Bioactivity of phenolic acids: Metabolites versus parent compounds: A review

Phenolic acids are present in our diet in different foods. In particular, mushrooms are a good source of these molecules. Due to their bioactive properties, phenolic acids are extensively studied and there is evidence of their role in disease prevention. Nevertheless, in vivo, these compounds are metabolized and circulate in the organism as glucuronated, sulfated and methylated metabolites, displaying higher or lower bioactivity. To clarify the importance of the metabolism of phenolic acids, the knowledge about the bioactivity of the metabolites is extremely important. In this review, chemical features, biosynthesis and bioavailability of phenolic acids are discussed as well as the chemical and enzymatic synthesis of their metabolites. Finally, the metabolites bioactive properties are compared with that of the corresponding parental compounds.The authors are grateful to Fundação para a Ciência e a Tecnologia (FCT, Portugal) and FEDER-COMPETE/QREN/EU for the financial support through the research centres (PEst-C/QUI/UI0686/2011 and PEst-OE/AGR/UI0690/2011). S.A. Heleno (BD/70304/2010) also thanks FCT, POPH-QREN and FSE for her grant

Phenolic compounds: current industrial applications, limitations and future challenges

Phenolic compounds are natural bioactive molecules found mainly in plant tissues that have shown interesting bioactivities, such as antioxidant, antimicrobial, anti-inflammatory, and antiproliferative activities, among others, which has led to great interest in their use by several industries. However, despite the large number of scientific studies on this topic, some issues still need to be studied and solved, such as the understanding of the main actions of these compounds in organisms. Besides their large potential applicability in industry, phenolic compounds still face some issues making it necessary to develop strategies to improve bioavailability, sustainable technologies of extraction and refinement, and stability procedures to increase the range of applicability. This review focuses on the most recent advances in the applications of phenolic compounds in different technological and medicinal areas. In addition, techniques to improve their sustainable resourcing, stability and bioavailability will be presented and discussed. This journal isFoundation for Science and Technology (FCT, Portugal) is acknowledged for financial support by national funds FCT/ MCTES to CIMO (UIDB/00690/2020). National funding by FCT, P. I., through the institutional scientific employment programcontract for Lillian Barros contract and through the individual scientific employment program-contract for Sandrina A. Heleno, and B. Albuquerque Research grant (SFRH/BD/136370/2018 ). European Regional Development Fund (ERDF) through the Regional Operational Program North 2020, within the scope of Project NORTE-01-0145-FEDER-023289: DeCodE and project Mobilizador Norte-01-0247-FEDER-024479: ValorNatural®. FEDER-Interreg España-Portugal programme is acknowledged for financial support through the project 0377_Iberphenol_6_E.info:eu-repo/semantics/publishedVersio

Improved maximum likelihood estimators in a heteroskedastic errors-in-variables model

This paper develops a bias correction scheme for a multivariate heteroskedastic errors-in-variables model. The applicability of this model is justified in areas such as astrophysics, epidemiology and analytical chemistry, where the variables are subject to measurement errors and the variances vary with the observations. We conduct Monte Carlo simulations to investigate the performance of the corrected estimators. The numerical results show that the bias correction scheme yields nearly unbiased estimates. We also give an application to a real data set.Comment: 12 pages. Statistical Paper

Avaliação de programa para reduzir dores nas costas em trabalhadores de enfermagem

OBJECTIVE: To evaluate the effectiveness of a program designed to reduce back pain in nursing aides. METHODS: Female nursing aides from a university hospital who had suffered episodes of back pain for at least six months were included in the study. Participants were randomly divided into a control group and an intervention group. The intervention program involved a set of exercises and an educational component stressing the ergonomic aspect, administered twice a week during working hours for four months. All subjects answered a structured questionnaire and the intensity of pain was assessed before and after the program using a visual analogue scale (VAS). Student's t-test or the Wilcoxon Rank Sum Test for independent samples, and Chi-square test or the Exact Fisher test for categorical analysis, were used. The McNemar test and the Wilcoxon matched pairs test were used to compare the periods before and after the program. RESULTS: There was a statistically significant decrease in the frequency of cervical pain in the last two months and in the last seven days in the intervention group. There was also a reduction in cervical pain intensity in the two periods (2 months, 7 days) and lumbar pain intensity in the last 7 days. CONCLUSIONS: The results suggest that a program of regular exercise with an emphasis on ergonomics can reduce musculoskeletal symptoms in nursing personnel.OBJETIVO: Avaliar o efeito de um programa na redução de dores nas costas em auxiliares de enfermagem. MÉTODOS: Participaram do estudo auxiliares de enfermagem com menos de 50 anos de idade, do sexo feminino, de um hospital universitário e que apresentavam dores nas costas por um período mínimo de 6 meses. O programa envolveu parte educativa, com abordagem ergonômica, e a realização de exercícios executados durante o horário de trabalho, duas vezes por semana, em um período de quatro meses. As participantes foram divididas aleatoriamente em grupo tratado e grupo controle. A intensidade das dores foi avaliada pela escala visual analógica. Foram utilizados os testes t de Student ou de Wilcoxon, para amostras independentes e os testes Qui-quadrado ou Exato de Fisher, para as categóricas. Para comparar as proporções do início e final do programa utilizou-se o teste de McNemar. RESULTADOS: Ocorreu diminuição estatisticamente significativa na freqüência de dor cervical durante os últimos dois meses e durante a ultima semana no grupo tratado. Houve também redução na intensidade da dor cervical em ambos os períodos (2 meses; 7 dias) e da dor lombar na última semana. CONCLUSÕES: O estudo sugere que programa regular de exercícios, acompanhado por abordagem instrucional ergonômica, pode reduzir sintomas músculo-esqueléticos em trabalhadores de enfermagem.35636

