Processing stability of squalene in amaranth and antioxidant potential of amaranth extract

Amaranthus crop for food security and sustainable food systems

MAIN CONCLUSION

This review ascertains amaranth grains as a potent crop for food security and sustainable food systems by highlighting its agricultural advantages, health benefits and applications in the food, packaging, and brewing industry. The global population surge and rapidly transitioning climatic conditions necessitate the maximization of nutritional crop yield to mitigate malnutrition resulting from food and nutrition insecurity. The modern agricultural practices adopted to maximize the yield of the conventional staple crops are heavily contingent on the depleting natural resources and are contributing extensively to the contamination of these natural resources. Furthermore, these agricultural practices are also causing detrimental effects on the environment like rising emission of greenhouse gasses and increased water footprints. To address these challenges while ensuring sustainable nutrient-rich crop production, it is imperative to utilize underutilized crops like Amaranthus. Amaranth grains are gluten-free pseudo-cereals that are gaining much prominence owing to their abundance in vital nutrients and bio-active components, potential health benefits, resilience to adverse climatic and soil conditions, minimum agricultural input requirements, potential of generating income for small holder farmers as well as various applications across the sustainable value chain. However, due to the limited awareness of these potential benefits of the amaranth grains among the consumers, researchers, and policymakers, they have remained untapped. This review paper enunciates the nutritional composition and potential health benefits of the grains while briefly discussing their various applications in food and beverage industries and accentuating the need to explore further possibilities of valorizing amaranth grains to maximize their utilization along the value chain.

Kinetics of Squalene Quenching Singlet Oxygen and the Thermal Degradation Products Identification

Squalene has been proven to possess various bioactive functions that are widely present in vegetable oils. A more comprehensive understanding of the reaction behavior of squalene under oxidative conditions was achieved by studying its antioxidant capacity and thermal degradation products. The total singlet oxygen quenching rate constant (kr + kq) of squalene was 3.8 × 107 M-1 s-1, and both physical and chemical quenching mechanisms equally contribute to the overall singlet oxygen quenching. Fourteen degradation products of squalene were identified at 180 °C by using gas chromatography-mass spectrometry (GC-MS). Combining with DFT calculations, the thermal degradation pathway of squalene was proposed: the aldehydes, ketones, and alcohols, and epoxy compounds were formed by the homolytic cleavage of squalene hydroperoxides to form alkoxy radicals, followed by β-scission of the alkoxyl radicals at adjacent C-C bonds or intramolecular cyclization.

Effect of Roasting on the Chemical Composition and Oxidative Stability of Tomato (Solanum lycopersicum L.) Seed Oil

In this study, tomato seed (TS) samples were subjected to different roasting conditions (90-170 °C and 10-30 min) to compare their effects on the chemical composition and oxidative stability of tomato seed oil (TSO). Unroasted TS was considered as a control sample. Our results revealed that moderate roasting (130 °C/20 min) can significantly increase the content of linoleic acid (54.01-54.89%), linolenic acid (2.17-2.41%), phytosterols (2789.56-3037.31 mg/kg), squalene (5.06-13.10 mg/kg), total phenols (22.37-22.67 mg GAE/100 g), and other functional components (p < 0.05) in TSO, while the antioxidant activity (via DPPH, ABTS, and FRAP assays) also increased. In addition, the tocopherol content decreased significantly (758.53-729.50 mg/kg). Accelerated oxidation experiments showed that roasting (170 °C/30 min) increased the oxidative stability index (OSI) of TSO from 5.35 to 7.07 h (p < 0.05). Furthermore, roasting gradually increased the content of 5-hydroxymethylfurfural (HMF) (0-1.74 mg/kg), which indicates that the oxidative stability and the degree of the Maillard reaction increased upon roasting. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed that moderate roasting (130 °C/20 min) improved the chemical composition, antioxidant activity, and oxidative stability of TSO. Furthermore, this work provides a useful theoretical basis for the processing and wide application of TSO in the pharmaceutical and food industries.

