Heavy Metals Presence in the Soil and Their Content in Selected Varieties of Chili Peppers in Slovakia.

Capsicum chili peppers are popular vegetables in Slovakia. They provide a supply of health-promoting substances, but contaminated vegetables can pose a serious health risk to the people who consume them. Therefore, the aim of this study was to determine the content of heavy metals (Mn, Zn, Cr, Cu, Ni, Cd, Pb and Hg) in the soil as well as in selected varieties of the genus Capsicum grown in southern Slovakia. The results were compared with the limit values given by the Law no. 220/2004 (valid in the SR) as well as threshold values proposed by the European Commission (EC) (2006). The gained result showed that the total content of Cd (1.64 mg/kg) as well as the available mobile forms of Cd (0.12 mg/kg) and Pb (0.26 mg/kg) was exceeded on the soil on which Capsicum cultivars were grown. The limit values of other monitored heavy metals (Mn, Zn, Cr, Cu, Ni, and Hg) were not exceeded. The studied species of the genus Capsicum did not accumulate monitored heavy metals. It can be stated that consumption of chili peppers does not pose any risk for human health.

Iridoids, Flavonoids, and Antioxidant Capacity of Cornus mas, C. officinalis, and C. mas × C. officinalis Fruits.

The fruits of Cornus mas and Cornus officinalis have been known and appreciated in folk medicine for years and have a high biological value, which is mainly connected with their polyphenols and iridoids content. However, hybrids of C. mas × C. officinalis have not been investigated. The aim of this study was to evaluate the iridoids, anthocyanins, and flavonols content, and antioxidant capacity of Cornus mas, Cornus officinalis, and C. mas × C. officinalis. Iridoids and flavonoids were quantified by the High-Performance Liquid Chromatography (HPLC) method. Antioxidant capacity (AC) was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH•), 2,2'-azino-bis (3-ethyl benzothiazoline-6-sulfonic acid (ABTS•+), and ferric reducing antioxidant power (FRAP) tests. Total phenolic content (TPC) was evaluated using the Folin-Ciocalteu reagent. Among the C. mas cultivars and C. officinalis genotypes, there was considerable variation in the content of iridoids, flavonoids, and AC. Interspecific hybrids C. mas × C. officinalis contained more iridoids than C. mas and more anthocyanins than C. officinalis and additionally had higher AC and TPC than C. officinalis and most C. mas. AC, TPC, and the presence of iridoids, anthocyanins, and flavonols in hybrids C. mas × C. officinalis are reported for the first time. The Cornus species deserve special attention due to their highly biologically active substances, as well as useful medicinal properties.

Evaluation of the antioxidant potential of Capsicum annuum L., C. baccatum L. and C. chinense Jacq. cultivars.

BACKGROUND: Economically important vegetables are a strong source of antioxidants with different characteristics. Capsicum L. (pepper) is an important agricultural plant because of its economical, medicinal, and nutritional values. METHODS: This study aimed to test antioxidant parameters in the fruits of 9 cultivars of Capsicum annuum L. (CA 01-09), 7 cultivars of C. baccatum L. (CB 01-07), and 11 cultivars of C. chinense Jacq. (CC 01-11). The antioxidant activity of the investigated Capsicum cultivars was measured, along with the free radical scavenging activity (FRSA), using the DPPH method, and the molybdenum reducing power (MRP) was expressed as mg TE (Trolox equivalent) per g of DW (dry weight). Total polyphenol content (TPC), expressed as mg GAE (gallic acid equivalent) per g of DW, total flavonoid content (TFC), expressed as mg QE (quercetin equivalent) per g of DW, and total phenolic acid content (TPAC), expressed as mg CAE (caffeic acid equivalent) per g of DW, were the basic antioxidant parameters of antioxidant activity in this study. RESULTS: All investigated Capsicum extracts exhibited FRSA from 1.45 (CC-06) to 8.21 (CC-05) mg TE/g and MRP from 24.84 (CA-06) to 198.21 (CB-07) mg TE/g. The TPC of the tested extracts ranged from 10.13 (CB-03) to 38.68 (CB-07) mg GAE/g. The TFC of the studied samples showed values from 5.73 (CB-03) to 27.32 (CB-07) mg QE/g and TPAC from 2.24 (CB-03) to 13.07 (CC-07) mg CAE/g. A very strong correlation was found in the investigated cultivars between TPC and TPAC (r = 0.932, 0.839 and 0.848, respectively), and between TPC and TFC (r = 0.921, 0.982 and 0.939, respectively). Very strong relations were also found between TPC and FRSA (r = 0.820) in the C. annuum cultivars and between TPC and MRP (r = 0.898) in the C. baccatum cultivars. CONCLUSIONS: This study found useful results concerning the antioxidant potential of the fruits of Capsicum cultivars. The data obtained demonstrate the strong antioxidant activity of cultivars of Capsicum, which can be used in the food industry because of the commercial importance of these fruits.

