Browsing by Author "Teixeira, Vítor"
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- Antiacetylcholinesterase activity and docking studies with chlorogenic acid, cynarin and arzanol from Helichrysum stoechas (Lamiaceae)Publication . Silva, Leticia; Rodrigues, Ana M.; Ciriani, Marina; Fale, Pedro Luís Vieira; Teixeira, Vítor; Madeira, Paulo; Machuqueiro, Miguel; Pacheco, Rita; Florêncio, Maria Helena; Ascensão, Lia; Serralheiro, Maria LuisaThis work was aimed at the study of the chemical composition in phenolic compounds responsible for the high antiacetylcholinesterase activity of aqueous extracts (decoctions) from Helichrysum stoechas aerial parts. Chlorogenic acid, cynarin, and arzanol were the main components of decoctions, detected by high-performance liquid chromatography with diode-array detection and liquid chromatography-mass spectrometry/mass spectrometry. Flowers and stems/leaves extracts inhibited antiacetylcholinesterase with IC50 values of 260.7 and 654.8 mu g/mL, respectively. The biological activity of these extracts was maintained after in vitro gastrointestinal digestion, indicating that the active compounds present in the extracts were not enzymatically modified by the gastrointestinal system used to simulate the digestion. Molecular docking studies with the main components were carried out in order to obtain information, at the molecular level, as to how these compounds access the enzyme's active site. The docking study showed for the first time that chlorogenic acid, cynarin, and arzanol fit nicely in the antiacetylcholinesterase active site channel, blocking all access to the catalytic triad. This explained the high inhibitory activity determined during in vitro experiments.
- Bioactivities of decoctions from Plectranthus species related to their traditional use on the treatment of digestive problems and alcohol intoxicationPublication . Brito, Elsa; Gomes, Emma; Fale, Pedro; Borges, Carlos; Pacheco, Rita; Teixeira, Vítor; Machuqueiro, Miguel; Ascensão, Lia; Serralheiro, Maria LuisaEthnopharmacological relevance Decoctions of Plectranthus species are traditionally ingested after large meals for treatment of food digestion and alcohol abuse. Aim of the study This study aims at associating the digestion-related ethno-uses of Plectranthus species decoctions to molecular mechanism that might explain them: easing digestion (AChE inhibition) and treating hangover (ADH inhibition) Material and methods Decoctions from Plectranthus species were analysed for their alcohol dehydrogenase (ADH) inhibition and acetylcholinesterase (AChE) inhibition, related with alcohol metabolism and intestinal motility, respectively. Identification of the active components was carried out by LC-MS/MS and the docking studies were performed with AChE and the bioactive molecules detected. Results All decoctions inhibited ADH activity. This inhibition was correlated with their rosmarinic acid (RA) content, which showed an IC50 value of 19 μg/mL, similar to the reference inhibitor CuCl2. The presence of RA also leads to most decoctions showing AChE inhibiting capacity. P. zuluensis decoction with an IC50 of 80 μg/mL presented also medioresinol, an even better inhibitor of AChE, as indicated by molecular docking studies. Furthermore, all decoctions tested showed no toxicity towards two human cell lines, and a high capacity to quench free radicals (DPPH), which also play a helpful in the digestive process, related with their RA content. Conclusions All activities presented by the RA-rich Plectranthus decoctions support their use in treating digestion disorders and P. barbatus could explain its use also for alleviating hangover symptoms. Medioresinol, which is present in P. zuluensis, exhibited a significant AChE inhibition and may provide, in the future, a new lead for bioactive compounds.