Coprinopsis atramentaria extract, its organic acids, and synthesized glucuronated and methylated derivatives as antibacterial and antifungal agents

Despite the available data regarding antimicrobial activity of phenolic acids, studies dealing with the effects of their metabolites or derivatives are scarce. Therefore, the antimicrobial and demelanizing activities of Coprinopsis atramentaria extract, its organic acids, and methylated and glucuronated derivatives were evaluated. The antifungal activity was stronger than the antibacterial effects. In general, individual compounds (mostly organic acids) exhibited higher activity than the extract and even higher than the standards used in the assays. Methylated derivatives presented the highest demelanizing activity toward Aspergillus niger, A. fumigatus and Penicillium verrucosum var. cyclopium. The inclusion of methyl groups in the parental compound (CoAM1, CoAM2 and CoAM3) strongly increased antibacterial and antifungal activities of CoA, while the inclusion of acetyl groups (CoAGP) increased the antifungal activity but the antibacterial properties were maintained. For HA and CA, the inclusion of methyl groups (HAM1, HAM2, HAM3 and CAM) increased the demelanizing activity, but decreased the antimicrobial properties. The present work contributes to the knowledge of the mechanisms involved in the antimicrobial properties of organic acids namely, phenolic acids, usually present in mushrooms. Organic acids, and methylated and glucuronated derivatives could be used as antimicrobial agents.The authors are grateful to Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) for financial support to the Portuguese NMR network and to FCT and FEDER-COMPETE/QREN/EU for the financial support through the research project PTDC/AGR-ALI/110062/2009 and the research centres (PEst-C/QUI/UI0686/2011 and PEst-OE/AGR/UI0690/2011). S. A. Heleno (BD/70304/2010) also thanks FCT, POPH-QREN and FSE for her grant. The authors also thank Serbian Ministry of Education, Science and Technological development (grant number 173032) for financial support

The contribution of phenolic acids to the anti-inflammatory activity of mushrooms: Screening in phenolic extracts, individual parent molecules and synthesized glucuronated and methylated derivatives

In the present study, the ethanolic extracts of fourteen edible mushrooms were investigated for their anti-inflammatory potential in LPS (lipopolysaccharide) activated RAW 264.7 macrophages. Furthermore the extracts were chemically characterized in terms of phenolic acids and related compounds. The identified molecules (p-hydroxybenzoic, p-coumaric and cinnamic acids) and their glucuronated and methylated derivatives obtained by chemical synthesis were also evaluated for the same bioactivity, in order to establish structure-activity relationships and to comprehend the effects of in vivo metabolism reactions in the activity of the compounds. The extracts of Pleurotus ostreatus, Macrolepiota procera, Boletus impolitus and Agaricus bisporus revealed the strongest anti-inflammatory potential (EC50 values 96 ± 1 to 190 ± 6 µg/mL, and also the highest concentration of cinnamic acid (656 to 156 µg/g), which was also the individual compound with the highest anti-inflammatory activity. The derivatives of p-coumaric acid revealed the strongest properties, specially the derivative methylated in the carboxylic group (CoA-M1) that exhibited similar activity to the one showed by dexamethaxone used as anti-inflammatory standard; by contrast, the derivatives of p-hydroxybenzoic revealed the lowest inhibition of NO production. All in all, whereas the conjugation reactions change the chemical structure of phenolic acids and may increase or decrease their activity, the glucuronated and methylated derivatives of the studied compounds are still displaying anti-inflammatory activity.The authors are grateful to Fundação para a Ciência e a Tecnologia (FCT, Portugal) and FEDER-COMPETE/QREN/EU for the financial support through the research projects PEst-OE/AGR/UI0690/2011 and PEst-C/QUI/UI0686/2011. S.A. Heleno (BD/70304/2010) and R.C. Calhelha (BPD/68344/2010) also thank FCT, POPH-QREN and FSE. C. Santos-Buelga is also thankful to the Spanish MINECO for financial support through the project BFU2012-35228

Non-edible parts of Solanum stramoniifolium Jacq. - a new potent source of bioactive extracts rich in phenolic compounds for functional foods

