Percorrer por autor "Dridi, Asma"
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- Aesculus hippocastanum L.: a simple ornamental plant or a source of compelling molecules for industry?Publication . Dridi, Asma; Reis, Filipa S.; Pires, Tânia C.S.P.; Calhelha, Ricardo C.; Pereira, Carla; Zaghdoudi, Khalil; Ferreira, Isabel C.F.R.; Barros, Lillian; Barreira, João C.M.Aesculus hippocastanum L., also known as horse chestnut, is an ornamental tree whose seeds are mostly discarded in landfills in the regions where they are grown. However, recent studies have shown that these seeds can be a source of interesting compounds for several industries. This work aimed to chemically characterize horse chestnut seeds at the level of compounds recognized for their wide bioactivity, i.e., organic acids, including phenolic compounds, using chromatographic methodologies (UFLC-DAD and LC-DAD-ESI/MSn). In addition, the bioactivity of these seeds was evaluated by in vitro methodologies, seeking to relate the respective (bio)activity to the compounds present in the endocarp (husk), seed coat (skin), and peeled seed (pulp). The antioxidant activity (lipid peroxidation inhibition and oxidative haemolysis inhibition), antibacterial potential (against Gram-positive and Gram-negative bacteria) and cytotoxicity (in human tumour cell lines and porcine liver primary cells) were evaluated. Kaempferol-O-pentoside-O-hexoside-O-hexoside was the main phenolic identified in the pulp. At the same time, (-)-epicatechin and beta-type (epi)catechin dimer were the major phenolics present in husk and skin, respectively. In general, A. hippocastanum extracts presented antioxidant and antibacterial potential, without toxicity up to the maximal tested dose. Overall, these findings anticipate potential applications of A. hippocastanum seeds in food- or pharmaceutical-related uses.
- Chemical composition and bioactivity of different botanical parts of Aesculus hippocastanum L. fruitsPublication . Dridi, Asma; Barreira, João C.M.; Zaghdoudi, Khalil; Ferreira, Isabel C.F.R.Since ancient times, natural products, especially those originated from plants have been an important source of therapeutic agents. Currently, several drugs are derived from natural products (plants, animals, bacteria and fungi). Although the focus the synthetic chemistry advances, research on natural pharmaceutical uses has been knowing an important increase in number. In addition, recent data from the pharmaceutical industry show that, for some complex diseases, natural products still represent an extremely valuable source for prospecting new chemical formulations, as they represent unique structures refined by evolutionary mechanisms throughout millions of years. The importance and contribution of natural substances in medicine treatments is especially evident in some Asian and African countries, where 80% of the population depends on traditional medicine, including herbal treatments like in our case of study the Aesculus hippocastanum L. A. hippocastanum (also known as horse chestnut fruits) is an important source of bioactive natural molecules. The biological activity of A. hippocastanum is mainly provided by its secondary metabolites, a class of molecules especially involved in the plant defence system against different threats. Thus, these secondary metabolites play an important role in the adaptation of plants to the environment, effectively participating in their tolerance to various stress factors (pathogen attacks, drought, UV light, among others). The evaluation of the therapeutic value of these metabolites is the subject of many researches, leading to the identification of the main bioactive compounds in this plant. Saponins (triterpenes or steroid glycosides) and phenolic compounds are among the main classes of secondary metabolites. These compounds are of great interest because of their wide range of biological activities, having already been increasingly applied in pharmaceutical related formulation. In order to achieve effective valorisation strategies for these bioactive compounds, it is necessary to optimize separation processes to obtain them from natural sources. In addition to the former extraction procedure, obtaining bioactive compounds also requires other techniques (sometimes slow and expensive) such as purification and identification, which might be a limitation for their industrial application. Accordingly, it is mandatory to develop analytical techniques to improve the extraction process, and achieve rapid separation, miniaturization and coupling methodologies, continuously performed following green chemistry principles. The aim of this work was to demonstrate the antioxidant potential (free radical scavenging effect, reducing power and inhibition of lipid peroxidation), antimicrobial (antibacterial using Gram-positive and Gram-negative strains and antifungal activity) and the absence of toxicity (porcine liver primary cells) of the ethanol/methanol extracts, obtained from the previously mentioned plant and to contribute with updated information on natural sources of bioactive compounds, thorough chemical characterization and possible applications. The extract of A. hippocastanum fruit presented antioxidant activity, without toxicity up to the maximal tested dose and contained different classes of various bioactive molecules, besides carbohydrates lipids, proteins, and minerals. Overall, the information collected from the different analyses realized on the extract samples reveal their potential use in developing new forms of biopharmaceuticals or could be replacing other chemical substances in cosmetic products without interfering with the product composition or affecting its characteristics.