Browsing by Author "Achour, Lotfi"
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- Arbutus unedo L. and Ocimum basilicum L. as sources of natural preservatives for food industry: A case study using loaf breadPublication . Takwa, Sallawi; Caleja, Cristina; Barreira, João C.M.; Soković, Marina; Achour, Lotfi; Barros, Lillian; Ferreira, Isabel C.F.R.; Takwa, SallawiThe aim of this work was to demonstrate the antioxidant potential, antimicrobial and the absence of toxicity of the ethanol extracts obtained from strawberry tree fruits and basil leaves, using optimal conditions. Subsequently, the extracts rich in catechin, from strawberry tree fruits, and rosmarinic acid from basil leaves, were incorporated as natural ingredients in loaf bread samples, with two objectives: to functionalize bread, introducing bioactive properties; and as natural ingredients with preservation capacity. Three more groups: control (without addition of any additive), bread incorporated with ascorbic acid - E300 and bread incorporated with potassium sorbate - E202 and for each group were 3 different times were analyzed: immediately after incorporation and after 3 and 7 days. Both natural extracts presented antioxidant activity, without toxicity up to the maximal tested dose (400 µg/mL), and the main compounds present were catechin and rosmarinic acid, respectively. The breads incorporated with the natural extracts, especial b asil, presented a higher antioxidant capacity than the loaf breads incorporated with ascorbic acid and potassium sorbate. Overall, the obtained results demonstrate that these extracts could be used in the development of new bread replacing the synthetic preservatives, without interfering with nutritional characteristics.
- Arbutus unedo L. and Ocinum basilicum L. as sources of natural ingredients for bread functionalizationPublication . Sallawi, Takwa; Caleja, Cristina; Achour, Lotfi; Barros, Lillian; Ferreira, Isabel C.F.R.The overwhelming growth of the world population is causing direct consequences on food demands, which has forced the food industry to apply synthetic additives in order to meet the needs of the consumer and ensuring the global quality of the food products including aspect, texture and flavor. However, due to the publication of some studies describing adverse effects associated with these synthetic additives, the natural ones have been gaining increasing interest. Arbutus unedo L. (strawberry tree) fruits and Ocimum basilicum L. (basil) leaves, are important sources of bioactive natural molecules, especially phenolic compounds, including flavan-3- ols and phenolic acids, respectively . The aim of this work was to demonstrate the antioxidant potential (free radical scavenging effect, reducing power and inhibition of lipid peroxidation) and the absence of toxicity (porcine liver primary cells) of ethanol extracts, obtained from the previously mentioned plants by using optimal conditions. Subsequently, the extracts were incorporated as natural ingredients in loaf bread samples, with two objectives: to functionalize loaf bread, introducing bioactive properties; and as natural ingredients with preservation capacity. Five groups of loaf bread samples were prepared: i) control (without natural or synthetic additives); ii) loaf bread incorporated with strawberry tree extract; iii) loaf bread incorporated with basil extract; iv) loaf bread incorporated with ascorbic acid- E300 (natural additive); and v) loaf bread incorporated with potassium sorbate- E202 (synthetic additive). Both extracts (strawberry tree fruits and basil leaves) presented antioxidant activity (EC50 values lower the 595 and 351 μg/mL, respectively), without toxicity up to the maximal tested dose, and the main compounds present were (+)-catechin and rosmarinic acid, respectively. The introduction of both natural and synthetic additives in loaf bread when compared to the control sample, did not cause significant changes, neither in pH values, nor in color or any of the evaluated nutritional parameters. The obtained results demonstrate that these extracts could be used in the development of new loaf bread replacing the synthetic preservatives, without interfering with the physical and nutritional characteristics.
