Coffee enriched with willow (Salix purpurea and Salix myrsinifolia) bark preparation – Interactions of antioxidative phytochemicals in a model system

The Antioxidative Effects of Picein and Its Neuroprotective Potential: A Review of the Literature

Neurodegenerative diseases (NDDs) are the main cause of dementia in the elderly, having no cure to date, as the currently available therapies focus on symptom remission. Most NDDs will progress despite treatment and eventually result in the death of the patient after several years of a burden on both the patient and the caregivers. Therefore, it is necessary to investigate agents that tackle the disease pathogenesis and can efficiently slow down or halt disease progression, with the hope of curing the patients and preventing further burden and mortality. Accordingly, recent research has focused on disease-modifying treatments with neuroregenerative or neuroprotective effects. For this purpose, it is necessary to understand the pathogenesis of NDDs. It has been shown that oxidative stress plays an important role in the damage to the central nervous system and the progression of neurodegenerative disorders. Furthermore, mitochondrial dysfunction and the accumulation of unfolded proteins, including beta-amyloid (Aβ), tau proteins, and α-synuclein, have been suggested. Accordingly, cellular and molecular studies have investigated the efficacy of several natural compounds (herbs and nutritional agents) for their neuroprotective and antioxidative properties. The most popular herbs suggested for the treatment and/or prevention of NDDs include Withania somnifera (ashwagandha), ginseng, curcumin, resveratrol, Baccopa monnieri, and Ginkgo biloba. In some herbs, such as ginseng, preclinical and clinical evidence are available for supporting its effectiveness; however, in some others, only cellular and animal studies are available. In line with the scant literature in terms of the effectiveness of herbal compounds on NDDs, there are also other herbal agents that have been disregarded. Picein is one of the herbal agents that has been investigated in only a few studies. Picein is the active ingredient of several herbs and can be thus extracted from different types of herbs, which makes it more available. It has shown to have anti-inflammatory properties in cellular and plant studies; however, to date, only one study has suggested its neuroprotective properties. Furthermore, some cellular studies have shown no anti-inflammatory effect of picein. Therefore, a review of the available literature is required to summarize the results of studies on picein. To date, no review study seems to have addressed this issue. Thus, in the present study, we gather the available information about the antioxidative and potential neuroprotective properties of picein and its possible effectiveness in treating NDDs. We also summarize the plants from which picein can be extracted in order to guide researchers for future investigations.

Coffee Phenolics and Their Interaction with Other Food Phenolics: Antagonistic and Synergistic Effects

Due to its strong aroma and stimulating effect, coffee is the most consumed beverage worldwide, following water. Apart from being a luscious food product, its contents of high phenolic compounds dominated by chlorogenic acid, caffeic acid, and their derivatives have caused coffee to be consumed by individuals at higher ratios and have also encouraged the number of varying research studies for its health-promoting properties. However, it should be noted that these desirable beneficial actions of coffee phenolics are in dynamic behaviors, highly dependent on the roasting process parameters and presence of different types of phenolic compounds in the media. Interactions between coffee phenolics and other phenols might end up with induced or reduced biological activities, which is called synergism or antagonism, respectively. In this paper, bioactive properties such as antioxidant, enzyme inhibition, and chelating power are reviewed in terms of synergism and antagonism of coffee phenolics and other bioactive compounds that are introduced into the matrix, such as cacao, ginger, cinnamon, willow bark, cardamom, and chili pepper. Furthermore, how these properties are affected after in vitro digestion and potential reasons for the outcomes are also briefly discussed with the aim of providing a better understanding of these interactions for the food industry. Revealing the synergistic and antagonistic interactions of the phenolics between coffee and different ingredients in a food matrix and their effects on bioactivity mechanisms is not only important for scientific studies but also for conscious food consumption of individuals.

Identification and accumulation of phenolic compounds in the leaves and bark of Salix alba (L.) and their biological potential

The study examines the phenolic compounds in hydromethanolic extracts of Salix alba (L.) leaves and bark as well as their antioxidant activity and cytotoxic potential. UPLC-PDA-Q/TOF-MS analysis showed a total of 29 phenolic compounds in leaves and 34 in bark. Total phenolic compound content was 5575.96 mg/100 g of dry weight (DW) in leaves and 2330.31 mg/100 g DW in bark. The compounds were identified as derivatives of phenolic acids (seven in leaves and five in bark), flavanols and procyanidins (eight in leaves and 26 in bark) and flavonols (14 in leaves and three in bark). Both extracts exhibited strong antioxidant potential, assessed by radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), but the bark extract was even stronger than the ascorbic acid used as a standard. The cytotoxicity of both extracts was evaluated against human skin fibroblasts and human epidermal keratinocytes cell lines using the Presto Blue cell viability assay. The keratinocytes were more resistant to tested extracts than fibroblasts. The leaf and bark extracts at concentrations which exhibited antioxidant activity were also not toxic against the keratinocyte cell line. Thus, S. alba extracts, especially the leaf extract, offer promise as a nontoxic natural antioxidant, in cosmetic products or herbal medicines, and as a source of bioactive secondary metabolites.

