Chemical Composition of Thyme (Thymus vulgaris) Extracts, Potential Inhibition of SARS-CoV-2 Spike Protein-ACE2 Binding and ACE2 Activity, and Radical Scavenging Capacity.

Water and ethanol extracts of dried thyme (Thymus vulgaris) were analyzed for chemical composition, inhibition of the SARS-CoV-2 spike protein-ACE2 interaction, inhibition of ACE2 activity, and free radical scavenging capacity. Thirty-two compounds were identified in water extract (WE) and 27 were identified in ethanol extract (EE) of thyme through HPLC-MS. The WE (33.3 mg/mL) and EE (3.3 mg/mL) of thyme inhibited the spike protein-ACE2 interaction by 82.6 and 86.4%, respectively. The thyme WE at 5 mg/mL inhibited ACE2 activity by 99%, and the EE at 5 mg/mL inhibited ACE2 by 65.8%. Total phenolics were determined to be 38.9 and 8.8 mg of GAE/g in WE and EE, respectively. The HO• scavenging capacities were 1121.1 and 284.4 µmol of TE/g in WE and EE, respectively. The relative DPPH• scavenging capacities were 126.3 µmol TE/g in WE and 28.2 µmol TE/g in EE. The ABTS•+ scavenging capacities were 267.1 µmol TE/g in WE and 96.7 µmol TE/g in EE. The results suggested that the thyme extract could be potentially used to prevent SARS-CoV-2 infection and mitigate the complications from the infection.

Effects of Blanching, Freezing and Canning on the Carbohydrates in Sweet Corn.

Sweet corn is frequently consumed in the US and contains carbohydrates as major macronutrients. This study examined the effects of blanching, freezing, and canning on carbohydrates in sweet corn. Fresh bi-color sweet corn was picked in the field and processed immediately into frozen and canned samples. Simple sugars, starch, and dietary fiber (DF) (including total DF (TDF), insoluble DF (IDF) and two fractions of soluble DF (SDF)) were measured according to the AOAC methods. Additional glycomic analysis including oligosaccharides, monosaccharide composition of total polysaccharides (MCTP) and glycosidic linkage of total polysaccharides (GLTP) were analyzed using UHPLC-MS. Sucrose is the major simple sugar, and IDF is the main contributor to TDF. Sucrose and total simple sugar concentrations were not altered after blanching or freezing but were significantly reduced in canned samples. Kestose was the only oligosaccharide identified in sweet corn and decreased in all heat-treated or frozen samples. Starch content decreased in frozen samples but increased in canned samples. While two SDF fractions did not differ across all samples, blanching, freezing and canning resulted in increases in TDF and IDF. Six monosaccharides were identified as major building blocks of the total polysaccharides from MCTP analysis. Glucose and total monosaccharide concentrations increased in two canned samples. GLTP was also profoundly altered by different food processing methods. This study provided insights into the changes in the content and quality of carbohydrates in sweet corn after food processing. The data are important for accurate assessment of the carbohydrate intake from different sweet corn products.

Effect of genotype, environment, and their interaction on phytochemical compositions and antioxidant properties of soft winter wheat flour.

The effect of genotype (G), growing environment (E), and their interaction (G×E) on the antioxidant properties and chemical compositions were investigated using the flour samples of 10 wheat varieties grown in four different locations in Maryland. Lutein content of wheat flour ranged from 0.10 to 0.69 µg/g, and α-tocopherol ranged from 0.12 to 0.83 µg/g. Total carotenoids were primarily affected by E (45.7%), while G×E interaction had a larger effect on the level of total tocopherols (71.6%). E had the largest effect on antioxidant activity against oxygen, hydroxyl, and ABTS(·+) radicals. G had the least influence on the measured phytochemicals and antioxidant activity assays. Total carotenoids had a significant correlation with average low air temperature (r=0.359, p<0.01) as well as precipitation level (r=0.214, p<0.01). ABTS(·+) radical scavenging capacity had a positive correlation with average air temperature (r=0.705, p<0.01), while hydroxyl radical scavenging capacity had a negative correlation with temperature (r=-0.269. p<0.01). These results show that environment, genotype, and their interaction could influence the levels of lipophilic antioxidants and antioxidant activities of wheat flour.

