Natural antioxidants, derived from plants, fruits, vegetables, and other natural sources, have been recognized for their potential health benefits. Natural antioxidants have gained widespread attention due to their potential therapeutic properties and their role in protecting human health from oxidative stress-related disorders. Natural antioxidants are crucial for reducing the harmful effects of reactive oxygen species (ROS), free radicals (FRs), and reactive nitrogen species (RNS), which are linked to oxidative stress (OS) and a number of illnesses and ailments. With an emphasis on the division of natural antioxidants into two classes—enzymatic and non-enzymatic—including polyphenols (phenolic compounds and flavonoids) and vitamins, this review explores the production of these reactive species as well as the idea of OS. The human body’s innate antioxidant defence systems are presented, demonstrating the synergy between multiple processes in preventing oxidative damage. The benefits of these natural antioxidants in scavenging free radicals have been extensively discussed and published in previous studies. The health benefits of natural antioxidants, including their anti-inflammatory, anti-cancer, cardiovascular protective, and neuroprotective effects, are also examined. Characteristics that encourage the use of natural antioxidants include their low cost, compatibility with food, and their less adverse effect in the human body. Furthermore, the importance of medicinal plants as antioxidant-rich sources is stressed, opening up new options for health promotion and illness prevention. This comprehensive overview aims to improve understanding and appreciation of natural antioxidants, their mechanisms, applications, and the delicate balance required for their safe and successful usage in health maintenance and disease prevention. Additionally, they support immune function, improve heart health, and reduce the risk of developing chronic diseases. This review summarizes the various natural sources of antioxidants, explores their chemical properties, and examines the scientific evidence supporting their health benefits.

Introduction: Around 10 million tons of coffee beans are consumed annually worldwide, resulting in the production of 6-8 million tons of spent coffee grounds (SCGs) [1,2]. Most of this waste is discarded in landfills, causing a threat to the environment [3]. Despite the brewing process, SCGs contain many valuable ingredients, such as lipids and antioxidants, which can be extracted as coffee oil and antioxidant extracts. Due to their antioxidant activity, those products are believed to have a positive effect on the skin and could find applications in the cosmetic industry. This study aimed to assess the feasibility of using these SCG-derived products as active ingredients in cosmetic emulsions.
Methods: O/W emulsions containing different concentrations of coffee oil and aqueous and ethanol antioxidant extracts were prepared by a hot-process emulsification technique. The antioxidant properties of the oil and antioxidant extracts after heating to emulsification temperature were measured via CUPRAC assay. The physical stability of emulsions was tested using the accelerated aging method. Emulsion cytotoxicity assessment was carried out on a 2D culture of keratinocytes from the HaCaT cell line. Cell viability was assessed using FDA/PI, MTT and resazurin assays.
Results: Heating coffee oil and antioxidant extracts did not lower their antioxidant activity. The addition of SCG-derived products to cosmetics did not affect their physical stability in an accelerated aging test. Emulsions containing different concentrations of coffee oil or antioxidant extract did not show a significant cytotoxic effect on HaCaT cells cultured in a monolayer.
Conclusion: Spent coffee grounds are a valuable source of antioxidants and coffee oil with potential use in the cosmetic industry. The studied
SCG-derived products could find application as active and base ingredients in cosmetic emulsions such as face or hand creams.

