Phytosterol Composition Research Articles

Effects of Enzymatic Pretreatment of Seeds on the Physicochemical Properties, Bioactive Compounds, and Antioxidant Activity of Pomegranate Seed Oil.

Enzymatic pretreatment of seeds is a novel approach that enhances the health benefits of the extracted oil. The study investigated the influence of the enzymatic pretreatment of seeds on the quality of oil from different pomegranate cultivars. The quality of the ultrasound-assisted (and ethanol-extracted) oil was studied, with respect to the refractive index (RI), yellowness index (YI), conjugated dienes (K232), peroxide value (PV) ρ-anisidine value (AV), total oxidation value (TOTOX), total carotenoid content (TCC), total phenolic compounds (TPC), fatty acid composition, phytosterol composition, ferric reducing antioxidant power (FRAP), and 2.2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging capacity. The seeds of three different pomegranate cultivars (‘Wonderful’, ‘Herskawitz’, and ‘Acco’) were digested with an equal mixture of Pectinex Ultra SPL, Flavourzyme 100 L, and cellulase crude enzymes, at a concentration, pH, temperature, and time of 1.7%, 4.5, 40 °C, and 5 h, respectively. Enzymatic pretreatment of PS increased oil yield, PV, TPC, TCC, and DPPH radical scavenging capacity, but decreased the YI. The levels of K232, AV and TOTOX, fatty acids, phytosterols, RI, and FRAP, were not significantly affected by enzymatic pretreatment of PS. Principal component analysis (PCA) established that oil extracted from the ‘Acco’ seed after enzymatic pretreatment had higher yield, TPC, TCC, and DPPH radical scavenging capacity. Therefore, enzyme-pretreated ‘Acco’ pomegranate fruit seed is a source of quality seed oil with excellent antioxidant properties.

The dehiscence process in Panax ginseng seeds and the stigmasterol biosynthesis pathway in terms of metabolomics

BackgroundGinseng, officially known as Panax ginseng Meyer, has been traditionally used as a medicinal herb, particularly in Asia. Ginseng is propagated from seeds; however, seed germination is challenging, especially in its natural environment on farms. The seeds typically exhibit morphophysiological dormancy and require release from both morphological and physiological dormancy before germination. Although some studies have proposed methods for increasing seed germination rates, the underlying mechanisms of its dormancy release process remain unclear. Here, we investigated metabolic alterations during dehiscence in P. ginseng to determine their potential roles in dormancy release. MethodsWe compared the ginseng seed metabolome before and after dehiscence and the ginsenoside and phytosterol compositions of the seeds in both periods in the presence of related enzymes. ResultsAfter seed dehiscence, the sugar, amino acid, and squalene concentrations were significantly altered, phytosterols associated with the stigmasterol biosynthesis pathway were increased, while ginsenoside and brassinosteroid levels were not significantly altered. In addition, squalene epoxidase, cycloartenol synthase, 24-methylenesterol C-methyltransferase, and the stigmasterol biosynthesis pathway were activated. ConclusionOverall, our findings suggest that morphological activities that facilitate ginseng seed growth are the primary phenomena occurring during the dehiscence process. This study improves the understanding of P. ginseng germination processes and promotes further research of its germination and cultivation.

Supplementation of durum wheat spaghetti with wheat bran protein concentrate: Impacts on phytochemical profile and starch digestion

AbstractBackground and objectivesWheat bran is commonly used in pasta products and is an excellent source of phytochemicals, but it creates various processing and consumer acceptability issues. Proteins extracted from bran (WBPC) have potential to improve the protein content and protein quality of pasta, but their contribution to the phytochemical content of pasta is unknown.FindingsIn this study, WBPC was added to a spaghetti formulae at 0, 1%, 5%, 10%, and 20% (w/w). The dried uncooked spaghetti were characterized for quali‐quantitative composition of phytosterols and phenolic acids. Also, both the uncooked and cooked samples were evaluated for total soluble phenolics (TSP) and antioxidant activity (AO). Results showed that pasta with 20%WBPC increased total phytosterol content (~55%), and phenolic acids content (~57%), with ferulic acid being the main component. Cooked spaghetti had reduced TSP and AO compared to the uncooked. However, cooked 20%WBPC spaghetti had significantly higher contents of both TSP (~37%) and AO (~93%) compared to 100% durum semolina spaghetti. The in vitro starch digestion of pasta was not affected by WBPC at these levels.ConclusionSpaghetti enriched with WBPC has improved phytochemical content without negative changes on pasta in vitro starch digestion.Significance and noveltyWBPC is a suitable ingredient to enhance the phytochemical content of regular spaghetti with potential health benefits.

