Chemical Diversity of Wild-Growing and Cultivated Common Valerian (Valeriana officinalis L. s.l.) Originating from Poland

Common valerian is a medicinal plant. The underground organs of this species are used as a mild sedative and sleeping aid. Poland is one of the largest producers of this raw material in Europe, with local cultivar 'Lubelski' as a primary cultivated form. Although valerian is the subject of more or less deliberate selection carried out by farmers, it is still genetically unstable. The aim of this study was to determine the diversity of the 'Lubelski' cultivar originating from four regions of Poland (forms: L1-L4) in relation to wild-growing populations of the species. The plants were assessed in terms of the mass of underground organs and the content of valerenic acids and essential oils (EOs). The content of valerenic acids was determined using HPLC, whereas the content of EOs was determined using hydrodistillation. The composition of EOs was assessed using GC-MS GC-FID. The ploidy level of the analyzed objects was determined as well. Wild-growing populations (diploids) were characterized by lower masses of underground organs and lower contents of valerenic acid than cultivated forms (tetraploids). However, they produced higher contents of EOs. All the cultivated forms were strongly diversified with respect to the analyzed traits, including the mass of the roots (CV 49-75%), the content of valerenic acids (CV 18-55%), and the content of EOs (CV 28-57%). A total of 44 compounds were identified in the EOs. The dominant compound of both wild-growing populations and the 'Lubelski' forms were: α-fenchene, bornyl acetate, and valerenal. Among 'Lubelski' forms, the most interesting seems to be the L2 form, which was characterized by a relatively high yield and high content of valerenic acids and EOs. Thus, it appears to be a promising source of objects for further valerian cultivar improvement.

Comparison of the Chemical Composition and Antioxidant Properties of Propolis from Urban Apiaries

Bee products from urban apiaries are increasingly used. They are mainly used to promote local apiaries and cities in which they are located. The aim of the study was to compare the chemical composition and antioxidant activity of propolis from 6 Polish apiaries located in cities (Legionowo, Torun, Cracow, Warsaw, Katowice, Lodz). The chemical composition was analyzed using liquid chromatography (HPLC-DAD) and the analysis of antioxidant activity by scavenging free radicals (ABTS and DPPH) and FRAP. The obtained results showed the presence of 24 phenolic compounds in propolis extracts. The tested samples showed differentiation in terms of the content of individual chemical components, however, cinnamic acid and its derivatives were dominant. High antioxidant activity of the tested extracts was demonstrated (ABTS was in the range of 16.80-51.53 mg Te/mL, DPPH was in the range of 7.54-22.13 mg Te/mL, while FRAP reduction was in the range of 10.93-29.55 mg Te/mL). The obtained results compared with literature data on propolis from agricultural areas allow to conclude that propolis samples from both Poland types of areas are similar and can be classified as poplar propolis.

Antioxidant and Antibacterial Activity of Helichrysum italicum (Roth) G. Don. from Central Europe

Helichrysum italicum (Roth) G. Don. is one of the most important cosmetic and medicinal plants originating from the Mediterranean region of Europe. The aim of this study was to assess the chemical profile as well as antioxidant and antibacterial potential of the species cultivated in the temperate climate of Central Europe. The analyses were carried out using herbs and inflorescences. The content of essential oil ranged from 0.25 g × 100 g⁻¹ in the herb to 0.31 g × 100 g⁻¹ in the inflorescences. Neryl acetate, accompanied by α-pinene in the herb (10.42%), and nerol in inflorescences (15.73%) were the dominants here. Rutoside, as well as rosmarinic, chlorogenic, neochlorogenic, isochlorogenic b and cichoric acids, were detected in both raw materials using HPLC-DAD. Within this group, cichoric acid was the dominant (2647.90 mg × 100 g⁻¹ in the herb, 1381.06 mg × 100 g⁻¹ in the inflorescences). The herb appeared to be more abundant in phenolics in comparison with the inflorescences. When given antioxidant activity (determined using DPPH and ABTS assays), both methanolic extract and essential oil obtained from the herb indicated higher potential than those originating from the inflorescences (74.72, 61.38 and 63.81, 58.59% in the case of DPPH, respectively). In turn, regarding antimicrobial activity, the essential oil from inflorescences was distinguished by stronger bacteriostatic power than the herb essential oil. Gram-positive bacteria were more sensitive to both essential oils in comparison with Gram-negative ones, with S. aureus ATCC 25923 as the most susceptible (MIC 1; MBC 16 mg × mL⁻¹) among tested strains.

