Evaluation of cytotoxic and apoptotic effects of individual and mixed 7-ketophytosterol oxides on human intestinal carcinoma cells

Exogenous oxidized phytosterol may modulate linoleic acid metabolism through upregulation of fatty acid desaturase in rats

Previous in vitro studies have indicated that oxidized phytosterol (OPS) exhibits some toxicity; however, the harmful effects of OPS on fatty acid metabolism are not completely understood yet. Therefore, this study examined the effects of exogenous phytosterol (PS) and OPS on growth parameters and lipid metabolism in rats. Rats were provided with AIN-76 basal diet, basal diet +0.5% PS, or basal diet +0.5% OPS. We found that the level of cholesterol and triacylglycerols in the liver was significantly lower in OPS-fed rats than in basal diet-fed rats. The ratio of Δ6 desaturation index (20:3(n-6) + 20:4(n-6))/18:2(n-6) in the plasma was significantly higher in the OPS-fed rats than in the PS-fed rats. Additionally, the proportion of arachidonic acid (20:4) in the liver was significantly higher in the OPS-fed group compared with the control group. The mRNA expression levels of Δ6 and Δ5 desaturases were significantly higher in OPS-fed rats than in basal diet-fed rats, but remained unchanged in PS-fed rats. Moreover, the protein level of Δ6 desaturase was significantly higher in both PS- and OPS-fed rats compared with basal diet-fed rats, while the protein level of Δ5 desaturase tended to be higher only in OPS-fed rats than in basal diet-fed rats. Thus, exogenous OPS, but not PS, altered fatty acid composition through the upregulation of mRNA and protein levels of fatty acid desaturation enzymes in the liver. This indicates that exogenous OPS, unlike PS, may modulate the production of eicosanoids from arachidonic acid, potentially promoting allergic reactions, inflammation, and atherosclerosis.

Antiproliferative Effect of 7-Ketositosterol in Breast and Liver Cancer Cells: Possible Impact on Ceramide, Extracellular Signal-Regulated Kinases, and Nuclear Factor Kappa B Signaling Pathways

Background: This study aimed to examine the effect of 7-Ketositosterol (7-KSS), on sphingomyelin/ceramide metabolites and apoptosis in human breast MCF-7 and human liver HepG2 cancer cells. Methods: Anti-proliferative effects of 7-KSS treatment were assessed at different concentrations and periods. Cell viability was assessed through MTT analysis, whereas the levels of sphingosine-1-phosphate (S1P), sphingomyelins (SMs), and ceramides (CERs) were measured using LC-MS/MS. Phosphorylated 44/42 ERK1/2 and NF-κB p65 (Ser536) protein levels were measured by Western blot analysis and immunofluorescence staining. Apoptosis was evaluated by TUNEL staining and flow cytometric assessment of annexin-V and propidium iodide (PI) labeling. Results: Treatment with 7-KSS significantly decreased cell survival and S1P, p-44/42 ERK1/2, and p-NF-κB p65 protein levels in cancer cells compared to controls. A substantial rise was detected in intracellular amounts of C16-C24 CERs and apoptosis in cancer cells incubated with 7-KSS. Conclusions: 7-KSS stimulated ceramide accumulation and apoptosis while decreasing cell proliferation via downregulating S1P, p-44/42 ERK1/2, and p-NF-κB p65 protein levels.

Liposomes as Carriers of Bioactive Compounds in Human Nutrition

This article provides an overview of the literature data on the role of liposomal structures and encapsulated substances in food technology and human nutrition. The paper briefly describes how liposomes are created and how they encapsulate food ingredients, which can either be individual compounds or plant extracts. Another very interesting application of liposomes is their use as antimicrobial carriers to protect food products from spoilage during storage. The encapsulation of food ingredients in liposomes can increase their bioavailability, which is particularly important for compounds with health-promoting properties but low bioavailability. Particular attention was paid to compounds such as phytosterols, which lower blood cholesterol levels but have very low absorption in the human body. In addition, consumer expectations and regulations for liposomes in food are discussed. To date, no in vivo human studies have been conducted to indicate which encapsulation methods give the best results for gastrointestinal effects and which food-added substances are most stable during food storage and processing. The paper identifies further lines of research that are needed before liposomes can be introduced into food.

