Protection by Ethanolic Extract from Ulva lactuca L. against Acute Myocardial Infarction: Antioxidant and Antiapoptotic Activities

Cardioprotective Effects of Tetrahydropalmatine on Acute Myocardial Infarction in Rats

Tetrahydropalmatine (THP) is an active component of Corydalis yanhusuo W. T. Wang. The current study investigates the possible cardioprotective effects of tetrahydropalmatine in acute myocardial ischemia (AMI) rats. The anterior descending coronary artery of SD rats was ligated to establish an AMI model. After two weeks of gavage of THP, cardiac function was determined by echocardiography. The organ index and the infarct size were assessed after the experiment, and the histopathological myocardial tissue changes were observed. In addition, the apoptosis index of myocardial cells was detected by the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The levels of SOD, MDA, CAT, GSH-Px, BNP, and cTn-I were measured by enzyme-linked immunosorbent assay. To determine relevant proteins, the Western blot and molecular docking were applied. Compared with the model group, THP could enhance rat cardiac ejection function to improve cardiac function, drastically lessen the infarct size, reduce myocardial cell damage and inflammatory cell infiltration. THP might also prevent ischemic myocardial damage by inhibiting myocardial cell apoptosis and efficiently reducing oxidative stress. Specifically, THP could decrease MDA, BNP, c-TnI activities, as well as the expression of Bax and Caspase-3 protein, while increasing SOD, GSH-Px, CAT activities, and Bcl-2 level. Furthermore, THP could significantly promote the phosphorylation of PI3K and Akt proteins. The involved pathways and proteins have also been verified through molecular docking. According to these findings, THP may preserve the myocardium due to its anti-oxidant and anti-apoptotic properties.

Anticancer efficacies of Krameria lappacea extracts against human breast cancer cell line (MCF-7): Role of oxidative stress and ROS generation

Breast cancer is a growing health issue globally and accounts as a second most cause of mortality. Natural products have been a fundamental of health care for long. Plants derived natural products have gained considerable attention over synthetic medicines, since they are safe and non-toxic. Krameria lappacea (Dombey) Burdet and B.B. Simpson plant belonging to Krameriaceae family, has been known for its beneficial effects against diseases. Herein, firstly, cytotoxic potential of petroleum ether (KLH), chloroform (KLC), ethyl acetate (KLEA), and ethanolic (KLET) extracts of K. lappacea was screened against MCF-7 cells exposed to 10–1000 μg/mL for 24 h. Secondly, the most cytotoxic extract (KLH) was used to explore the mechanisms of cytotoxicity in MCF-7 cells. MCF-7 cells were treated with KLH at 250–1000 μg/mL to measure the oxidative stress markers (glutathione (GSH) and lipid peroxidation (LPO)) and reactive oxygen species (ROS) generation. Further, loss of mitochondrial membrane potential (MMP) and caspase-3 and -9 enzyme activities were studied. The viability of MCF-7 cells were decreased from 44% to 90% for KLH, from 7% to 71% for KLEA, from 39% to 80% for KLC, and from 3% to 81% for KLET, respectively at 250–1000 μg/mL as observed by MTT assay. An increase of 91% in LPO and 2.2-fold in ROS generation and a decrease of 59% in GSH and 68% in MMP levels at 1000 μg/mL showed that KLH induced MCF-7 cell death via oxidative stress and elevated level of ROS generation which further leads to mitochondrial membrane dysfunction and activation of caspase enzymes. The findings of this study provide a mechanistic insight on anticancer efficacies of K. lappacea extracts against MCF-7 cells and support the use of it for the treatment of breast cancer diseases.

Activation of SIRT1/PGC 1α/SIRT3 pathway by melatonin provides protection against mitochondrial dysfunction in isoproterenol induced myocardial injury

AIMS

Preventing mitochondrial dysfunction and enhancing mitochondrial health and biogenesis is a crucial therapeutic approach to ameliorate injury following acute myocardial infarction. Although the antioxidant role of melatonin against ischemia/reperfusion injury has been reported, the exact mechanism of protection, in vivo, remains poorly understood. This study aims to identify and elaborate upon mechanism of melatonin protection of rat cardiac mitochondria against acute myocardial infarction.

MAIN METHODS

Rats were pre-treated with melatonin (10 mg/kg body weight (b.w.); intraperitoneally, i.p.) before isoproterenol bitartrate (ISO) administration (25 mg/kg body weight (b.w.) subcutaneously,s.c.) and their effect on rat heart mitochondrial structure and function was studied. Biochemical changes in activity of biomarkers of oxidative stress, antioxidant enzymes as well as Krebs' cycle enzymes were analyzed. Gene expression studies and Isothermal titration calorimetric studies with pure catalase and ISO were also carried out.

KEY FINDINGS

Melatonin was shown to reduce ISO induced oxidative stress, by stimulating superoxide dismutase activity and removing the inhibition of Krebs' cycle enzymes. Herein we report for the first time in rat model that melatonin activates the SIRT1-PGC-1α-SIRT3 signaling pathways after ISO administration, which ultimately induces mitochondrial biogenesis. Melatonin exhibited significant protection of mitochondrial architecture and topology along with increased calcium ion permeability and reactive oxygen species (ROS) generation induced by ISO. Isothermal calorimetric studies revealed that melatonin binds to ISO molecules and sequesters them from the reaction thereby limiting their interaction with catalase along with occupying the binding sites of catalase themselves.

SIGNIFICANCE

Activation of SIRT1-PGC-1α-SIRT3 pathway by melatonin along with its biophysical properties prevents ISO induced mitochondrial injury in rat heart.