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

Abstract

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.

In Vitro Human Skin Penetration, Antioxidant and Antimicrobial Activity of Ethanol-Water Extract of Fireweed (Epilobium angustifolium L.)

“…In our study, phenolic acids such as ChA, GA, 4-HB, 3,4-DHB, and CA were identified by HPLC, and GA was found in a considerable amount. GA and ChA were also found in the leaves of E. angustifolium by Ruszová et al and Lasinskas et al [ 3 , 41 ]. Shikov et al found a higher GA content than other acids identified by authors, including 3,4-DHB [ 27 ].…”

“…E. angustifolium has been used for a long time in folk medicine as a useful herb for skin infections, septic wounds, and against important human skin pathogens [ 1 , 22 ]. In addition, due to the high content of polyphenols, including phenolic acids, high antioxidant activity was also observed [ 3 , 23 , 24 , 25 , 26 , 27 , 28 ]. We demonstrated that the FEE has antibacterial and antioxidant activity.…”

“…On the other hand, the higher content of CA and 4-HB in E. hirsutum was found by Wojdyło et al [ 43 ]. The observed differences in phenolic acid content may be partly due to different growing conditions, environmental factors, state of ripening, and processing techniques [ 3 , 28 ].…”

“…Fireweed ( Epilobium angustifolium (L.) Holub) (Onagraceaeis) is a well-known medicinal plant [ 1 , 2 ] due to its anti-inflammatory, antioxidant [ 3 , 4 ], antibacterial [ 5 ], analgesic, and anti-cancer [ 3 ] properties. Traditionally, the infusion of leaves of this plant could be beneficial for headache, cold, gastrointestinal disorders, and prostate problems [ 3 ]. It is also used topically as an antiseptic for wounds and various skin and mucous membrane diseases [ 1 , 6 ].…”

Studies of the Variability of Polyphenols and Carotenoids in Different Methods Fermented Organic Leaves of Willowherb (Chamerion angustifolium (L.) Holub)

“…It is expectedthat cutting and pressing during SPF could intensify cell wall degradation, thus improving diffusion of bioactive compounds from the inner cell parts, and then initiating better extraction. In addition, there is evidence that some solid-phase fermentation parameters may activate the accumulation process of some bioactive compounds in willowherb leaves [6,7].…”