Phytosterols: From Preclinical Evidence to Potential Clinical Applications.

Phytosterols (PSs) are plant-originated steroids. Over 250 PSs have been isolated, and each plant species contains a characteristic phytosterol composition. A wide number of studies have reported remarkable pharmacological effects of PSs, acting as chemopreventive, anti-inflammatory, antioxidant, antidiabetic, and antiatherosclerotic agents. However, PS bioavailability is a key issue, as it can be influenced by several factors (type, source, processing, preparation, delivery method, food matrix, dose, time of administration into the body, and genetic factors), and the existence of a close relationship between their chemical structures (e.g., saturation degree and side-chain length) and low absorption rates has been stated. In this sense, the present review intends to provide in-depth data on PS therapeutic potential for human health, also emphasizing their preclinical effects and bioavailability-related issues.

The dopaminergic neuroprotective effects of different phytosterols identified in rice bran and rice bran oil.

Phytosterols are important bioactive compounds in rice bran and rice bran oil, and the compositions of different phytosterols in rice bran and rice bran oil were investigated in our previous research. In this study, the dopaminergic neuroprotective effects and the underlying mechanisms of sitosterol, cycloartenyl ferulate, 24-methylenecycloartanyl ferulate and campesteryl ferulate identified in rice bran and rice bran oil were investigated in a rotenone-treated C. elegans model. The results indicated that the increased oxidative stress resistance induced by the activation of the DAF-16/FOXO pathway and the inhibition of the apoptotic protein CED-3 overexpression might play an important role in protecting the dopaminergic neurons. The results of this research reveal a new bioactivity of different phytosterols and are helpful for the further nutritional evaluation of rice bran and rice bran oil.

Thermo-Oxidation of Phytosterol Molecules in Rapeseed Oil during Heating: The Impact of Unsaturation Level of the Oil.

Phytosterols are naturally occurring substances in foods of plant origin that have positive effects on the human body. Their consumption can reduce the level of low density lipoprotein (LDL) cholesterol. The presence of unsaturated bonds in their structure leads to their oxidation during production, storage, and thermal processes. The aim of the study was to determine how the degree of unsaturation of rapeseed oil affects the oxidation of phytosterols in oil during 48 h of heating. In all not-heated oils, the dominant groups of oxyphytosterols were 7α- and 7β-hydroxy sterols. During 48 h of heating, the rapid decrease of phytosterols’ levels and the increase of the content of oxyphytosterols were observed. The main dominant group in heated samples was hydroxy and epoxy sterols. Despite differences in fatty acid composition and content and composition of single phytosterols in unheated oils samples, the total content of oxyphytosterols after finishing of heating was on a similar level for each of the tested oils. This showed that the fatty acid composition of oil is not the only factor that affects the oxidation of phytosterols in foods during heating.

Inga laurina crude extract to control Aedes aegypti

Aedes aegypti is the um mosquito responsible for the transmission of several diseases to humans such as dengue, chikungunya, Zika virus and urban yellow fever. The control of this culicid is done by utilizing insecticides that cause insect resistance. Therefore, natural alternatives to control A. aegypti have been sought. Thus, the objective of our work was to characterize the chemical composition of the crude extract of the leaves of Inga laurina and to evaluate the insecticidal activity of the extract on the larvae of A. aegypti. The crude extract was prepared form dry leaves by dynamic maceration using alcohol 96º GL as extracting solvent. The chemical identification of the compounds found in the crude extract was done by a gas chromatography coupled to mass spectrometry. The larvicidal activity was determined by larval packet test in third-stage development larvae A. aegypti. Fifteen compounds were identified in the leaves and the major ones were γ- sitosterol (34.39%), phytol (14.51%), squalene (8.57%) and stigmasterol (7.38%). I. laurina leaf crude extract presented larvicidal activity potential against A. aegypti larvae presenting lethal concentration of 50% (CL50) of 0.98 mg/mL and 99% (CL99) of 2.69 mg/mL. Thus, I. laurina leaf crude extract presented rich composition of phytosterols and promising insecticide activity against A. aegypti larvae, offering new possibilities for the application and development of products.

