Flavonoids, Phenolic Acids, and Tannin Quantities and Their Antioxidant Activity in Fermented Fireweed Leaves Grown in Different Systems.

The increasing demand for organic and biodynamically cultivated fireweeds worldwide has led to a paucity of studies on the effects of solid-phase fermentation and various growth techniques on the quantities of biologically active substances and their antioxidant activity. This experiment was carried out in 2023 at the organic farm in the Jonava district (Safarkos village, Lithuania). The aim of this work was to investigate polyphenols (flavonoids and phenolic acids) and antioxidant activity in fireweed (Chamerion angustifolium (L.) Holub) leaves fermented for 24 and 48 h in solid-phase fermentation and natural, organic, and biodynamic cultivation. Fireweeds have high quantities of polyphenols and strong antioxidant activity. The method employed for determining antioxidant activity was spectrophotometric, for measuring polyphenols, high-performance liquid chromatography (HPLC). Principal component analysis (PCA) was used to determine the relationships between the average content of total polyphenols and antioxidant activity in fermented fireweed leaves grown in different systems. This study's findings demonstrated that the leaves of fireweed cultivated organically had the greatest concentration of total flavonoids, total phenolic acids, and total polyphenols. Comparing the fermentation process effect, the amount of predominant phenolic acids-chlorogenic, p-coumaric, and ellagic acids-as well as the content of oenothein B, during the fermentation process significantly decreased, but the concentration of quercetin-3-O-glucoside after a short time of the fermentation process significantly increased. According to the obtained results, it would be possible to create various health-giving and nature-friendly products from fireweeds.

Effects of the dose of administration, co-antioxidants, food matrix, and digestion-related factors on the in vitro bioaccessibility of rosmarinic acid - A model study.

This study aimed to determine the effect of the administration dose, combinations with co-antioxidants (vitamin C, caffeic acid, chlorogenic acid, catechin, rutin), and different food matrices (cooked and lyophilized hen eggs, chicken breast, soybean seeds, potatoes) on the potential bioaccessibility of rosmarinic acid (RA) in simulated digestion conditions, depending on the digestion stage (gastric and intestinal) and the contribution of physicochemical and biochemical digestion factors. The in vitro bioaccessibility of RA depended on the digestion stage and conditions. The physicochemical factors were mainly responsible for the bioaccessibility of RA applied alone. The higher RA doses improved its bioaccessibility, especially at the intestinal stage of digestion. Furthermore, the addition of vitamin C and protein-rich food matrices resulted in enhanced intestinal bioaccessibility of RA. In the future, the knowledge of factors influencing the bioaccessibility of RA can help enhance its favorable biological effects and therapeutic potential.

Studies of the Variability of Biologically Active Compounds and Antioxidant Activity in Organically, Biodynamically, and Naturally Grown and Fermented Fireweed (Chamerion angustifolium (L.) Holub) Leaves.

With the growing global demand for organically and biodynamically grown fireweeds, little research is being conducted on them, and little is known about how the different growing systems and the process of solid-phase fermentation changes biologically active substances and antioxidant activity. Our experiment was conducted in 2022 in Jonava district, Safarkos village, Giedres Nacevicienes organic farm (No. SER-T-19-00910, Lithuania, 55°00'22″ N 24°12'22″ E). This study aimed to investigate the influence of various growing systems (natural, organic, and biodynamic) and technological parameters (different duration: 24, 48 and 72 h) of aerobic solid-phase fermentation on the change of flavonoids, phenolic acids, tannins, carotenoids, chlorophylls, and antioxidant activity. High-performance liquid chromatography (HPLC) for polyphenols, carotenoids, and chlorophylls as well as the spectrophotometric method for antioxidant activity determinations were used. The results of the study showed that different growing systems (natural, organic, and biodynamic) and solid-phase fermentation had a significant effect on the quantitative composition of biologically active substances in the leaves of the fireweeds. According to these data, it would be possible to recommend fermented fireweed leaves grown organically as a source of polyphenols (especially: phenolic acids and flavonoids), leaves grown biodynamically as a source of carotenoids (exceptionally: lutein and beta-carotene) and chlorophyll, and leaves grown naturally for better antioxidant activity.

