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Research Project
Associated Laboratory for Green Chemistry - Clean Technologies and Processes
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Publications
GC- and UHPLC-MS Profiles as a Tool to Valorize the Red Alga Asparagopsis armata
Publication . Pinto, Diana C. G. A.; Lesenfants, Marie L.; Rosa, Gonçalo P.; Barreto, Maria do Carmo; Silva, Artur M. S.; Seca, Ana M. L.
Asparagopsis armata Harvey is a red alga native from the southern hemisphere and then introduced in the Mediterranean Sea and the Atlantic Ocean, including the Azores Archipelago, where it is considered an invasive alga. Some studies show that the extracts exhibit antimicrobial and antifouling activities, and it is incorporated in some commercialized cosmetic products. (e.g., Ysaline®). However, knowledge of this species chemical composition is scarce. The GC-MS and UHPLC-MS profiles of both the nonpolar and polar extracts were established to contribute to this problem solution. According to the results, A. armata is rich in a great structural variety of halogenated lipophilic and aromatic compounds, some of them identified here for the first time. In the lipophilic extract, 25 compounds are identified, being the halogenated compounds and fatty acids, the two major compound families, corresponding to 54.8% and 35.7% of identified compounds (224 and 147 mg/100 g of dry algae, respectively). The 1,4-dibromobuten-1-ol and the palmitic acid are the two most abundant identified compounds (155 and 83.4 mg/100 g of dry algae, respectively). The polar extract demonstrated the richness of this species in brominated phenolics, from which the cinnamic acid derivatives are predominant. The results obtained herein open new perspectives for valuing the A. armata as a source of halogenated compounds and fatty acids, consequently improving its biotechnological and economic potential. Promoting this seaweed and the consequent increase in its demand will contribute to biodiversity conservation and ecosystem sustainability.
Secondary Metabolites and Their Applications
Publication . Gallardo, Eugenia; Seca, Ana M. L.
The identification of secondary metabolites present in both terrestrial and marine species continues to be a fundamental and privileged path for the emergence of new and fundamental natural products available on the market with very different applications. For example, aplidine is a new natural anticancer agent, and it was approved in Australia in 2018 to treat multiple myeloma and was isolated from the first time from tunicate “Aplidium albicans” Milne Edwards. (+)-Nootkatone is a natural sesquiterpene compound, found in very small amounts in several species such as “Chamaecyparis nootkatensis” (D. Don) Sudworth, ”Chrysopogon zizanioides” (L.) Roberty and “Citrus paradise” Macfad., which exhibits highly appreciated organoleptic properties and is, therefore, highly demanded as a flavoring agent or adjuvant in the food, pharmaceutical and perfumery industries. This same natural secondary metabolite is applied as insecticide and acaricide, and it was very recently authorized by United Sates Environmental Protection Agency to be include on formulations to control the spread of mosquitoes that transmit infectious diseases as dengue and zika. And who does not know the application of ascorbic acid, found for example in acerola and lemon fruits, as an antioxidant agent, widely used by the food industry?
The successful application of secondary metabolites in diverse requests often involves the use of, more or less, complex mixtures of metabolites, extracted by different methods and from different natural sources, but whose chemical composition and active principles are perfectly established. For example, there are the defined botanical mixtures, called natural product botanicals, which are recognized by the FDA as medicinal entities, successfully used in clinical therapy for the treatment of various diseases. This is the case of the mixture of the secondary metabolites of ”Solanum sodomaeum” L., solamargine, solasonine, and mono- and di-glycosides derivatives of solasodine, approved by the European Medicine Agency (trade name Curaderm) for the treatment of basal cell carcinoma of the skin.
One area in which the application of secondary metabolites mixtures rather than of pure compounds is common is in the formulation of biopesticides. For example, the insecticide Grandevo® is a mixture of metabolites produced in the fermentation of “Chromobacterium subtsugae”, which includes pigments from the violacein family and proteins that are repellent and antifeeding.
Despite the great successes already achieved regarding the secondary metabolites’ identification and the development of new applications for these metabolites, this is an area of research that should not slow down. Research must continue identifying and isolating secondary metabolites in unexplored natural sources; new methodologies for extracting secondary metabolites should be tested and optimized to develop greener and more efficient processes; pure secondary metabolites and chemically characterized mixtures must be tested in different biological activities in order to enhance new applications responding to the growing needs of humanity.
The Special Issue of Applied Sciences, “Advances in Applications of Natural Bioactive Compounds”, aims to contribute to the desired continuous advance in this scientific field, bringing together publications focused on the most recent advances in the identification of secondary metabolites from terrestrial and marine sources, in new extractive methodologies, and in proposals for applications that add value to natural resources and contributes to a more sustainable development.
