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Phytochemistry Jul 2019Diatoms are abundant unicellular marine photosynthetic algae that have genetically diversified their physiology and metabolism while adapting to numerous environments.... (Review)
Review
Diatoms are abundant unicellular marine photosynthetic algae that have genetically diversified their physiology and metabolism while adapting to numerous environments. The metabolic repertoire of diatoms presents opportunities to characterise the biosynthesis and production of new and potentially valuable microalgal compounds, including sterols. Sterols of plant origin, known as phytosterols, have been studied for health benefits including demonstrated cholesterol-lowering properties. In this review we summarise sterol diversity, the unique metabolic features of sterol biosynthesis in diatoms, and prospects for the extraction of diatom phytosterols in comparison to existing sources. We also review biotechnological efforts to manipulate diatom biosynthesis, including culture conditions and avenues for the rational engineering of metabolism and cellular regulation.
Topics: Diatoms; Molecular Structure; Phytosterols
PubMed: 31005802
DOI: 10.1016/j.phytochem.2019.03.018 -
Molecules (Basel, Switzerland) Jan 2022Phytosterols are natural sterols widely found in plants that have a variety of physiological functions, and their role in reducing cholesterol absorption has garnered... (Review)
Review
Phytosterols are natural sterols widely found in plants that have a variety of physiological functions, and their role in reducing cholesterol absorption has garnered much attention. Although the bioavailability of phytosterols is only 0.5-2%, they can still promote cholesterol balance in the body. A mechanism of phytosterols for lowering cholesterol has now been proposed. They not only reduce the uptake of cholesterol in the intestinal lumen and affect its transport, but also regulate the metabolism of cholesterol in the liver. In addition, phytosterols can significantly reduce the plasma concentration of total cholesterol, triglycerides, and low-density lipoprotein cholesterol (LDL-C), with a dose-response relationship. Ingestion of 3 g of phytosterols per day can reach the platform period, and this dose can reduce LDL-C by about 10.7%. On the other hand, phytosterols can also activate the liver X receptor α-CPY7A1 mediated bile acids excretion pathway and accelerate the transformation and metabolism of cholesterol. This article reviews the research progress of phytosterols as a molecular regulator of cholesterol and the mechanism of action for this pharmacological effect.
Topics: Anticholesteremic Agents; Bile Acids and Salts; Cholesterol; Cholesterol, LDL; Humans; Intestinal Absorption; Phytosterols
PubMed: 35056839
DOI: 10.3390/molecules27020523 -
Journal of AOAC International 2015Plant sterols or phytosterols have been shown to be effective in improving blood lipid profile and thereby protective against cardiovascular disease. In addition to... (Review)
Review
Plant sterols or phytosterols have been shown to be effective in improving blood lipid profile and thereby protective against cardiovascular disease. In addition to their cardioprotective effects, phytosterols have gained more insight for their protective effect against various forms of cancer. Phytosterols have been reported to alleviate cancers of breast, prostate, lung, liver, stomach and ovary. Reductions in growth of various cancer cells including liver, prostate and breast by phytosterols treatment have been demonstrated. Although exact mechanisms of phytosterols for their anticancer effects are not very well delineated, there have been several mechanisms proposed such as inhibition of carcinogen production, cancer cell growth and multiplication, invasion and metastasis and induction of cell cycle arrest and apoptosis. Other mechanisms including reduction of angiogenesis, invasion and adhesion of cancer cells and production of reactive oxygen species have also been suggested. However, cancer therapy using phytosterol formulations have yet to be designed, largely due to the gap in the literature with regards to mode of action. Furthermore, most of the studies on anticancer effects of phytosterols were conducted in vitro and animal studies and need to be confirmed in humans.
Topics: Animals; Anticarcinogenic Agents; Breast Neoplasms; Female; Humans; Male; Neoplasms; Phytosterols; Plants; Prostatic Neoplasms
PubMed: 26086253
DOI: 10.5740/jaoacint.SGERamprasath -
Archives of Biochemistry and Biophysics Aug 2020β-Sitosterol (βSito) is the most abundant phytosterol found in elevated concentrations in vegetable oils, nuts, seeds, cereals, fruits, and in many...
