Screening for Bioactive Compounds from Algae

At present, functional foods are seen as a good alternative to maintain or even improve human health, mainly for the well-known correlation between diet and health. This fact has brought about a great interest for seeking new bioactive products of natural origin to be used as functional ingredients, being, nowadays, one of the main areas of research in Food Science and Technology. Among the different sources that can be used to extract bioactives, algae have become one of the most promising. Algae have an enormous biodiversity and can be seen as natural factories for producing bioactive compounds since either by growing techniques or by genetic engineering approaches, they can improve their natural content of certain valuable compounds. In this book chapter, a revision about the different types of bioactives that have been described in algae is presented including compounds, such as lipids, carotenoids, proteins, phenolics, vitamins, polysaccharides, etc. Also, the modern green techniques used to achieve the selective extraction of such bioactives are presented and the methods for fast screening of bioactivity described.Peer Reviewe

Búsqueda de nuevos ingredientes funcionales naturales procedentes de algas

Tesis doctoral inédita. Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química-Física Aplicada. Fecha de lectura: 17-12-201

Pressurized hot water extraction of bioactives

In the last years, the fact that water is a "green" solvent capable of tunable their properties by changing temperature has tended to increase publications using pressurized hot water extraction (PHWE) as a "green" extraction technique. PHWE has been established as a special extraction technique employed in obtaining bioactive compounds such as polyphenols, diterpenes and polysaccharides, among others from natural sources. Therefore, the main goal of this review is to provide the reader with a brief description of PHWE fundamentals, an up-to-date overview on the use of PHWE to recover bioactive compounds (2015-present), following our previous work by Plaza and Turner (Trends in Analytical Chemistry 71 (2015) 39-57). The last and future trends in PHWE are presented such as its combination with ionic liquids or deep eutectic solvents as well as its coupling with drying steps in order to get higher extraction yields and dried particle formation from extracts, respectively. (C) 2019 Published by Elsevier B.V

Enzyme-assisted extraction of bioactive non-extractable polyphenols from sweet cherry (Prunus avium L.) pomace

Sweet cherries processing produces big amounts of wastes mainly constituted by cherry pomace that can be a source of bioactive polyphenols. However, during the extraction process, an important fraction called non-extractable polyphenols (NEPs) remains retained in the extraction residue. This work describes the development of an enzyme-assisted extraction (EAE) method to obtain NEPs from sweet cherry pomace employing three different enzymes. Box-Behnken experimental designs were employed to select the optimal conditions of extraction time, temperature, enzyme concentration, and pH. The total phenolic and proanthocyanidin contents and the antioxidant and antihypertensive capacities were measured. Optimal EAE conditions extracted higher content of proanthocyanidins and with higher bioactivity from extraction residue than alkaline and acid hydrolysis. Moreover, there were higher amounts of bioactive phenolics in the extraction residue than in the sweet cherry pomace extract. The estimation of NEPs molecular weight distribution by HPLC-SEC demonstrated that EAE extracted NEPs with high molecular weight

In vitro assessment of the bioavailability of bioactive non-extractable polyphenols obtained by pressurized liquid extraction combined with enzymatic-assisted extraction from sweet cherry (Prunus avium L.) pomace

In vitro digestion and absorption simulation processes of non-extractable polyphenols (NEPs) obtained by pressurized liquid extraction combined with enzymatic-assisted extraction with Promod enzyme (PLE-EAE) from the residue of conventional extraction of sweet cherry pomace were studied. In general, total phenolic and proanthocyanidin contents decreased in each phase of the digestion. However, the antioxidant capacity increased when the digestion process progressed. In addition, the highest total phenolic and proanthocyanidin contents and antioxidant capacity were obtained in the absorbed fraction. NEPs from PLE-EAE extract, digestive fractions, absorbed and unabsorbed fractions were analyzed by ultra-high-performance liquid chromatography coupled to electrospray ionization quadrupole Exactive-Orbitrap mass spectrometry (UHPLC-ESI-Q-Orbitrap-MS). Fifteen NEPs were identified in the intestinal fraction and five in the absorbed fraction after the digestion process. Results obtained in this study define for the first time the bioavailability of antioxidant NEPs obtained from sweet cherry pomace