Genetic regulation and fermentation strategy for squalene production in Schizochytrium sp

Squalene, as an important terpenoid, is extensively used in the medicine and health care fields owing to its functions of anti-oxidation, blood lipid regulation and cancer prevention. The marine microalgae, Schizochytrium sp., which acts as an excellent strain with potential of high squalene production was selected as the starting strain. The overexpressed strain with sqs gene got the reduced biomass and lipid, while the squalene titer was increased by 79.6% ± 4.7% to 12.8 ± 0.2 mg/L. In order to further increase squalene production, the recombinant strain (HS strain) with sqs and hmgr gene co-overexpression was further constructed. The biomass and squalene titer of the HS strain were increased by 13.6% ± 1.2% and 88.8% ± 5.3%, respectively, which indicated the carbon flux of the mevalonate pathway was enhanced for squalene accumulation. Regarding the squalene synthesis is completely coupled with cell growth, fermentation strategy to prolong the logarithmic growth phase was conducive to improve squalene production. Under the condition of optimal composition and concentrated medium, the squalene titer of HS strain was 27.0 ± 1.3 mg/L, which was 2.0 times that of the basal medium condition (13.5 ± 0.4 mg/L). This study which combined the metabolic engineering and fermentation strategy provides a new strategy for squalene production in Schizochytrium sp. KEY POINTS: •The overexpression of sqs and hmgr genes promoted carbon metabolism for squalene. •The optimal and concentrated media can increase squalene yield.

Molecular docking assisted biological functions and phytochemical screening of Amaranthus lividus L. extract

In this study, the phytochemical content of Amaranthus lividus extract and its multi-biological activities were investigated. Total protein, phenol, flavonoid, saponin and condensed tannin contents were determined for phytochemical analysis. In addition, GC-MS and HPLC analyzes were carried out for the determination of the active components of the extract. In determining the multi-biological activities, radical scavenging, anti-mutagenic, anti-proliferative and anti-microbial activities of the extract were investigated. GC-MS analysis revealed that the leaf extract of A. lividus contains phytol and β-sitosterol as major compounds and the presence of gallic acid, caffeic acid, quercetin, vanillin and kaemferol compounds were determined with HPLC analysis. The radical scavenging effect of A. lividus extract was determined as 75.6% against 2,2-diphenyl-1-picrylhydrazyl and 85.2% against superoxide. In anti-bacterial studies, it was determined that A.lividus extract formed different inhibition zones against all tested bacteria. The highest inhibition zone was 14.3 ± 0.7 mm against Bacillus subtilis. In addition, the anti-microbial activity of the extract was demonstrated by molecular docking studies of the binding of gallic acid and phytol to aquaporin and arginase enzyme of bacteria, and the mechanism of anti-microbial activity was explained. A. lividus extract, which provided a 68.59-33.13% reduction in the formation of chromosomal aberrations such as unequal distribution of chromatin, micronucleus formation, fragment, sticky chromosome, bridge and vagrant chromosome, exhibited a strong anti-mutagenic effect. A. lividus extract has a reducing effect on the number of dividing cells and exhibits an anti-proliferative effect of 25.7% compared to the control group. The antiproliferative mechanism of action was investigated by molecular docking and it was determined that the gallic acid and phytol in the extract decreased proliferation by interacting with telomerase. As a result, A.lividus extract consumed as food is a potential natural anti-microbial, anti-oxidant, anti-mutagenic and anti-proliferative source with its rich phytochemical content.

Recycling deteriorated silage to remove hazardous mycotoxins and produce a value-added product

Silage, an important forage feed, contains hazardous mycotoxins due to spoilage caused by unreasonable management. Deteriorated silage becomes a mycotoxin source and threatens human health and the eco-environment. Recycling deteriorated silage and exploiting beneficial substances would be profitable and environmentally friendly. Squalene [60.3-73.9 mg/kg fresh matter (FM)] and 6 types of mycotoxins (4.56-10,080 ug/kg FM) were found in deteriorated silages. To clarify the source and synthesis mechanism of squalene, alfalfa was ensiled at low temperature (LT, 3-20 ℃), 25 ℃ (T25), 30 ℃ (T30) or 35 ℃ (T35) for 10, 40 and 70 d. The highest squalene was detected when alfalfa ensiled for 40 d (P = 0.033) or ensiled at LT and T30 (P < 0.001). Squalene source was traced as lactic acid bacteria (LAB) using next-generation sequencing. Multiple linear regression models inferred that squalene synthase of LAB positively contributed to the squalene synthesis but was negatively adjusted by ammonia-N during ensiling. Two promising squalene-producing LAB strains were screened from alfalfa silage, which fermented deteriorated silage to enhanced squalene yield (190~279 mg/L) with low cost and high mycotoxin removal ratios (up to 85.5%). Therefore, the environmentally friendly strategy of recycling deteriorated silage to produce beneficial squalene was created.