- Arbutus unedo L. e Ocimum basilicum L. como conservantes naturais de pãoPublication . Sallawi, Takwa; Caleja, Cristina; Barreira, João C.M.; Soković, Marina; Achour, Lotfi; Barros, Lillian; Ferreira, Isabel C.F.R.Atualmente, existe uma preocupação da indústria alimentar na substituição de aditivos sintéticos por ingredientes naturais. Os extratos naturais obtidos a partir de plantas surgem como possíveis alternativas aos conservantes sintéticos, nomeadamente dos antioxidantes. Neste trabalho, pretendeu-se comprovar a eficácia de extratos ricos em catequina, obtido a partir de frutos de Arbutus unedo L. (medronho) e em ácido rosmarínico obtido a partir de folhas de Ocimum basilicum L. (manjericão), como conservantes naturais de pão, comparando a sua eficácia com aditivos sintéticos normalmente aplicados a produtos de panificação. Após a avaliação das propriedades antioxidantes (valores EC50 do efeito bloqueador de radicais de DPPH = 595 e 351 μg/ mL, para medronho e manjericão, respetivamente) e antimicrobianas (contra 8 bactérias e 8 fungos) e confirmação da ausência de citoxicidade (numa cultura primária de células de fígado), os extratos ricos em (+)-catequina e ácido rosmarínico foram incorporados no pão. O seu efeito foi comparado com o ácido ascórbico (E300), o sorbato de potássio (E202) e com uma amostra controlo (pão sem aditivos) imediatamente após a incorporação e após 3 e 7 dias de armazenamento, à temperatura ambiente e protegidos da luz. Os pães aditivados com os extratos naturais, especialmente de manjericão, apresentaram maior capacidade antioxidante do que os pães com ácido ascórbico e sorbato de potássio, tendo todos mantido as suas propriedades nutricionais. Em geral, os resultados obtidos demonstraram que os extratos podem ser utilizados no desenvolvimento de pão, substituindo os conservantes sintéticos, sem interferir nas características físicas e nutricionais dos produtos finais.
- Bioactive properties and functional constituents of Hypericum androsaemum L.: A focus on the phenolic profilePublication . Jabeur, Inès; Tobaldini, Flávia; Martins, Natália; Barros, Lillian; Martins, Ivone; Calhelha, Ricardo C.; Henriques, Mariana; Silva, Sónia; Achour, Lotfi; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.Hypericum androsaemum L. ethanol:water extract acted as a lipid peroxidation inhibitor and free radical scavenger. Amarked inhibition of the growth of breast, lung, cervical and hepatocellular human carcinoma cell lineswas also observed, whereas no toxicity was shown against non-tumor porcine liver cells (N400 μg/mL). The extract was also effective in inhibiting nitric oxide production, as an indicator of the anti-inflammatory potential. The anti-Candida effects varied among different strains of the same species, C. glabrata and C. tropicalis being the most sensible species with an effect directly related with the extract concentrations tested. A significant antibiofilm formation potential was also observed, namely for C. glabrata and C. tropicalis (biofilm reduction N90%). 5-O-Caffeoylquinic and 3-O-caffeoylquinic acids were themost abundant phenolic compounds identified in the extract, and might be related with the observed bioactive effects. Nevertheless, future studies should be carried out to obtain dose-response curves of the isolated active compounds, in order to perform further preclinically testing to quantify the presence of the most active compounds in the extract.