Smoke tree (Cotinus coggygria Scop., Anacardiaceae family) is an important source of essential oils and extracts, with a wide range of health-promoting effects, such as antioxidant, antibacterial, antigenotoxic, antimicrobial, hepatoprotective, and anti-inflammatory potential. The antioxidant activity of plant products is of great interest due to their ability to preserve food, pharmaceutical, and cosmetic formulations from the toxic and degrading influence of oxidants or free radicals. The encapsulation of various plant extracts within delivery systems can provide prolonged and controlled recovery and protection of their antioxidants. Hence, in the current research, the stability of C. coggygria extract-loaded liposomes (non-treated and UV-irradiated) was monitored for 60 days via the impact of storage on their physical and antioxidant properties. The vesicle size, polydispersity index (PDI), and zeta potential were determined using photon correlation spectroscopy in a 60-day storage study at 4 °C. The liposome size varied over a narrow range for the 60 days, from 3131.0±17.0 nm to 3078.0±42.0 nm (for non-treated) and from 2092.0±22.0 nm to 2136.0±37.0 nm (for UV-irradiated). The PDI values obtained were between 0.273±0.089 and 0.313±0.051 (for non-treated) and 0.829±0.074 and 0.911±0.078 (for UV-irradiated). The zeta potential was -28.2±0.4 mV on the 1^st day and -29.6 mV on the 60^th day for the non-treated sample, while for the UV-irritated liposomes, the zeta potential was -21.5±0.8 mV on the 1^st day and -22.0±1.1 mV on the 60^th day. The obtained extract-loaded liposomes neutralized 81.9±0.4% of the free DPPH radicals before UV irradiation and 80.9±0.4% after irradiation. In the case of the ABTS assay, UV irradiation also significantly reduced the antioxidant capacity of the extract-loaded liposomes, from 12.02±0.54 µmol Trolox equivalent (TE)/mL to 10.55±0.28 µmol TE/mL. Furthermore, the ABTS and DPPH radicals’ scavenging activity of the UV-irradiated liposomes significantly decreased after 60 days of storage (75.4±0.7% and 8.93±0.45 µmol TE/mL, respectively), whereas in the non-treated sample, this drop in antioxidant capacity was not observed.

Introduction:

Sideritis raeseri Boiss. & Heldr., native to the Balkan Peninsula, is renowned for its composition, which is rich in diterpenoids and flavonoids. Its cultivation is rapidly expanding to meet the increasing demand for its aerial parts, particularly in beverage production and the pharmaceutical and cosmetic industries.

Methods:

S. raeseri cultivated in the Prefecture of Achaia (Peloponnese, Greece) was harvested in June 2024 and the aerial parts were air-dried. Ultrasound-assisted extraction was performed, first with petroleum ether to remove volatile and lipid contents and then with 50% aqueous methanol. Additionally, infusions were prepared by steeping the plant material in water initially heated to 95°C for 10 minutes. The hydromethanolic extract and the infusion were analyzed using Liquid Chromatography coupled with Mass Spectrometry and UV/Vis spectroscopy. Antioxidant capacity was evaluated through Total Phenolic Content (TPC), Ferric Reducing Antioxidant Power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl radical activity (DPPH•) assays.

Results:

The primary constituents in the extract were verbascoside (19.22 mg/g dry extract weight), 4′-O-methyl-isoscutellarein 7-O-[6′″-O-acetyl-β-D-allopyranosyl-(1→2)]-β-D-glucopyranoside (15.93 mg/g), echinacin (14.26 mg/g), and chlorogenic acid (11.82 mg/g). The infusion contained fewer compounds but was rich in melittoside (31.39 mg/g dry infusion weight), with chlorogenic acid (4.29 mg/g) as the second most abundant compound. Despite differences in their quantitative profiles, the polar extract (TPC: 22.69 mg GAE/g; FRAP: 66.46 mg Fe(II)/g; DPPH scavenging: IC₅₀ 2.17 mg/mL) and the infusion (19 mg GAE/g, 73.75 mg Fe(II)/g, and IC₅₀ 2.58 mg/mL, respectively) exhibited comparable antioxidant activities across all assays.

Conclusion:

These findings indicate that mountain tea infusions confer equipotent antioxidant protection to the hydromethanolic extract despite compositional variations, which can, however, affect other biological properties, warranting further investigation. Overall, this study highlights the potential of S. raeseri as a valuable natural source of antioxidants for industrial applications.

