Maria do Carmo Barreto

Anti-acetylcholinesterase and Antioxidant Activity of Essential Oils from Hedychium gardnerianum Sheppard ex Ker-Gawl

Acetylcholinesterase inhibition, antioxidant and cytotoxic activities of Hedychium gardnerianum leaf essential oils from S. Miguel Island were determined. All the oils inhibited acetylcholinesterase, with IC50 values of approximately 1 mg/mL, showing no statistical differences between collection sites. Three oils presented mixed inhibition, whilst one was almost truly competitive. This activity can be attributed to the presence of sesquiterpenes, which constituted more than 60% of the composition of the oils. Regarding the antioxidant activity as measured by the DPPH method, all the oils presented activities similar to reference compounds, although with statistical differences between collection sites. Cytotoxicity measured using Artemia salina classified these oils as moderately toxic, with LC50 values ranging from 300 to 500 µg/mL. These results indicate a possible application of these oils in aromatherapy as coadjuvants in the treatment of cognitive diseases such as Alzheimer, since they may contribute to increase acetylcholine in cholinergic neurons and simultaneously fight deleterious oxidations responsible by neurological degeneration.

Recent Breakthroughs in the Antioxidant and Anti-Inflammatory Effects of Morella and Myrica Species.

Oxidative stress is one of the risk factors for the development of several chronic diseases, such as diabetes, cancer, cardiovascular and neurodegenerative diseases. Antioxidants are therefore highly sought and can be seen as a type of preventive medicine against several diseases. Myrica and Morella genus (Myricaceae) are taxonomically very close and their species are trees or shrubs with edible fruits that exhibit relevant uses in traditional medicine, for instance in Chinese or Japanese folk medicine they are used to treat diarrhea, digestive problems, headache, burns and skin diseases. Nearly 36 compounds were isolated from different morphological parts of Myrica and/or Morella species and their antioxidant and anti-inflammatory activities evaluated. Thirteen of these compounds exhibit greater effects than the positive controls used. Adenodimerin A was the most active compound reported (in a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay EC50= 7.9 ± 0.3 µM). These results are just one aspect of the antioxidant and anti-inflammatory evaluations reported regarding Myrica and Morella species, so a comprehensive overview on the current status, highlighting the antioxidant health promoting effect of these species, their key antioxidant compounds as well as the compounds with protective effects against oxidative stress related diseases such as inflammation, is relevant.Oxidative stress is one of the risk factors for the development of several chronic diseases, such as diabetes, cancer, cardiovascular and neurodegenerative diseases. Antioxidants are therefore highly sought and can be seen as a type of preventive medicine against several diseases. Myrica and Morella genus (Myricaceae) are taxonomically very close and their species are trees or shrubs with edible fruits that exhibit relevant uses in traditional medicine, for instance in Chinese or Japanese folk medicine they are used to treat diarrhea, digestive problems, headache, burns and skin diseases. Nearly 36 compounds were isolated from different morphological parts of Myrica and/or Morella species and their antioxidant and anti-inflammatory activities evaluated. Thirteen of these compounds exhibit greater effects than the positive controls used. Adenodimerin A was the most active compound reported (in a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay EC50= 7.9 ± 0.3 µM). These results are just one aspect of the antioxidant and anti-inflammatory evaluations reported regarding Myrica and Morella species, so a comprehensive overview on the current status, highlighting the antioxidant health promoting effect of these species, their key antioxidant compounds as well as the compounds with protective effects against oxidative stress related diseases such as inflammation, is relevant.

Xanthenedione Derivatives, New Promising Antioxidant and Acetylcholinesterase Inhibitor Agents

Natural and synthetic xanthone derivatives are well-known for their ability to act as antioxidants and/or enzyme inhibitors. This paper aims to present a successful synthetic methodology towards xanthenedione derivatives and the study of their aromatization to xanthones. Additionally their ability to reduce Fe(III), to scavenge DPPH radicals and to inhibit AChE was evaluated. The results demonstrated that xanthenedione derivative 5e, bearing a catechol unit, showed higher reduction capacity than BHT and similar to quercetin, strong DPPH scavenging activity (EC50 = 3.79 ± 0.06 µM) and it was also showed to be a potent AChEI (IC50 = 31.0 ± 0.09 µM) when compared to galantamine (IC50 = 211.8 ± 9.5 µM).

Allocation of nutrients during the reproductive cycle of Ophidiaster ophidianus (Echinodermata: Asteroidea)

The reproductive cycle of Ophidiaster ophidianus (strictly protected status) from São Miguel Island, in the Azorean Archipelago was studied. The reproductive strategy; the energy allocation of each sex during the reproductive cycle and the nutritional condition of the population were analyzed. Gonadal index (GI) showed a clear seasonal pattern with spawning between August and October but histological examination revealed that gamete release can occur throughout the entire year. The pyloric caeca index (PCI) showed little annual variation but with an inverse relationship with the GI. Allocation of energy to the gonads and to the pyloric caeca reflected the seasonal reproductive strategy of this species. Individuals were able to simultaneously develop gonads, pyloric caeca, and quickly regenerate lost arms. There was a major expenditure of energy by females compared to males but, sexual size dimorphism was not observed. The reproductive pattern observed in O. ophidianus combining rich food availability and seawater temperatures characteristic of a temperate zone may be the key to the success of this species in the Azorean oceanic Island.