- Bioactivity and chemical characterization of Opuntia macrorhiza Engelm. seed oil: potential food and pharmaceutical applicationsPublication . Chahdoura, Hassiba; Barreira, João C.M.; Adouni, Khawla; Mhadhebi, Lamia; Calhelha, Ricardo C.; Snoussi, Mejdi; Majdoub, Hatem; Flamini, Guido; Ferreira, Isabel C.F.R.; Achour, LotfiIn the food industry, there is a continuous search for ingredients that might provide advantageous properties to food products, either considering their nutritional value or bioactivity, as well as flavouring and technological aspects. Crude oils are good examples of this type of ingredient, especially if obtained from nonconventional sources. Accordingly, the Opuntia macrorhiza Engelm. seed oil (OMSO) was chemically characterized and evaluated for different in vitro and in vivo bioactivities. OMSO presented physicochemical characteristics appropriate to be considered as an edible oil, namely low acidity value, stability to oxidation (high peroxide value and low K 232 and K 270 values), and high contents of unsaturated fatty acids (as shown by the iodine value) and saponifiable matter. Furthermore, this natural oil, owing to its rich phytochemical profile, showed relevant antioxidant activity (especially in lipid peroxidation inhibition assays), a-glucosidase inhibitory activity, cytotoxicity against human tumour cell lines, antibacterial (mainly against Gram positive species) and antifungal properties, as well as anti-inflammatory and analgesic activities. Furthermore, OMSO did not show any sign of acute toxicity on animals, highlighting its possible use in different applications, considering that this natural product is not expected to induce the adverse effects typically associated with synthetic bioactive agents (e.g., ampicillin, amphotericin B, or lysine acetylsalicilate).
- Bioactivity, hydrophilic, lipophilic and volatile compounds in pulps and skins of Opuntia macrorhiza and Opuntia microdasys fruitsPublication . Chahdoura, Hassiba; Barreira, João C.M.; Barros, Lillian; Dias, Maria Inês; Calhelha, Ricardo C.; Flamini, Guido; Soković, Marina; Achour, Lotfi; Ferreira, Isabel C.F.R.Opuntia genus includes several species able to grow in arid regions and known for producing delicate fruits, which are far from being thoroughly characterized. Herein, fruits from O. macrorhiza and O. microdasys were divided in skins and pulps (without including seeds) and studied for chemical composition, individual phytochemicals and bioactivity. The major volatiles were camphor and ethyl acetate, while citric acid was the main organic acid. The fatty acids detected in highest percentages were linoleic acid (skins) and lauric acid (pulps); α- tocopherol was the major isoform of vitamin E. Quercetin-3-O-rutinoside and quercetin-O-(deoxyhexoside-rutinoside) were the main phenolics in fruit skins of O. macrorhiza and O. microdasys (respectively), similarly to piscidic acid in O. macrorhiza pulp (O. microdasys pulp showed no quantifiable compounds). Betanin and isobetanin were the major betalains. All samples were antioxidant (particularly O. macrorhiza), but antimicrobial activity was only detected in skins. Cytotoxicity was low in all cases. Overall, these fruits proved to be potential new ingredients for food or pharmaceutical related applications, adding value to these natural species able to grow in arid environments.
- Bioactivity, proximate, mineral and volatile profiles along the flowering stages of Opuntia microdasys (Lehm.): defining potential applicationsPublication . Chahdoura, Hassiba; Barreira, João C.M.; Fernández-Ruiz, Virginia; Morales, Patricia; Calhelha, Ricardo C.; Flamini, Guido; Soković, Marina; Ferreira, Isabel C.F.R.; Achour, LotfiOpuntia spp. flowers have been traditionally used for medical purposes, mostly because of their diversity in bioactive molecules with health promoting properties. The proximate, mineral and volatile compound profiles, together with the cytotoxic and antimicrobial properties were characterized in O. microdasys flowers at different maturity stages, revealing several statistically significant differences. O. microdasys stood out mainly for its high contents of dietary fiber, potassium and camphor, and its high activities against HCT15 cells, Staphylococcus aureus, Aspergillus versicolor and Penicillium funiculosum. The vegetative stage showed the highest cytotoxic and antifungal activities, whilst the full flowering stage was particularly active against bacterial species. The complete dataset has been classified by principal component analysis, achieving clearly identifiable groups for each flowering stage, elucidating also the most distinctive features, and comprehensively profiling each of the assayed stages. The results might be useful to define the best flowering stage considering practical application purposes.