Extracts prepared from leaves, roots, and stems of Solanum stramoniifolium Jacq. (Solanaceae) in 80% ethanol have been tested for their in vitro antioxidant, anti-inflammatory, antimicrobial, and cytotoxic activities with an aim to find new sources of substances for functional foods and food additives. The root extract revealed the highest antioxidant activity in all assays exceeding the trolox capacity, and was the only extract that inhibited nitric oxide production in mouse macrophage cells, showing also the capacity to suppress the growth of all tested human tumor cell lines (MCF-7, NCI-H460, HeLa and HepG2). The leaf extract showed the strongest antimicrobial activity inhibiting all tested clinical isolates. To the author's best knowledge it was the first time that all individual parts of this plant were tested for biological activity together with the phenolic compound characterization.Foundation for Science and Technology (FCT, Portugal) [UID/AGR/00690/2013, SFRH/BPD/107855/2015, SFRH/BPD/101413/2014, SFRH/BPD/BPD/68344/2010]; FEDER [UID/AGR/00690/2013, SFRH/BPD/107855/2015, SFRH/BPD/101413/2014, SFRH/BPD/BPD/68344/2010]; FEDER, through POCI-COMPETE [POCI-01-0145-FEDER-006984]; FCT [POCI-01-0145-FEDER-006984]; Internal Grant Agency of Tomas Bata University in Zlin [IGA/FT/2016/003]POCI-01-0145-FEDER-006984, CIMO, Kansainvälisen Liikkuvuuden ja Yhteistyön Keskus; POCI-COMPETE2020, FCT, Fundació Catalana de Trasplantament; SFRH/BPD/101413/2014, CIMO, Kansainvälisen Liikkuvuuden ja Yhteistyön Keskus; SFRH/BPD/107855/2015, CIMO, Kansainvälisen Liikkuvuuden ja Yhteistyön Keskus; SFRH/BPD/BPD/68344/2010, CIMO, Kansainvälisen Liikkuvuuden ja Yhteistyön Keskus; UID/AGR/00690/2013, CIMO, Kansainvälisen Liikkuvuuden ja Yhteistyön Keskus; FEDER, Federación Española de Enfermedades Rara

Recovery of citric acid from citrus peels: ultrasound-assisted extraction optimized by response surface methodology

The production of citrus juice generates a large quantity of by-products, which are often discarded or used for animal feed. However, several studies have shown its richness in valuable compounds, namely organic acids. Thus, this work intended to valorize orange and lime peels as renewable sources of citric acid. An experimental design combining five levels of the independent variables time (2–45 min), ultrasonic power (50–500 W), and ethanol proportion (0–100%) was implemented and response surface methodology (RSM) was applied to optimize the extraction process. The UPLC-PDA analysis showed that orange peel presented a higher citric acid content than lime. For lime and orange peels, the extraction yield was maximized by sonicating at low power for 5.8 or 35.5 min, using a low ethanol proportion or only water as a solvent, respectively. Overall, optimal UAE conditions were defined for the sustainable extraction of citric acid from citrus by-products, thus contributing to its valorization and upcycling into natural food ingredients.Fundação para a Ciência e a Tecnologia | Ref. UIDB/00690/2020Xunta de Galicia | Ref. ED431F 2020/1

Phenolic, polysaccharidic and lipidic fractions of mushrooms from northeast Portugal: chemical compounds with antioxidant properties

Mushrooms do not constitute a significant portion of the human diet, but their consumption continues to increase due to their functional benefits and presence of bioactive compounds. Some of those compounds can be found in the phenolic, polysaccharidic and lipidic fractions of edible and inedible species. Herein, those fractions of five wild mushrooms (Coprinopsis atramentaria, Lactarius bertillonii, Lactarius vellereus, Rhodotus palmatus and Xerocomus chrysenteron) from Northeast Portugal were studied for their chemical composition and antioxidant properties. Protocatechuic, p-hydroxybenzoic, p-coumaric and cinnamic acids were found in the phenolic fraction, ramnose, xylose, fucose, arabinose, fructose, glucose, manose, mannitol, sucrose, maltose and trehalose were quantified in polysaccharidic fraction, linoleic and stearic (only in Lactarius sp.) acids, and β- and γ-tocopherols were the main compounds in the lipidic fraction. C. atramentaria and X. chrysenteron phenolic fractions gave the highest free radical scavenging activity, reducing properties and lipid peroxidation inhibition in brain homogenates, which is in agreement with its highest content in total phenolics. Furthermore, among the polysaccharidic fractions C. atramentaria also gave the highest antioxidant activity, which is accordingly with its highest total polysaccharides content and sugars obtained after hydrolysis.The authors are grateful to Fundação para a Ciência e a Tecnologia (FCT, Portugal) and COMPETE/QREN/EU (research project PTDC/AGR-ALI/110062/2009) for financial support. L. Barros (BPD/4609/2008) and S.A. Heleno (BD/70304/2010) also thank FCT, POPH-QREN and FSE. The GIP-USAL is financially supported by the Spanish Ministerio de Ciencia e Innovación through the Consolider-Ingenio 2010 Programme (FUN-C-FOOD, CSD2007-00063), and Junta de Castilla y León (Grupo de Investigación de Excelencia, GR133)