Hydroxycinnamic Acids and Their Derivatives: Cosmeceutical Significance, Challenges and Future Perspectives, a Review

Fucoxanthin-Containing Cream Prevents Epidermal Hyperplasia and UVB-Induced Skin Erythema in Mice

Microalgae represent a source of bio-active compounds such as carotenoids with potent anti-inflammatory and antioxidant properties. We aimed to investigate the effects of fucoxanthin (FX) in both in vitro and in vivo skin models. Firstly, its anti-inflammatory activity was evaluated in LPS-stimulated THP-1 macrophages and TNF-α-stimulated HaCaT keratinocytes, and its antioxidant activity in UVB-irradiated HaCaT cells. Next, in vitro and ex vivo permeation studies were developed to determine the most suitable formulation for in vivo FX topical application. Then, we evaluated the effects of a FX-containing cream on TPA-induced epidermal hyperplasia in mice, as well as on UVB-induced acute erythema in hairless mice. Our results confirmed the in vitro reduction of TNF-α, IL-6, ROS and LDH production. Since the permeation results showed that cream was the most favourable vehicle, FX-cream was elaborated. This formulation effectively ameliorated TPA-induced hyperplasia, by reducing skin edema, epidermal thickness, MPO activity and COX-2 expression. Moreover, FX-cream reduced UVB-induced erythema through down-regulation of COX-2 and iNOS as well as up-regulation of HO-1 protein via Nrf-2 pathway. In conclusion, FX, administered in a topical formulation, could be a novel natural adjuvant for preventing exacerbations associated with skin inflammatory pathologies as well as protecting skin against UV radiation.

Novel Phenolic Constituents of Pulmonaria officinalis L. LC-MS/MS Comparison of Spring and Autumn Metabolite Profiles

Lungwort (Pulmonaria officinalis L., Boraginaceae) is considered to possess therapeutic properties and it has been traditionally used as a remedy against various lung disorders in many countries. Nevertheless, very few data concerning its phytochemical composition are available. This research aims to provide a detailed description of specialized metabolites from the aerial parts of lungwort. Nine previously undescribed and 36 known phenolic compounds were detected in the 50% methanolic extract. Following multistep preparative procedures, structures of newly discovered compounds were determined using one- and two-dimensional techniques of NMR spectroscopy. Among the identified compounds were caffeic acid esters with aliphatic hydroxycarboxylic acids, conjugates of dicaffeic acid with rosmarinic acid, and previously unknown isomers of isosalvianolic acid A and yunnaneic acid E, as well as other lignans. Concentrations of all identified phenolic derivatives in the investigated herbal material were estimated using a method based on liquid chromatography with high-resolution mass spectrometry detection. Seasonal changes in the concentration of metabolites were also investigated using targeted and untargeted metabolomics techniques.

Nutritional properties of Tempranillo grapevine leaves are affected by clonal diversity, mycorrhizal symbiosis and air temperature regime

Tempranillo grapevine is widely cultivated in Spain and other countries over the world (Portugal, USA, France, Australia, and Argentina, among others) for its wine, but leaves are scarcely used for human or animal nutrition. Since high temperatures affect quality of fruits and leaves in grapevine and the association of Tempranillo with arbuscular mycorrhizal fungi (AMF) enhances the antioxidant properties of berries and leaves, we assessed the effect of elevated air temperature and mycorrhization, separately or combined, on the nutritional properties of Tempranillo leaves at the time of fruit harvest. Experimental assay included three clones (CL-260, CL-1048, and CL-1089) and two temperature regimes (24/14 °C or 28/18 °C day/night) during fruit ripening. Within each clone and temperature regime there were plants not inoculated or inoculated with AMF. The nutritional value of leaves increased under warming climate: elevated temperatures induced the accumulation of minerals, especially in CL-1089; antioxidant capacity and soluble sugars also increased in CL-1089; CL-260 showed enhanced amounts of pigments, and chlorophylls and soluble proteins increased in CL-1048. Results suggested the possibility of collecting leaves together with fruit harvest with different applications of every clone: those from CL-1089 would be adequate for an energetic diet and leaves from CL-260 and CL-1048 would be suitable for culinary processes. Mycorrhization improved the nutritional value of leaves by enhancing flavonols in all clones, hydroxycinnamic acids in CL-1089 and carotenoids in CL-260.