β-Sitosterol (βSito) is the most abundant phytosterol found in elevated concentrations in vegetable oils, nuts, seeds, cereals, fruits, and in many phytosterol-enriched foods. Although the benefits, there is a concern in terms of food quality and health due to the increasing consumption of phytosterols and the possible adverse side effects of their oxidation products, oxyphytosterols. βSito has a similar structure to cholesterol, with an unsaturated double bond at C5-C6, which is susceptible to oxidation by reactive oxygen species like ozone, generating oxyphytosterols. In this work we propose a mechanism of formation of three oxyphytosterols 2-[(7aR)-5-[(1R,4S)-4-hydroxy-1-methyl-2-oxocyclohexyl]-1,7a-dimethyl-1,2,3,3a,4,5,6,7- octahydroinden-4-yl] acetaldehyde (βSec), (2-[(7aR)-5-[(2R,5S)-5-hydroxy-2-methyl-7-oxo-oxepan- 2-yl]-1,7a-dimethyl-1,2,3,3a,4,5,6,7-octahydroinden-4- yl] acetaldehyde (βLac) and 2-((7aR)-5-((1R,4S)-4-hydroxy-1-methyl-2- oxocyclohexyl)-1,7a-dimethyloctahydro-1Hinden-4-yl) acetic acid (βCOOH) generated by ozonization of βSito, through their synthesis and molecular characterization. The cytotoxic effect of βSito and its main oxyphytosterol βSec was evaluated and both reduced the HepG2 cell viability.
Topics: Cell Survival; Hep G2 Cells; Humans; Oxidation-Reduction; Ozone; Phytosterols; Reactive Oxygen Species; Sitosterols
PubMed: 32590065
DOI: 10.1016/j.abb.2020.108472 -
Critical Reviews in Food Science and... Jun 2017Phytosterols and phytostanols (PAP) compete with cholesterol absorption in the intestine, resulting in a 5-15%-reduction in plasma total and LDL cholesterol. An... (Review)
Review
Influence of phytosterol and phytostanol food supplementation on plasma liposoluble vitamins and provitamin A carotenoid levels in humans: An updated review of the evidence.
Phytosterols and phytostanols (PAP) compete with cholesterol absorption in the intestine, resulting in a 5-15%-reduction in plasma total and LDL cholesterol. An important issue is the PAP potential to reduce the plasma concentrations of fat-soluble vitamins and provitamin A carotenoids. Here, an update of the scientific evidence is reviewed to evaluate plant PAP-enriched foods impact on plasma fat-soluble vitamins and carotenoid levels, and to discuss potential implications in terms of cardiovascular risk. Based on 49 human interventional and 3 bioavailability studies, results showed that regular consumption, particularly over the long term, of foods fortified with PAP as recommended in labeling does not significantly impact plasma vitamins A, D, and K concentration. A 10% significant median reduction was observed for α-tocopherol. Concerning carotenoids, while 13 studies did not demonstrate statistically significant plasma β-carotene reduction, 20 studies showed significant reductions, with median effect size of -24%. This decline can be mitigated or offset by increased fruits and vegetables consumption. Furthermore, higher cardiovascular risk was observed for differences in plasma β-carotene concentration of the same magnitude as the estimated average decrease by PAP consumption. These results are supported by the only study of β-carotene bioavailability showing decrease in absorption by phytosterols daily intake.
Topics: Carotenoids; Dietary Supplements; Food Analysis; Humans; Phytosterols; Vitamins
PubMed: 26193046
DOI: 10.1080/10408398.2015.1033611 -
Nutrients May 2022Nonalcoholic fatty liver disease is now recognized as the most common cause of chronic liver disease with an increasing prevalence in both adults and children. Although... (Review)
Review
Nonalcoholic fatty liver disease is now recognized as the most common cause of chronic liver disease with an increasing prevalence in both adults and children. Although the symptoms are absent or poorly expressed in most cases, some patients may progress to end-stage liver disease. The pathogenesis of NAFLD is known to be multifactorial. Current therapeutic recommendations focus on lifestyle changes in order to reduce the incidence of risk factors and drugs targeting major molecular pathways potentially involved in the development of this disease. Given that a pharmacological treatment, completely safe and effective, is not currently known in recent years more research has been done on the effects that some bio-active natural compounds, derived from plants, have in preventing the onset and progression of NAFLD. Numerous studies, in animals and humans, have shown that phytosterols (PSs) play an important role in this pathology. Phytosterols are natural products that are found naturally in plant. More than 250 phytosterols have been identified, but the most common in the diet are stigmasterol, β-sitosterol, and campesterol. Consumption of dietary PSs can reduce serum cholesterol levels. Due to these properties, most studies have focused on their action on lipid metabolism and the evolution of NAFLD. PSs may reduce steatosis, cytotoxicity oxidative stress, inflammation, and apoptosis. The purpose of this review is to provide an overview of the importance of dietary phytosterols, which are a window of opportunity in the therapeutic management of NAFLD.