Chemical composition of 13 commercial soybean samples and their antioxidant and anti-inflammatory properties.

A total of 13 commercial soybean samples were investigated and compared for their tocopherol and carotenoid compositions, fatty acid profile, total phenolic content (TPC), isoflavone and sterol compositions, and free radical scavenging properties. Free radical scavenging activities were estimated against peroxyl, hydroxyl, and ABTS(•) (+) radicals. The commercial soybean samples differed in their chemical compositions and health properties. Among the tested samples, CN-DB soybean showed the highest TPC and antioxidant activities and the greatest amount of total isoflavones and lutein and tocopherol contents. In addition, four of the soybean samples were further tested for their potential anti-inflammatory activity. The four samples behaved differently in suppressing the IL-1ß, IL-6, and COX-2 mRNA expressions, suggesting their different potential of anti-inflammatory activities. The results from this study suggested a need of improved quality control and measurement system to better reflect the health properties of commercial soybeans for general consumers and food manufacturers to improve the use of this important food ingredient.

Phytochemical composition, anti-inflammatory, and antiproliferative activity of whole wheat flour.

Whole wheat flour from five wheat cultivars was evaluated for phenolic, carotenoid, and tocopherol compositions as well as anti-inflammatory and antiproliferative activities against HT-29 cells. The total ferulic acid content ranged from 452 to 731 µg/g among the five cultivars and was primarily present in the insoluble-bound form. Lutein was the only carotenoid detected and ranged from 1.5 to 4.0 µg/g, and α-tocopherol levels ranged from 12 to 61 µg/g. Extracts of four cultivars demonstrated significant anti-inflammatory activity, measured as inhibition of interleukin-1ß (IL-1ß) mRNA expression; however, none of the extracts inhibited tumor necrosis factor-α (TNF-α) mRNA expression, a second indicator of anti-inflammatory activity. Proliferation of HT-29 adenocarcinoma cells was inhibited by extracts from all cultivars at the dose of 100 mg botanical equivalent/mL. The cultivar WestBred 936 had the greatest antiproliferative activity at lower concentrations (20 and 50 mg botanical equivalent/mL), had the greatest anti-inflammatory effect against IL-1ß, and also had the highest levels of ferulic acid and α-tocopherol. This research shows that whole wheat flours of these five cultivars varied significantly in their contents of phenolics, carotenoids, and α-tocopherol as well as in their anti-inflammatory and antiproliferative potentials, suggesting the possibility that wheat varieties can be selected based on potential health benefits.

Phenolic composition and nutraceutical properties of organic and conventional cinnamon and peppermint.

Conventional and organic cinnamon and peppermint were investigated for their phenolic profile, anti-proliferative, anti-inflammatory, and antioxidant properties. Accelerated solvent extraction with 75% acetone was used to extract samples. Caffeic acid was the most abundant phenolic acid in peppermint. Catechin, (-)-epigallocatechin gallate, syringic acid, gallic acid, vanillic acid, and p-coumaric acid were also detected in both spices. There was no significant difference between conventional and organic spices in the composition of most individual phenolics. All conventional and organic peppermint and cinnamon extracts exhibited strong anti-proliferative and anti-inflammatory properties. Cinnamon was more efficient in inhibiting IL-1ß and COX-2 expression, while peppermint showed better inhibitory effect on IL-6 and MCP-1. This study indicates that cinnamon and peppermint may potentially be used as dietary sources of bioactive phytochemicals for improving health.

Isoflavone composition and antioxidant capacity of modified-lipoxygenase soybeans grown in Maryland.

