Topical application of spent coffee ground extracts protects skin from ultraviolet B-induced photoaging in hairless mice

Unlocking the potential of spent coffee grounds via a comprehensive biorefinery approach: production of microbial oil and carotenoids under fed-batch fermentation

The valorization of renewable feedstock to produce a plethora of value-added products could promote the transition towards a circular bioeconomy. This study presents the development of cascade processes to bioconvert spent coffee grounds (SCGs) into microbial oil and carotenoids employing sustainable practices. The stepwise recovery of crude phenolic extract and coffee oil was carried out using green or recyclable solvents, i.e., aqueous ethanol and hexane. Palmitic acid (43.3%) and linoleic acid (38.9%) were the major fatty acids in the oil fraction of SCGs. The LC-MS analysis of crude phenolic extracts revealed that chlorogenic acid dominated (45.7%), while neochlorogenic acid was also detected in substantial amounts (24.0%). SCGs free of coffee oil and phenolic compounds were subjected to microwave-assisted pretreatment under different irradiations and solvents to enhance subsequent enzymatic saccharification. Microwave/water pretreatment at 400 W, followed by enzymatic hydrolysis with proteases, hemicellulases, and cellulases, at 50 g/L initial SCGs, led to satisfying overall yields of cellulose (75.4%), hemicellulose (50.3%), and holocellulose (55.3%). Mannan was the most extractable polysaccharide followed by galactan and arabinan. SCGs hydrolysate was used in fed-batch bioreactor fermentations with Rhodosporidium toruloides to produce 24.0 g/L microbial oil and carotenoids of 432.9 μg/g biomass.

Preventive and Therapeutic Benefits of Natural Ingredients in Photo-Induced Epidermal Dysfunction

BACKGROUND

The skin, particularly the epidermis, is subjected to various external stresses, including ultraviolet (UV) irradiation. UV irradiation, mainly UVB at wavelength of 280-315 nm, can alter several epidermal functions, including cutaneous inflammation, epidermal hyperproliferation, DNA damage, disruption of epidermal permeability barrier and reduction in stratum corneum hydration levels. Because of the negative impacts of UVB irradiation on epidermal functions, great efforts have been made to develop regimens for the protection of alterations in epidermal function induced by UV irradiation.

SUMMARY

While sunscreen can provide physical barrier to UV light, some natural ingredients can also effectively protect the skin from UVB irradiation-induced damages. Studies have demonstrated that either topical or oral administrations of some natural ingredients attenuate UVB irradiation-induced alterations in the epidermal function. The underlying mechanisms by which natural ingredients improve epidermal functions are attributable to antioxidation, stimulation of keratinocyte differentiation, increases in the content of epidermal natural moisturizers and inhibition of inflammation.

KEY MESSAGE

Some natural ingredients exhibit protective and therapeutical benefits in photo-induced epidermal dysfunctions via divergent mechanisms.

The Promising Role of Polyphenols in Skin Disorders

The biochemical characteristics of polyphenols contribute to their numerous advantageous impacts on human health. The existing research suggests that plant phenolics, whether consumed orally or applied directly to the skin, can be beneficial in alleviating symptoms and avoiding the development of many skin disorders. Phenolic compounds, which are both harmless and naturally present, exhibit significant potential in terms of counteracting the effects of skin damage, aging, diseases, wounds, and burns. Moreover, polyphenols play a preventive role and possess the ability to delay the progression of several skin disorders, ranging from small and discomforting to severe and potentially life-threatening ones. This article provides a concise overview of recent research on the potential therapeutic application of polyphenols for skin conditions. It specifically highlights studies that have investigated clinical trials and the use of polyphenol-based nanoformulations for the treatment of different skin ailments.

Proteomics analysis to investigate the potential mechanism of theacrine against UV-induced skin photodamage

AIM

This study aimed to explore the underlying mechanism of theacrine treatment of UV-induced skin photodamage.

MATERIALS AND METHODS

Tandem Mass Tag (TMT) relative quantitative proteomics analysis was used to characterize the proteins and pathways associated with the ability of theacrine to combat photodamage in mouse skin by modeling UV irradiation of the backs of ICR mice.