Antioxidant and Antibacterial Activity of Essential Oils and Hydroethanolic Extracts of Greek Oregano (O. vulgare L. subsp. hirtum (Link) Ietswaart) and Common Oregano (O. vulgare L. subsp. vulgare)

Greek oregano and common oregano were compared in respect of the antioxidant and antibacterial activity of the corresponding essential oils and hydroethanolic extracts in relation with their chemical profile. The chemical composition of essential oils was determined by GC-MS and GC-FID, while extracts (phenolic acids and flavonoids fractions) were analyzed by HPLC-DAD. Based on given volatiles, the investigated subspecies represented two chemotypes: a carvacrol/γ-terpinene/p-cymene type in the case of Greek oregano and a sabinyl/cymyl type rich in terpinen-4-ol in common oregano. Within non-volatile phenolic compounds, rosmarinic acid appeared to dominate in both subspecies. Lithospermic acid B, chlorogenic acid and isovitexin were present only in Greek oregano extracts. However, the total content of flavonoids was higher in common oregano extracts. The essential oil and extract of Greek oregano revealed visibly stronger antibacterial activity (expressed as MIC and MBC) than common oregano, whereas the antioxidant potential (determined by DPPH, ABTS and FRAP) of these extracts was almost equal for both subspecies. In the case of Origanum plants, the potential application of essential oils and extracts as antiseptic and antioxidant agents in the food industry should be preceded by subspecies identification followed by recognition of their chemotype concerning both terpene and phenolics composition.

Bioactive compounds, total antioxidant capacity and yield of kiwiberry fruit under different nitrogen regimes in field conditions

BACKGROUND

Actinidia arguta known as the 'kiwiberry' or 'mini kiwi' is relatively new among the cultivated berry species. Recent studies indicate the kiwiberry fruit could be an important source of many health-promoting compounds. A knowledge-based fertilisation concept was evolved to define optimal strategies for feeding Actinidia with nitrogen (N) because a deficit and excess of N both have a negative impact on plants and the surrounding environment.

RESULTS

Kiwiberry yield and fruit internal quality significantly depended on soil N level, cultivar and growing season. A higher soil N led to an increase in carotenoid content and a decrease in phenolic content, whereas ascorbic acid and glutathione contents were not affected by soil N fertility. Under the highest N dose, enzymatic antioxidants were activated. Trolox equivalent antioxidant capacity clearly decreased with an increasing N level.

CONCLUSIONS

Competent and skilful fertilisation management should focus on balancing a high fruit yield and maintaining their high quality. Based on yield level and fruit antioxidant potential, the N guide values for A. arguta vary between 30 and 50 mg N per kg^-1 of soil. The recommended N dose may depend on overall soil quality traits and cultivar N demand, as well as on weather conditions. © 2020 Society of Chemical Industry.

