Organic Chemistry, Natural Products and Food Stuffs

Funder

Organizational Unit

Publications

Hepatoprotection of mentha aquatica L., lavandula dentata L. and leonurus cardiaca L.

Publication . Pereira, Olívia R.; Macias, Rócio I.R.; Domingues, Maria R.M.; Marin, Jose J.G.; Cardoso, Susana M.

The phenolic composition of hydroethanolic extracts of Mentha aquatica L., Lavandula dentata L. and Leonurus cardiaca L., obtained from plants grown under organic cultivation, was determined and their hepatoprotective effects were investigated in vitro . L. cardiaca extract was rich in phenylethenoid glycosides, especially lavandolifolioside (254 ± 36 μg/mg), whereas rosmarinic acid and eriodictyol-O-rutinoside were the major phenolic compounds of L. dentata and M. aquatica extracts, accounting for 68 ± 7 μg/mg and 145 ± 22 μg/mg, respectively. These differential phenolic components presumably account for their dissimilar antioxidant properties. While L. cardiaca extract showed moderate biological effects, M. aquatica extract displayed high antioxidant activity in chemical models, and that of L. dentata was effective in counteracting potassium dichromate-induced ROS generation in human hepatocarcinoma cells. Moreover, M. aquatica extract (50 μg/mL) and its mixture (50%/50%) with L. dentata extract displayed an effective cytoprotective effect.

2019Journal article

Open access

High hydrostatic pressure as a tool to improve the antioxidant activity of watercress extracts

Publication . Pinela, José; Añibarro-Ortega, Mikel; Barros, Lillian; Saraiva, Jorge A.; Ferreira, Isabel C.F.R.

Watercress (Nasturtium officinale R. Br.) belongs to the Brassicaceae family together with broccoli, cabbage, mustard and Brussels sprouts. This semiaquatic plant is source of bioactive phytochemicals such as polyphenols, glucosinolates, and carotenoids, which have received great importance due to their several health benefits linked to antioxidant activity [1,2]. To obtain plant extracts, the extraction method must be thought out carefully to ensure successful recovery of the bioactive compounds. Therefore, the selection of an appropriate extraction method is important for the production of high quality antioxidant extracts, otherwise the extraction can lead to degradation of the target compounds. High pressure processing (HPP) has been used in the extraction of bioactive molecules from plant matrices with very promising results because, since no heat is used, it avoids harmful effects on thermosensitive compounds and, consequently, preserves better their biological activities. HPP provides higher extraction yields and selectivity for target compounds than conventional extraction methods [3]. Pressure can disrupt plant tissues and enhance mass transfer of solvent into the materials and the soluble constituents into the solvent. Thus, this study was carried out to outline the best extraction conditions to obtain antioxidant extracts from watercress. Powdered watercress was processed according to a central composite design of 20 runs, in which five levels of time (1.5–33.5 min), pressure (0.1–600 MPa) and ethanol concentration (0–100%, v/v) were combined. The antioxidant activity of the obtained extracts was measured in vitro by the DPPH• scavenging activity and reducing power assays, and the results were presented as EC50 values and used as response variables in the optimization by response surface methodology. Design Expert software was used for regression and graphical analysis of the data. A quartic polynomial equation that correlates the response as a function of the independent variables and their interaction was developed. The models were successfully fitted to the experimental data, statistically validated based on high F-values (>64.9) and R2adj (>0.96), and used to navigate the design space and predict the optimal extraction conditions. Considering both response criteria, the HHP conditions that sustainably maximized the extract antioxidant activity required a low processing time (1.5 min) and an intermediate pressure (319 MPa) and solvent concentration (55% ethanol, v/v), and yielded EC50 values of 0.45 mg/mL and 0,41 mg/mL for the DPPH and reducing power assays, respectively. HHP extraction revealed so to be a time-saving process comparatively with conventional methods.

2021Conference object

Open access

The antioxidant activity of prenylflavonoids

Publication . Santos, Clementina M.M.; Silva, Artur

Prenylated flavonoids combine the flavonoid moiety and the lipophilic prenyl side-chain. A great number of derivatives belonging to the class of chalcones, flavones, flavanones, isoflavones and other complex structures possessing di erent prenylation patterns have been studied in the past two decades for their potential as antioxidant agents. In this review, current knowledge on the natural occurrence and structural characteristics of both natural and synthetic derivatives was compiled. An exhaustive survey on the methods used to evaluate the antioxidant potential of these prenylflavonoids and the main results obtained were also presented and discussed. Whenever possible, structure-activity relationships were explored.

2020Journal article

Open access

The health-benefits and phytochemical profile of Salvia apiana and Salvia farinacea var. Victoria blue decoctions

Publication . Afonso, Andrea Luísa Fernandes; Pereira, Olívia R.; Fernandes, Ângela; Calhelha, Ricardo C.; Silva, Artur; Ferreira, Isabel C.F.R.; Cardoso, Susana M.

Salvia apiana and Salvia farinacea var. Victoria Blue decoctions were screened for diverse bioactivities, including the ability to counteract oxidative and inflammatory events, as well as to act as cytotoxic and antimicrobial agents. Both extracts showed good activities and that of S. apiana origin was particularly effective regarding the ability to prevent lipid peroxidation and to prevent nitric oxide (NO ) production in lipopolysaccharide (LPS)-activated murine macrophage RAW 264.7 cell line (EC50 = 50 µg/mL). Moreover, it displayed high cytotoxic capacity against hepatocellular carcinoma HepG2, cervical carcinoma HeLa, and breast carcinoma cells MCF-7, but comparatively low effects in porcine liver primary cells, which highlights its selectivity (GI50 = 41–60 µg/mL vs. 362 µg/mL, respectively). Further, it exhibited inhibitory and lethal potential against a panel of Gram-positive and Gram-negative bacteria. It is possible that the bioactive properties of the two Salvia extracts are associated to their phenolic components and, in the particular case of S. apiana, to its richness in phenolic terpenes, namely in rosmanol, hydroxycarnosic acid and a derivative of sageone, which were found in the extract.

2019Journal article

Open access

An overview on the market of edible flowers

Publication . Fernandes, Luana; Casal, Susana; Pereira, J.A; Saraiva, Jorge A.; Ramalhosa, Elsa

Edible flowers have become the latest food fashion, such as in United Kingdom, Portugal and Australia, making this niche market very challenging. Producers and points of sale of edible flowers (supermarkets, local markets, online) are increasing around the world, whereas consumers and professional chefs are demanding higher quality products. Despite being a growing market, information available on production, export and import is still scarce, without statistical data, with information restricted to that given by some producers and points of sale. So, this review aims to provide valuable information on the current situation of the edible flowers’ world market, with particular emphasis in Portugal, as well as, to give knowledge about legislation, promotional projects and campaigns, consumers and chefs perceptions, and to indicate the future trends regarding edible flowers.

2020Journal article

Restricted access