RESULTS

Apoptosis-related proteins and signaling pathways play a key role in the ability of theacrine to protect against skin photodamage, according to proteomic and bioinformatics analysis; molecular docking and Western blotting further revealed that theacrine was associated with apoptosis-related proteins (p53, Bcl-2, Bax, caspase-3, and cleaved-caspase-3) with strong binding affinity, which can significantly reduce skin cell apoptosis induced by UV exposure.

CONCLUSION

The findings revealed that theacrine can reduce UVB-induced epidermal damage by controlling the apoptosis signaling pathway, implying that theacrine could be a useful anti-UVB damage agent.

Sustainability issues along the coffee chain: From the field to the cup

The coffee industry is one of the most important commercial value chains worldwide. Nonetheless, it is also associated to several social, economic, and environmental concerns that impair its sustainability. The present review is focused on these main sustainability concerns from the field to the coffee cup, as well as on the strategies that are being developed and/or implemented to attain sustainability and circular economy principles in the different chain segments. In this context, distinct approaches have been applied, such as sustainable certifications (e.g., voluntary sustainability standards), corporate sustainability initiatives, direct trade, relationship coffee concepts, geographical indication, legislations, waste management, and byproducts valorization, among others. These strategies are addressed and discussed throughout this review, as well as their recognized advantages and limitations. Overall, there is still a long way to go to attain the much-desired sustainability in the coffee chain, being essential to join the efforts of all actors and entities directly or indirectly involved, namely, producers, retailers, roasters, governments, educational institutions (such as universities and scientific research institutes), and organizations.

Spent Coffee Grounds’ Valorization towards the Recovery of Caffeine and Chlorogenic Acid: A Response Surface Methodology Approach

The amount of spent coffee grounds (SCGs) created, represents an environmental challenge worldwide. In this context, the aim of the present study was to exploit the potential of SCGs as a source of bioactive compounds that can be utilized in high value-added products. Thus, a cost-effective and environmentally friendly extraction technique was developed to ensure extracts with high total phenolic content and antioxidant activity, as well as significant amounts of caffeine and chlorogenic acid. Response surface methodology was implemented to evaluate the effects of the main extraction parameters (i.e., time, temperature, and ethanol-to-water ratio) and their interactions on the defined responses. The ethanol ratio was found to be the most significant variable. Then, a set of optimum values was determined (i.e., 7 min, 75 °C, and ethanol:water ratio 5:95), where the predicted values for responses were found to be 5.65% for the yield (Y1), 152.68 mg gallic acid equivalents per L for total phenolic content (Y2), 0.797 μmol Trolox equivalent per mL for the antioxidant activity (Y3), 30.5 ppm for caffeine concentration (Y4), and 17.4 ppm for chlorogenic acid concentration (Y5). Furthermore, the corresponding high experimental values from the validation experiment fitted well to these predictions, clearly clarifying the high potential of SCG extracts for use in high value-added applications.

Neural stem cells and the secreted proteins TIMPs ameliorate UVB-induced skin photodamage

UV-induced skin damage is involved in ROS overproduction and the overexpression of matrix metalloproteinases (MMPs), which are inhibited by TIMPs (tissue inhibitor of neural stem cells (NSCs)). These proteins may be associated with skin regeneration through the activation of TIMP proteins, but there have been no reports of treatment of skin photodamage using NSCs and their secreted proteins TIMP-1 and TIMP-2. Here we investigated the photoprotective role of NSCs and their TIMP proteins for the inhibition of UVB-irradiation damage in fibroblasts in SKH-1 mice. SKH-1 hairless mice were divided into three groups (n = 4 per group): normal, treatment, and control groups. The latter two groups were dorsally exposed to UVB irradiation for 12 weeks. After UVB irradiation, treatments with NSC-CM and its secreted factors TIMP-1 and TIMP-2, markedly ameliorated the photodamage triggered by the increase in MMP expression and activity through ROS production, and the subsequent activation of the NF-κB pathway in UVB-irradiated fibroblasts and the treatment mouse group. In addition, the topical application of NSC-CM to mice in the treatment group after irradiation clearly inhibited the expression of γ-H2AX, a DNA damage marker, through the activation of the DNA repair enzyme Rad50. These results demonstrate that NSC-CM or TIMPs proteins can ameliorate skin photodamage induced by UVB-irradiation in in vitro and in vivo systems.