Analysis of biochemical composition and antioxidant properties of nuts sold in the consumer marke

The results of studies of the biochemical composition and antioxidant properties of nuts sold in the consumer market of St. Petersburg were presented in the work. The objects of research were kernels of nuts: sweet almonds, hazelnuts, cashews, walnuts. Total Soxhlet lipids, fatty acid composition, vitamin E, fractional composition of tocopherols and phytosterols, total phenolic compounds and flavonoids, antioxidant activity by FRAP with ferric chloride, o-phenanthroline and Triton X 100 were determined in nuts. Nuts varied in lipid content (42.6–65.4%) with a predominance of unsaturated fatty acids from 80.4 to 92.4 relative%. Oleic acid prevailed in the fatty acids of almonds, hazelnuts and cashews, while linoleic acid prevailed in walnuts. Walnuts contained the highest amount of polyunsaturated fatty acids. The antioxidant properties of nuts were formed by a complex of water and fat-soluble antioxidants. Fat-soluble antioxidants included vitamin E with a predominance of ?-tocopherol in the kernels of sweet almonds and hazelnuts, ?-tocopherol - in walnuts and cashews. Only sweet almond kernels contained all the tocopherol fractions. ?- and ?-tocopherols were absent in hazelnut lipids, while ?-tocopherols were absent in cashews and walnuts. ?-sitosterol, campesterol and stigmasterol with a predominance of ?-sitosterol were identified in the composition of phytosterols in all nut kernels. Water-soluble antioxidants are mainly represented by phenolic compounds, the amount of which varies widely depending on the type of nuts: cashews

Effect of Microwave Pretreatment of Seeds on the Quality and Antioxidant Capacity of Pomegranate Seed Oil.

Microwave pretreatment of oilseeds is a novel technique used to enhance oil nutraceutical properties. In this study, the effect of microwave pretreatment of seeds was investigated on pomegranate seed oil quality attributes including oil yield, yellowness index, refractive index, peroxide value, ρ-anisidine value, total oxidation value, conjugated dienes, total phenolic content, total carotenoids content, phytosterol composition, fatty acid composition, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, and ferric reducing antioxidant power (FRAP). The seeds of three different pomegranate cultivars (‘Acco’, ‘Herskawitz’, and ‘Wonderful’) were microwave heated at 261 W for 102 s. Pomegranate seeds microwave pretreatment enhanced oil yield, yellowness index, total carotenoids content, total phenolic content, FRAP and DPPH radical scavenging capacity, despite an increase in conjugated dienes, and peroxide value. Palmitic acid, oleic acid, linoleic acid, saturated, and monosaturated fatty acids were increased after pomegranate seeds microwave pretreatment, whilst the levels of punicic acid and β-sitosterol were reduced. Nevertheless, the refractive index, the ratio of unsaturated to saturated fatty acid of the extracted oil were not significantly (p > 0.05) affected by pomegranate seeds microwave pretreatment. Principal component analysis and agglomerative hierarchical clustering established that ‘Acco’ and ‘Wonderful’ oil extracts from microwave pretreated PS exhibited better oil yield, whilst ‘Herskawitz’ oil extracts showed higher total carotenoids content, total phenolic content, and antioxidant capacity.

Effect of cultivar and blanching of pomegranate seeds on physicochemical properties, nutritional qualities and antioxidant capacity of extracted oil

This study investigated the effect of cultivar and blanching of pomegranate seeds (PS) on quality attributes of the extracted oil. The quality attributes studied included oil yield, refractive index (RI), yellowness index (YI), conjugated dienes (K232), peroxide value (PV), ρ-anisidine value (AV), total oxidation value (TOTOX), total carotenoids content (TCC), total phenolic content (TPC), fatty acid composition, phytosterol composition, ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity. Three different cultivars of PS (‘Wonderful’, ‘Herskawitz’ and ‘Acco’) were blanched at 95 °C for 3 min. In each experiment, unblanched PS were used as the control. Blanching of PS improved oil yield, YI and DPPH radical scavenging capacity, while it decreased TCC, FRAP and TOTOX. The effect of blanching PS varied among the individual fatty acids and phytosterols. Interestingly, blanching of PS increased punicic acid content and the ratio of unsaturated to saturated fatty acid (UFA: SFA). The K232, RI and TPC of the oil extracts were not significantly (p > 0.05) affected by blanching. TPC was strongly correlated (r = 0.876) with FRAP. Principal component analysis established that ‘Wonderful’ and ‘Acco’ oil extracts from blanched PS were associated with oil yield, YI and β-sitosterol, whereas ‘Herskawitz’ oil extracts from blanched PS were correlated with punicic acid, FRAP and DPPH radical scavenging capacity. In conclusion, blanching ‘Wonderful’ and ‘Acco’ PS may improve oil yield, β-sitosterol content and colour, whilst blanching ‘Herskawitz’ PS may enhance the antioxidant capacity of extracted oil, which is beneficial in the cosmetic, nutraceutical, pharmaceutical and food industries.