The Health-Promoting Potential of Salix spp. Bark Polar Extracts: Key Insights on Phenolic Composition and In Vitro Bioactivity and Biocompatibility

Salix spp. have been exploited for energy generation, along with folk medicine use of bark extracts for antipyretic and analgesic benefits. Bark phenolic components, rather than salicin, have demonstrated interesting bioactivities, which may ensure the sustainable bioprospection of Salix bark. Therefore, this study highlights the detailed phenolic characterization, as well as the in vitro antioxidant, anti-hypertensive, Staphylococcus aureus growth inhibitory effects, and biocompatibility of Salix atrocinerea Brot., Salix fragilis L., and Salix viminalis L. bark polar extracts. Fifteen phenolic compounds were characterized by ultra-high-performance liquid chromatography-ultraviolet detection-mass spectrometry analysis, from which two flavan-3-ols, an acetophenone, five flavanones, and a flavonol were detected, for the first time, as their bark components. Salix bark extracts demonstrated strong free radical scavenging activity (5.58–23.62 µg mL⁻¹ IC₅₀ range), effective inhibition on angiotensin-I converting enzyme (58–84%), and S. aureus bactericidal action at 1250–2500 µg mL⁻¹ (6–8 log CFU mL⁻¹ reduction range). All tested Salix bark extracts did not show cytotoxic potential against Caco-2 cells, as well as S. atrocinerea Brot. and S. fragilis L. extracts at 625 and 1250 µg mL⁻¹ against HaCaT and L929 cells. These valuable findings can pave innovative and safer food, nutraceutical, and/or cosmetic applications of Salix bark phenolic-containing fractions.

Species of the Genus Salix L.: Biochemical Screening and Molecular Docking Approach to Potential Acetylcholinesterase Inhibitors

The genus Salix includes about 500 different, mainly woody species with potentially significant medicinal values. The aim of this study was to evaluate the chemical composition and antioxidant activity of little-studied bark and leaves extracts of seven different species of the genus Salix, and to examine the acetylcholinesterase (AChE) inhibitory potential of selected compounds. The extracts were characterized by High Pressure Liquid Chromatography (HPLC). Total phenolics and flavonoids content was determined spectrophotometrically and the antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and hydroxyl radical (•OH) scavenging assays. Molecular docking studies were conducted in order to elucidate the interaction and binding affinity between selected compounds of willow bark and leaves against AChE. The major components in bark and leaves of most of the species were rutin (1.26–22.09 mg/g), salicin (1.62–17.33 mg/g), chlorogenic acid (0.74–7.53 mg/g) and epicatechin (0.71–4.83 mg/g). The latter three compounds demonstrated significant inhibitory potential against AChE in docking studies. All extracts exhibited notable antioxidant activity as scavengers of both DPPH• and •OH. The obtained results indicate that willow species other than those in commercial use, and not only bark, but willow leaves as well, could be utilized as sources of valuable phytocompounds with antioxidant and neuroprotective properties.

Bioactive Characteristics and Storage of Salt Mixtures Seasoned with Powdered Cereal Sprouts

Sprouting is a process that can improve nutritional and beneficial properties of seeds. This work studies the design of the new healthier product salt seasoned with freeze-dried powdered cereal sprouts. The cereal sprouts mixture (SM), including barley sprouts (BS), oat sprouts (OS), and wheat sprouts (WS), was optimized in terms of total phenolic content (TPh) and antioxidant capacity (AC). The sprouts mixture with optimal features (OSM), composed of 92.9% BS, 0% OS, and 7.1% WS, had 482.82 mg GAE/100 g of polyphenols and 797.97 µmol TE/100 g antioxidant capacity. HPLC analysis showed that the most abundant phenolic compound in OMS was gallic acid (94.27 mg/100 g). OSM was mixed with salt in different ratios (1 : 1, 1 : 2, and 1 : 3) and stored in transparent and amber bottles for six months. Colour, TPh, and AC retention of seasoned salts and OSM was significantly better (p<0.05) preserved in amber bottles during storage, protected from light. The sprout content was in correlation with TPh and AC retention and colour change. These results suggest that cereal sprouts can be used as a safe ingredient for food products such as seasoned salt, adding value to the basic daily diet with no changes in dietary habits.

Effects of sprouting and postharvest storage under cool temperature conditions on starch content and antioxidant capacity of green pea, lentil and young mung bean sprouts

The effects of germination of selected legumes and further storage of sprouts under cool conditions on the phenolics, antioxidant activity and starch content and their potential bioaccessibility were elucidated. In green pea and mung bean sprouts a slight increase of chemically extractable phenolics (including flavonoids) during the first 4 days of sprouting was observed. Digestion in vitro released phenolics; however, flavonoids were poorly bioaccessible. Storage of green pea sprouts decreased reducing power and increased the antiradical ability. Reducing potential of potentially bioaccessible fraction of stored lentil sprouts was elevated of 40%, 31% and 23% in 3-, 4- and 5-day-old sprouts, respectively. Postharvest storage significantly increases the starch digestibility and values of expected glycemic index (eGI)--the highest eGIs were determined for 5-day-old stored sprouts; 75.17-green pea, 83.18-lentil and 89.87-mung bean. Bioactivity and nutritional quality of legumes is affected by sprouting and further storage at low temperatures.