In many countries, apple pomace (AP) is one of the most produced types of agri-food waste (globally, it is produced at a rate of ~4 million tons/year). If not managed properly, such bio-organic waste ...can cause serious pollution of the natural environment and public health hazards, mainly due to the risk of microbial contamination. This review shows that AP can be successfully reused in different industrial sectors-for example, as a source of energy and bio-materials-according to the idea of sustainable development. The recovered active compounds from AP can be applied as preservatives, antioxidants, anti-corrosion agents, wood protectors or biopolymers. Raw or processed forms of AP can also be considered as feedstocks for various bioenergy applications such as the production of intermediate bioenergy carriers (e.g., biogas and pyrolysis oil), and materials (e.g., biochar and activated carbon). In the future, AP and its active ingredients can be of great use due to their non-toxicity, biodegradability and biocompatibility. Given the increasing mass of produced AP, the commercial applications of AP could have a huge economic impact in the future.
Apples are among the most popular fruits in the world. They are rich in phenolic compounds, pectin, sugar, macro- and microelements. Applying different extraction techniques it is possible to isolate ...a particular group of compounds or individual chemicals and then test their biological properties. Many reports point to the antioxidant, antimicrobial, anticancer and many other beneficial effects of apple components that may have potential applications in food, pharmaceutical and cosmetic industries. This paper summarizes and compiles information about apple phenolic compounds, their biological properties with particular emphasis on health-related aspects. The data are reviewed with regard to different apple varieties, part of apple, cultivation model and methods of extraction.
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•Content of individual phenolic compounds strongly depends on apple variety.•Phenolic compounds act as modulators of signaling pathway in the body.•Chemopreventive properties of apple extracts are well documented.
In the study the cold-pressed, natural (unfiltered, unrefined) vegetable oils: hemp and milk thistle seed oils were tested for their chemical composition and antioxidant properties. The ...physico-chemical parameters, content of saturated and unsaturated fatty acids were determined. Solid phase extraction and simple extraction with the use of methanol, ethanol, 80% methanol, 80% ethanol were used to obtain the extracts for the analysis of antioxidant activity and phenolic compounds in oils. The composition of phenolic compounds was studied by means of high-performance liquid chromatography (HPLC-DAD) and spectrophotometric test with the Folin-Ciocalteu reagent. The antioxidant property of extracts was established by means of the following methods: with the DPPH
(2,2-diphenyl-1-picrylhydrazyl) radical, ABTS
(2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) cation radical, FRAP (ferric ion reducing antioxidant parameter) and CUPRAC (cupric-reducing antioxidant capacity). Moreover the influence of chlorogenic acid on the inhibition of lipid peroxidation process in the hemp and milk thistle seed oils was also investigated. The tested oils showed different antioxidant properties which was related to the their different chemical composition. The main phenolic compounds present in hemp seed oil were vanillic, ferulic and p-coumaric acids, (-)epicatechin, catechin, kaempferol and procyanidin B2, whereas in milk thistle seed oil-catechins, procyanidin B2, procyanidin C1, p-coumaric acid, phloridzin, quercetin, protocatechuic acid, kaempferol, and syringic acid. The methanolic extracts of hemp and milk thistle seed oils showed the highest antiradical activity, whereas the ethanolic extracts revealed the best reducing properties. The obtained antioxidant parameters for hemp seed oil were: the IC
= 3.433 ± 0.017 v/v (DPPH test), the percent of ABTS
inhibition = 93.301 ± 1.099%, FRAP value = 1063.883 ± 39.225 µmol Fe
, CUPRAC value = 420.471 ± 1.765 µmol of Trolox. Whereas the antioxidant parameters for milk thistle seed oil were: the IC
= 5.280 ± 0.584 v/v (DPPH test), 79.59 ± 3.763% (ABTS test), 2891.08 ± 270.044 µmol Fe
(FRAP test), 255.48 ± 26.169 µmol of Trolox (CUPRAC assay). Chlorogenic acid effectively inhibited the lipid peroxidation process in hemp and milk thistle seed oils.
