Health benefits of 4,4-dimethyl phytosterols: an exploration beyond 4-desmethyl phytosterols

Comprehensive gas chromatography with mass spectrometry analysis of sterols in red goji berries (Lycium sp.)

Gas chromatography with mass spectrometry (GC/MS) and fractionation steps were used to determine the sterol patterns of red goji berries in detail. Twenty-five sterols were detected in fresh berries of two species (Lycium barbarum and L. chinense) from bushes grown in the botanical garden of the University of Hohenheim, and 20 sterols were identified. The rarely occurring campesta-5,24(25)-dienol, β-sitosterol, Δ5-avenasterol, campesterol, and cycloartenol represented >60 % of the total sterol content. Maturity and drying of fresh red goji berries caused small changes but did not affect the characteristic sterol pattern. This was confirmed by analyzing various commercial dried red goji berry samples from different sources. Separated flesh and seed samples revealed pronounced differences in the sterol pattern. A new method of merging GC/MS chromatograms showed that ∼75 % of the sterols were present in seeds and ∼25 % in flesh. The unique sterol profile may be exploited to authenticate red goji berries.

4,4-Dimethylsterols Reduces Fat Accumulation via Inhibiting Fatty Acid Amide Hydrolase In Vitro and In Vivo

4,4-Dimethylsterols constitute a unique class of phytosterols responsible for regulating endogenous cannabinoid system (ECS) functions. However, precise mechanism through which 4,4-dimethylsterols affect fat metabolism and the linkage to the ECS remain unresolved. In this study, we identified that 4,4-dimethylsterols, distinct from 4-demethseterols, act as inhibitors of fatty acid amide hydrolases (FAAHs) both in vivo and in vitro. Genetic ablation of FAAHs (faah-1) abolishes the effects of 4,4-dimethylsterols on fat accumulation and locomotion behavior in a Caenorhabditis elegans model. We confirmed that dietary intervention with 4,4-dimethylsterols in a high-fat diet (HFD) mouse model leads to a significant reduction in body weight (>11.28%) with improved lipid profiles in the liver and adipose tissues and increased fecal triacylglycerol excretion. Untargeted and targeted metabolomics further verified that 4,4-dimethylsterols influence unsaturated fatty acid biosynthesis and elevate oleoyl ethanolamine levels in the intestine. We propose a potential molecular mechanism in which 4,4-dimethylsterols engage in binding interactions with the catalytic pocket (Ser241) of FAAH-1 protein due to the shielded polarity, arising from the presence of 2 additional methyl groups (CH3). Consequently, 4,4-dimethylsterols represent an unexplored class of beneficial phytosterols that coordinate with FAAH-1 activity to reduce fat accumulation, which offers new insight into intervention strategies for treating diet-induced obesity.

Exploring the characteristics, digestion behaviors, and nutraceutical potential of the underutilized Chimonanthus praecox (L.) link kernel oil: A combined in vitro and in vivo study

Chimonanthus praecox (L.) Link kernel oil (LMO) has the potential to expand the variety of nutraceutical plant oils available and provide support for the application of functional food. This study aimed to assess the edible potential of LMO by examining its physicochemical characteristics, digestion behaviors, and nutraceutical properties. The results revealed that LMO has a high oil content of 40.84% and is particularly rich in linoleic acid (53.37-56.30%), oleic acid (22.04-25.08%) and triacylglycerol (TAG) of linoleic acid -palmitoleic acid- oleic acid (10.57-12.70%). The quality characteristics and phytochemical composition of LMO were found to be influenced by variety and extraction methods used. In simulated in vitro digestion tests, LMO showed a better lipid release rate and degree. Animal studies further demonstrated that LMO led to better TAG and cholesterol excretion compared to soybean oil and camellia oleifera oil. Overall, this study highlights the potential of LMO as a high-quality edible oil.