Assessment of antioxidant and antimicrobial activities of Crambe spp. during vegetation.

BACKGROUND: The search for new plant raw material as a potential source of antioxidants is still ongoing. This study aimed to evaluate the antioxidant and antimicrobial capacity of the plant raw material of Crambe spp. during vegetation. METHODS: The free radical scavenging activity and molybdenum reducing power of the extracts were used to determine antioxidant activity. The quantification of polyphenol compounds was conducted with Folin-Ciocalteu reagent. Flavonoids and phenolic acids were also determined. The disc diffusion method was used to determine antimicrobial activity. RESULTS: It was determined that the free radical scavenging activity, assessed using the DPPH-method, was 4.38-8.20 mg TE/g DW, the molybdenum reducing power of the extracts was 40.07-129.12 mg TE/g DW, total polyphenol content was 20.24-70.88 mg GAE/g DW, total flavonoid content was 5.73-29.92 mg QE/g DW, and phenolic acid content was 3.00-10.63 mg CAE/g DW. Antimicrobial activity depended on the stage of growth and the part of the plant used. CONCLUSIONS: Crambe spp. possess the antioxidant and antimicrobial potential to mean that they could be used in pharmaceutical studies and the food industry.

Comparison of Heavy Metal Intake by Different Species of the Genus Allium L.

Allium vegetables belong to the most widespread and commonly grown vegetables in Slovakia. In this study, we dealt with the content of selected heavy metals (Zn, Mn, Cr, Cu, Ni, Pb, and Cd) in cultivated garlic (Záhorský, Lukan, Makoi), onion (Amika, Red Matte, Diamant), and leek (Bavaria, Golem, Tango). We determined the total content of heavy metals (aqua regia), and available-mobile forms of heavy metals (1 M NH4NO3) in soils. Analytical final procedure was flame AAS. The results were compared with the limit values given by the Law no. 220/2004 (valid in the SR) as well as threshold values proposed by the European Commission (EC) (2006). Gained result showed that the total content of Cd (1.26 mg.kg-1) as well as the available mobile forms of Cd (0.16 mg.kg-1) and Pb (0.64 mg.kg-1) was exceeded on the soil on which Allium species were grown. Determined contents of heavy metals in garlic were in the range of 0.03-0.07 mg Cd.kg-1 FM (fresh matter), 0.02-0.11 mg Pb.kg-1 FM (fresh matter), in onion ranged from ND (not detected) to 0.03 mg Cd.kg-1 FM (fresh matter), 0.09-0.2 mg Pb.kg-1 FM (fresh matter), and in leek were in the range of, 0.07-0.13 mg Cd.kg-1 FM (fresh matter), and 0.3-0.5 mg Pb.kg-1 FM (fresh matter). Based on the obtained BAF values, we can conclude that the genus Allium does not belong to the accumulator of evaluated hazardous metals. Safe food production requires constant monitoring of hazardous metals in raw materials of plant origin, as these metals can have serious negative effects on human health.

Biological properties of sea buckthorn (Hippophae rhamnoides L.) derived products.