The Impact of Solid-Phase Fermentation on Flavonoids, Phenolic Acids, Tannins and Antioxidant Activity in Chamerion angustifolium (L.) Holub (Fireweed) Leaves.

At present, the consumption of medical plants and functional foods is growing across the whole world. Fireweed (Chamerion angustifolium (L.) Holub), an important medicinal plant that has various pharmacological effects (antioxidant, anti-inflammatory, anticancer and others), can improve the state of health and well-being and reduce the risk of various diseases. The aim of this work was to investigate polyphenols (flavonoids, phenolic acids and tannins) and antioxidant activity in fireweed leaves fermented for 24, 48 and 72 h in solid-phase fermentation under aerobic and anaerobic conditions. High-performance liquid chromatography (HPLC) for polyphenols and the spectrophotometric method based on quenching of stable colored radical (ABTS•+) for antioxidant activity determinations were used. The results showed that the highest amounts of total polyphenols, total flavonoids and tannin oenothein B in the dried matter were found after 72 h and the highest total phenolic acids after 48 h of anaerobic solid-phase fermentation. The highest antioxidant activity was found after 72 h of solid-phase fermentation under aerobic conditions.

The Effect of Storage Conditions on the Content of Molecules in Malus domestica 'Chopin' cv. and Their In Vitro Antioxidant Activity.

The apple fruit is one of the most widely cultivated temperate fruits and a rich source of bioactive compounds. Since a growing number of consumers are increasingly seeking safe and healthy food production, organic apple production provides this possibility. In this study, the content of bioactive compounds in organic apples depending on temperature and storage time were determined. 'Chopin' apples were stored for 7, 14 and 21 days at 5 °C and 20 °C. All analyses were performed using the HPLC method. The control samples of fresh apples contained the highest content of vitamin C (21.87 mg/100 g FW), L-ascorbic (11.50 mg/100 g FW), DHA (10.37 mg/100 g FW), total carotenoids (2.82 mg/100 g FW), ß-carotene (0.21 mg/100 g FW) and lutein (2.41 mg/100 g FW). Samples stored at 20 °C had the highest content of total carotenoids and lutein, but samples stored at 5 °C contained the most ß-carotene and zeaxanthin. Apples stored at 20 °C contained significantly more chlorophyll a (0.05 g/100 g FW). The samples stored at 5 °C contained the most total polyphenols. Samples stored for 14 days were characterized by the highest content of total flavonoids. Samples stored for 21 days were characterized by the highest content of epigallocatechin and quercetin-3-O-rutinoside, but the highest content of quercetin and kaempferol was found in control samples. The highest content of total flavonoids was found in apples stored at 5 °C.

Phenolic Acid Content and Antioxidant Properties of Edible Potato (Solanum tuberosum L.) with Various Tuber Flesh Colours.