R. vesicarius L. exerts nephroprotective effect against cisplatin-induced oxidative stress

BACKGROUND

Cisplatin is an outstanding anticancer drug, but its use has been decreased remarkably due to sever nephrotoxicity. R. vesicarius L. is a leafy vegetable that is evident with anti-angeogenic, anti-inflammatory, anti-proliferative, hepatoprotective, and nephroprotective potential. Therefore, this study was designed to inspect its methanol extract (RVE) for possible nephroprotective effect.

METHODS

Primarily, in vitro antioxidant activity of RVE was confirmed based on 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging aptitude. Thereafter, Swiss Albino male mice were treated with cisplatin (2.5 mg/kg) for 5 successive days to induce nephrotoxicity. Recovery from nephrotoxicity was scrutinized by treating the animals with RVE (25, 50, and 100 mg/kg) intraperitoneally (i.p.) for the next 5 consecutive days. After completion of treatment, mice were sacrificed and kidneys were collected. Part of it was homogenized in sodium phosphate buffer for evaluating malondialdehyde (MDA) level, another part was used to evaluate gene (NQO1, p53, and Bcl-2) expression. Moreover, the hydrogen peroxide (H2O2) neutralizing capacity of RVE was evaluated in HK-2 cells in vitro. Finally, bioactive phytochemicals in RVE were determined using gas chromatography-mass spectrometry (GC-MS).

RESULTS

RVE showed in vitro antioxidant activity in a dose-dependent fashion with 37.39 ± 1.89 μg/mL IC50 value. Treatment with RVE remarkably (p < 0.05) decreased MDA content in kidney tissue. Besides, the expression of NQO, p53, and Bcl-2 genes was significantly (p < 0.05) mitigated in a dose-dependent manner due to the administration of RVE. RVE significantly (p < 0.05) reversed the H2O2 level in HK-2 cells to almost normal. From GC-MS, ten compounds including three known antioxidants "4H-Pyran-4-one, 2, 3-dihydro-3,5-dihydroxy-6-methyl-", "Hexadecanoic acid", and "Squalene" were detected. The extract was rich with an alkaloid "13-Docosenamide".

CONCLUSION

Overall, RVE possesses a protective effect against cisplatin-induced kidney damage.

Fatty Acid Profile, Lipid Quality and Squalene Content of Teff (Eragrostis teff (Zucc.) Trotter) and Amaranth (Amaranthus caudatus L.) Varieties from Ethiopia

Teff and amaranth are gluten-free cereals with significant nutritional and health benefits. However, they are underutilized and known in limited areas of the world. The present study evaluated the fatty acid profile, crude fat, squalene content and lipid quality of seven teff (Eragrostis teff (Zucc.) Trotter) and three amaranth (Amaranthus caudatus L.) varieties from Ethiopia. The fat content ranged from 2.92 to 3.34% (averaging 3.06%) and from 8.28 to 9.21% (averaging 8.6%) for teff and amaranth, respectively. Linoleic, oleic and palmitic acid were predominant in both teff and amaranth, accounting for approximately 89 and 85% of total fatty acid content, respectively. The saturated to unsaturated fatty acids ratio ranged from 0.30 to 0.32 in teff and from 0.38 to 0.40 in amaranth. The parameters used to describe lipid quality, i.e., thrombogenicity and atherogenicity indices, show that teff was superior over amaranth, suggesting a preference for the former for healthy food formulation. The squalene content of white amaranth (486.54 mg/100 g DM) was significantly higher than that of the other two varieties (327.54 and 340.81 mg/100 g DM for red and brown amaranth, respectively). In general, both gluten-free crops should be exploited for their potential as ingredients for the development of novel functional foods.

Metabolic engineering of Yarrowia lipolytica for improving squalene production

The aim of this present research is to enhance the squalene production in Yarrowia lipolytica using pathway engineering and bioprocess engineering. Firstly, to improve the production of squalene, the endogenous HMG-CoA reductase (HMG1) was overexpressed in Y. lipolytica to yield 208.88 mg/L squalene. Secondly, the HMG1 and diacylglycerol acyltranferase (DGA1) were co-overexpressed, the derived recombinant Y. lipolytica SQ-1 strain produced 439.14 mg/L of squalene. Thirdly, by optimizing the fermentation medium, the improved titer of squalene with 514.34 mg/L was obtained by the engineered strain SQ-1 grown on YPD-80 medium. Finally, by optimizing the addition concentrations of acetate, citrate and terbinafine, the 731.18 mg/L squalene was produced in the engineered strain SQ-1 with the addition of 0.5 mg/L terbinafine. This work describes the highest reported squalene titer in Y. lipolytica to date. This study will provide the foundation for further engineering Y. lipolytica capable of cost-efficiently producing squalene.