Defense potential of secondary metabolites in medicinal plants under UV-B stress

Ultraviolet-B (UV-B) radiation has, for many decades now, been widely studied with respect to its consequences on plant and animal health. Though according to NASA, the ozone hole is on its way to recovery, it will still be a considerable time before UV-B levels reach pre-industrial limits. Thus, for the present, excessive UV-B reaching the Earth is a cause for concern, and UV-B related human ailments are on the rise. Plants produce various secondary metabolites as one of the defense strategies under UV-B. They provide photoprotection via their UV-B screening effects and by quenching the reactive oxygen- and nitrogen species produced under UV-B influence. These properties of plant secondary metabolites (PSMs) are being increasingly recognized and made use of in sunscreens and cosmetics, and pharma- and nutraceuticals are gradually becoming a part of the regular diet. Secondary metabolites derived from medicinal plants (alkaloids, terpenoids, and phenolics) are a source of pharmaceuticals, nutraceuticals, as well as more rigorously tested and regulated drugs. These metabolites have been implicated in providing protection not only to plants under the influence of UV-B, but also to animals/animal cell lines, when the innate defenses in the latter are not adequate under UV-B-induced damage. The present review focuses on the defense potential of secondary metabolites derived from medicinal plants in both plants and animals. In plants, the concentrations of the alkaloids, terpenes/terpenoids, and phenolics have been discussed under UV-B irradiation as well as the fate of the genes and enzymes involved in their biosynthetic pathways. Their role in providing protection to animal models subjected to UV-B has been subsequently elucidated. Finally, we discuss the possible futuristic scenarios and implications for plant, animal, and human health pertaining to the defense potential of these secondary metabolites under UV-B radiation-mediated damages.

Protection of UVB-Induced Photoaging by Fuzhuan-Brick Tea Aqueous Extract via MAPKs/Nrf2-Mediated Down-Regulation of MMP-1

Ultraviolet B (UVB) irradiation is viewed as the principal inducer of skin photo-aging, associated with acceleration of collagen degradation and upregulation of matrix metalloproteinases (MMPs). The ethnic groups of southern/western China use Fuzhuan brick-tea (FBT) as a beverage and as a nutritional supplement. In this study, we scrutinized the antagonistic effects of aqueous extract of Fuzhuan-brick tea (FBTA) on skin photo-aging in UVB-exposed human keratinocyte (HaCaT) cells. FBTA exhibited strong antioxidant activity and quenched UVB-induced generation of cellular reactive oxygen species (ROS) without showing any toxicity. FBTA was capable of combating oxidative stress by augmenting messenger RNA (mRNA) and protein levels of both phase I and phase II detoxifying enzymes, especially heme oxygenase 1 (HO-1), by upregulating the nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated pathway in HaCaT cells via the phosphorylation of p38 and extracellular signal-regulated kinase (ERK). FBTA also downregulated the expression of matrix metalloproteinase-1 (MMP-1) while upregulating type I procollagen by modulating Nrf2 signaling in UVB-irradiated HaCaT cells. Collectively, our results show that FBTA might be useful as a functional food while being a good candidate in the development of cosmetic products and medicines for the remedy of UVB-induced skin photo-aging.

Flavonoids and Other Phenolic Compounds from Medicinal Plants for Pharmaceutical and Medical Aspects: An Overview

Phenolic compounds as well as flavonoids are well-known as antioxidant and many other important bioactive agents that have long been interested due to their benefits for human health, curing and preventing many diseases. This review attempts to demonstrate an overview of flavonoids and other phenolic compounds as the interesting alternative sources for pharmaceutical and medicinal applications. The examples of these phytochemicals from several medicinal plants are also illustrated, and their potential applications in pharmaceutical and medical aspects, especially for health promoting e.g., antioxidant effects, antibacterial effect, anti-cancer effect, cardioprotective effects, immune system promoting and anti-inflammatory effects, skin protective effect from UV radiation and so forth are highlighted.