Antioxidants are either man-made or natural substances that neutralize free radicals and prevent or delay some types of cell damage caused by oxidative stress, even at low concentrations. They can be classified as endogenous (glutathione and uric acid) and exogenous. Exogenous antioxidants include natural antioxidants, synthetic antioxidants like butylated hydroxytoluene (BHT), BHT analogs, butylated hydroxy-anisole (BHA) and Gallic Acid (GA) esters, nanoscale inorganic materials, and the most controversial and most recently discovered nano-encapsulated antioxidant molecules. Several foods, including fruits and vegetables, possess antioxidant potential, like vitamins (A, C, E, B3), carotenoids (lutein, β-carotene), and polyphenols (3,6-dihydroxyflavone), which exhibit free radical-scavenging activity. They are considered potent therapeutic agents for several ailments. However, some natural antioxidants possess poor water solubility, storage instability, and limited bioavailability due to their poor absorption and their degradation upon delivery. Synthetic antioxidants can cause reductive stress, which limits their applications. To overcome these problems, inorganic nanoparticles have been thoroughly studied for their antioxidant properties, and recently, nano-antioxidants have shown the ability to ameliorate oxidative stress with higher sensitivity, cellular antioxidant activity, lowest cytotoxicity, and targeted delivery. Nano-antioxidants are nanoparticles that are capable of capturing chain-carrying radicals and decreasing the number of initiation processes to alleviate the rate of autoxidation. Despite having their own antioxidant potentials, nanomaterials can be used as passive delivery systems for smaller antioxidants. Various combinations, including covalent interaction or the encapsulation of antioxidants with a variety of nanomaterials such as inorganic nanomaterials, metal nanomaterials, natural polymer-based nanomaterials, liposomes, or protein-polysaccharide-based conjugated nanomaterials, have been developed and are under examination for diverse applications. Nanomaterials are optimal for medicine and drug delivery systems because of their smaller size and extensibility. However, a complete understanding of the mechanism of action, origin, and physical and chemical nature of nano-antioxidant composites is required to understand their biological and catalytic activity.

Keywords: antioxidants; nanoantioxidants; oxidative stress; free radicals.

As the consumer demand for healthier foods free from chemical preservatives grows, the food industry faces increasing pressure to develop minimally processed, natural, "clean label" products [1]. One promising approach is the use of natural preservatives, such as bioactive metabolites produced by microorganisms. Wickerhamomyces anomalus is a yeast that produces extracellular peptides with biopreservative potential. Previous studies have demonstrated their effectiveness against the spoilage yeast D. bruxellensis and the reference strain S. cerevisiae DBPVG 6500 [2], positioning these peptides as a valuable tool for natural food preservation.

Therefore, this study evaluated the antimicrobial and antioxidant properties of peptides derived from W. anomalus's metabolism. The peptides were obtained by culturing W. anomalus DBVPG 3003 in YEPD medium, followed by ultrafiltration to isolate a 2–10 kDa fraction. Antimicrobial assays demonstrated strong bactericidal activity against Escherichia coli, Listeria monocytogenes, and Salmonella sp. at 1 mg/mL, with CFU reductions of 4–5 orders of magnitude. At 0.5 mg/mL, bacteriostatic effects were observed against L. monocytogenes and Salmonella sp., while the yeast strains (Candida albicans and C. krusei) showed resistance at all of the tested concentrations.

Antioxidant activity, assessed using DPPH and FRAP assays, highlighted the peptides’ substantial radical scavenging and ferric-reducing capabilities. At 1 mg/mL, the peptides achieved a DPPH inhibition of 1856 ± 37.5µM TE/mL and a FRAP value of 5843 ± 220µM TE/mL, demonstrating their strong antioxidant potential.

These results underscore the potential of W. anomalus peptides as natural preservatives for the food industry, enhancing safety, extending shelf life, and supporting the development of healthier "clean label" products. Beyond food applications, their antioxidant and antimicrobial properties also present opportunities in the pharmaceutical, cosmetic, and nutraceutical industries.

