Bioactive properties and organosulfur compounds profiling of newly developed garlic varieties of Bangladesh

Studies are being carried out on achieving the maximum quality of garlic through various approaches. In Bangladesh, new garlic varieties (BARI 1-4, BAU-1, BAU-2, BAU-5) have been recently developed by artificial selection to enhance their quality. The present study aimed to evaluate their potency in terms of bioactive properties and organosulfur compounds content using different bioassay and GC-MS techniques while comparing them with other accessible varieties (Chinese, Indian, Local). The new variety, BARI-3 showed the highest antioxidant activity and total phenolic content. It was also found with the highest level of a potent blood pressure-lowering agent, 2-vinyl-4H-1,3-dithiine (78.15 %), which is never reported in any garlic at this percentage. However, the local variety exhibited greater inhibitory properties against the tested organisms including multidrug-resistant pathogens compared to other varieties. This study primarily shows the potential of these two kinds of garlic for their further utilization and development.

Black garlic: A review of its biological significance

Garlic has been used as a vegetable since ancient times, and it has proved versatility in preventative and therapeutic approaches. The use of garlic in the food business was restricted because of its strong flavor and harsh odor. Fermentation and different chemical processes, such as the Millard reaction and microbial fermentation, produce black garlic. Thermal processing at precise temperatures and relative humidity enhanced flavor and prolonged shelf life. This article holds the most up-to-date information about the resourcefulness and complexity of garlic processing and its biological implications. Recent findings have shown proof of the superior qualitative features and physical activities of black garlic. Before introducing this to the food market, researchers must conduct high-quality research to evaluate the changes of metabolites to achieve largest antioxidant, anticancer, anti-obesity, anti-inflammatory, immune, hepatoprotective, cardioprotective, neuroprotective, and anti-allergenic performance. Researchers should evaluate the quality, marketing, post-harvest handling, and consumption practices of black garlic.

The content of bioactive compounds and antioxidant activity of garlic (Allium sativum L.)

Garlic (Allium sativum L.) is one of the most commonly grown vegetables and thanks to its sensory properties, it has an important place in numerous world cuisines. Garlic is also known for its health-promoting properties, which are attributed to its chemical composition. The health benefits of garlic depending on the content of biologically active compounds, which vary between cultivars and geographical areas. Seven cultivars of garlic, namely Sukoradsky, Zahorsky, Germidour, Mojmir, Karel IV., Arkus, Makoi, were analyzed in this study. This study aimed to determine the total polyphenol content, total flavonoid content, and antioxidant activity of garlic. Studied characteristics were analyzed by the UV-VIS spectrometry method. Total polyphenol content ranged from 430.26 to 640.04 mg GAE.kg-1 FW. Total flavonoid content ranged from 10.29 to 60.49 mg CE.kg-1 FW. Antioxidant activity measured by ABTS assay ranged from 1.098 to 1.955 mmol TE.kg-1 FW. Antioxidant activity measured by FRAP assay ranged from 0.63 to 1.467 mmol.kg-1 FW. Highest TPC, TFC, and AA were determined in the cultivar Mojmir. The lowest TPC and TFC were determined in the cultivar Zahorsky. The lowest AA was determined in the cultivar Sukoradsky. High positive correlations were determined between individual parameters.

Solvent Mixture Optimization in the Extraction of Bioactive Compounds and Antioxidant Activities from Garlic (Allium sativum L.)

Garlic is a health promoter that has important bioactive compounds. The bioactive extraction is an important step in the analysis of constituents present in plant preparations. The purpose of this study is to optimize the extraction with the best proportion of solvents to obtain total phenolic compounds (TPC) and thiosulfinates (TS) from dried garlic powder, and evaluate the antioxidant activities of the optimized extracts. A statistical mixture simplex axial design was used to evaluate the effect of solvents (water, ethanol, and acetone), as well as mixtures of these solvents, after two ultrasound extraction cycles of 15 min. Results showed that solvent mixtures with a high portion of water and pure water were efficient for TPC and TS recovery through this extraction procedure. According to the regression model computed, the most significant solvent mixtures to obtain high TPC and TS recovery from dried garlic powder are, respectively, the binary mixture with 75% water and 25% acetone and pure water. These optimized extracts presented oxygen radical absorbance capacity. Pure water was better for total antioxidant capacity, and the binary mixture of water–acetone (75:25) was better for DPPH scavenging activity. These optimized extracts can be used for industrial and research applications.

