Insight into the cardiovascular mechanisms of blood pressure lowering effect of gitogenin: a steroidal saponin

Gitogenin suppresses lung cancer progression by inducing apoptosis and autophagy initiation through the activation of AMPK signaling

Lung cancer is a leading cause of tumor-associated death worldwide. Autophagy plays a key role in regulating lung cancer progression, and is a promising option for lung cancer treatment. Saponins are a group of naturally occurring plant glycosides, characterized by their strong foam-forming properties in aqueous solution, and exert various biological properties, such as anti-inflammation and anti-cancer. In the present study, we for the first time explored the effects of gitogenin (GIT), an important saponin derived from Tribulus longipetalus, on lung cancer progression both in vitro and in vivo. We found that GIT markedly reduced the proliferation and induced apoptosis in lung cancer cells through increasing the cleavage of Caspase-3 and poly (ADP-ribose) polymerases (PARPs). In addition, GIT-incubated lung cancer cells exhibited clear accumulation of autophagosome, which was essential for GIT-suppressed lung cancer. Mechanistically, GIT-induced autophagy initiation was mainly through activating AMP-activated protein kinase (AMPK) and blocking protein kinase B (AKT) signaling pathways, respectively. Moreover, the autophagic flux was disrupted in GIT-treated lung cancer cells, contributing to the accumulation of impaired autophagolysosomes. Importantly, we found that suppressing autophagy initiation could abolish GIT-induced cell death; however, autophagosomes accumulation sensitized lung cancer cells to cell death upon GIT treatment. More in vitro experiments showed that GIT led to reactive oxygen species (ROS) production in lung cancer cells, which was also involved in the modulation of apoptosis. The in vivo findings confirmed the effects of GIT against lung cancer progression with undetectable toxicity to organs. In conclusion, we provided new insights into the treatment of lung cancer, and GIT might be an effective strategy for future clinical application.

Antihypertensive Activity in High Salt-Induced Hypertensive Rats and LC-MS/MS-Based Phytochemical Profiling of Melia azedarach L. (Meliaceae) Leaves

Melia azedarach L. leaves have been traditionally used but not scientifically evaluated for antihypertensive activity. The focus of the present work was to carry out the detailed phytochemical profiling and antihypertensive potential of methanolic extract and subsequent fractions of this plant. The tandem mass spectrometry-based phytochemical profiling of M. azedarach extract (Ma.Cr) and fractions was determined in negative ionization mode while molecular networking was executed using the Global Natural Product Social (GNPS) molecular networking platform. This study resulted in the identification of 29 compounds including flavonoid O-glycosides, simple flavonoids, triterpenoidal saponins, and cardenolides as the major constituents. Ma.Cr at the concentration of 300 mg/kg resulted in a fall in blood pressure (BP), i.e., 81.44 ± 2.1 mmHg in high salt-induced hypertensive rats in vivo, in comparison to normotensive group, i.e., 65.36 ± 1.8 mmHg at the same dose. A decrease in blood pressure was observed in anaesthetized normotensive and hypertensive rats treated with extract and various fractions of M. azedarach. A reasonable activity was observed for all fractions except the aqueous fraction. The highest efficacy was shown by the ethyl acetate fraction, i.e., 77.06 ± 3.77 mmHg in normotensive and 88.96 ± 1.3 mmHg in hypertensive anaesthetized rats. Ma.Cr and fractions showed comparatively better efficacy towards hypertensive rats as compared to rats with normal blood pressure. Blood pressure-lowering effects did not change upon prior incubation with atropine. In vitro testing of Ma.Cr and polarity-based fractions resulted in L-NAME sensitive, endothelium-dependent vasodilator effects on aortic tissues. Pretreatment of aorta preparations with Ma.Cr and its fractions also blocked K+-induced precontractions indicating Ca2+ channel blocking activity comparable to verapamil. The extract and polarity-based fractions did not reveal a vasoconstrictor response in spontaneously beating isolated rat aorta. Ma.Cr and fractions when used in atrial preparations resulted in negative inotropic and chronotropic effects. These effects in atrial preparations did not change in the presence of atropine. These effects of extract and fractions explained the antihypertensive potential of M. azedarach and thus provided a scientific basis for its ethnopharmacological use in the treatment of hypertension. Among the constituents observed, flavonoids and flavonoid O-glycosides were previously reported for antihypertensive potential.