Gas chromatography with mass spectrometry analysis of 4,4-dimethylsterols and 4-methylsterols in edible oils after their enrichment by means of solid phase extraction

4-Methylsterols (4-M-sterols) and 4,4-dimethylsterols (4,4-D-sterols) are a group of underexplored minor sterols that occur in almost all living organisms. Here, we developed a strategy for the determination of the biochemical precursors of the predominant 4-desmethylsterols in edible oils. Due to their low contribution to the sterol content in the samples, a solid phase extraction (SPE) method was developed for the enrichment of 4-M- and 4,4-D-sterols in the hexane extracts of saponified oils. In a two-fold SPE procedure, the bulk of 4,4-D-sterols was collected in one fraction. The residual sample was subjected to a second SPE step which targeted all 4-M-sterols and low shares of 4,4-D-sterols in one fraction and the predominant 4-desmethylsterols in another one. After silylation of the SPE fractions, gas chromatography with mass spectrometry (GC/MS) was used to analyze 4,4-D- and 4-M-sterols. The results were used to define eight subgroups whose characteristic structural features could be linked with the presence of specific m/z values. These m/z values were measured sensitively by GC/MS operated in selected ion monitoring (SIM) mode. Application of the GC/MS method to eighteen edible oils enabled the detection of 55 mostly very low abundant 4-M- and 4,4-D-sterols. Twenty-four of the 4-M- and 4,4-D-sterols could be assigned and the remaining 31 unknown sterols could be traced back to their basic structures.

The critical role of the phytosterols in modulating tumor microenvironment via multiple signaling: A comprehensive molecular approach

Cancer is the leading cause of mortality and morbidity worldwide, and its cases are rapidly increasing every year. Several factors contribute to the development of tumorigenesis. including radiation, dietary lifestyle, smoking, environmental, and genetic factors. The cell cycle is regulated by a variety of molecular signaling proteins. However, when the proteins involved in the cell cycle regulation are altered, cellular growth and proliferation are significantly affected. Natural products provide an important source of new drug development for a variety of ailments. including cancer. Phytosterols (PSs) are an important class of natural compounds reported for numerous pharmacological activities, including cancer. Various PSs, such as ergosterol, stigmasterol, sitosterol, withaferin A, etc., have been reported for their anti-cancer activities against a variety of cancer by modulating the tumor microenvironment via molecular signaling pathways discussed within the article. These signaling pathways are associated with the production of pro-inflammatory mediators, growth factors, chemokines, and pro-apoptotic and anti-apoptotic genes. These mediators and their upstream signaling are very active within the variety of tumors and by modulating these signalings, thus PS exhibits promising anti-cancer activities. However, further high-quality studies are needed to firmly establish the clinical efficacy as well the safety of the phytosterols.

Effect of Encapsulation Material on Lipid Bioaccessibility and Oxidation during In Vitro Digestion of Black Seed Oil

Different encapsulation materials might not only affect lipid hydrolysis but also lipid oxidation during in vitro digestion. Thus, this study aimed to investigate the effect of two commonly used shell materials, starch and gelatin, on the extent of lipolysis and bioaccessibility of the main and some minor lipid compounds, as well as on the oxidative status in encapsulated black seed oil (Nigella sativa) during in vitro digestion. The study was carried out using ¹H nuclear magnetic resonance spectroscopy, liquid chromatography-mass spectrometry and high-performance liquid chromatography-UV. It was shown that starch increased the level of lipid hydrolysis in black seed oil during gastric in vitro digestion, while no differences were observed in the intestinal digestates between starch-encapsulated oil and gelatin-encapsulated oil. Similarly, the bioaccessibility of minor compounds (tocopherols, sterols and thymoquinone) was not influenced by the shell materials. However, regarding lipid oxidation, a 20- and 10-fold rise of free oxylipins was obtained in oils encapsulated by starch and gelatin, respectively, after intestinal in vitro digestion. This study evidenced that gelatin rather than starch should be used for the encapsulation of oils to minimize the digestion-induced formation of bioactive oxylipins.

Absorption, Pharmacokinetics, Tissue Distribution, and Excretion Profiles of Sea Cucumber-Derived Sulfated Sterols in Mice

Sea cucumber-derived sulfated sterols exhibited more significant bioactivities compared to plant sterols due to the distinctive structure of the sulfate group at the C-3 position; however, their absorption, pharmacokinetics, tissue distribution, and excretion profiles are unknown, which limits the analysis of molecular mechanisms related to their unique activities. In this study, the absorption characteristics of sea cucumber sterols were determined by oral gavage administration, and their pharmacokinetics, excretion, and tissue distribution were studied by tail vein injection. The results showed that SS1 and SS2 reached the peak at 3 h (20.14 ± 1.2 μg/mL) and 4 h (13.32 ± 0.9 μg/mL) in serum, respectively, after oral gavage administration, suggesting the faster absorption rate of SS1 than SS2 due to the difference in the side-chain groups. Besides, lipid-containing food media improved the digestion and absorption rates of sea cucumber sterols. Moreover, SS1 exhibited a relatively longer duration of efficacy than SS2, and they were almost completely excreted within 9 h through urine. Additionally, sea cucumber sterols were found to be mainly accumulated in the liver (P < 0.05), followed by the kidney and spleen. These findings might provide a theoretical basis for the research and development of functional foods and nutraceuticals associated with sea cucumber sterols.