Prolonging the Shelf Life of Cherry Tomatoes by Pullulan Coating with Ethanol Extract of Propolis During Refrigerated Storage

Cherry tomatoes are one of the most popular tomato varieties known for their bioactive compounds and sensory properties. One way to reduce the contamination of tomato is to coat them with natural or antimicrobial substances. In this study, an ethanolic extract of propolis (EEP) was obtained, and its chemical composition was analyzed using high-performance liquid chromatography with diode array detector (HPLC-DAD), and minimum inhibitory concentration (MIC) and the minimum bactericidal/fungicidal concentration (MBC/MFC) were determined using the serial microdilution method. The antimicrobial activity of 5 and 10% EEP and pullulan films containing EEP (5 and 10%) against Listeria monocytogenes, Salmonella Typhimurium, Escherichia coli O157, Penicillium chrysogenum, Fusarium solani, and Botrytis cinerea were compared. The influence of a pullulan coating containing EEP (5 and 10%) on reducing the number of bacteria and molds, physicochemical properties (weight loss (WL), total soluble solids (TSS), titratable acidity (TA), maturity index, pH, and color), and sensory properties (color and brightness of skin, aroma, flavor, overall quality, and general preference) of cherry tomatoes during refrigerated storage was evaluated. Pullulan films with EEP inhibited the growth of microorganisms on cherry tomatoes. These coatings did not affect the TSS and pH values of tomatoes, but a slight decrease in TA and WL was observed. Cherry tomatoes coated with pullulan coatings containing EEP did not show any adverse changes in their sensory properties. It was found that the addition of EEP to the pullulan coatings enriched them with antimicrobial properties and enhanced their action while reducing the WL and maturation time of cherry tomatoes.

Chemical Diversity of Bastard Balm (Melittis melisophyllum L.) as Affected by Plant Development

The phytochemical diversity of Melittis melissophyllum was investigated in terms of seasonal changes and age of plants including plant organs diversity. The content of phenolics, namely: coumarin; 3,4-dihydroxycoumarin; o-coumaric acid 2-O-glucoside; verbascoside; apiin; luteolin-7-O-glucoside; and o-coumaric; p-coumaric; chlorogenic; caffeic; ferulic; cichoric acids, was determined using HPLC-DAD. Among these, luteolin-7-O-glucoside, verbascoside, chlorogenic acid, and coumarin were the dominants. The highest content of flavonoids and phenolic acids was observed in 2-year-old plants, while coumarin in 4-year-old plants (272.06 mg 100 g-1 DW). When considering seasonal changes, the highest content of luteolin-7-O-glucoside was observed at the full flowering, whereas verbascoside and chlorogenic acid were observed at the seed-setting stage. Among plant organs, the content of coumarin and phenolic acids was the highest in leaves, whereas verbascoside and luteolin-7-O-glucoside were observed in flowers. The composition of essential oil was determined using GC-MS/GC-FID. In the essential oil from leaves, the dominant was 1-octen-3-ol, whilst from flowers, the dominant was α-pinene.

Effect of Shading on Development, Yield and Quality of Bastard Balm Herb (Melittis melissophyllum L.)

The aim of the study was to assess the effects of Melittis melissophyllum shading on its development and accumulation of phenolics. Their content (verbascoside, apiin, luteolin-7-O-glucoside, coumarin, 3,4-dihydroxycoumarin, o-coumaric acid 2-O-glucoside as well as o-coumaric, p-coumaric, chlorogenic, caffeic, ferulic and cichoric acid) was determined in the herb using HPLC-DAD. The results showed that the content of abovementioned flavonoids and phenolic acids was highest in plants grown under full sunlight. On the other hand, a higher content of coumarin was observed in shaded plants, especially after the seed-setting stage. A similar tendency was noted for the amount of chlorophyll a and b. The content of hydrogen peroxide and malondialdehyde, the activity of polyphenol oxidase and catalase and the antioxidant capacity of plant extracts (measured using DPPH, ABTS and FRAP assays) were found to be the highest in the plants grown in full sunlight. However, the plants grown in moderate (30%) shade were found to thrive best.