Topics: Animals; Diet; Humans; Lipid Metabolism; Non-alcoholic Fatty Liver Disease; Phytosterols; Stigmasterol
PubMed: 35683987
DOI: 10.3390/nu14112187 -
Food Research International (Ottawa,... Aug 2022The impact of photosensitizer and wavelength on photooxidation of phytosterols (PS) in soymilk and the oxidative stability of lipid and protein was determined. The...
The impact of photosensitizer and wavelength on photooxidation of phytosterols (PS) in soymilk and the oxidative stability of lipid and protein was determined. The oxidation of lipid and the consumption of dissolved oxygen showed a close relationship with PS oxidation. Riboflavin (Rb) leads to extra oxidation of both lipid and protein, and chlorophyll (Chl) prefer to absorb to and change the structure of protein. The influence of Rb and Chl on PS degradation under different wavelengths of light in the range of 365-665 nm was measured. Original soymilk emulsion placed under UVA (365-375 nm) and violet (400-410 nm) light underwent the most PS deterioration, whereas riboflavin was responsible for oxidation around blue (465-475 nm) region and extra formation of 6β-OH sterols, and chlorophyll enriched emulsion was vulnerable under red (645-665 nm) light. The wavelength of light (UVA > violet > blue > green > red > yellow) showed a great different effect in oxidation of PS and formation of phytosterol oxidation products (POPs). The UVA, violet, blue and red light gives rise to the prior five kind oxides of phytosterol: 6α-OH, 7α-OH, 7β-OH, 5,6β-epoxy and 7-keto.
Topics: Chlorophyll; Emulsions; Photosensitizing Agents; Phytosterols; Riboflavin
PubMed: 35840217
DOI: 10.1016/j.foodres.2022.111508 -
Progress in Lipid Research Apr 2015In mammals, the central nervous system (CNS) is the most cholesterol rich organ by weight. Cholesterol metabolism is tightly regulated in the CNS and all cholesterol... (Review)
Review
In mammals, the central nervous system (CNS) is the most cholesterol rich organ by weight. Cholesterol metabolism is tightly regulated in the CNS and all cholesterol available is synthesized in situ. Deficits in cholesterol homeostasis at the level of synthesis, transport, or catabolism result in severe disorders featured by neurological disability. Recent studies indicate that a disturbed cholesterol metabolism is involved in CNS disorders, such as Alzheimer's disease (AD), multiple sclerosis (MS), and amyotrophic lateral sclerosis (ALS). In contrast to circulating cholesterol, dietary plant sterols, can cross the blood-brain barrier and accumulate in the membranes of CNS cells. Plant sterols are well-known for their ability to lower circulating cholesterol levels. The finding that they gain access to the CNS has fueled research focusing on the physiological roles of plant sterols in the healthy and diseased CNS. To date, both beneficial and detrimental effects of plant sterols on CNS disorders are defined. In this review, we discuss recent findings regarding the impact of plant sterols on homeostatic and pathogenic processes in the CNS, and elaborate on the therapeutic potential of plant sterols in CNS disorders.
Topics: Animals; Central Nervous System Diseases; Humans; Multiple Sclerosis; Phytosterols
PubMed: 25623279
DOI: 10.1016/j.plipres.2015.01.003 -
Steroids Aug 2022Insects cannot synthesize sterols, such as cholesterol, and require sterols in their diet. Phytophagous insects use dietary phytosterols as a source of cholesterol....
