Protective effects of Schisandrin on high glucose-induced changes of RhoA and eNOS activity in human umbilical vein endothelial cells

Schisandrol A, the Major Active Constitute in Schisandra chinensis: A Review of Its Preparation, Biological Activities, and Pharmacokinetics Analysis

Schisandra chinensis (S. chinensis) has a long history as a traditional Chinese medicine that is astringent, beneficial to vital energy, tonifies the kidney, tranquilizes the heart, etc. Significantly, Schisandrol A (SA) is extracted from S. chinensis and shows surprising and satisfactory biological activity, including anti-inflammatory, hepatoprotective, cardiovascular protection, and antitumor properties, among others. SA has a more pronounced protective effect on central damaged nerves among its numerous pharmacological effects, improving neurodegenerative diseases such as Alzheimer's and Parkinson's through the protection of damaged nerve cells and the enhancement of anti-oxidant capacity. Pharmacokinetic studies have shown that SA has a pharmacokinetic profile with a rapid absorption, wide distribution, maximal concentration in the liver, and primarily renal excretion. However, hepatic and intestinal first-pass metabolism can affect SA's bioavailability. In addition, the content of SA, as an index component of S. chinensis Pharmacopoeia, should not be less than 0.40%, and the content of SA in S. chinensis compound formula was determined with the help of high-performance liquid chromatography (HPLC), which is a stable and reliable method, and it can lay a foundation for the subsequent quality control. Therefore, this paper systematically reviews the preparation, pharmacological effects, pharmacokinetic properties, and content determination of SA with the goal of updating and deepening the understanding of SA, as well as providing a theoretical basis for the study of SA at a later stage.

Ginsenoside Rg-1 prevents elevated cytosolic Ca2+ via store-operated Ca2+ entry in high-glucose–stimulated vascular endothelial and smooth muscle cells

Background

Ginsenoside Rg-1 (Rg-1), a triterpenoid saponin abundantly present in Panax ginseng, is a type of naturally occurring steroid with known anti-diabetic and anti-inflammatory effects. In this study, we sought to confirm the effects and mechanisms of action of Rg-1 on store-operated Ca²⁺ entry (SOCE) in human vascular endothelial cell line (EA) and murine aortic vascular smooth muscle cell line (MOVAS) cells exposed to high glucose.

Methods

Cytosolic Ca²⁺ concentrations in EA and MOVAS cells were measured by monitoring fluorescence of the ratiometric Ca²⁺-indicator, Fura-2 AM.

Results

High glucose significantly increased Ca²⁺ influx by abnormally activating SOCE in EA and MOVAS cells. Notably, this high glucose-induced increase in SOCE was restored to normal levels in EA and MOVAS cells by Rg-1. Moreover, Rg-1 induced reductions in SOCE in cells exposed to high glucose were significantly inhibited by the plasma membrane Ca²⁺ ATPase (PMCA) blocker lanthanum, the Na⁺/K⁺-ATPase blocker ouabain, or the Na⁺/Ca²⁺ exchanger (NCX) blockers Ni²⁺ and KB-R7943. These observations suggest that the mechanism of action of Rg-1 inhibition of SOCE involves PMCA and Na⁺/K⁺-ATPase, and an increase in Ca²⁺ efflux via NCXs in both EA and MOVAS cells exposed to high glucose.

Conclusions

These findings indicate that Rg-1 may protect vascular endothelial and smooth muscle cells from Ca²⁺ increases following exposure to hyperglycemic conditions.

Potential of Schisandra chinensis (Turcz.) Baill. in Human Health and Nutrition: A Review of Current Knowledge and Therapeutic Perspectives

Schisandra chinensis (Turcz.) Baill. (SCE) is a plant with high potential for beneficial health effects, confirmed by molecular studies. Its constituents exert anti-cancer effects through the induction of cell cycle arrest and apoptosis, as well as inhibition of invasion and metastasis in cancer cell lines and experimental animals. SCE displays antimicrobial effects against several pathogenic strains. It has anti-diabetic potential, supported by hypoglycemic activity. A diet rich in SCE improves pancreatic functions, stimulates insulin secretion, and reduces complications in diabetic animals. SCE prevents lipid accumulation and differentiation of preadipocytes, indicating its anti-obesity potential. SCE exerts a protective effect against skin photoaging, osteoarthritis, sarcopenia, senescence, and mitochondrial dysfunction, and improves physical endurance and cognitive/behavioural functions, which can be linked with its general anti-aging potency. In food technology, SCE is applied as a preservative, and as an additive to increase the flavour, taste, and nutritional value of food. In summary, SCE displays a variety of beneficial health effects, with no side effects. Further research is needed to determine the molecular mechanisms of SCE action. First, the constituents responsible for its beneficial effects should be isolated and identified, and recommended as preventative nutritional additives, or considered as therapeutics.