Cinnamic acid derivatives in cosmetics: current use and future prospects

Cinnamic acid derivatives are widely used in cosmetics and possess various functions. This group of compounds includes both naturally occurring and synthetic substances. On the basis of the Cosmetic Ingredient Database (CosIng) and available literature, this review summarizes their functions in cosmetics, including their physicochemical and biological properties as well as reported adverse effects. A perfuming function is typical of many derivatives of cinnamaldehyde, cinnamyl alcohol, dihydrocinnamyl alcohol and cinnamic acid itself; these substances are commonly used in cosmetics all over the world. Some of them show allergic and photoallergic potential, resulting in restrictions in maximum concentrations and/or a requirement to indicate the presence of some substances in the list of ingredients when their concentrations exceed certain fixed values in a cosmetic product. Another important function of cinnamic acid derivatives in cosmetics is UV protection. Ester derivatives such as ethylhexyl methoxycinnamate (octinoxate), isoamyl p-methoxycinnamte (amiloxiate), octocrylene and cinoxate are used in cosmetics all over the world as UV filters. However, their maximum concentrations in cosmetic products are restricted due to their adverse effects, which include contact and a photocontact allergies, phototoxic contact dermatitis, contact dermatitis, estrogenic modulation and generation of reactive oxygen species. Other rarely utilized functions of cinnamic acid derivatives are as an antioxidant, in skin conditioning, hair conditioning, as a tonic and in antimicrobial activities. Moreover, some currently investigated natural and synthetic derivatives of cinnamic acid have shown skin lightening and anti-ageing properties. Some of them may become new cosmetic ingredients in the future. In particular, 4-hydroxycinnamic acid, which is currently indexed as a skin-conditioning cosmetics ingredient, has been widely tested in vitro and in vivo as a new drug candidate for the treatment of hyperpigmentation.

Caffeic Acid-layered Double Hydroxide Hybrid: A New Raw Material for Cosmetic Applications

Bioactive ingredients from natural sources possess well-known positive effects in cosmetic applications. Among them, phenolic acids have emerged with very interesting potential. Caffeic acid (CAF) is one of the most promising active compounds because it possess antioxidant, anti-inflammatory, antitumoral and anti-wrinkle effects. In order to increase its local bioavailability in topical applications, the vehiculation of caffeic acid can lead to a new raw material of cosmetic interest. For this purpose, clay minerals possess excellent properties, such as low or null toxicity and good biocompatibility. Clays are able to host a wide range of active ingredients in the interlayer region, using a green process known as intercalation reaction. The hosting of cosmetic actives into the layered structure of anionic clays allows the preparation of new materials with enhanced stability towards oxidation and photodegradation, better local bioavailability, and easier workability. In this paper, the successful vehiculation of caffeic acid into anionic clay is presented. The obtained hybrid is very promising for the cosmetic market because of its higher bioavailability and prolonged antioxidant activity.

Phytochemical composition and in vitro antioxidant activities of Citrus sinensis peel extracts

BACKGROUND

Citrus sinensis peels are usually discarded as wastes; however, they are rich sources of Vitamin C, fibre, and many nutrients, including phenolics and flavonoids which are also good antioxidant agents. This study aimed to examine phytochemical composition and antioxidant capabilities of C. sinensis peel extracted conventionally with different methanol/water, ethanol/water, and acetone/water solvents.

METHODS

C. sinensis peels were subjected to extraction with 100%, 70% and 50% of methanol, ethanol, and acetone, respectively, as well as hot water extraction. Antioxidant activities of the peel extracts were examined via the 2,2-diphenylpicrylhydrazyl (DPPH) free radical scavenging activity, ferric reducing antioxidant power (FRAP) assay, and oxygen radical absorbance capacity (ORAC) assay. Total phenolic content and total flavonoid content of the extracts were measured via the Folin-Ciocalteau method and the aluminium chloride colorimetric method, respectively. Phenolic acid and organic acid composition of the peel extracts were further determined via high performance liquid chromatography (HPLC) while flavonoid content was identified via ultra performance liquid chromatography (UPLC).