Antibacterial and Antioxidant Activity of Extracts from Rose Fruits (Rosa rugosa)

The aim of the present study was to determine the antioxidant and antimicrobial properties in freeze-dried extracts of rose fruits (Rosa rugosa) obtained using various extraction techniques and to determine the effect of a selected extract on bacterial survival in model fluids imitating protein food. Ethanolic extracts from rose fruits showed higher antioxidant activity compared to other tested extracts. The rose fruits aqueous extract showed the highest inhibitory activity against most of the 10 bacterial strains tested. From the group of Gram-positive bacteria, the Bacillus cereus strain proved to be the most sensitive to the action of the rose extract. From the Gram-negative bacteria: Escherichia coli and Klebsiella pneumoniae were the most sensitive. The reduction in the number of bacterial cells in matrices imitating protein food depended on the concentration of the aqueous extract used. However, at none of the concentrations used was a complete inhibition of bacterial growth observed. We have confirmed that the traditional extraction and freeze-drying of rose fruits is still suitable for the food industry due to obtaining extracts with good antibacterial and antioxidant properties and the use of bio-solvents, such as water or ethanol, which are easily available in high purity and completely biodegradable.

Growth Biocontrol of Foodborne Pathogens and Spoilage Microorganisms of Food by Polish Propolis Extracts

Propolis is a natural mixture produced by bees from plant resin substances. This study focuses on the general characteristics of five samples of Polish extract propolis originating from agricultural areas. Chemical composition with high performance liquid chromatography‒diode array detector method, total content of flavonoids and polyphenols, and antioxidative activity were determined in the ethanol extracts of propolis (EEP) samples. Minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration (MBC/MFC) and time-kill curves were studied for foodborne pathogens and food spoilage microorganisms. In EEPs the predominant flavonoid compounds were pinocembrin, chrysin, pinobanksin, apigenin, and kaempferol and the predominant phenolic acids were p-coumaric acid, ferulic acid, and caffeic acid. A strong antioxidative action of propolis in vitro was observed (IC50 for DPPH radical was at the level of 0.9-2.1 µg/mL). EEPs had MIC values for bacteria in the range of 1-16 mg/mL, whereas MIC for fungi ranged from 2 to 32 mg/mL. Extract of propolis originating from southern Poland was distinguished by higher content of bioactive components, and stronger antioxidative and antimicrobial activity than EPPs from the remaining areas of Poland. The results indicate the possibility of applying ethanol extracts from Polish propolis to protect food against microbiological spoilage.

Chemical variability of common skullcap (Scutellaria galericulata L.) wild growing in the area of eastern Poland

Introduction. In the group of plants revealing adaptogenic activity, species belonging to Scutellaria genus are considered to be the most important ones. Common skullcap (Scutellaria galericulata L.) is less known species from this genus, growing wild in Poland in wet habitats. Its herb has been used in the past as a sedative and diuretic agent.

Objective. The aim of the study was to determine the variability of common skullcap in terms of the accumulation of flavonoids in the herb.

Methods. The objects of the study were 17 common skullcap populations growing wild in eastern Poland. At each natural site, the list of main flowering plant species was carried out, according to Braun-Blanquet scale of plant abundance. The total content of flavonoids was determined according to EP 8th. The analysis of flavonoids was carried out using HPLC, Shimadzu chromatograph.

Results. The total content of flavonoids ranged from 0.21 to 0.50% dry matter (DM). Using HPLC, eight compounds were identified within the group, with chrysin-7-O-glucuronide (30.91–589.27 mg × 100 g−1 DM), baicalin (61.90–482.93 mg × 100 g−1 DM) and scutellarin (43.77–213.54 mg × 100 g−1 DM) as dominants. Chrysin was the compound which in the highest degree differentiated investigated populations (CV=0.77).

Conclusion. Obtained results indicate that investigated common skullcap populations differed in terms of the total content of flavonoids as well as the content of indentified flavonoids in the herb. However, there was no clear relationship between geographical localization of populations and the content of identified flavonoids in raw material.

Accumulation of phenolic compounds in the purple betony herb (Stachys officinalis L.) originated from cultivation

Introduction: Purple betony (Stachys officinalis L., Lamiaceae) is a perennial of versatile medicinal usage. Nowadays, in Poland betony herb is collected exclusively from wild growing plants. Decreasing number of its natural sites results in lack of the herb supply and thus, in its limited usage.