Possible interactions between selected food processing and medications

The impact of food processing on drug absorption, metabolism, and subsequent pharmacological activity is a pressing yet insufficiently explored area of research. Overlooking food-processing-drug interactions can significantly disrupt optimal clinical patient management. The challenges extend beyond merely considering the type and timing of food ingestion as to drug uptake; the specific food processing methods applied play a pivotal role. This study delves into both selected thermal and non-thermal food processing techniques, investigating their potential interference with the established pharmacokinetics of medications. Within the realm of thermal processing, conventional methods like deep fat frying, grilling, or barbecuing not only reduce the enteric absorption of drugs but also may give rise to side-products such as acrylamide, aldehydes, oxysterols, and oxyphytosterols. When produced in elevated quantities, these compounds exhibit enterotoxic and pro-inflammatory effects, potentially impacting the metabolism of various medications. Of note, a variety of thermal processing is frequently adopted during the preparation of diverse traditional herbal medicines. Conversely, circumventing high heat through innovative approaches (e.g., high-pressure processing, pulsed electric fields, plasma technology), opens new avenues to improve food quality, efficiency, bioavailability, and sustainability. However, it is crucial to exercise caution to prevent the excessive uptake of active compounds in specific patient categories. The potential interactions between food processing methods and their consequences, whether beneficial or adverse, on drug interactions can pose health hazards in certain cases. Recognizing this knowledge gap underscores the urgency for intensified and targeted scientific inquiry into the multitude of conceivable interactions among food composition, processing methods, and pharmaceutical agents. A thorough investigation into the underlying mechanisms is imperative. The complexity of this field requires substantial scrutiny and collaborative efforts across diverse domains, including medicine, pharmacology, nutrition, food science, food technology, and food engineering.

Anti-proliferative potential and oxidative reactivity of thermo-oxidative degradation products of stigmasterol and stigmasteryl esters for human intestinal cells

Stigmasterol in free and esterified form is incorporated in LDL cholesterol-lowering food products, intended for direct consumption and cooking, baking, and frying. Under thermal treatment, stigmasterol compounds may constitute a source of thermo-oxidative degradation products and oxyderivatives with potentially adverse health effects. This study aimed to analyze the anti-proliferative potential and genotoxicity of thermo-oxidatively treated stigmasterol (ST), stigmasteryl linoleate (ST-LA), and oleate (ST-OA). The effects on cell viability and proliferation, cell cycle progression, intracellular reactive oxygen species (ROS) generation, and DNA damage were analyzed in normal human intestinal cells. The mutagenic potential was assessed in a bacterial reverse mutation test using Salmonella enterica serovar Typhimurium strains involving metabolic activation. Stigmasteryl esters showed a significantly lower potential to affect intestinal cell viability and proliferation than non-esterified ST, regardless of heating. Thermo-oxidatively treated ST suppressed intestinal cell proliferation by arresting the cell cycle in the G₂/M phase and DNA synthesis inhibition. The enhanced intracellular ROS generation and caspase 3/7 activity suggest targeting intestinal cells to the apoptosis pathway. Also, heated ST-LA intensified ROS production and elicited pro-apoptotic effects. Thermo-oxidative derivatives of ST and ST-LA may evoke harmful gastrointestinal effects due to their high oxidative reactivity towards intestinal cells.

Acyl moiety and temperature affects thermo-oxidative degradation of steryl esters. Cytotoxicity of the degradation products

Phytosterols and their esters are often used as functional ingredients in food products due to its lowering blood cholesterol properties. Products containing phytosterols and its esters are recommended for direct consumption, cooking, baking and frying, however during food preparation it is possible thermo-oxidative degradation is possible. Unsaturation of fatty acid present in steryl ester may further stimulates degradation. Free stigmasterol degraded faster than its esters, even with linoleic acid attached. The highest amount of degradation products was observed for free stigmasterol, followed by esters with linoleic and oleic acids. Polar dimers were fund in all heated samples, although for free stigmasterol heated at 60 °C were not detected. Whereas non-polar dimers were observed only in heated stigmasterol. Degradation of esterified stigmasterol generated degradation products with lower cytotoxicity.

Serum Concentration of Plant Sterol Oxidation Products (POP) Compared to Cholesterol Oxidation Products (COP) after Intake of Oxidized Plant Sterols: A Randomised, Placebo-Controlled, Double-Blind Dose‒Response Pilot Study

Plant sterols (PS) are oxidized to PS oxidation products (POP). This study quantified the change in serum POP compared to cholesterol oxidation products (COP) after the intake of increasing POP doses. This was a double-blind, randomized, placebo-controlled, dose‒response pilot study with healthy individuals in four groups (15 per group). The control group received products with no added PS or POP and treatment groups received daily 20–25 g margarine with added PS (mean 3 g/d) and two cookies (~28 g) for six weeks. Cookies delivered 8.7 (low-dose), 15.2 (medium-dose), or 37.2 (high-dose) mg/d POP. Fasting serum POP and COP were measured at the baseline, days 14, 28, and 42 in all participants and days 7, 21, and 35 in a subset. Sixty individuals completed the study; 52 were included in per protocol analysis. Serum POP increased with increasing POP intake and plateaued at dose >15 mg/d. Stabilized POP concentrations were (mean ± SD) 38.9 ± 6.9, 91.0 ± 27.9, 144.4 ± 37.9 and 203.0 ± 63.7 nmol/L, for control, low-, medium-, and high-dose POP groups, respectively. For all groups, the serum COP ranged from 213 to 262 nmol/L and the average POP/COP ratio was <1. Serum POP concentrations increased non-linearly, reaching stabilized concentrations in <7 days, and remained below COP concentrations after the intake of increasing POP doses.