Squalene: More than a Step toward Sterols

Squalene (SQ) is a natural triterpene widely distributed in nature. It is a metabolic intermediate of the sterol biosynthetic pathway and represents a possible target in different metabolic and oxidative stress-related disorders. Growing interest has been focused on SQ’s antioxidant properties, derived from its chemical structure. Strong evidence provided by ex vivo models underline its scavenging activity towards free radicals, whereas only a few studies have highlighted its effect in cellular models of oxidative stress. Given the role of unbalanced free radicals in both the onset and progression of several cardiovascular diseases, an in depth evaluation of SQ’s contribution to antioxidant defense mechanisms could represent a strategic approach in dealing with these pathological conditions. At present experimental results overall show a double-edged sword role of squalene in cardiovascular diseases and its function has to be better elucidated in order to establish intervention lines focused on its features. This review aims to summarize current knowledge about endogenous and exogenous sources of SQ and to point out the controversial role of SQ in cardiovascular physiology.

Identification of Active Compound Extracts from Noni Fruit (Morinda citrifolia L.) and Its Potential as Antioxidants

Antioxidants are compounds that can inhibit oxidation reactions by binding to free radicals and highly reactive molecules. One form of reactive oxygen compounds is free radicals, these compounds are formed in the body and are triggered by various factors. Noni fruits have been used by the community as a medicine for high blood pressure, beriberi, urinating, inflammation of bile, inflammation of the intestine, dysentery, constipation, spleen pain, liver pain, diabetes and lumbago. Nevertheless, research on the identification of the active compounds of noni fruit which act as antioxidants yet. This study aims to extract and fractionation of Noni fruit, determine the antioxidant activity of Noni fruit extract, and identify the types of bioactive compounds that act as antioxidants. Noni fruit was extracted used maceration technique with 96% ethanol and then fractionated using n-hexane, chloroform and ethyl acetate solvents. Antioxidant activity from the results of noni fruit fractionation was measured by the DPPH (1.1 diphenyl-2-picrylhydrachyl) method and identification of bioactive compounds was carried out by GCMS. The results showed the greatest antioxidant activity was found in chloroform fraction with a percentage of inhibition of 78.19%. For the first time this study revealed the types of bioactive compounds from noni fruit ethyl acetate fraction which act as antioxidants are n-hexadecanoic acid, squalene, pyridin-3-carboxamide, oxime, n- (2-trifluoro methyl phenyl), and beta-sitosterol

Emerging opportunities in exploring the nutritional/functional value of amaranth

Amaranthusspp. is a highly nutritive pseudocereal, rich in macronutrients and micronutrients, including vitamins and minerals.

Comprehensive Evaluation of Antioxidant Potential of 10 Salvia Species Using High Pressure Methods for the Isolation of Lipophilic and Hydrophilic Plant Fractions

Common sage (Salvia officinalis) is a well-known source of antioxidants and other bioactive compounds, while many other species within the Salvia genus have been poorly studied. The total content of phenolic compounds (TPC) and antioxidant capacity indicators were evaluated for the extracts of 10 Salvia spp. consecutively isolated by supercritical carbon dioxide (SFE-CO2) and pressurized liquid extraction with ethanol and water. Antioxidant properties of solid plant material were evaluated by the direct antioxidant capacity measurement by the so-called QUENCHER method. Total antioxidant capacity values were calculated by integrating the results obtained for all extracts and the whole plant material. TPC and antioxidant capacity of the extracts were greatly dependent on the plant species and extraction solvent. Ethanol extracts possessed significantly higher antioxidant capacity and TPC comparing to the extracts isolated with other solvents. In general, all studied Salvia species demonstrated strong antioxidant capacity; however, the antioxidant potential of such species as S. forsskaolii and S. verticillata was the highest and comparable with that of S. officinalis. The majority of studied Salvia species may be considered as promising sources of functional ingredients to be used in human nutrition for functional food and nutraceutical formulations.

Revealing the seed proteome of the health benefitting grain amaranth (Amaranthus cruentus L.)