RESULTS

DPPH radical scavenging activity of C. sinensis peel extracts varied from 8.35 to 18.20 mg TE/g, FRAP ranged from 95.00 to 296.61 mmol Fe(II)/g, while ORAC value ranged from 0.31 to 0.92 mol TE/g. Significant level of association between the assays was observed especially between TPC and FRAP (R-square = 0.95, P < 0.0001). TPC of various C. sinensis peel extracts ranged from 12.08 to 38.24 mg GAE/g, with 70% acetone/water extract (AEC) showing the highest TPC. TFC ranged from 1.90 to 5.51 mg CE/g. Extraction yield ranged from 0.33 to 0.54 g/g DW and tended to increase with increasing water concentration in the solvent. In the phytochemical investigation, five phenolic acids were identified using HPLC, including gallic acid, protocatechuic acid, 4-hydroxybenzoic acid, caffeic acid and ferulic acid. A total of five organic acids including lactic acid, citric acid, L-mallic acid, kojic acid and ascorbic acid were quantified via HPLC. In addition, concentrations of six flavonoids including catechin, epigallocatechin, vitexin, rutin, luteolin and apigenin were determined via UPLC.

DISCUSSION AND CONCLUSION

Phytochemicals including phenolics and flavonoids in C. sinensis peel extracts exhibited good antioxidant properties. Among the extracts, 70% AEC with highest TPC and high TFC content showed greatest antioxidant activity in all three assays. Different phenolic acids, organic acids and flavonoids were also identified from the extracts. This study indicated that C. sinensis peels contained potential antioxidant compounds which could be exploited as value added products in the food industry.

Design, synthesis and evaluation of cinnamic acid ester derivatives as mushroom tyrosinase inhibitors

Tyrosinase is a key enzyme in melanin biosynthesis, and is also involved in the enzymatic browning of plant-derived foods. Tyrosinase inhibitors are very important in medicine, cosmetics and agriculture. In order to develop more active and safer tyrosinase inhibitors, an efficient approach is to modify natural product scaffolds. In this work, two series of novel tyrosinase inhibitors were designed and synthesized by the esterification of cinnamic acid derivatives with paeonol or thymol. Their inhibitory effects on mushroom tyrosinase were evaluated. Most of these compounds (IC50: 2.0 to 163.8 μM) are found to be better inhibitors than their parent compounds (IC50: 121.4 to 5925.0 μM). Among them, (E)-2-acetyl-5-methoxyphenyl-3-(4-hydroxyphenyl)acrylate (5a), (E)-2-acetyl-5-methoxyphenyl-3-(4-methoxyphenyl)acrylate (5g) and (E)-2-isopropyl-5-methylphenyl-3-(4-hydroxyphenyl)acrylate (6a) showed strong inhibitory activities; the IC50 values were 2.0 μM, 8.3 μM and 10.6 μM, respectively, compared to the positive control, kojic acid (IC50: 32.2 μM). Analysis of the inhibition mechanism of 5a, 5g and 6a demonstrated that their inhibitory effects on tyrosinase are reversible. The inhibition kinetics, analyzed by Lineweaver-Burk plots, revealed that 5a acts as a non-competitive inhibitor while 5g and 6a are mixed-type inhibitors. Furthermore, docking experiments were carried out to study the interactions between 6a and mushroom tyrosinase.

Fate of p-hydroxycinnamates and structural characteristics of residual hemicelluloses and lignin during alkaline-sulfite chemithermomechanical pretreatment of sugarcane bagasse

BACKGROUND

Preparing multiple products from lignocellulosic biomass feedstock enhances the profit and sustainability of future biorefineries. Grasses are suitable feedstocks for biorefineries as they permit a variety of possible by-products due to their particular chemical characteristics and morphology. Elucidating the fate of p-hydroxycinnamates (ferulates-FAs and p-coumarates-pCAs) and major structural components during bioprocessing helps to discriminate the sources of recalcitrance in grasses and paves the way for the recovery of p-hydroxycinnamates, which have multiple applications. To address these subjects, we assessed sugarcane bagasse biorefining under alkaline-sulfite chemithermomechanical (AS-CTM) pretreatment and enzymatic saccharification.