Objective: The aim of the study was to determine the effects of the age of plant and term of raw material harvest on its yield and quality in cultivation conditions.

Methods: The observations were carried out on 2- and 3-year-old plants. During vegetation the herb was collected for four times. The raw material was subjected to chemical analysis. Tannins (as pyrogallol equivalent) were determined according to Polish Pharmacopoeia, phenolic acids and flavonoids – by HPLC.

Results: The mass of herb, both in the second and third year, had increased from the beginning of vegetation up to seed setting. The highest content of tannins was found in the herb collected at the vegetative stage of plant development (2.05% in the second and 2.91% in the third year). Four phenolic acids (chlorogenic, ferulic, caffeic and rosmarinic acids) and five flavonoid compounds (orientin, luteolin-7-glucoside, apigenin-7-glucoside, apigenin-3-glucoside, apigenin) were identified in the obtained raw materials. In these groups, the dominant compounds were caffeic acid and apigenin. The highest content of caffeic acid was found at the beginning of plant vegetation, whereas apigenin – at the stage of full blooming and seed setting.

Conclusion: In cultivation conditions, purple betony produces high mass of herb which may be used as a valuable raw material in herbal industry.

Variability of southern sweet-grass (Hierochloë australis /Schrad./ Roem. & Schult.) wild growing populations occurring in eastern Poland

Southern sweet-grass is a perennial grass distributed through north-eastern Europe. In Poland, this rare, partially protected plant grows wild in well-lit coniferous or mixed forests. Its leaves, rich in coumarin compounds, are used for aromatization of alcohols. Taking into account high demand on this raw material and decrease in the number of southern sweet-grass populations it is recommended to introduce the plant into cultivation systems. In this study 12 populations of southern sweet-grass were selected and assessed in terms of their cultivation usefulness. The presence of associated plant species growing on its natural sites was investigated as well as light irradiance on those stands. The species was found in 3 types of forest communities. Air dry mass of leaves per plant varied in analyzed populations from 1.73 to 11.07 g. They were significantly diversified in the total content of coumarins (0.36–0.96%), flavonoids (0.09–0.26%) and polyphenolic acids (0.13–0.29%). The diversity concerning the content of coumarin, a quality indicator of leaves, was even higher. The content of this compound varied from 52.03 to 275.74 mg/100 g d. m. Among the analyzed populations, the most interesting seem to be population No. 12 (Jedwabno) and population No. 10 (Ruciane) characterized with relatively high mass of leaves and the highest content of the identified active compounds, including coumarin.

Effect of meadowsweet flower extract-pullulan coatings on rhizopus rot development and postharvest quality of cold-stored red peppers

The study involved an examination of the antifungal activity on red peppers of pullulan coating (P) and pullulan coating containing either water-ethanol (P + eEMF) or ethanol extract of meadowsweet flowers (P + eEMF). Pullulan was obtained from a culture of Aureobasidium pullulans B-1 mutant. Both non-inoculated peppers and those artificially inoculated with Rhizopus arrhizus were coated and incubated at 24 °C for 5 days. The intensity of the decay caused by Rhizopus arrhizus in the peppers with P and P + eEMF coatings was nearly 3-fold lower, and in the case of P + weEMF 5-fold lower, than that observed in the control peppers. Additionally, the P + weEMF coating decreased, almost two-fold the severity of pepper decay compared to other samples. The influence of coating of pepper postharvest quality was examined after 30 days of storage at 6 °C and 70%-75% RH. All coatings formed a thin and well-attached additional layer of an intensified gloss. During storage, color, total soluble solid content and weight loss of coated peppers were subject to lower changes in comparison with uncoated ones. The results indicate the possibility of the application of pullulan coatings containing MFEs as an alternative to the chemical fungicides used to combat pepper postharvest diseases.