Asparagopsis Genus : What We Really Know About Its Biological Activities and Chemical Composition
Publication . Ponte, José M. S.; Seca, Ana M. L.; Barreto, Maria do Carmo
Although the genus Asparagopsis includes only two taxonomically accepted species, the published literature is unanimous about the invasive nature of this genus in different regions of the globe, and about the availability of large amounts of biomass for which it is important to find a commercial application. This review shows that extracts from Asparagospsis species have already been evaluated for antioxidant, antibacterial, antifungal, antiviral, antifouling, cytotoxic, antimethanogenic and enzyme-inhibitory activity. However, the tables presented herein show, with few exceptions, that the activity level displayed is generally low when compared with positive controls. Studies involving pure compounds being identified in Asparagopsis species are rare. The chemical compositions of most of the evaluated extracts are unknown. At best, the families of the compounds present are suggested. This review also shows that the volatile halogenated compounds, fatty acids and sterols that are biosynthesized by the Asparagopsis species are relatively well known. Many other non-volatile metabolites (halogen compounds, flavonoids, other phenolic compounds) seem to be produced by these species, but their chemical structures and properties haven’been investigated. This shows how much remains to be investigated regarding the secondary-metabolite composition of these species, suggesting further studies following more targeted methodologies.
Laurus azorica : Valorization through Its Phytochemical Study and Biological Activities
Publication . Viveiros, Mariana Moniz; Barreto, Maria do Carmo; Seca, Ana M. L.
Laurus azorica (Seub.) Franco is an endemic species from the Azores, traditionally used in all the islands as a seasoning in cooking. The studies carried out with this species refer mainly to its essential oils. The study that was developed here allowed, for the first time, to determine the chemical composition and biological activities of the ethanol extract, fractions, and pure compounds from L. azorica. The hexane fraction was analyzed by GC–MS and revealed the presence of 48 compounds, comprising mainly fatty acids, fatty alcohols and terpenes, the family of fatty alcohols identified here for the first time in the genus Laurus. Three sesquiterpene lactones—costunolide, 11,13-dehydrosantonin and reynosin—were isolated for the first time in L. azorica from the same fraction, and structurally characterized using spectroscopic techniques. The compounds identified belong to families known to have relevant medicinal and nutritional properties. Regarding antioxidant activities, the results obtained showed a moderate radical scavenging effect of extracts and fractions, while in the β-carotene bleaching assay, costunolide was shown to be the most active (IC₅₀ = 4.08 ± 0.76 μg/mL), about 3.6 times more active than the standard, gallic acid, which presented IC₅₀ = 14.56 ± 0.13 μg/mL. Although the inhibition of extracellular matrix-degrading enzymes was not detected, the ethanol extract showed good inhibitory activity of tyrosinase, with an IC₅₀ of 12.04 ± 0.23 μg/mL, only 6.6-fold lower than the control kojic acid. The results presented deepen the knowledge about a little studied species, opening new perspectives for the development of value-added applications in the food and cosmeceutical fields.
Bio-Guided Optimization of Cystoseira abies-marina Cosmeceuticals Extraction by Advanced Technologies
Publication . Rosa, Gonçalo P.; Peixoto, Andreia F.; Barreto, Maria do Carmo; Seca, Ana M. L.; Pinto, Diana C. G. A.
Cystoseira abies-marina (reclassified as Gongolaria abies-marina) is a brown seaweed species rich in meroterpenoids, presenting interesting antioxidant, antitumor, and anti-inflammatory activities. However, there is still a lot to uncover regarding the bioactive potential of this species, as evidenced by the lack of records of antiaging activities from Cystoseira abies-marina, making this macroalga an excellent candidate for studies of its cosmeceutical potential. Ultrasound-(UAE) and microwave-assisted extraction (MAE) are advanced sustainable technologies that are very efficient in enhancing bioactive compound extraction. Applying these extraction techniques to a new biological matrix often calls for optimizing the parameters toward the best extraction yield. Since Cystoseira abies-marina is a new matrix for both UAE and MAE techniques, the present work proposes the optimization of the extraction process, using a novel approach: instead of only focusing on increasing the yield, the goal of this work is to determine the parameters for UAE and MAE that lead to extracts with better antiaging activities. For this bio-guided approach, several Cystoseira abies-marina extracts were prepared by UAE and MAE under varying conditions of solvent, time, and algae/solvent ratios. Their antiaging activities were then determined, and all the results combined to unveil the conditions yielding extracts with higher cosmeceutical potential. Using statistical tools, it was found that, for UAE, the best conditions were ethyl acetate, 15 min, and a ratio of 1:4, which led to an extract with high yield, and causing the strong inhibition of tyrosinase and elastase. In turn, ethanol, 10 min, and a ratio of 1:4 were the best conditions for MAE, leading to the extract with the best antioxidant activity. The results show that the proposed bio-guided approach was effective in obtaining extracts with high cosmeceutical potential, unveiling the possibility of modulating an extract’s activity by changing the extraction method.
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Funding agency
Fundação para a Ciência e a Tecnologia
Funding programme
6817 - DCRRNI ID
Funding Award Number
UIDB/50006/2020