RESULTS

The mass balances of the major bagasse components were combined with 2D-NMR structural evaluation of process solids to advance our understanding of sugarcane bagasse changes during biorefining. AS-CTM pretreatment provided a high yield and thoroughly digestible substrates. The pretreated material was depleted in acetyl groups, but retained 62 and 79% of the original lignin and xylan, respectively. Forty percent of the total FAs and pCAs were also retained in pretreated material. After pretreatment and enzymatic hydrolysis, the residual solids contained mostly lignin and ester-linked pCAs, with minor amounts of FAs and non-digested polysaccharides. Saponification of the residual solids, at a higher alkali load, cleaved all the ester linkages in the pCAs; nevertheless, a significant fraction of the pCAs remained attached to the saponified solids, probably to lignin, through 4-O ether-linkages.

CONCLUSION

AS-CTM pretreatment provided soundly digestible substrates, which retain substantial amounts of xylans and lignin. Acetyl groups were depleted, but 40% of the total FAs and pCAs remained in pretreated material. Ester-linked pCAs detected in pretreated material also resisted to the enzymatic hydrolysis step. Only a more severe saponification reaction cleaved ester linkages of pCAs from residual solids; nevertheless, pCAs remained attached to the core lignin through 4-O ether-linkages, suggesting the occurrence of an alkali-stable fraction of pCAs in sugarcane bagasse.

Flavonoids and Phenolic Acids from Oregano: Occurrence, Biological Activity and Health Benefits

Several herb species classified as oregano have been widely used in folk medicine to alleviate inflammation-related diseases, respiratory and digestive disorders, headaches, rheumatism, diabetes and others. These potential health benefits are partially attributed to the phytochemical compounds in oregano such as flavonoids (FL) and phenolic acids (PA). Flavonoids and phenolic acids are among the most abundant and most studied phytochemicals in oregano species. Epidemiological, in vitro and in vivo experiments have related long-term consumption of dietary FL and PA with a decreased risk of incidence of chronic diseases. The aim of this manuscript is to summarize the latest studies on the identification and distribution of flavonoids and phenolic compounds from oregano species and their potential antioxidant, anti-inflammatory and anti-cancer health benefits.

Characterization of tyrosinase inhibitory constituents from the aerial parts of Humulus japonicus using LC-MS/MS coupled online assay

In the screening of natural products for the development as cosmetic ingredients, the EtOAc-soluble fraction of Humulus japonicus showed tyrosinase inhibitory activity. HPLC-MS/MS coupled online tyrosinase assay of EtOAc-soluble fraction of H. japonicus characterized the twenty-eight constituents including two unknown ones and their tyrosinase inhibitory activity. Fractionation of H. japonicus using various chromatographic techniques yielded thirty-eight compounds. The chemical structures of isolated compounds were identified by spectroscopic analysis. As characterized by HPLC-MS/MS analysis, we isolated twenty-four predicted compounds and further identified two unknown ones, named humulusides A (1) and B (2). Additional ten compounds were also identified by purification. Tyrosinase inhibitory activity of isolated compounds were evaluated, which was closely correlated with the results from HPLC-MS/MS coupled online tyrosinase assay. Consistent with predicted data, two major compounds, trans-N-coumaroyltyramine (14) and cis-N-coumaroyltyramine (15) showed tyrosinase inhibition with IC₅₀ values of 40.6 and 36.4 μM. Taken together, H. japonicus is suggested as whitening ingredient in cosmetic products. In addition, HPLC-MS/MS coupled tyrosinase assay is powerful tool for predicting active compounds with short time and limited amounts, although identification of new compounds and verification of predicted data are also needs to be demonstrated by further experiment.

Bioprospecting on invasive plant species to prevent seed dispersal

The most anthropized regions of the world are characterized by an impressive abundance of invasive plants, which alter local biodiversity and ecosystem services. An alternative strategy to manage these species could be based on the exploitation of their fruits in a framework of bioprospecting to obtain high-added value compounds or phytocomplexes that are useful for humans. Here we tested this hypothesis on three invasive plants (Lonicera japonica Thunb., Phytolacca americana L., and Prunus serotina Ehrh.) in the Po plain (northern Italy) which bear fruits that are highly consumed by frugivorous birds and therefore dispersed over large distances. Our biochemical analyses revealed that unripe fruit shows high antioxidant properties due to the presence of several classes of polyphenols, which have a high benchmark value on the market. Fruit collection for phytochemical extraction could really prevent seed dispersal mediated by frugivorous animals and produce economic gains to support local management actions.