Amaranth, a staple food source in ancient Aztec, Maya and Inca cultures, has been recognized as a 21st century crop. This superfood, known as Inca wheat, attracts the worldwide attention of researchers and farmers for its superior agronomical and technological properties but especially because of its exceptional nutritive value. A combination of two-dimensional electrophoresis (2-DE) with MS facilitating the effective differentiation of 13 classes of

Effects of popping on nutrient contents of amaranth seed

Amaranth seeds can be popped by heating. The traditional method of popping in a skillet is simple, but it is difficult to control the heating time and temperature. To overcome these disadvantages, we developed a fluidized bed continuous processing system based on hot air heating for producing popped amaranth seeds in bulk. Using this system, we evaluated the effects of heat treatment at 260 °C for 15 s on the contents of B-group vitamins and essential and trace elements in amaranth seeds. The results showed that the treatment did not affect the content of B-group vitamins, and the recovery for essential and trace elements was 97-196%. This popping system is useful for processing amaranth seeds in terms of the product quality and nutrition.

Nutritional Components of Amaranth Seeds and Vegetables: A Review on Composition, Properties, and Uses

 A few decades ago Amaranthus was rediscovered as a most promising plant genus that may provide high-quality protein, unsaturated oil, and various other valuable constituents. Since then research has focused on various Amaranthus spp. and has been rapidly expanding, and a large number of reports have been published. Several review articles focusing on different aspects, such as botanical, agrotechnological, compositional, biological, chemical, and technological properties, as well as applications and health effects, have also been published since then. This comprehensive review is focused on amaranth composition, antioxidant properties, applications, and processing. The composition includes macrocomponets (lipids, proteins, carbohydrates, and dietary fiber) and other important constituents, such as squalene, tocopherols, phenolic compounds, phytates, and vitamins. These aspects of amaranth studies have not been comprehensively reviewed for a long time.

Lipid lowering by hydroalcoholic extracts of Amaranthus caudatus L. induces regression of rabbits atherosclerotic lesions

Background

The antihypercholesterolemic and antiatherogenic effect of hydroalcoholic extracts of Amaranthus caudatus L(A. caudatus). on regression of atherosclerosis in experimental rabbits maintained on a high cholesterol diet.

Methods

Twenty five rabbits were randomly divided into five groups of five each and treated 75 days as follows: Group I: normal diet(ND), Group II: Hypercholesterolemic diet (HCD) for 45 days; Group III: Hypercholesterolemic diet (HCD) for 75 days, Group IV and V: HCD for 45 days and then normal diet and normal diet + A. caudatus(150 mg·kg day) respectively for an additional 30 days(regression period). Blood samples were collected before (0 time) and after 45 days and 75 days of experimental diets for measurement of biochemical factors. The aortas were removed at the end of the study for assessment of atherosclerotic plaques.

Results

In regression period dietary use of A. caudatus in group V significantly decreased total cholesterol, LDL-cholesterol, malondialdehyde, C-reactive protein while apolipoproteinA and HDL- cholesterol was significantly increased compared to group IV. The atherosclerotic area was significantly decreased in group V. Whereas, the animals that in regression period received only normal diet showed no regression but rather progression of atherosclerosis.

Conclusion

These results thus suggest that hydroalcoholic extracts of A. caudatus can reduce risk factors and cause regression of fatty lesons in aorta.

Squalene protects against oxidative DNA damage in MCF10A human mammary epithelial cells but not in MCF7 and MDA-MB-231 human breast cancer cells

Until now, very little has been known about the antioxidant capacity of squalene and its effect on human breast tumourigenesis. In the present work, we investigated squalene's scavenging properties and its effect on cell proliferation, cell cycle profile, apoptosis, reactive oxygen species (ROS) level and oxidative DNA damage, using human breast cell lines. Our results showed that squalene neither possesses scavenging activity nor significantly alters cell proliferation rates, the cell cycle profile or cell apoptosis in human mammary epithelial cells (MCF10A), minimally invasive (MDA-MB-231) breast cancer cells, and highly invasive (MCF7) breast cancer cells. However, we found that squalene did exert the following effects on MCF10A epithelial cells in a dose-dependent manner: (a) it decreased intracellular ROS level, (b) it prevented H(2)O(2)-induced oxidative injury, and (c) it protected against oxidative DNA damage. Interestingly, squalene did not exert these effects on MCF7 and MDA-MB-231 cancer cells. Therefore, our data suggest that squalene, found in high amounts in virgin olive oils, could be partially responsible for the lower incidence of breast cancer in populations that consume the Mediterranean diet due to its protective activity against oxidative DNA damage in normal mammary cells.