The aim of the paper was to evaluate the phenolic acid content and antioxidant properties in potato cultivars with coloured flesh and bright flesh. The study material included eight cultivars of edible potato grown in a temperate climate in Poland. Five cultivars were potato tubers with coloured flesh: "Rote Emma", "Blue Salad", "Vitelotte", "Red Emmalie", and "Blue Congo"; and three were potato tubers with bright flesh: "Bella Rosa", "Lord", and "Tajfun". In all potato samples under study, four phenolic acids were identified: chlorogenic acid, gallic acid, p-coumaric acid, and caffeic acid. The predominant acid was chlorogenic acid, the levels of which ranged from 62.95 mg·100 g-1 FM to 126.77 mg·100 g-1 FM. The total concentration of the identified phenolic acids was diverse and depended on the genotype of the cultivar and the tuber flesh colour, with coloured-fleshed potatoes having higher phenolic acid contents in comparison to bright-fleshed potato cultivars. The average concentration of phenolic acids in the samples was 89.19 mg∙100 g-1 FM, and the average concentrations of the individual phenolic acids identified were as follows: chlorogenic acid (86.19 mg∙100 g-1 FM), gallic acid (1.18 mg∙100 g-1 FM), p-coumaric acid (0.64 mg∙100 g-1 FM), and caffeic acid (1.18 mg∙100 g-1 FM). In addition, three groups of anthocyanins were identified: pelargonidin-3,5-di-O-glucoside, peonidin-3,5-di-O-glucoside, and petunidin-3,5-di-O-glucoside. Anthocyanins were not found in the "Lord" or "Tajfun" varieties characterised by white tuber flesh. The predominant pigment was petunidin-3,5-di-O-glucoside, with an average content of 23.15 mg∙100 g-1 FM, and the highest value was observed in the "Vitelotte" variety (51.27 mg∙100 g-1 FM). The antioxidant activity of the flesh of the potatoes under study was diverse depending on flesh colour. The FRAP (Ferric Reducing Antioxidant Power) assay indicated higher antioxidant activity of coloured-fleshed potato cultivars. The highest concentration was identified in the "Vitelotte" cultivar flesh and was 114% higher than in the "Lord" cultivar. Similar dependencies were found in the case of the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay; however, in this case, the "Vitelotte" cultivar flesh demonstrated nearly 6.4 times higher antioxidant activity than the "Lord" cultivar. Summarizing our own research, we can conclude that potato varieties with coloured flesh are characterised by a higher content of biologically active substances, including phenolic acids, and antioxidant properties compared to potato tubers with bright flesh.

Polyphenols, Antioxidant Activity and Volatile Compounds in Fermented Leaves of Medicinal Plant Rosebay Willowherb (Chamerion angustifolium (L.) Holub).

At present, the consumption of medical plants and functional foods is growing in the whole world. Rosebay willowherb (Chamerionangustifolium (L.) Holub) is an important medicinal plant that has various pharmacological effects (antioxidant, anti-inflammatory, anticancer, and others), can improve the state of health and well-being, and reduce the risk of various diseases. The aim of this work was to investigate volatile compounds, polyphenols, and antioxidant activity in rosebay willowherb leaves fermented for 24 and 48 h in solid state fermentation under aerobic and anaerobic conditions. High-performance liquid chromatography (HPLC) for polyphenols and the spectrophotometric method for antioxidant activity determinations were used. To recognize and identify the leaves' fragrances, electronic nose (Alpha M.O.S) measurement technology was used. The results showed that the highest amounts of total polyphenols in dried matter were after 48 h aerobic solid state fermentation (SSF). Antioxidant activity was higher under 48 h SSF compared to the control. The most abundant flavoring compound groups were esters, terpenes, and aldehydes. In unfermented leaves, (z)-3-hexen-1-ol, acetate, hexyl acetate, and trans-hex-2-enyl acetate prevailed, characterized by fragrances of greenery, flowers, and fruits. The undesired esters group compounds, ethyl butyrate and butyl acetate, with pungent odor, were detected after 48 h anaerobic SSF.

Effect of Different Durations of Solid-Phase Fermentation for Fireweed (Chamerion angustifolium (L.) Holub) Leaves on the Content of Polyphenols and Antioxidant Activity In Vitro.

Fireweed has recently been recognized as a plant with high antioxidant potential and phenolic content. Its leaves can be fermented to prepare an infusion with ideal antioxidant activity. The aim of this study was to investigate and to determine the influence of solid-phase fermentation of different durations on the variation of polyphenols in the leaves of fireweed. Laboratory experiments were conducted in 2017-2018. The leaves of fireweed, naturally growing, were fermented for different periods of time: not fermented (control) and fermented for 24 and 48 h. The evaluation of polyphenols and antioxidant activity in leaves was performed using high- performance liquid chromatography (HPLC). Additionally, principal component analysis was used to characterize differences in bioactive compounds between fireweed samples fermented at different durations. Solid-phase fermented leaves were characterized by higher contents of oenothein B, quercetin and benzoic acid but had lower contents of quercetin-3-O-rutinoside, luteolin and chlorogenic and gallic acids. Antioxidant activity in short- (24 h) and long-term (48 h) fermentation (compared to control) gave the highest level of regression in 2017, but in 2018 the effect was observed only with short-term fermentation and control. In conclusion, solid-phase fermentation can be used to modulate biologically active compounds in fireweed leaves.