Colony-level pesticide exposure affects honey bee (Apis mellifera L.) royal jelly production and nutritional composition

Honey bees provision glandular secretions in the form of royal jelly as larval nourishment to developing queens. Exposure to chemicals and nutritional conditions can influence queen development and thus impact colony fitness. Previous research reports that royal jelly remains pesticide-free during colony-level exposure and that chemical residues are buffered by the nurse bees. However, the impacts of pesticides can also manifest in quality and quantity of royal jelly produced by nurse bees. Here, we tested how colony exposure to a multi-pesticide pollen treatment influences the amount of royal jelly provisioned per queen and the additional impacts on royal jelly nutritional quality. We observed differences in the metabolome, proteome, and phytosterol compositions of royal jelly synthesized by nurse bees from multi-pesticide exposed colonies, including significant reductions of key nutrients such as 24-methylenecholesterol, major royal jelly proteins, and 10-hydroxy-2-decenoic acid. Additionally, quantity of royal jelly provisioned per queen was lower in colonies exposed to pesticides, but this effect was colony-dependent. Pesticide treatment had a greater impact on royal jelly nutritional composition than the weight of royal jelly provisioned per queen cell. These novel findings highlight the indirect effects of pesticide exposure on queen developmental nutrition and allude to social consequences of nurse bee glandular degeneration.

Fatty Acids, Tocopherols, and Phytosterol Composition of Seed Oil and Phenolic Compounds and Antioxidant Activity of Fresh Seeds from Three Dalbergia Species Grown in Vietnam

This research aimed to investigate the chemical composition of seed oils extracted from three Vietnamese Dalbergia species (D. tonkinensis, D. mammosa, and D. entadoides). The fatty acid profiles and contents of tocopherols and sterols of the seed oils, and total phenolic compounds extracted from the fresh seeds were characterized using different methods. Among the examined samples, D. tonkinensis seed oils showed high contents of linoleic acid (64.7%), whereas in D. mammosa, oleic acid (51.2%) was predominant. In addition, α- and γ-tocopherol and β-sitosterol were major ingredients in the seed oils, whereas ferulic acid and rosmarinic acid are usually predominant in the seeds of these species. Regarding sterol composition, the D. entadoides seed oil figured for remarkably high content of Δ5,23-stigmastadienol (1735 mg/kg) and Δ7-stigmastenol (1298 mg/kg). In addition, extracts with methanol/water (80:20, v/v) of seeds displayed significant in vitro antioxidant activity which was determined by DPPH free radical scavenging assay.

Physicochemical and biochemical characterizations of some Tunisian seed oils

Four Tunisian vegetable oils extracted from seeds (Nigella sativa,Opuntia ficus indica,Pistacia lentiscusandHibiscus sabdariffa) have been characterized in this study. The following parameters were determined: acidity, peroxide value, saponification value, specific extinction coefficients K232, K270, chlorophylls and carotenoids content. The triglyceride and tocopherol compositions of the oils were determined using reversed phase high performance liquid chromatography with diode array detection (HPLC-DAD) and the fatty acids (FA) and phytosterol compositions were determined using a gas chromatography (GC) with a flame ionization detector (FID). Polyunsaturated fatty acids were predominant in all tested samples except inPistacia lentiscusoil where monounsaturated fatty acids were predominant. Major FA were linoleic and oleic acids. β-sitosterol was the most abundant phytosterol. All samples had high content of TAGs with an equivalent carbon number of 44, 46 and 48.Nigella sativaoil had the highest content of tocopherols.

Phytosterol compositions of enriched products influence their cholesterol-lowering efficacy: a meta-analysis of randomized controlled trials.