Coffee Silverskin: A Review on Potential Cosmetic Applications

Coffee silverskin, the major coffee-roasting by-product, is currently used as fuel and for soil fertilization. However, there are several studies reporting silverskin as a good source of bioactive compounds that can be extracted and further used by cosmetic industry. Its high antioxidant potential may be due to the synergistic interaction of chlorogenic acids (1–6%), caffeine (0.8–1.25%), and melanoidins (17–23%), among other antioxidant compounds. The bioactive compounds of silverskin can answer to the new fields of cosmetic industry on natural active ingredient resources that improve health skin appearance, counteract skin aging and related diseases, in an environmentally friendly approach. Skin aging is a complex process associated with oxidative metabolism and reactive oxygen species (ROS) generation. ROS production increase matrix metalloproteinases (MMPs), as well as pro-inflammatory mediators, resulting in consequent skin damage and aging. To counteract this process, cosmetic industry is looking for compounds able to increase MMP inhibitory activities, hyaluronidase inhibitory activity, expression of collagen and elastase inhibitory activity, as potential bioactive ingredients with anti-aging purposes. This review focuses on skin aging factors and the potential anti-aging, anti-inflammatory, antimicrobial, anti-cellulite and anti-hair loss activity, as well as protection against UV damage, of coffee silverskin and their bioactive compounds.

Plant extracts and natural compounds used against UVB-induced photoaging

Skin is continuously exposed to a variety of environmental stresses, including ultraviolet (UV) radiation. UVB is an inherent component of sunlight that crosses the epidermis and reaches the upper dermis, leading to increased oxidative stress, activation of inflammatory response and accumulation of DNA damage among other effects. The increase in UVB radiation on earth due to the destruction of stratospheric ozone poses a major environmental threat to the skin, increasing the risk of damage with long-term consequences, such as photoaging and photocarcinogenesis. Extracts from plants and natural compounds have been historically used in traditional medicine in the form of teas and ointments but the effect of most of these compounds has yet to be verified. Regarding the increasing concern of the population with issues related to quality of life and appearance, the cosmetic market for anti-aging and photoprotective products based on natural compounds is continuously growing, and there is increasing requirement of expansion on research in this field. In this review we summarized the most current and relevant information concerning plant extracts and natural compounds that are able to protect or mitigate the deleterious effects caused by photoaging in different experimental models.

Alleviation of Ultraviolet B-Induced Photodamage by Coffea arabica Extract in Human Skin Fibroblasts and Hairless Mouse Skin

Coffea arabica extract (CAE) containing 48.3 ± 0.4 mg/g of chlorogenic acid and a trace amount of caffeic acid was found to alleviate photoaging activity in human skin fibroblasts. In this study, polyphenol-rich CAE was investigated for its antioxidant and antiinflammatory properties, as well as for its capability to alleviate ultraviolet B (UVB)-induced photodamage in BALB/c hairless mice. The results indicated that 500 μg/mL of CAE exhibited a reducing power of 94.7%, ferrous ion chelating activity of 46.4%, and hydroxyl radical scavenging activity of 20.3%. The CAE dose dependently reduced UVB-induced reactive oxygen species (ROS) generation in fibroblasts. Furthermore, CAE inhibited the UVB-induced expression of cyclooxygenase-2 and p-inhibitor κB, and the translocation of nuclear factor-kappa B (NF-κB) to the nucleus of fibroblasts. In addition, CAE alleviated UVB-induced photoaging and photodamage in BALB/c hairless mice by restoring the collagen content and reduced UVB-induced epidermal hyperplasia. CAE also inhibited UVB-induced NF-κB, interleukin-6, and matrix metalloproteinase-1 expression in the hairless mouse skin. The results indicated that CAE exhibits antiphotodamage activity by inhibiting UV-induced oxidative stress and inflammation. Therefore, CAE is a candidate for use in antioxidant, antiinflammatory, and antiphotodamage products.