Basil – a comparison of the total phenolic content and antioxidant activity in selected cultivars

During the lifetime, the human body forms a considerable amount of free radicals damaging DNA, cell membranes, and their components. A wider application of basil (Ocimum basilicum), an aromatic plant and one of the common gastronomic commodities in the human diet could help to prevent the formation of free radicals and to remove them from the human body. Therefore, determination of antioxidant activity and total content of phenolic substances in selected cultivars of basil (Ohře, Sweet green, Salad leaf, Purple opal, Thai) in a fresh and frozen state and the mixture with another plant (garlic, mint, rocket, spinach) in the fresh and refrigerated state was performed. The total content of phenolic substances in basil was established by the spectrophotometric Folin-Ciocalteu method. DPPH spectrophotometric method was used to analyze the antioxidant activity. The results have shown statistically significant differences between basil cultivars under the same growing conditions. The values of antioxidant activity in frozen samples ranged from 5.1 ±0.4 mg.g-1 AA FW to 11.71 ±0.18 mg.g-1 AA FW and the total phenolic content varied between 2.77 ±0.16 mg.g-1 GAE FW in TH and 8.93 ±0.13 mg.g-1 GAE FW. A statistically significant difference between fresh and frozen samples was established only in the “Ohře” cultivar. After the storage in cold temperatures, all mixtures showed a reduction in the antioxidant activity and total content of phenolic substances. The mixture of basil and mint performed the highest values of antioxidant activity and total content of phenolic substances and significantly differed from the other mixtures most often. The addition of basil and its mixtures to food and beverages can substantially increase their biological value and subsequently also the quality of human nutrition.

Polyphenols and antioxidant activity in pseudocereals and their products

Pseudocereals are important as gluten-free crops that could be utilized as functional foods. They contain proteins with high biological value and also bioactive compounds such as phenolic compounds, flavonoids, vitamins, and minerals that can possess positive health effects on the body. Three types of pseudocereals (amaranth, buckwheat, and quinoa) were evaluated for polyphenols and antioxidant activity. Spectrophotometric methods were used for the determination of free phenols amount with Folin-Ciocalteu reagent, and total antioxidant capacity (TAC) with DPPH and ABTS reagents. Free phenols, the predominant part of polyphenols, were in pseudocereals in the range from 12.4 to 678.1 mg GAE.100g-1. The highest content of FP was found in buckwheat products (146.8 - 678.1 mg GAE.100g-1); quinoa and amaranth products reached much lower values (up to 226.1 mg GAE.100g-1). Antioxidant activity was in an agreement with the FP amounts order, the highest TAC values were again for buckwheat products (167.3 - 473.9 and 876.9 - 3524.8 mg TE.100g-1), followed by quinoa (78.2 - 100.6 and 738.9 - 984.5 mg TE.100g-1) and amaranth ones (25.0 - 69.7 and 118.2 - 431.4 mg TE.100g-1). A high positive correlation between FP amount and TAC values was evaluated for analyzed pseudocereals. The highest content of free phenols and the best antioxidant potential showed buckwheat wholemeal flour, so buckwheat could be characterized as a great source of free phenols with high antioxidant activity.

Total phenolic content and antioxidant activity of methanolic extract of selected wild leafy vegetables grown in Bangladesh: A cheapest source of antioxidants