Facts about the formation of newantioxidants in natural samples after subcritical water extraction

8 páginas, 3 figuras, 3 tablas.-- El pdf del artículo es la versión pre-print.Subcritical water extraction (SWE) is a very promising technique for obtaining bioactives (mainly antioxidants) from natural sources; even if sometimes the high operation temperatures have been suggested as responsible for thermal degradation of bioactives, the fact is that this type of extraction processes may generate new bioactive (antioxidant) compounds. The present study involved the analysis of antioxidants either naturally found in raw samples and/or those formed during extraction via Maillard reaction and other chemical events. Samples of different nature like microalgae (Chlorella vulgaris), algae (Sargassum vulgare, Porphyra spp., Cystoseira abies-marina, Sargassum muticum, Undaria pinnatifida, and Halopitys incurvus) and plants (rosemary, thyme and verbena) were studied. Amino acid availability, sugar content, fluorescence and absorbance at different wavelengths were determined to follow chemical changes due to reactions such as Maillard, caramelization and thermoxidation. Folin reaction also provided information related to total phenol content of the samples. ABTS•+, peroxyl as well as superoxide radical scavenging assays were used to measure the antioxidant capacity of the extracts. Results obtained from this study suggest that neoformed compounds derived from Maillard, caramelization and thermoxidation reactions affect the overall antioxidant capacity of water subcritical extracts depending on the nature of the sample. The brown algae U. pinnatifida was the sample in which these chemical events contributed to a higher extent to improve the antioxidant capacity (from 0.047 to 1.512 mmol/g and from 45.356 to 1522.692 μmol/g for the TEAC and ORACFL methods, respectively) when the extraction temperature was raised from 100 to 200 °C. To the best of our knowledge, this is the first work supporting the formation of neoantioxidants in natural complex matrices during subcritical water extraction.This work has been financed by AGL2008-05108-C03-01 (Ministerio de Educacion y Ciencia), CSD2007-00063 FUN-CFOOD (Programa CONSOLIDER-INGENIO 2010) and by ALIBIRD, S2009/AGR- 1469 (Comunidad de Madrid) projects. M.H. would like to thank the Spanish Science and Innovation Ministry (MICINN) for a post-doc contract (“Juan de la Cierva” programme). M.P. thanks CSIC for her I3P fellowship. M.A.B. thanks for a Danone Institute fellowship.Peer reviewe

Separation and identification of peptides in hydrolysed protein extracts from edible macroalgae by HPLC-ESI-QTOF/MS

Macroalgae contain significant amounts of high-quality proteins which, because of their structural diversity, contain a range of yet undiscovered peptides within their primary structures. In this work, an analytical methodology was developed for the separation and identification of peptides present in protein hydrolysates from three different edible macroalgae used for human consumption (Saccharina latissima (brown macroalga), Codium spp. (green macroalga), and Mastocarpus stellatus (red macroalga)). The extraction of aqueous and alkaline soluble proteins was carried out followed by their precipitation with HCl or acetone. The protein extracts obtained were submitted to enzymatic digestion with alcalase and subsequently analyzed by reversed-phase high-performance liquid chromatography-quadrupole-time-of flight mass spectrometry (RP-HPLC-QTOF/MS) and de novo sequencing tool to separate and identify different short chain peptides. Thirty-seven peptides were identified in the hydrolysed protein extracts from the three macroalgae, five of them being common in brown and red macroalgae. After checking against BIOPEP database, several sequenced peptides were found within longer peptides with potential antibacterial activity. Any of the identified peptides had previously been identified in macroalgae

A Sustainable Approach for Extracting Non-Extractable Phenolic Compounds from Mangosteen Peel Using Ultrasound-Assisted Extraction and Natural Deep Eutectic Solvents