Insights into an α-Glucosidase Inhibitory Profile of 4,4-Dimethylsterols by Multispectral Techniques and Molecular Docking

Inhibition of α-glucosidase activity is closely related to the treatment of type 2 diabetes. However, the potential mechanism by which 4,4-dimethylsterols inhibit α-glucosidase has not been elucidated. In this work, the inhibitory activity and mechanism of 4,4-dimethylsterols against α-glucosidase were studied through kinetic analysis, fluorescence spectroscopy, ultraviolet spectroscopy, circular dichroism, and molecular docking. 4,4-Dimethylsterols showed higher inhibition activity against α-glucosidase than acarbose with an IC₅₀ value of 0.71 mg/mL and a noncompetitive inhibition type. They could bind to α-glucosidase through van der Waals forces and hydrogen bonds and quench its endofluorescence with a static quenching mechanism. Changes in the secondary structure of α-glucosidase were induced by its binding interaction with 4,4-dimethylsterols. Molecular docking further indicated that a hydrogen bond was generated between OH at the C-3 position of 4,4-dimethylsterols and the α-glucosidase residue Arg-442. This study provides new insights into the potential utilization of 4,4-dimethylsterols as antidiabetic phytochemicals in dietary supplements.

Phytosterols: Potential Metabolic Modulators in Neurodegenerative Diseases

Phytosterols constitute a class of natural products that are an important component of diet and have vast applications in foods, cosmetics, and herbal medicines. With many and diverse isolated structures in nature, they exhibit a broad range of biological and pharmacological activities. Among over 200 types of phytosterols, stigmasterol and β-sitosterol were ubiquitous in many plant species, exhibiting important aspects of activities related to neurodegenerative diseases. Hence, this mini-review presented an overview of the reported studies on selected phytosterols related to neurodegenerative diseases. It covered the major phytosterols based on biosynthetic considerations, including other phytosterols with significant in vitro and in vivo biological activities.

Differentiated 4,4-dimethylsterols from vegetable oils reduce fat deposition depending on the NHR-49/SCD pathway in Caenorhabditis elegans

Consumption of 4-desmethylsterols has been claimed to have many beneficial effects, but the benefits of 4,4-dimethylsterols are less appreciated. We utilized a nematode model, Caenorhabditis elegans (C. elegans), to explore the anti-obesity effects of different classes of 4,4-dimethylsterols purified from rice bran oil (RST) and shea nut butter (SST). Both SST and RST significantly reduced fat deposition in C. elegans with smaller sizes and numbers of lipid droplets. But the food intake was not significantly affected. Metabolomics analysis indicated a significantly altered pathway after treatment with 4,4-dimethylsterols. Finally, it was found that 4,4-dimethylsterols targeted stearoyl-CoA desaturases (SCD) and nuclear hormone receptor-49 (NHR-49), resulting in a reduced desaturation index as proved by a lower ratio of oleic acid (C18:1n-9) to stearic acid (C18:0). Overall, 4,4-dimethylsterols can inhibit fat deposition via regulating the NHR-49/SCD pathway in C. elegans.

Bioactive Compounds of Raspberry Oil Emulsions Induced Oxidative Stress via Stimulating the Accumulation of Reactive Oxygen Species and NO in Cancer Cells

There are growing interests in the complex combinations of natural compounds that may advance the therapy of cancer. Such combinations already exist in foods, and a good representative is seed oils. Two raspberry oils: cold pressed (ROCOP) and one extracted by supercritical CO₂ (ROSCO2) were evaluated for their chemical characteristics and oil emulsions for cell suppression potential against colon adenocarcinoma (LoVo), doxorubicin-resistant colon adenocarcinoma (LoVo/DX), breast cancer (MCF7), doxorubicin-resistant breast cancer (MCF7/DX), and lung cancer (A549) cell lines. The cytotoxicity was also assessed on normal human dermal fibroblasts (NHDFs). With increasing concentration of raspberry oil emulsions (0.5–10%), increasing inhibition of cancer cell viability and proliferation in all of the lines was observed, with different degrees of potency between cancer types and oil tested. ROSCO2 strongly induced free radical production and DNA strand damage in LoVo and MCF7 cells especially doxorubicin-resistant lines. This suggests that ROSCO2 engages and effectively targets the vulnerabilities of the cancer cell. Generally, both ROSCO2 and ROCOP could be a nontoxic support in therapy of selected human cancers.