Maryland-grown soybean lines modified for low lipoxygenase-1 (LOX-1) content and a traditional nonmodified cultivar were analyzed for fatty acid composition, total phenolic content (TPC), isoflavone composition, relative DPPH• scavenging capacity (RDSC), and hydroxyl radical scavenging capacity (HOSC). Soybean lines included black, brown, and yellow soybeans. TPC of all soybean lines ranged from 2.84 to 4.74 mg gallic acid equiv (GAE)/g flour. Total isoflavones were between 2.78 and 8.66 µmol/g flour. RDSC of all lines was between 0.48 and 14.62 µmol Trolox equiv (TE)/g flour, and HOSC ranged from 53.57 to 135.52 µmol TE/g flour. Some modified-LOX genotypes demonstrated antioxidant capacity and/or isoflavone content similar to or higher than those of the nonmodified cultivar (P < 0.05). Black soybeans demonstrated higher TPC and RDSC than most yellow soybean lines, although they did not have higher isoflavone content. The results demonstrate that modification of the LOX trait did not necessarily alter the antioxidant capacity or chemical composition of the experimental soybean lines when compared with a nonmodified cultivar. These soybean lines may be studied further for nutraceutical properties and use in functional foods.

Phytochemical, antioxidant, and antiproliferative properties of seed oil and flour extracts of Maryland-grown tobacco cultivars.

To determine the possible alternative use of tobacco, the seeds representing seven Maryland tobacco cultivars were investigated for their phytochemical, antioxidant, and antiproliferative properties. Tobacco seed oils were extracted by the Soxhlet method, and analyzed for their yield, density, refractive index, fatty acid profiles, and tocopherol profile. The defatted flours were extracted in 50% acetone and 80% ethanol. The tobacco seed oil and flour extracts were analyzed for total phenolic contents (TPC) and scavenging capacities against peroxyl, hydroxyl and 2,2-diphenyl-1-picryhydrazyl (DPPH) radicals. The fatty acid compositions of phospholipids and the protein content of the flours were also analyzed. In addition, oil and flour extracts of varieties MD609 and MD609LA were evaluated for their antiproliferative effects on HT-29 human colon cancer cells. All of the tested extracts significantly inhibited HT-29 cell proliferation except that from MD609 oil. The data from this study suggest the potential alternative use of tobacco seeds in developing natural antioxidants and antiproliferative agents for improving human health.

Preparation and characterization of zein/chitosan complex for encapsulation of α-tocopherol, and its in vitro controlled release study.

Chitosan (CS) nanoparticles coated with zein has been newly demonstrated as a promising encapsulation and delivery system for hydrophilic nutrient with enhanced bioactivities in our previous study. In this study, a hydrophobic nutrient, α-tocopherol (TOC), was successfully encapsulated into zein/CS complex. The fabrication parameters, including zein concentration, zein/CS weight ratio, and TOC loading percentage, were systematically investigated. The physicochemical and structural analysis showed that the electrostatic interactions and hydrogen bonds were major forces responsible for complex formation. The scanning electron microscopy study revealed the spherical nature with smooth surface of complex. TOC encapsulation was also evidenced by differential scanning calorimetry. The particle size and zeta potential of the complex varied from 200 to 800 nm and +22.8 to +40.9 mV, respectively. The kinetic release profile of the TOC showed burst effect followed by slow release. Compared with zein nanoparticles, zein/CS complex provided better protection of TOC release against gastrointestinal conditions, due to CS coatings. Zein/CS complex is believed to be a promising delivery system for supplementation or treatment of hydrophobic nutrients or drugs.

Fatty acid composition, oxidative stability, antioxidant and antiproliferative properties of selected cold-pressed grape seed oils and flours.