Nowadays, more attention has been paid on wild plants as new source of natural antioxidants. Therefore, methanolic extracts of 10 traditionally consumed wild leafy vegetables of Bangladesh were analyzed for their total phenolic content (TPC) and free radical scavenging activity. Folin–Ciocalteu method followed by spectrophotometric measurement was used to quantify the TPC of the selected wild leafy vegetables. Free radical scavenging activity was examined utilizing 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assay. Different concentrations of the plant extract were applied to ascertain the dose response relationship in inhibiting DPPH free radical. The results revealed that the TPC ranged from 102.20 to 710.42 mg GAE/100g dry weight (DW). The highest TPC was observed in Bauhinia acuminata (Shetokanchan) while Leucas aspera (Shetodhron) exhibited the lowest TPC among the undertaken vegetables. The studied samples proportionately inhibited DPPH with increasing concentrations. At high concentration (500 µg.mL-1), the percentage inhibition of DPPH radical by plant extract ranged from 68.1 ±2.65 % to 93.1 ±1.23 %. The highest DPPH radical inhibition was observed in Bauhinia acuminata (Shetokanchan) (93.10 ±1.23 %), followed by Commelina benghalensis (Bat baittashak) (91.97 ±1.31 %), Hydrocotyle sibthorpiodes L. (Sakumubakla) (91.83 ±2.13 %). The lowest DPPH radical inhibition among the studied samples was observed in Leucas aspera (Shetodhron) (68.1 ±2.65 %). IC50 values measured by DPPH assay in this study ranged from 11.64 to 313.79 µg.mL-1. The study findings indicated that the samples under study possesses strong activity against DPPH, and thus could be used as natural antioxidants in the food and/or pharmaceutical industry.

Bioactive compounds evaluation in different types of Czech and Slovak honeys

Honey contains important bioactive compounds (enzymes, phenolic compounds, vitamins, and minerals) with several positive health effects for humans. In the study six types of honey (acacia, rape, floral, multi flower, forest, and honeydew honeys), of Czech and Slovak origin, were evaluated for bioactive compounds by means of color, polyphenols and antioxidant capacity analyses. The brightest color of honeys, the lowest values measured spectometrically, had acacia and rape honeys, followed by floral, and darker multi flower and forest honeys, and honeydew honeys. Polyphenols (PP) amount, determined by spectrophotometric method with Folin-Ciocalteu reagent, was highest for the darkest honeydew honeys, followed by multi flower and forest honey, brighter floral honeys, and rape and acacia honey. Honeys polyphenols were in the range from 54.0 to 254.2 mg GAE.100g-1. The total antioxidant capacity (TAC) was analyzed by spectrometric methods with ABTS and DPPH reagents. Antioxidant capacity values are in agreement with the PP contents order. They were highest also for honeydew honeys (59.2 - 89.6 and 73.1 - 118.7 mg TE.100g-1), followed by multi flower (66.0 and 56.7 mg TE.100g-1) and forest honey (56.0 and 49.1 mg TE.100g-1), then floral honeys (33.0 - 49.2 and 27.8 - 38.7 mg TE.100g-1) and the lowest values for rape (19.0 and 28.1 mg TE.100g-1) and acacia (15.5 and 11.3 mg TE.100g-1)honey. A positive correlation between color, PP amount and TAC was evaluated for analyzed honeys. Darker honey samples showed higher values of phenolic compounds and antioxidant potential, therefore they belong to the honey types with higher amount of bioactive compounds such as antioxidants.

Antioxidant Activities of Dialium indum L. Fruit and Gas Chromatography-Mass Spectrometry (GC-MS) of the Active Fractions

The fruit of Dialium indum L. (Fabaceae) is one of the edible wild fruits native to Southeast Asia. The mesocarp is consumed as sweets while the exocarp and seed are regarded as waste. This study aimed to evaluate the antioxidant activities of the fruit by using four assays, which measure its capabilities in reducing phosphomolybdic-phosphotungstic acid reagents, neocuproine, 2,2-diphenyl-picrylhydrazyl (DPPH), and inhibiting linoleic acid peroxidation. The active fractions were then analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the seed methanol fraction (SMF) exhibited the strongest antioxidant activity with significantly higher (p < 0.05) gallic acid equivalence (GAE), total antioxidant capacity (TAC), and DPPH radical scavenging activity (IC50 31.71; 0.88 µg/mL) than the other fractions. The exocarp dichloromethane fraction (EDF) was the discriminating fraction by having remarkable linoleic acid peroxidation inhibition (IC50 121.43; 2.97 µg/mL). A total of thirty-eight metabolites were detected in derivatized EDF and SMF with distinctive classes of phenolics and amino acids, respectively. Bioautography-guided fractionation of EDF afforded five antioxidant-enriched subfractions with four other detected phenolics. The results revealed the antioxidant properties of D. indum fruit, which has potential benefits in pharmaceutical, nutraceutical, and cosmeceutical applications.