References:

[1] Asioli, D., et al. (2017). https://doi.org/10.1016/j.foodres.2017.07.022

[2] Comitini, Fet al. (2004). https://doi.org/10.1111/j.1574-6968.2004.tb09761.x

Coffee is one of the most popular beverages in the world. Europe has the highest consumption of green coffee beans and generates about 3.4 million tons of spent coffee grounds (SCGs) every year. Despite the long and complex processing of coffee beans, SCGs still contain numerous valuable compounds, including antioxidants. These compounds have a beneficial influence on various aspects of human health and even anticancer activity. Cancer is one of the leading causes of death worldwide. The skin, as the largest organ of our body, is exposed to dangerous external factors such as UV, which has been defined as the main cause of skin cancers. This research aims to investigate the possible usage of a full antioxidant extract from SCGs, as well as single compounds like caffeine and chlorogenic acid. in anti-cancer therapies.

The antioxidant extract, caffeine and chlorogenic acid were obtained by way of an optimized extraction process. The influence of the obtained compounds and the entire extract on normal and cancer skin cell lines was checked. The effect on melanoma cells at various metastatic stages and on squamous-cell carcinoma was tested. The impact of the tested compounds was assessed using cytotoxicity tests such as FDA/PI, MTT and resazurin staining.

The impact of each tested extract, along with caffeine and chlorogenic acid, varied depending on the cell lines analyzed. Notably, differences were observed even among melanoma cells at distinct metastatic stages. For instance, the ethanolic extract demonstrated a suppressive effect on the metabolic activity of primary melanoma cells.

SCGs are a remarkable source of various antioxidants with possible applications in various fields. This study allows us to gain unique knowledge about the impact of the antioxidants contained in SCGs on normal and cancerous skin cells.

This work was supported by the National Science Centre (Poland) Grants no.2023/49/N/NZ5/03578.

Cichorium intybus, a medicinal plant, is valued for its bioactive compounds, such as flavonoids, phenolic acids, and other phytochemicals. In particular, quercetin is a flavonoid with potent antioxidant properties that combat oxidative stress and aid in preventing chronic diseases. Additionally, quercetin exhibits anti-inflammatory, antihistaminic, and immunomodulatory effects, making it a popular choice for promoting overall health. The objective of this study was to compare the extraction efficiency of quercetin using natural deep eutectic solvents (NADESs) based on glucose and glycerol with commercial solvents from the aerial parts of Cichorium intybus cultivated at the Institute “Dr. Josif Pančić.” Extraction was performed using eight solvents: five NADES formulations (glycerol–citric acid 1:1, glycerol–urea 1:1, glucose–lactic acid 1:1, glucose–urea 1:2, and glucose–glycerol 1:2) and three commercial solvents (water, ethanol, and methanol). Quercetin content was quantified using ultrasonic-assisted extraction. All NADESs outperformed the commercial solvents in extracting quercetin. The quercetin content extracted using NADESs ranged from 1.52 to 2.69 mg/g of crude extract, with the glucose–lactic acid NADES yielding the highest quercetin content at 2.69 mg/g of crude extract. In contrast, the quercetin levels obtained with commercial solvents ranged from 0.40 to 1.37 mg/g of crude extract. The NADESs demonstrated remarkable efficiency in extracting bioactive compounds such as quercetin due to their tunable physicochemical properties, including high polarity and hydrogen bonding capacity, which enhance solubility and selectivity. Additionally, NADESs are environmentally friendly, biodegradable, and non-toxic, making them a sustainable alternative to conventional organic solvents while improving extraction efficiency. Their unique ability to mimic natural cellular environments stabilizes sensitive bioactive compounds during extraction, preserving their antioxidant potential and functional properties.

Acknowledgement:

This work is supported by Provincial Secretariat for Higher Education and Scientific Research, Province of Vojvodina (Grant No. 142-451-3474/2023).