5-O-Caffeoylquinic acid (5-CQA, chlorogenic acid) is one of the major chlorogenic acids present in many fruits, vegetables and herbs. Because of its high biological importance and the widespread ...confusion in the literature concerning the nomenclature of caffeoylquinic acids, the comprehensive structural, spectroscopic and biological studies are necessary. In this work the FT-IR, FT-IR ATR, FT-Raman, UV, 1H (400.15 MHz), 13C (100.63 MHz) and 2D (COSY, HSQC, HMBC) NMR, as well as theoretical (at B3LYP/6-311++G(d,p) level) studies of 5-O-caffeoylquinic acid were carried out. Accurate geometrical parameters as well as atomic charges are reported. Full and proper assignments of bands on vibrational as well as 1H and 13C NMR spectra are made. In addition, 5-CQA was tested for its minimum inhibitory concentration (MIC) against Escherichia coli, Staphylococcus aureus, Enterococcus faecium, Proteus vulgaris, Pseudomonas aeruginosa, Klebsiella pneumoniae and Candida albicans. The obtained MIC values were in the range 5–10 mg/ml. Out of the tested microorganisms, 5-CQA possesses the strongest antimicrobial activity against Klebsiella pneumonia.
•Correct assignment of bands on the 1H and 13C NMR spectra of 5-CQA is reported.•Analysis of the vibrational spectra supported by high-level calculations is done.•The MIC values against the selected bacteria and fungus is found to be 5–10 mg/ml.
The copper (II) complex of ursolic acid (Cu(II) UA) was synthesized and discussed in terms of its infrared, UV-visible spectra, quantum-chemical calculations at B3LYP/6-31G(d) level and antioxidant ...capacity. The copper (II) complex was stable in methanolic solution with the molar ratio metal:ligand 1:1. The data obtained by FT-IR confirmed the metal ion coordination through the carboxylate anion. The antioxidant properties of ursolic acid and its complex with Cu were discussed on the basis of energy of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and values of chemical reactivity parameters. The antiradical properties of ursolic acid and the Cu (II) complex were examined against DPPH
and HO
radicals, and the ferric reducing antioxidant power (FRAP) was examined. The Cu(II) complex showed higher antioxidant activity than ursolic acid, i.e., in DPPH
assay, the EC
for UA was 47.0 mM, whereas, for Cu(II), UA EC
= 19.5 mM; the FRAP value for UA was 20.8 µM
, and 35.4 µM
for Cu(II) UA (compound concentration 3 mM). Although there was no distinct difference in the antioxidant activity against HO
between these two chemicals, they were both better HO
scavengers than DPPH
and showed different kinetics in the reaction with DPPH
.
The cytoprotective and anticancer action of dietary in-taken natural polyphenols has for long been attributed only to their direct radical scavenging activities. Currently it is well supported that ...those compounds display a broad spectrum of biological and pharmacological outcomes mediated by their complex metabolism, interaction with gut microbiota as well as direct interactions of their metabolites with key cellular signaling proteins. The beneficial effects of natural polyphenols and their synthetic derivatives are extensively studied in context of cancer prophylaxis and therapy. Herein we focus on cell signaling to explain the beneficial role of polyphenols at the three stages of cancer development: we review the recent proceedings about the impact of polyphenols on the cytoprotective antioxidant response and their proapoptotic action at the premalignant stage, and finally we present data showing how phenolic acids (e.g., caffeic, chlorogenic acids) and flavonols (e.g., quercetin) hamper the development of metastatic cancer.
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In this study the peels of ecologically grown apple (Malus domestica) cultivars: Gold Milenium (a new scab-resistant variety) and Papierowka (Papirovka; an old, sensitive to apple scab variety) were ...examined for their composition (phenolic compounds, triterpenoids, simple organic acids, macro-, microelements, reducing sugars, L-ascorbic acid), pro- and antioxidant properties as well as their application in reduction of the oxidative stress in cultured human skin fibroblast. The higher content of phenolic compounds correlated with the greater pro- and antioxidant activity of the peels of Papierowka compared to Gold Milenium in DPPH·, ABTS
, FRAP and CUPRAC assays as well as an ability to inhibition of lipid peroxidation. The quantity of the compounds strongly depended on the type of extraction. The extract of Papierowka peels possessed much higher amount of phenolic compounds compared to Gold Milenium (Papierowka: 3.68 ± 0.20 mg/g peel ultrasound assisted extraction (u.a.e); 2.02 ± 0.13 mg/g peel conventional extraction (c.e.); Gold Milenium: 1.46 ± 0.19 mg/g peel u.a.e; 1.15 ± 0.04 mg/g peel c.e. according the HPLC measurement). The pro-oxidant activity of the extract from Papierowka peels can be correlated with the content of phenolic compounds and metal ions as well. The apple peel extract is promising agent reducing the oxidative stress in skin fibroblast.