Highly efficient synthesis of 4,4-dimethylsterol oleates using acyl chloride method through esterification

In this study, the 4,4-dimethylsterol oleates were efficiently synthesized through esterification of 4,4-dimethylsterols and oleoyl chloride. The impact of reaction parameters on the 4,4-dimethylsterol conversion were investigated. The 4,4-dimethylsterol conversion increased with pyridine dosage, molar ratio of oleoyl chloride to 4,4-dimethylsterols, and temperature. The highest conversion of 99.27% was obtained with molar ratio of 1.1:1 at 313 K for 60 min. A second-order kinetic model describing acyl chloride esterification featuring high correlation coefficients was established. Arrhenius-Van't Hoff plot suggested activation energy and pre-exponential factor were 15.54 kJ mol^-1 and 1.78 × 10³ L mol^-1 min^-1, respectively. The molecular structure of 4,4-dimethylsterol oleates were finally identified by attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR), ultra-performance liquid chromatography system coupled with quadrupole time of flight mass spectrometry (UPLC-Q-TOF-MS), and nuclear magnetic resonance (NMR).

Characterization of press and solvent extraction oils from new sunflower seeds with modified phytosterol compositions

BACKGROUND

Phytosterols are plant components with health benefits. Oleaginous seed hybridization can be relevant to increase phytosterols in diet through enriched oils. Sunflower oils obtained by press (PO) and subsequent solvent extraction (SO) from three types of phytosterol-enriched seeds were characterized. One presented a phytosterol composition of common sunflower seeds, whereas the other two were rich in campesterol and Δ7-stigmasterol, respectively. Seeds from two different harvests, 2015 and 2017, were studied.

RESULTS

The type of extraction did not have a significant influence on the fatty acid composition. However, considerable differences were found between harvests. The oleic-to-linoleic ratio decreased from 0.71 in 2015 to 0.47 in 2017. The phytosterol compositions of the PO were similar to their SO homologues and no substantial differences were found between harvests. However, the SO presented higher total contents of phytosterols (4849-9249 mg kg^-1 ) than the PO (2839-5284 mg kg^-1 ) and the oils of 2017 showed higher levels (4476-9249 mg kg^-1 ) compared to 2015 (2839-5754 mg kg^-1 ). Unlike phytosterols, no significant differences were found in the tocopherol contents between the PO and SO or between harvests. The PO met Codex specifications for edible oils, except for trace metals, with concentrations close or above the limits for Cu, Fe, Pb and As.

CONCLUSIONS

Differences in environmental and/or cultivation conditions between harvests may result in substantial differences in the fatty acid composition and phytosterol content in oils from the new sunflower seeds. Rigorous measures and controls to avoid trace metal contamination are required so that the PO can be considered as edible virgin oils. © 2020 Society of Chemical Industry.

Characterization and determination of free phytosterols and phytosterol conjugates: The potential phytochemicals to classify different rice bran oil and rice bran

Phytosterols are important beneficial compounds found in rice bran (RB) and rice bran oil (RBO). Although relationships have been confirmed between the forms of phytosterols and their bioactivities, the analysis of different forms of phytosterols in RB and RBO has been lacking. In this study, high temperature gas chromatography-mass spectrometry (HTGC-MS) was combined with the single standard to determine multi-components (SSDMC) method to determine free sterols (FSs) and steryl glycosides (SGs) in RB and RBO. High-performance liquid chromatography (HPLC) was used to determine steryl ferulates (SFs). There was clear variation in the composition of FS, SF and SG, indicating that different forms of phytosterols can discriminate between different RB and RBO. The developed method may be also useful for the detection of other compounds of interest in oils, oil seeds or cereals.