Mangosteen (Garcinia mangostana L.) peel is a potential source of phenolic compounds with beneficial properties. Natural deep eutectic solvents (NaDES) have been considered an environmentally friendly and cheap alternative to conventional organic solvents. In this work, a green extraction methodology was developed using ultrasound-assisted extraction (UAE) and NaDES for the extraction of antioxidant non-extractable polyphenols (NEPs) from mangosteen peel. To select the best NaDES to extract NEPs from mangosteen peel, seven NaDES were studied. Antioxidant capacity and total phenolic and proanthocyanidin contents were determined for the extracts. The molecular weights for the NEPs present in those extracts were evaluated by size exclusion chromatography. Experimental results showed that choline chloride&-lactic acid (1:2) was the NaDES allowing the highest antioxidant proanthocyanidin content in the extracts. A Box&-Behnken experimental design was employed to optimize the main parameters in UAE with NaDES: water percentage, ultrasound amplitude, and extraction time. The optimal extraction conditions were 18.8% (v/v) water, 60% ultrasound amplitude, and 15 min as the extraction time. In addition, the cytotoxicity of the NEP extracts obtained under optimal extraction conditions was evaluated. Results indicated for the first time that the use of NaDES in combination with UAE could be a sustainable alternative for the extraction of antioxidant NEPs from mangosteen peel for important applications in the food, pharmaceutical, agrochemical, and cosmetic fields, as the extracts presented low cytotoxicity

Revalorization of Passiflora species peels as a sustainable source of antioxidant phenolic compounds

Food industry generates a big amount of residues. Nowadays, there is interest in adding value to these residues with the aim of increasing the sustainability of the food chain and to reduce the environmental impact of this waste whose revalorization could also originate an economical benefit. Passion fruits are cultivated for juice and pulp production generating high amounts of vegetable residues. The scarce information about passion fruit peels confers a high interest to the study of their phenolic profiles. In this work, an efficient extraction method based on pressurized hotwater extractionwas employed to obtain antioxidants from four Passiflora species peels (P. ligularis, P. edulis, P. edulis flavicarpa and P. mollissima). Antioxidant properties of the extracts were tested by in vitro assays and intracellular reactive oxygen species scavenging. P. mollissima and P. edulis peel extracts presented higher antioxidant capacity and phenolic content than P. ligularis and P. edulis flavicarpa. Tentative structural elucidation of 57 phenolics was achieved by high-performance liquid chromatography-quadrupole-time of flight mass spectrometry. Flavones, chalcones and phenolic acids were the polyphenol classes that may contribute to antioxidant capacity of the Passiflora peel

Antiviral compounds obtained from microalgae commonly used as carotenoid sources

Pressurized liquid extraction (PLE), an environmentally friendly technique, has been used to obtain antiviral compounds from microalgae commonly used as carotenoid sources: Haematococcus pluvialis and Dunaliella salina. The antiviral properties of PLE extracts (hexane, ethanol and water) were evaluated against herpes simplex virus type 1 (HSV-1) at different stages during viral infection. Pretreatment of Vero cells with 75 μg mL -1 of H. pluvialis ethanol extract inhibited virus infection by approximately 85%, whereas the same concentration of water and hexane extracts reduced the virus infectivity 75% and 50%, respectively. D. salina extracts were less effective than H. pluvialis extracts and presented a different behaviour since water and ethanol extracts produced a similar virus inhibition (65%). Moreover, H. pluvialis ethanol extract was also the most effective against HSV-1 intracellular replication. The antiviral activity of water PLE extracts was found to correlate with polysaccharides since the polysaccharide-rich fraction isolated from these extracts showed higher antiviral activity than the original water extracts. A gas chromatography-mass spectrometry (GC-MS) characterization of the H. pluvialis ethanol extract showed the antiviral activity of this extract could be partially related with the presence of short-chain fatty acids, although other compounds could be involved in this activity; meanwhile, in the case of D. salina ethanol extract other compounds seemed to be implied, such as: β-ionone, neophytadiene, phytol, palmitic acid and α-linolenic acid. The results demonstrate the use of PLE allows obtaining antiviral compounds from microalgae used as carotenoids sources, which gives the microalgae biomass an added value. © 2011 Springer Science+Business Media B.V.This work has been financed by the Spanish Ministry of Education and Science (AGL2005-06726-C04), the programme CONSOLIDER-INGENIO 2010 (CDS2007-00063) and the regional programme ALIBIRD-CM S-0505/AGR-0153 from the Comunidad de Madrid, Spain.S0505/AGR-0153/ALIBIRDPeer Reviewe