BACKGROUND: Sea buckthorn is a good and possible source of a wide range of bioactive compounds with     a positive effect on the human body, especially polyphenols and carotenoids. METHODS: The present study aimed to evaluate the antioxidant and antimicrobial activities of Hippophae rhamnoides L. products - 100% oil, 100% juice, dry berries, and tea (dry berries, leaves, and twigs). The antioxidant activity was determined by DPPH radical scavenging and molybdenum reducing antioxidant power methods. The content of phytochemicals (polyphenols, flavonoids, carotenoids) was measured by colorimetric methods. The detection of antimicrobial activity was carried out using the disc diffusion method and an evaluation of minimal inhibition concentration against three species of Gram-negative bacteria: Escherichia coli CCM 3988, Salmonella enterica subsp. enterica CCM 3807, Yersinia enterocolitica CCM 5671, and three Gram-positive bacteria: Bacillus thuringiensis CCM 19, Listeria monocytogenes CCM 4699, Staphylococcus aureus subsp. aureus CCM 2461. RESULTS: All the tested sea buckthorn products had a high antioxidant activity. The highest content of total polyphenols (204.26 mg GAE/g), flavonoids (30.00 mg QE/g), and carotenoids (0.34 mg/g) were identified in 100% sea buckthorn juice. Maximal values of the antioxidant activity were found using the DPPH method for 100% oil (8.75 mg TE/g) and molybdenum reducing power for tea (196.41 mg TE/g). All the tested products showed strong antimicrobial activity against the tested bacteria, confirmed by both methods - disc diffusion (especially for Yersinia enterocolitica CCM 5671) and minimal inhibitory concentration. CONCLUSIONS: The pronounced antioxidant and antibacterial properties of sea buckthorn products indicate the importance of sea buckthorn application in health promotion and agricultural practice.

Evaluation of the antioxidant activity and phenolic content of Chinese quince (Pseudocydonia sinensisSchneid.) fruit.

BACKGROUND: Neglected and underutilized plant species could serve as a valuable source of natural bioactive compounds. The objective of this study was to evaluate the biological activity of Chinese quince (Pseudocydonia sinensis Schneid) genotypes of Ukrainian and Slovak origin. METHODS: The content of the total antioxidant activity (DPPH method and molybdenum reducing antioxidant power), total polyphenol, flavonoid and phenolic acid compounds in the pulp and peel of Chinese quince were compared across five genotypes from Slovakia and three from Ukraine. RESULTS: All tested samples exhibited DPPH• radical scavenging activities with values from 6.17 to 9.56 mg TEAC (Trolox equivalent antioxidant capacity) per gram of dry matter (DM). Antioxidant activity, measured using the molybdenum reducing antioxidant power method, ranged from 69.82 to 225.04 mg TEAC per gram of DM. Total polyphenol content was from 34.73 to 82.02 mg GAE (gallic acid equivalent), while total flavonoid content was from 0.50 to 26.72 mg QE (quercetin equivalent) per gram DM. Phenolic acid content varied from 1.12 to 8.39 mg CAE (caffeic acid equivalent) per gram DM. The peel extracts contained the highest content of bioactive compounds when compared with the pulp extract (from 15.30 to 32.60%). All observed parameters differed significantly between the genotypes. Strong positive correlations (p ≤ 0.05) were observed between the content of phenolic acids and flavonoids in the peel in plants from Slovakia (r = 0.951, r = 0.928, respectively); between the phenolic acid and antioxidant capacities detected using the MRP method – r = 0.950 and r = 0.955 for peel and pulp, respectively; between the determination of antioxidant activity by the DPPH and MRP methods in the peel and pulp in plants from Ukraine (r = 0.986, r = 0.998, respectively). Significantly positive correlations were found between all the parameters in the samples of Ukrainian origin. CONCLUSIONS: The results showed that all fruit extracts exhibited strong antioxidant activities, which generally correlated positively with the total phenolic content. This study demonstrates that Chinese quince fruit grown in Ukraine and Slovakia is a perspective source of valuable polyphenol content with high antioxidant activity and is a valuable fruit for use in the agriculture and food industries.

Determination of microbiological contamination, antibacterial and antioxidant activities of natural plant hazelnut (Corylus avellana L.) pollen.