Pseudomonas putida F1 uses energy taxis to sense hydroxycinnamic acids

Soil bacteria such as pseudomonads are widely studied due to their diverse metabolic capabilities, particularly the ability to degrade both naturally occurring and xenobiotic aromatic compounds. Chemotaxis, the directed movement of cells in response to chemical gradients, is common in motile soil bacteria and the wide range of chemicals detected often mirrors the metabolic diversity observed. Pseudomonas putida F1 is a soil isolate capable of chemotaxis toward, and degradation of, numerous aromatic compounds. We showed that P. putida F1 is capable of degrading members of a class of naturally occurring aromatic compounds known as hydroxycinnamic acids, which are components of lignin and are ubiquitous in the soil environment. We also demonstrated the ability of P. putida F1 to sense three hydroxycinnamic acids: p-coumaric, caffeic and ferulic acids. The chemotaxis response to hydroxycinnamic acids was induced during growth in the presence of hydroxycinnamic acids and was negatively regulated by HcaR, the repressor of the hydroxycinnamic acid catabolic genes. Chemotaxis to the three hydroxycinnamic acids was dependent on catabolism, as a mutant lacking the gene encoding feruloyl-CoA synthetase (Fcs), which catalyzes the first step in hydroxycinnamic acid degradation, was unable to respond chemotactically toward p-coumaric, caffeic, or ferulic acids. We tested whether an energy taxis mutant could detect hydroxycinnamic acids and determined that hydroxycinnamic acid sensing is mediated by the energy taxis receptor Aer2.

Polyphenols from Root, Tubercles and Grains Cropped in Brazil: Chemical and Nutritional Characterization and Their Effects on Human Health and Diseases

Throughout evolution, plants have developed the ability to produce secondary phenolic metabolites, which are important for their interactions with the environment, reproductive strategies and defense mechanisms. These (poly)phenolic compounds are a heterogeneous group of natural antioxidants found in vegetables, cereals and leguminous that exert beneficial and protective actions on human health, playing roles such as enzymatic reaction inhibitors and cofactors, toxic chemicals scavengers and biochemical reaction substrates, increasing the absorption of essential nutrients and selectively inhibiting deleterious intestinal bacteria. Polyphenols present in some commodity grains, such as soy and cocoa beans, as well as in other vegetables considered security foods for developing countries, including cassava, taro and beetroot, all of them cropped in Brazil, have been identified and quantified in order to point out their bioavailability and the adequate dietary intake to promote health. The effects of the flavonoid and non-flavonoid compounds present in these vegetables, their metabolism and their effects on preventing chronic and degenerative disorders like cancers, diabetes, osteoporosis, cardiovascular and neurological diseases are herein discussed based on recent epidemiological studies.

Synthesis and biological evaluation of caffeic acid derivatives as potent inhibitors of α-MSH-stimulated melanogenesis

We have disclosed our effort to develop caffeic acid derivatives as potent and non-toxic inhibitors of α-MSH-stimulated melanogenesis to treat pigmentation disorders and skin medication including a cosmetic skin-whitening agent. The SAR studies revealed that cyclohexyl ester and secondary amide derivatives of caffeic acid showed significant inhibitory activities.

Spectrophotometric Characterization of the Action of Tyrosinase on p-Coumaric and Caffeic Acids: Characteristics of o-Caffeoquinone

New methods are proposed to determine the activity of tyrosinase on caffeic and p-coumaric acids. Because o-quinone from caffeic acid is unstable in its presence, it has been characterized through spectrophotometric measurements of the disappearance of coupled reducing agents, such as nicotinamide adenine dinucleotide reduced form. It has also been characterized by a chronometric method, measuring the time that a known concentration of ascorbic acid takes to be consumed. The activity on p-coumaric acid has been followed by measuring the formation of o-quinone of caffeic acid at the isosbestic point originated between caffeic acid and o-caffeoquinone and measuring the formation of o-quinone at 410 nm, which is stable in the presence of p-coumaric acid (both of them in the presence of catalytic amounts of caffeic acid, maintaining the ratio between p-coumaric acid and caffeic acid constant; R = 0.025). The k_cat value of tyrosinase obtained for caffeic acid was higher than that obtained for p-coumaric acid, while the affinity was higher for p-coumaric acid. These values agree with those obtained in docking studies involving these substrates and oxytyrosinase.