The wood apple, or Limonia acidissima Groff, is a tropical fruit that is a member of the Rutaceae family. It grows extensively in Southeast Asia and has its origins in Sri Lanka, India, and Myanmar. This fruit has a long history of use in traditional medicine due to its remarkable nutritional and medicinal properties. Wood apple pulp is high in β-carotene, a precursor to vitamin A. It also contains a lot of B vitamins, such as riboflavin and thiamine, and trace levels of ascorbic acid. Furthermore, a variety of phytochemicals associated with L. acidissima have been linked to health benefits such as antioxidant, hepatoprotective, antimicrobial, neuroprotective, antidiabetic, anti-inflammatory, analgesic, antiulcer, and antihyperlipidemic properties. These include polyphenolic chemicals, saponins, phytosterols, tannins, triterpenoids, coumarins, and amino acids. According to the findings of several studies, wood apple fruit has a high anticancer effect because it inhibits cancer cell multiplication. The wood apple finds wide-ranging commercial applications, which include the preparation of ready-to-drink beverages, syrups, jellies, chutneys, and a variety of other food products. In conclusion, this review discusses the nutritional and phytochemical contents of wood apple, shows its antioxidant, anti-inflammatory, and anti-diabetic properties, and investigates its potential for value-added product creation. Nonetheless, it is critical to recognise that the molecular mechanisms behind these traits remain an unexplored domain. To assure the safe integration of wood apple fruit into the culinary, cosmetics, and pharmaceutical industries, comprehensive clinical trials with toxicity evaluations are required. This review offers a comprehensive look at this fascinating fruit, detailing its health benefits, nutritional profile, and traditional uses in medicine.

Thymus serpyllum extracts express antioxidative, antispasmodic, anti-inflammatory, antihypertensive, cytotoxic, antiseptic, antibacterial, and antifungal activities due to the presence of polyphenols. Polyphenol compounds from T. serpyllum extracts are sensitive to temperature, light, oxidation, and pH changes, possess low bioavailability, and have a bitter taste. Thus, despite their great bioactive potential, their application in different industries is quite limited. Liposomes can enhance the stability of encapsulated sensitive compounds and the bioavailability of poorly hydrosoluble components. Additionally, liposomal particles have outstanding biodegradability and a strong affinity for cells. Furthermore, the bilayer membrane of liposomes and its permeability can be modified by adding sterols, such as ergosterol, which can change the end product’s properties and pharmacological behavior. Thus, the antioxidant activity of ergosterol–phospholipid liposomes with encapsulated T. serpyllum ethanol extract was examined. The DPPH and ABTS radical scavenging activity and ferric ion-reducing potential of the extract-loaded liposomes with different proportions of ergosterol (10 and 20 mol %) were investigated. The percentage neutralization of DPPH radicals for the samples with 10 and 20 mol % of ergosterol was 56.3±2.2% and 53.1±3.5%, respectively. The elimination of ABTS radicals was significantly higher and amounted to 95.3±2.6% (10 mol % of ergosterol) and 98.2±1.7% (20 mol % of ergosterol). The Fe³⁺-reducing potential of the liposomes was 0.14±0.01 mmol FeSO4/L and 0.15±0.03 mmol FeSO₄/L (for 10 and 20 mol % of ergosterol, respectively). Therefore, there was no significant difference between the antioxidant capacity of the liposomes with differing amounts of ergosterol. Using LC/DAD/MS analysis, the polyphenol compounds identified in the encapsulated extract included chlorogenic, caffeic, rosmarinic, and salvianolic acids, salvianolic acid K isomer, 6,8-Di-C-glucosylapigenin, 6-hydroxyluteolin 7-O-glucoside, luteolin 7-O-glucuronide, and apigenin glucuronide. The antioxidant potential demonstrated in this study highlights the potential applications of liposomes prepared with ergosterol and active compounds of T. serpyllum extract in functional foods, pharmaceutics, or cosmetics.