The aim of our study is to determine microbial contamination, antibacterial and antioxidant activities of 14 pollen samples of Corylus avellana collected from different locations in Slovakia. Microbiological analysis was carried out in two steps: microbiological assays and studies of antibacterial activity of pollen extracts. The antimicrobial properties of pollen extracts were carried out with the disc-diffusion method. Methanol (70%), ethanol (70%) and distilled water were used for pollen extracts. Five strains of bacteria such as gram-negative (Salmonella enterica subsp. enterica CCM 3807, Escherichia coli CCM 2024, and Yersinia enterocolitica CCM 5671) and gram-positive (Staphylococcus aureus CCM 2461 and Bacillus thuringiensis CCM 19T) were tested. Antioxidant activity of pollen extracts was determined by the DPPH method. Bacterial analysis includes the determination of the total bacterial count ranged from 4.08 to 4.61 log CFU g-1, mesophilic aerobic bacteria ranged from 3.40 to 4.89 log CFU g-1, mesophilic anaerobic bacteria ranged from 3.20 to 4.52 log CFU g-1, coliform bacteria ranged from 3.30 to 4.55 log CFU g-1, yeasts and filamentous fungi ranged from 3.00 to 3.56 log CFU g-1. Microscopic filamentous fungi Aspergillus spp., Alternaria spp., Penicillium spp., Cladosporium spp., Rhizopus spp., and Paecylomyces spp. were isolated from hazelnut pollen. Yersinia enterocolitica was the most sensitive strain among ethanolic and methanolic pollen hazelnut extracts. Staphylococcus aureus was the most sensitive strain against aqueous hazelnut pollen extracts. We determined the following sensitivity against ethanol pollen extracts respectively: Yersinia enterocolitica > Salmonella enterica > Staphylococcus aureus > Bacillus thuringiensis > Escherichia coli. Methanol pollen extracts had shown following sensitivity: Yersinia enterocolitica > Salmonella enterica > Escherichia coli > Staphylococcus aureus > Bacillus thuringiensis. Aqueous extracts had shown the following sensitivity: Staphylococcus aureus > Salmonella enterica > Escherichia coli > Bacillus thuringiensis > Yersinia enterocolitica. Hazelnut pollen extracts have over 82% antioxidant capacity in samples from non-urban zones. An elevated level of antioxidant potential in the pollen is determined by its biological properties conditioned by biologically active substances. DPPH method allowed characterizing pollen as a source of antioxidants.

Antioxidant activities and phenolic compounds in fruits of various genotypes of American persimmon (Diospyros virginiana L.).

BACKGROUND: American persimmons (Diospyros virginiana L.) are known as a widespread cultivar which were traditionally used by Native Americans as a food source, and since ancient times have been used in folk medicine. The objective of this study was to evaluate the antioxidant activity and phenolic content of Diospyros virginiana genotypes. METHODS: The content of the total antioxidant activity and phenolic compounds from the fruits of the American persimmon (Diospyros virginiana L.) of six genotypes were compared. Antioxidant activity (AOA) was measured using three different photometric methods – DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) and FRAP (ferric-reducing antioxidant power). Total phenolic content (TPC) was evaluated using Folin-Ciocalteu reagent assay. RESULTS: The results for AOA (μMol Trolox/g) determined by the DPPH method varied from 51.68 (DV-05) to 100.87 (DV-03), those obtained by the ABTS method varied from 65.40 (DV-05) to 142.26 (DV-03), and those obtained by the FRAP method varied from 45.06 (DV-05) to 109.30 (DV-03). The results for TPC varied from 590.75 ±27.98 mg/100 g (DV-05) to 1325.12 ±77.30 mg/100 g (DV-03). The highest results for AOA and TPC were achieved for the fruits of genotypes DV-03 and DV-05. A positive linear correlation was found between antioxidant activity and total phenolic content in the examined plant material. CONCLUSIONS: The results showed that all fruit extracts exhibited strong antioxidant activities, which generally correlated positively with the total phenolic content. This study demonstrates the potential of the fruits of Diospyros virginiana grown in Ukraine as a possible source of valuable polyphenol content, with high anti- oxidant activities and health-promoting properties. The high contents of phenolic compounds and significant linear correlation between the values of the concentration of phenolic compounds and antioxidant activity indicated that these compounds contributed to the strong antioxidant activity.