Antidiabetes constituents, cycloartenol and 24-methylenecycloartanol, from Ficus krishnae

Ficus krishnae stem bark and leaves are used for diabetes treatment in traditional medicines. Stem bark of F. krishnae was sequentially extracted with hexane, methanol and water, and these extracts were tested for their antihyperglyceamic activity by oral glucose tolerance test (OGTT) in overnight fasted glucose loaded normal rats. Hexane extract showed significant glucose lowering activity in OGTT, and the triterpene alcohols (cycloartenol+24-methylenecycloartanol) (CA+24-MCA) were isolated together from it by activity guided isolation and characterized by NMR and mass spectroscopy. The ratio of the chemical constituents CA and 24-MCA in (CA+24-MCA) was determined as 2.27:1.00 by chemical derivatization and gas chromatographic quantification. (CA+24-MCA) in high fat diet-streptozotocin induced type II diabetic rats showed significant antidiabetes activity at 1 mg/kg and ameliorated derailed blood glucose and other serum biochemical parameters. Cytoprotective activity of (CA+24-MCA) from glucose toxicity was evaluated in cultured RIN-5F cells by MTT assay and fluorescent microscopy. (CA+24-MCA) in in vitro studies showed enhanced cell viability in RIN-5F cells and significant protection of beta cells from glucose toxicity. Both in in vivo and in vitro studies (CA+24-MCA) showed enhancement in insulin release from the beta cells. In short term toxicity studies in mice (CA+24-MCA) did not show any conspicuous toxic symptoms. The combination of the phytosterols (CA+24-MCA) obtained through activity guided isolation of the stem bark of F. krishnae showed significant activity, and therefore is a promising candidate for new generation antidiabetes drug development.

Study of the In Vitro Digestion of Olive Oil Enriched or Not with Antioxidant Phenolic Compounds. Relationships between Bioaccessibility of Main Components of Different Oils and Their Composition

The changes provoked by in vitro digestion in the lipids of olive oil enriched or not with different phenolic compounds were studied by proton nuclear magnetic resonance (¹H NMR) and solid phase microextraction followed by gas chromatography/mass spectrometry (SPME-GC/MS). These changes were compared with those provoked in the lipids of corn oil and of virgin flaxseed oil submitted to the same digestive conditions. Lipolysis and oxidation were the two reactions under consideration. The bioaccessibility of main and minor components of olive oil, of phenolic compounds added, and of compounds formed as consequence of the oxidation, if any, were matters of attention. Enrichment of olive oil with antioxidant phenolic compounds does not affect the extent of lipolysis, but reduces the oxidation degree to minimum values or avoids it almost entirely. The in vitro bioaccessibility of nutritional and bioactive compounds was greater in the olive oil digestate than in those of other oils, whereas that of compounds formed in oxidation was minimal, if any. Very close quantitative relationships were found between the composition of the oils in main components and their in vitro bioaccessibility. These relationships, some of which have predictive value, can help to design lipid diets for different nutritional purposes.

A Global Study by 1H NMR Spectroscopy and SPME-GC/MS of the in Vitro Digestion of Virgin Flaxseed Oil Enriched or not with Mono-, Di- or Tri-Phenolic Derivatives. Antioxidant Efficiency of These Compounds

The effect of enriching virgin flaxseed oil with dodecyl gallate, hydroxytyrosol acetate or gamma-tocopherol on its in vitro digestion is studied by means of proton nuclear magnetic resonance and solid phase microextraction followed by gas chromatography/mass spectrometry. The extent and pattern of the lipolysis reached in each sample is analyzed, as is the bioaccessibility of the main oil components. None of the phenolic compounds provokes inhibition of the lipase activity and all of them reduce the lipid oxidation degree caused by the in vitro digestion and the bioaccessibility of oxidation compounds. The antioxidant efficiency of the three tested phenols is in line with the number of phenolic groups in its molecule, and is dose-dependent. The concentration of some minor oil components such as terpenes, sesquiterpenes, cycloartenol and 24-methylenecycloartenol is not modified by in vitro digestion. Contrarily, gamma-tocopherol shows very low in vitro bioaccessibility, probably due to its antioxidant behavior, although this increases with enrichment of the phenolic compounds. Oxidation is produced during in vitro digestion even in the presence of a high concentration of gamma-tocopherol, which remains bioaccessible after digestion in the enriched samples of this compound.