Sophora alopecuroides, which is a traditional Chinese herbal medicine that has been used widely. In this study, we used thoracic aorta rings isolated from Sprague-Dawley rats to explore the vasodilative activity of OSR and its potential mechanisms. The isolated rat thoracic aorta rings were used to observe the effects of different concentrations of OSR (0.4-2.0 g·L-1) on the resting normal rings and the phenylephrine precontracted endothelium-intact or endothelium-denudedisolated thoracic aorta rings, respectively. The interactions among OSR and barium chloride (BaCl2), tetraethylamine, 4-aminopyridine, glibenclamide (Gli), L-nitroarginine methyl ester (L-NAME), and cyclooxygenase (COX) inhibitor indomethacin (INDO) were evaluated. The experimental results show that OSR had no effect on the tension of resting vascular rings, but the vasodilating effect could be confirmed in a concentration-dependent manner on both endothelium-intact and endothelium-denuded vascular rings. This vasodilation effect of OSR on thoracic aorta vascular rings could be inhibited significantly by potassium channel blockers glibenclamide (Gli, 10 µmol·L-1) and 4-aminopyridine (4-AP, 5 mmol·L-1). In addition, vasodilatory effects of OSR were not inhibited in the presence of potassium channel blockers barium chloride (BaCl2, 1 mmol·L-1) and tetraethylamine (TEA, 10 mmol·L-1), nitric oxide synthase inhibitor (L-NAME, 0.1 mmol·L-1) and COX inhibitor (INDO, 10 µmol·L-1). In conclusion, the vasodilatory effects of OSR on thoracic aorta rings is associated with KV and KATP.

Vasorelaxation effect of 18ß-glycyrrhetinic acid on the thoracic aorta of rats: proposed mechanism.

18ß-Glycyrrhetinic acid (18ß-GA) is an effective component extracted from the traditional Chinese medicine Radix glycyrrhizae (Leguminosae) and has various biological activities. This study was performed to investigate the vasodilatory effects of 18ß-GA on isolated rat thoracic aortic rings and explore the underlying mechanisms. The rings were obtained from normal Sprague-Dawley rats and then precontracted with norepinephrine (NE) (1 µM) or KCl (60 mM). 18ß-GA (1.883-11.297mg/L) was added successively by cumulative dosing to observe and record the changes in the tension of the vascular ring. The effects of NG-nitro-l-arginine methylester (L-NAME), indomethacin (INDO), barium chloride (BaCl2), 4-aminopyridine(4-AP), tetraethylammonium (TEA), and glibenclamide on the vascular diastolic function of 18ß-GA were determined. 18ß-GA substantially exhibited a dose-dependent vasorelaxant effect on the NE-induced and KCl-induced contractions of the rings. The integrity of the vascular endothelium had no influence on the 18ß-GA-induced vasorelaxation effect in the rings. L-NAME and IDON showed no significant differences in their effects on this vasorelaxation process in the rings precontracted with NE. This result suggests that the vasorelaxation mechanism of 18ß-GA may be independent of the vascular endothelium . BaCl2 and 4-AP antagonized the vasorelaxation effect of 18ß-GA, but TEA and glibenclamide showed no remarkable effect on the vasodilation of 18ß-GA. Findings suggest that 18ß-GA induces vasorelaxation in thoracic aortic rings via the receptor-operated Ca2+ channels and voltage-operated Ca2+ channels and the opening of inward rectifier potassium channels and voltage-operated potassium.