- Biological activities evaluation of enantiopure isoxazolidine derivatives: in vitro, in vivo and in silico studiesPublication . Mosbah, Habib; Chahdoura, Hassiba; Mannai, Asma; Snoussi, Mejdi; Aouadi, Kaïss; Abreu, Rui M.V.; Bouslama, Ali; Achour, Lotfi; Selmi, BoulbabaA series of enantiopure isoxazolidines (3a–c) were synthesized by 1,3-dipolar cycloaddition between a (−)-menthone-derived nitrone and various terminal alkenes. The screened compounds were evaluated for their antioxidant activity by two in vitro antioxidant assays, including β-carotene/linoleic acid bleaching, and inhibition of lipid peroxidation (thiobarbituric acid reactive species, TBARS). The results revealed that compound 3b (EC50 = 0.55 ± 0.09 mM) was the most potent antioxidant as compared to the standard drug (EC50 = 2.73 ± 0.07 mM) using the TBARS assay. Furthermore, the antimicrobial activity was assessed using disc diffusion and microdilution methods. Among the synthesized compounds, 3c was found to be the most potent antimicrobial agent as compared to the standard drug. Subsequently, the acute toxicity study has also been carried out for the newly synthesized compounds and the experimental studies revealed that all compounds were safe up to 500 mg/kg and no death of animals were recorded. The cytotoxicity of these compounds was assessed by the MTT cell proliferation assay against the continuous human cell lines HeLa and compound 3c (GI50 = 46.2 ± 1.2 μM) appeared to be more active than compound 3a (GI50 = 200 ± 2.8 μM) and 3b (GI50 = 1400 ± 7.8 μM). Interestingly, all tested compounds displayed a good α-amylase inhibitory activity in competitive manner with IC50 values ranging between 23.7 and 64.35 μM when compared to the standard drug acarbose (IC50 = 282.12 μM). In addition, molecular docking studies were performed to understand the possible binding and the interaction of the most active compounds to the α-amylase pocket.
- Chemical and antioxidant parameters of dried forms of ginger rhizomesPublication . Jelled, Aicha; Fernandes, Ângela; Barros, Lillian; Chahdoura, Hassiba; Achour, Lotfi; Ferreira, Isabel C.F.R.; Cheikh, Hassen BenThere are various products that can be obtained from ginger (Zingiber officinale Roscoe) rhizomes, such as dried products, being difficult to choose the best option for antioxidant purposes. In this study, three different dried forms of ginger rhizomes (freshly dried, dried and powder dried) were characterized in terms of chemical composition including individual profiles in sugars, organic acids, fatty acids, tocopherols, and antioxidants (phenolics and flavonoids). The in vitro antioxidant properties (free radicals scavenging activity, reducing power and lipid peroxidation inhibition) of their methanolic extracts were also evaluated. The results of this study indicate that the ginger form has significant influence in chemical and antioxidant parameters of the plant; dried ginger (DG) proved to be the best choice. Overall, this study could help the consumer in the selection of the most suitable option regarding antioxidant purposes.
- Chemical characterization of carob seeds (Ceratonia siliqua L.) and use of different extraction techniques to promote its bioactivityPublication . Ben Ayache, Siwar; Reis, Filipa S.; Dias, Maria Inês; Pereira, Carla; Glamočlija, Jasmina; Soković, Marina; Saafi, Emna Behija; Ferreira, Isabel C.F.R.; Barros, Lillian; Achour, LotfiNowadays, the use of carob (Ceratonia siliqua L.) is reduced to its seeds. In fact, the food additive E410, locust bean gum, is obtained from its endosperm. However, the available information regarding the bioactive potential of carob seeds is limited and, often, with poorly established terminologies, not allowing the reader to know if the studied samples included seedless or seeded samples. So, the present study intended to carry out a chemical characterization of carob seeds focused on their bioactive compounds and test their bioactive properties. Carob seeds proved to be a source of tocopherols and organic acids, including phenolic compounds. Its antioxidant potential was demonstrated in vitro, as well as its antimicrobial capacity. This work proves that carob seeds have other functions in addition to those associated with E410. Thus, another potential can be given to the locust bean seed, namely the function of food preservative.
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