Effects of hydrophilic and lipophilic beta-sitosterol derivatives on cholesterol absorption and plasma cholesterol levels in rats

Unveiling the molecular mechanisms: dietary phytosterols as guardians against cardiovascular diseases

Until recently, the main pharmaceuticals used to control cholesterol and prevent cardiovascular disease (CVD) were statin-related drugs, known for their historical side effects. Therefore, there is growing interest in exploring alternatives, such as nutritional and dietary components, that could play a central role in CVD prevention. This review aims to provide a comprehensive understanding of how natural phytosterols found in various diets combat CVDs. We begin with a description of the overall approach, then we explore in detail the different direct and indirect mechanisms that contribute to reducing cardiovascular incidents. Phytosterols, including stigmasterol, β-sitosterol, ergosterol, and fucosterol, emerge as promising molecules within nutritional systems for protection against CVDs due to their beneficial effects at different levels through direct or indirect cellular, subcellular, and molecular mechanisms. Specifically, the mentioned phytosterols exhibit the ability to diminish the generation of various radicals, including hydroperoxides and hydrogen peroxide. They also promote the activation of antioxidant enzymes such as superoxide dismutase, catalase, and glutathione, while inhibiting lipid peroxidation through the activation of Nrf2 and Nrf2/heme oxygenase-1 (HO-1) signaling pathways. Additionally, they demonstrate a significant inhibitory capacity in the generation of pro-inflammatory cytokines, thus playing a crucial role in regulating the inflammatory/immune response by inhibiting the expression of proteins involved in cellular signaling pathways such as JAK3/STAT3 and NF-κB. Moreover, phytosterols play a key role in reducing cholesterol absorption and improving the lipid profile. These compounds can be used as dietary supplements or included in specific diets to aid control cholesterol levels, particularly in individuals suffering from hypercholesterolemia.

Advances and Challenges in Plant Sterol Research: Fundamentals, Analysis, Applications and Production

Plant sterols (PS) are cholesterol-like terpenoids widely spread in the kingdom Plantae. Being the target of extensive research for more than a century, PS have topped with evidence of having beneficial effects in healthy subjects and applications in food, cosmetic and pharmaceutical industries. However, many gaps in several fields of PS's research still hinder their widespread practical applications. In fact, many of the mechanisms associated with PS supplementation and their health benefits are still not fully elucidated. Furthermore, compared to cholesterol data, many complex PS chemical structures still need to be fully characterized, especially in oxidized PS. On the other hand, PS molecules have also been the focus of structural modifications for applications in diverse areas, including not only the above-mentioned but also in e.g., drug delivery systems or alternative matrixes for functional foods and fats. All the identified drawbacks are also superimposed by the need of new PS sources and technologies for their isolation and purification, taking into account increased environmental and sustainability concerns. Accordingly, current and future trends in PS research warrant discussion.

Impact of molecular interactions between hydrophilic phytosterol glycosyl derivatives and bile salts on the micellar solubility of cholesterol

Hydrophilic phytosterol glycosyl derivatives are synthetic phytosterol analogues by coupling with the glycosyl moiety to improve the water solubility and bioaccessibility of free phytosterols. The aim of this study is to clarify the molecular interaction of phytosterol glycosyl derivatives with bile salts and the consequent impact on cholesterol solubilization. Sharp nonlinear decrease in the micellar solubility of cholesterol and accompanying changes in particle size, zeta potential and microtopography of mixed micelles were observed when phytosterol glycosyl derivatives were introduced in cholesterol-loaded bile salt micelles. These results suggested that β-sitosterol glycosyl derivatives molecules indeed participated in the formation of mixed micelles. Further, nuclear magnetic resonance showed that the structural change of mixed micelles was caused by the insertion of β-sitosterol glycosyl derivatives via hydrogen bonds with sodium taurocholate, which resulted in the low cholesterol solubilization. Moreover, the hydrogen-bond interactions were apparently influenced by the glycosyl moiety of β-sitosterol glycosyl derivatives. These molecular mechanisms may contribute to the development of cholesterol-absorption inhibitors.

The preparation of phytosteryl succinyl sucrose esters and improvement of their water solubility and emulsifying properties

Phytosterols have gained much attention due to their outstanding cholesterol-reducing effect, while the insolubility in water limits their application. The aim of this study was to synthesize a novel hydrophilic phytosteryl derivatives-phytosteryl succinyl sucrose esters (PSSEs) and investigated their water solubility and emulsifying properties. PSSEs were synthesized by esterifying phytosterol hemisuccinates with sucrose through a mild chemical reaction. PSSEs were characterized by fourier transform infrared spectroscopy, mass spectroscopy, and nuclear magnetic resonance spectroscopy. The yield of PSSEs exceeded 84% in N,N-dimethylformamide for 36 h of reaction under the selected conditions: 100 mmol/L phytosteryl hemisuccinates, 150 mmol/L sucrose, 110 mmol/L 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochlide, 10 mmol/L 4-dimethylaminopyridine and 10 mmol/L p-toluenesulfonic acid. The water insolubility of phytosterols was overcome and the water solubility of PSSEs achieved 2.13 mg/mL. The emulsifying activity of PSSEs was 2.5 times that of phytosterols, reaching 0.95 mg/mL. PSSEs with better water solubility and emulsification properties could facilitate the widespread use of phytosterols in foods.

Cholesterol-lowering effects of plant steryl and stanyl laurate by oral administration in mice

The present study was conducted to investigate the efficacy of synthesized plant steryl and stanyl laurate in lowering the cholesterol level and to further examine the cholesterol-lowering potential of the free plant sterols and stanols dissolved in liquid emulsion on serum and liver lipids in mice by oral administration. Experimental results showed that both plant steryl and stanyl laurate could significantly decrease the serum levels of TC, LDL-C, LDL-C/HDL-C, and liver cholesterol contents and markedly increase fecal cholesterol concentrations but have no effect on serum TAG level, indicating that the produced plant steryl and stanyl laurate retained the cholesterol-lowering potential of natural plant sterols and stanols. However, no statistical difference in cholesterol-lowering efficacy was observed between plant steryl laurate and plant stanyl laurate, and free plant sterols and stanols dissolved in liquid emulsion could also significantly decrease serum cholesterol levels and markedly increase fecal cholesterol excretion. These results suggested that the esterified plant sterols/stanols had comparable effects to the free plant sterols/stanols in lowering serum TC levels but that they did gain a solubility advantage from the free plant sterols/stanols. Therefore, plant steryl/stanyl laurate could be considered as a potential nutraceutical or functional ingredient to reduce or prevent atherosclerosis and its related complications.