The composition of phytosterol (PS) formulations used to enrich food and supplements are typically different due to varying natural sources. Sitosterol and it's hydrogenated form: sitostanol are the major PSs in most of these formulations. This review aimed to investigate whether the proportion of sitosterol plus sitostanol in a PS formulation is a determinant of the hypocholesterolaemic effect of PS products. If the amount of sitosterol plus sitostanol in a PS composition is ≥80%, the product is considered to be high in sitosterol plus sitostanol, otherwise the product is considered to be low in sitosterol plus sitostanol. We conducted a meta-analysis on the cholesterol-lowering potential of PS products that were high or low in sitosterol plus sitostanol. Databases including PubMed, EMBASE, and Cochrane Library were searched, and published RCTs investigating the efficacy of dietary PSs intervention (≥1.5 g/d) on blood lipid profile improvement were selected. After strict screening and quality assessment, a total of 51 RCTs were included. As expected, PSs with all compositions significantly reduced LDL-C (p < 0.00001), while the LDL-C lowering effect associated with the high sitosterol plus sitostanol group was significantly greater than that of the low sitosterol plus sitostanol group (p = 0.002). PSs also significantly reduced TG (p = 0.009) without affecting HDL-C. Thus, the composition might affect the hypocholesterolaemic effect of PS products. PS products with higher sitosterol plus sitostanol proportions might have superior cholesterol-lowering potential than those with lower sitosterol plus sitostanol proportions.

Phytosterol Contents of Edible Oils and Their Contributions to Estimated Phytosterol Intake in the Chinese Diet.

Phytosterols are important micronutrients in human diets. Evidence has shown that phytosterols play an essential role in the reduction of cholesterol in blood and therefore decrease cardiovascular morbidity. In this study, the content and composition of phytosterols in different kinds of vegetable oils were analyzed, and the total phytosterol intake and contribution of foods to intake were estimated based on consumption data. The results showed that the phytosterol contents of rice bran oil, corn oil, and rapeseed oil were higher than those of other vegetable oils and the intake of phytosterol in the Chinese diet was about 392.3 mg/day. The main sources of phytosterols were edible vegetable oils (46.3%), followed by cereals (38.9%), vegetables (9.2%), nuts (2.0%), fruits (1.5%), beans and bean products (1.4%), and tubers (0.8%). Among all vegetable oils, rapeseed oil was the main individual contributor to phytosterol intake (22.9%), especially for the southern residents of China.

Oil Phytosterol Concentration in Sunflower Presents a Dilution Response with Oil Weight per Grain

AbstractPhytosterols are plant sterols that present several benefits for human health. In crop species, such as sunflower, oil phytosterol concentration shows genetic and environmental variations. The reasons that cause such varied concentration of phytosterols in the oil are unknown. The aim of this work was to investigate the relationships between phytosterol concentration and composition and grain oil content in sunflower. Two sets of samples, with lines and hybrids grown in different environments in Argentina and Spain, were used to establish and validate the relationships between phytosterols and grain oil content. Oil phytosterol concentration decreased in both types of genotypes, lines, and hybrids, when oil content per grain increased. A dilution‐like relationship accounted for 82% of the variability in phytosterol concentration among genotypes and environments. Phytosterol concentration rapidly increased with oil contents lower than 11.4 mg per grain. This relationship was observed for total phytosterols and each type of the phytosterols analyzed. With low oil per grain, phytosterol composition varied, with higher proportions of β‐sitosterol and Δ7‐stigmastenol. The relationships established in this work could serve to design breeding and crop management strategies.

Effect of Sowing Dates on Fatty Acids and Phytosterols Patterns of Carthamus tinctorius L.

Field experiments were carried out at the Regional Centre of Experimentation in Organic agriculture at Auch (near Toulouse, South west of France). Due to the high potential applications for its oil components such as fatty acids and phytosterols, safflower (Carthamus tinctorius L.) is considered as an emerging crop. Safflower plants, as many other oil crops, are submitted to environmental stresses that modify seed composition. Nevertheless, few reports are available about the effects of environmental conditions on fatty acid and phytosterol compositions in safflower. Different rainfall supplies can be managed by delaying the sowing dates. In this study, fatty acid and phytosterol contents have been evaluated in safflower seeds cultivated at two sowing dates (conventional and late) that led to a differential of rainfall during seed development. At harvest, seeds were used for oil extraction. Fatty acid composition was performed by using GC-FID. A set of seeds was dehulled to separate the almond (embryo) and hull to release the extraction and measurement of sterol contents in the two compartments by GC-FID. A delay of sowing increased the content of all sterol categories but induced a significant decrease in fatty acids. The ratio of saturated to unsaturated fatty acids increased under a delaying sowing. The repartition of phytosterols was ¾ and ¼ of total sterols in the embryo and the hull, respectively. These results could make the use of hull (considered as waste) possible, help breeders to improve safflower oil composition and develop new industrial applications.