Cold-pressed chardonnay, muscadine, ruby red, and concord grape seed oils and their defatted flours were studied for their fatty acid composition, oxidative stability and antioxidant and antiproliferative activities. The phenolic profiles of the seed flours were also measured. The most abundant fatty acid in the oils was linoleic acid, ranging from 66.0g/100g of total fatty acids in ruby red seed oil to 75.3g/100g of total fatty acids in concord seed oil. The oils were also high in oleic acid and low in saturated fat. Ruby red grape seed oil recorded the highest oxidative stability index of 40h under the accelerated conditions. Total phenolic content (TPC) was up to 100 times lower in the oils than in the flours. Lutein, zeaxanthin, cryptoxanthin, ß-carotene, and α-tocopherol levels were also measured. DPPH radical-scavenging capacity ranged from 0.07 to 2.22mmol trolox equivalents (TE)/g of oil and 11.8 to 15.0mmol TE/g of flour. Oxidative stability of menhaden fish oil containing extracts of the seed flours was extended by up to 137%. HPLC analysis was conducted to determine the levels of free soluble, soluble conjugated and insoluble bound phenolics in the seed flours. The phenolic compounds analyzed included catechin, epicatechin, epicatechin gallate, quercetin, gallic acid, and procyanidins B1 and B2. Antiproliferative activity was tested against HT-29 colon cancer cells. All of the seed flours and muscadine seed oil registered significant (P<0.05) inhibition of cancer cell growth. The results from this study demonstrate the potential of developing value-added uses for these seed oils and flours as dietary sources of natural antioxidants and antiproliferative agents for optimal health.

High-throughput assay for detection of soybean lipoxygenase-1.

A high-throughput assay was developed to detect soybean lipoxygenase 1 (LOX-1) using a multilabel plate reader. The assay was also adapted to a single cell fluorometer. Fluorescein is degraded by linoleic hydroperoxide produced from soybean lipoxygenase and linoleic acid. The decrease in fluorescence is measured over time, and the area-under-the-curve (AUC) is used to quantify the LOX-1 content of soybean extract. A dose-dependent response is seen with varied dilutions of pure LOX enzyme or soybean extracts. Percent recovery was between 97% and 108%, and relative standard deviation was 4.3%. Advantages of the assay include the reduced preparation time of samples and reduced use of reagents in the high-throughput assay. Multiple samples can be measured in a single run with a multilabel plate reader.

Chemical composition of five commercial Gynostemma pentaphyllum samples and their radical scavenging, antiproliferative, and anti-inflammatory properties.

Five Gynostemma pentaphyllum (GP) samples were investigated and compared for their chemical compositions and their antioxidant, antiproliferative, and anti-inflammatory effects. Extracts (50% acetone, 75% ethanol, and 100% ethanol) of the five GP samples (GP1-5) differed in their total phenolic, saponin, and flavonoid contents and in their rutin and quercetin concentrations. The highest level of total flavonoids was 63.5 mg of rutin equiv/g in GP4, and the greatest total phenolic content was 44.3 mg of gallic acid equiv/g in GP1 with 50% acetone as the extraction solvent. GP2 had the highest total saponin content of 132.6 mg/g with 100% ethanol as the extraction solvent. These extracts also differed in their scavenging capacity against DPPH and hydroxyl radicals, although they all showed significant radical scavenging capacity. The 100% ethanol extracts also showed dose-dependently strong inhibition on IL-6 and Ptgs2 mRNA expression and weak inhibition on TNF-α mRNA expression. In addition, GP1 had the highest antiproliferative activity at 3.2 mg equiv/mL concentration in HT-29 human colon cancer cells. The results from this study will be used to promote the application of G. pentaphyllum for improving human health.

Effect of genotype, environment, and their interaction on chemical composition and antioxidant properties of low-linolenic soybeans grown in Maryland.

Eight soybean genotypes grown in three environments in Maryland were analyzed for total phenolic content (TPC), antioxidant capacity, isoflavone composition, lutein, tocopherols, fatty acid composition, and oil content. Fatty acid composition, isoflavones, lutein, tocopherols, and specific antioxidant assays had significant variation by genotype (G) (P < 0.05). Environment (E) had a significant effect on fatty acids, lutein, individual tocopherols, oxygen radical absorbance capacity (ORAC), and the isoflavone glycitein (P < 0.05). In addition, the interaction between genotype and environment (G x E) showed a significant effect on antioxidant capacity, isoflavones, lutein, tocopherols, and fatty acids (P < 0.05). Factorial designed analysis of variance of all data indicated that G had a larger effect than E on the majority of fatty acids, total isoflavones, lutein, and total tocopherols. E had a larger effect than G on stearic acid (18:0), glycitein, delta-tocopherol, and ORAC. The results of this study show that the genotype, growing environment, and their interactions in Maryland-grown soybeans may alter the levels of specific health-enhancing properties.