For many years, metal–flavonoid complexes have been widely studied as a part of drug discovery programs, but in the last decade their importance in materials science has increased significantly. A ...deeper understanding of the role of metal ions and flavonoids in constructing simple complexes and more advanced hybrid networks will facilitate the assembly of materials with tailored architecture and functionality. In this Review, we highlight the most essential data on metal–flavonoid systems, presenting a promising alternative in the design of hybrid inorganic–organic materials. We focus mainly on systems containing CuII/I and FeIII/II ions, which are necessary in natural and industrial catalysis. We discuss two kinds of interactions that typically ensure the formation of metal–flavonoid systems, namely coordination and redox reactions. Our intention is to cover the fundamentals of metal–flavonoid systems to show how this knowledge has been already transferred from small molecules to complex materials.
Natural carboxylic acids are plant-derived compounds that are known to possess biological activity. The aim of this review was to compare the effect of structural differences of the selected ...carboxylic acids (benzoic acid (BA), cinnamic acid (CinA), p-coumaric acid (p-CA), caffeic acid (CFA), rosmarinic acid (RA), and chicoric acid (ChA)) on the antioxidant, antimicrobial, and cytotoxic activity. The studied compounds were arranged in a logic sequence of increasing number of hydroxyl groups and conjugated bonds in order to investigate the correlations between the structure and bioactivity. A review of the literature revealed that RA exhibited the highest antioxidant activity and this property decreased in the following order: RA > CFA ~ ChA > p-CA > CinA > BA. In the case of antimicrobial properties, structure-activity relationships were not easy to observe as they depended on the microbial strain and the experimental conditions. The highest antimicrobial activity was found for CFA and CinA, while the lowest for RA. Taking into account anti-cancer properties of studied NCA, it seems that the presence of hydroxyl groups had an influence on intermolecular interactions and the cytotoxic potential of the molecules, whereas the carboxyl group participated in the chelation of endogenous transition metal ions.
The coronavirus pandemic (SARS CoV-2) that has existed for over a year, constantly forces scientists to search for drugs against this virus.
research and selected experimental data have shown that ...compounds of natural origin such as phenolic acids and flavonoids have promising antiviral potential. Phenolic compounds inhibit multiplication of viruses at various stages of the viral life cycle, e.g., attachment (disturbance of the interaction between cellular and viral receptors), penetration (inhibition of viral pseudo-particle fusion to the host membrane), replication (inhibition of integrase and 3C-like protease), assembly and maturation (inhibition of microsomal triglyceride transfer protein (MTP) activity hydrolysis) and release (inhibition of secretion of apolipoprotein B (apoB) from infected cells). Phenolic compounds also indirectly influence on the viral life cycle by affecting the host cell's biochemical processes that viruses use for their own benefit. Phenolic compounds may inhibit the proteasomes and cellular deubiquitinating activity that causes an increase in the ubiquitinated proteins level in host cells. This, in turn, contributes to the lowering the available ubiquitin molecules that viruses could use for their own replication. One of the drug design strategy for the treatment of viral diseases may be an enhancement of the antiviral properties of phenolic compounds by metal complexation. Many studies have shown that the presence of a metal ion in the structure can significantly affect the affinity of the compound to key structural elements of the SARS CoV-2, such as M
protease, RNA-dependent RNA polymerase (RdRp) and spike protein. We believe that in the era of coronavirus pandemic, it is necessary to reconsider the search for therapeutics among well-known compounds of plant origin and their metal complexes.
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