Phytosterols in Salvia Seeds: Content and Composition and Correlation with Environmental Parameters

The purpose of this study was to determine the oil yield, content and composition of phytosterols in the seeds of six wild-grown Salvia species from Iran, including S. ceratophylla L. (3 populations), S. nemorosa L. (6 populations), S. reuteriana Boiss. (6 populations), S. spinosa L. (5 populations), S. verticillata L. (3 populations) and S. virgata Jacq. (3 populations). We also evaluated the effects of some environmental parameters on their chemical variations and characterized the investigated populations based on the sterol chemo-types. The results showed that seed oil yields ranged between 16.51 and 42.48%, with an average of 28.93%. The total sterol contents in Salvia seeds varied significantly and ranged from 145.13 to 386.75 mg 100g oil −1 . β-Sitosterol, campesterol and stigmasterol were the main sterol constituents in all of the Salvia seed oils, with the average values of 60.13%, 27.32% and 12.55% of the total sterols, respectively. Among all the tested species, the highest level of total phytosterol and β-sitosterol contents was obtained for the seeds of S. ceratophylla. Moreover, the percentages of these compounds varied depending on climatic factors such as precipitation, humidity and temperature. The cluster analysis based on the β-sitosterol/campesterol ratio contents of the seeds categorized different populations of Salvia species into three distinct campesterol, β-sitosterol and β-sitosterol-rich chemo-types.

Bioactive properties and antioxidant capacity of oils extracted from citrus fruit seeds

This study aimed at identifying the presence of bioactive compounds and evaluating the antioxidant capacity of oils extracted from citron, kinkan, and orange. Therefore, determination of fatty acid profile, tocopherol and phytosterol composition, phenolic compounds, and total carotenoids was performed in the oils extracted from seeds. To determine the antioxidant capacity, the tests DPPH˙, ABTS˙+, FRAP, β-carotene/linoleic acid, and oxidative stability were performed. The citrus fruit seeds presented high lipid level, with predominance of unsaturated fatty acids, especially linolenic essential fatty acid, with 7.9 and 8.5% in citron and kinkan seed oils, respectively. The presence of tocopherols and phytosterols induced a higher antioxidant capacity on the oils analysed. The collected information might help new alternative sources of vegetable oils obtained from agroindustrial waste to serve as raw material for food, chemical, and pharmaceutical industries.

Modification of phytosterol composition influences cotton fiber cell elongation and secondary cell wall deposition

BackgroundCotton fiber is a single cell that arises from the epidermis of ovule. It is not only a main economic product of cotton, but an ideal material for studying on the growth and development of plant cell. Our previous study indicated that phytosterol content and the ratio of campesterol to sitosterol fluctuated regularly in cotton fiber development. However, what effects of modified phytosterol content and composition on the growth and development of cotton fiber cell is unknown. In this study, we overexpressed the GhSMT2–1, a cotton homologue of sterol C-24 methyltransferase 2 gene in transgenic upland cotton plants to modify phytosterol content and composition in fiber cells and investigated the changes on fiber elongation and secondary cell wall deposition.ResultsGhSMT2–1 overexpression led to changes of phytosterol content and the ratio of campesterol to sitosterol in fiber cell. At the rapid elongation stage of fiber cell, total phytosterol and sitosterol contents were increased while campesterol content was decreased in transgenic fibers when compared to control fibers. Accordingly, the ratio of campesterol to sitosterol declined strikingly. Simultaneously, the transgenic fibers were shorter and thicker than control fibers. Exogenous application of sitosterol or campesterol separately inhibited control fiber cell elongation in cotton ovule culture system in vitro. In addition, campesterol treatment partially rescued transgenic fiber elongation.ConclusionThese results elucidated that modification of phytosterol content and composition influenced fiber cell elongation and secondary cell wall formation. High sitosterol or low ratio of campesterol to sitosterol suppresses fiber elongation and/or promote secondary cell wall deposition. The roles of sitosterol and campesterol were discussed in fiber cell development. There might be a specific ratio of campesterol to sitosterol in different developmental stage of cotton fibers, in which GhSMT2–1 play an important role. Our study, at a certain degree, provides novel insights into the regulatory mechanisms of fiber cell development.