Insects cannot synthesize sterols, such as cholesterol, and require sterols in their diet. Phytophagous insects use dietary phytosterols as a source of cholesterol. Sterols are transported from the midgut by the insect lipoprotein, lipophorin (Lp), although mechanisms for uptake of phytosterols into tissues are unclear. This study characterizes Scavenger Receptor class B type1 (SR-B1) from Bombyx mori (BmSR-B1) as molecules related to phytosterol uptake. According to sterol quantification using LC-MS/MS analysis, the midgut and fat body were phytosterol-rich relative to cholesterol-rich brain and prothoracic glands. Gene expression analysis of Bmsr-b1 in silkworm tissues showed that the genes Bmsr-b1_2, 3, 4, 6, and 10 were expressed in the midgut and fat body. To characterize the function of BmSR-B1, 11 BmSR-B1 homologs expressed in Bombyx ovary-derived BmN cells and Drosophila melanogaster embryo-derived Schneider 2 (S2) cells were incubated with purified Lp. Our analysis showed that BmSR-B1_3 induced the accumulation of campesterol and BmSR-B1_4 induced the accumulation of β-sitosterol and campesterol in culture cells. BmSR-B1 incorporated specific phytosterols into insect cells by selective uptake across the cell membrane where BmSR-B1 was localized. In conclusion, our study demonstrated that one function of BmSR-B1 is the uptake of phytosterols into silkworm tissues.
Topics: Animals; Bombyx; Cholesterol; Chromatography, Liquid; Drosophila melanogaster; Female; Phytosterols; Sterols; Tandem Mass Spectrometry
PubMed: 35588900
DOI: 10.1016/j.steroids.2022.109039 -
Applied and Environmental Microbiology Jul 2020Androst-4-ene-3,17-dione (AD) and androst-1,4-diene-3,17-dione (ADD) are valuable steroid pharmaceutical intermediates obtained by soybean phytosterol biotransformation...
Androst-4-ene-3,17-dione (AD) and androst-1,4-diene-3,17-dione (ADD) are valuable steroid pharmaceutical intermediates obtained by soybean phytosterol biotransformation by Cyclodextrins (CDs) are generally believed to be carriers for phytosterol delivery and can improve the production of AD and ADD due to their effects on steroid solubilization and alteration in cell wall permeability for steroids. To better understand the mechanisms of CD promotion, we performed proteomic quantification of the effects of hydroxypropyl-β-CD (HP-β-CD) on phytosterol metabolism in TCCC 11978 C2. Perturbations are observed in steroid catabolism and glucose metabolism by adding HP-β-CD in a phytosterol bioconversion system. AD and ADD, as metabolic products of phytosterol, are toxic to cells, with inhibited cell growth and biocatalytic activity. Treatment of mycobacteria with HP-β-CD relieves the inhibitory effect of AD(D) on the electron transfer chain and cell growth. These results demonstrate the positive relationship between HP-β-CD and phytosterol metabolism and give insight into the complex functions of CDs as mediators of the regulation of sterol metabolism. Phytosterols from soybean are low-cost by-products of soybean oil production and, owing to their good bioavailability in mycobacteria, are preferred as the substrates for steroid drug production via biotransformation by However, the low level of production of steroid hormone drugs due to the low aqueous solubility (below 0.1 mmol/liter) of phytosterols limits the commercial use of sterol-transformed strains. To improve the bioconversion of steroids, cyclodextrins (CDs) are generally used as an effective carrier for the delivery of hydrophobic steroids to the bacterium. CDs improve the biotransformation of steroids due to their effects on steroid solubilization and alterations in cell wall permeability for steroids. However, studies have rarely reported the effects of CDs on cell metabolic pathways related to sterols. In this study, the effects of hydroxypropyl-β-CD (HP-β-CD) on the expression of enzymes related to steroid catabolic pathways in were systematically investigated. These findings will improve our understanding of the complex functions of CDs in the regulation of sterol metabolism and guide the application of CDs to sterol production.
Topics: 2-Hydroxypropyl-beta-cyclodextrin; Bacterial Proteins; Excipients; Mycobacteriaceae; Phytosterols; Proteomics
PubMed: 32414803
DOI: 10.1128/AEM.00441-20