Antioxidant activity and cholinesterase inhibition studies of four flavouring herbs from Alentejo

In Alzheimer’s disease, the most common form of dementia, the loss of cholinergic neurons leads to the progressive reduction of acetylcholine in the brain, resulting cognitive impairment. Inhibition of the hydrolysis of acetylcholine by blocking acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) has been considered as a potential target in the treatment of Alzheimer’s disease. Essential oils and extracts of aromatic plants may have an important role in the oxidative stress protection. Traditionally, in Alentejo (Portugal), aromatic herbs Calamintha nepeta, Foeniculum vulgare, Mentha spicata and Thymus mastichina are often used by local population as condiments in food preparations. In this study, essential oils (EOs) and aqueous extracts (decoction waters) of these flavouring herbs were selected in order to evaluate its antioxidant potential and ability to inhibit AChE and BChE activities. Results suggest the potential use of EOs and extracts as nutraceutical or pharmaceutical preparations in the prevention of the oxidative stress and degenerative diseases

Antimicrobial and antitumoral potential use of essential oils from Calamintha nepeta, Origanum virens and Thymus mastichina (Alentejo)

Aromatic plants are appreciated as food flavors, being preserved and consumed by the local population in daily diets, and in Mediterranean Diet. Essential oils (EOs), complex mixtures rich in terpene compounds, have shown several biological properties, mainly as antimicrobials and antioxidants. Alentejo, S.W. of Portugal, is very rich in flavoring autochthones aromatic plants. Therefore, it is important to evaluate their phytotherapeutic potential for their application as food preservatives, nutraceuticals and/or therapeutically products. For this study were selected autochthonous Lamiaceae plants: Calamintha nepeta, Origanum virens and Thymus mastichina in order to evaluate the chemical composition and antioxidant, antimicrobial and antiproliferative activities of their essential oils. EOs were extracted by hydrodistillation from aerial parts of flowering plants, and their chemical composition was evaluated by GC-FID. EOs antioxidant potential of was evaluated in vitro by radical DPPH, total reducing power and β-carotene linoleic acid methods. Antimicrobial activity was assessed by solid diffusion disk assays and minimal inhibitory concentration. Cell viability was performed by methylthiazol tetrazolium (MTT) assay using MDA-MB-231 breast cancer cells. Results showed EOs very rich in oxygenated monoterpenes but O. vulgare EO showed similar content in oxygenated monoterpenes and monoterpene hydrocarbons. EOs are important antioxidants, with ability to scavenge free radicals, inhibit Fe2+ oxidation and protect the lipid substrate oxidation. EOs presented a large antimicrobial spectrum, with high inhibitory activity against Gram-positive and Gram-negative strains Additionally, EOs showed high antiproliferative activity for breast cancer cell line. Results point out the antioxidant, antimicrobial and antiproliferative potential of EOs of C. nepeta, O virens and T. mastichina of Alentejo and suggest their potential use as health promoting agents in food and/or pharmaceutical industries. This work was supported by: MEDUSA (ALT20-03-0145-FEDER-000015) and by E-RIHS.pt, co-financed by European Union through Alentejo and Portugal 2020

Avaliação do conteúdo fenólico e potencial antioxidante de extratos aquosos de Calamintha nepeta e Mentha spp. do Alentejo

Os extratos de plantas, são ricos em polifenóis que possuem um importante potencial antioxidante devido à sua capacidade de captação de radicais livres ou de proteção de oxidação dos substratos lipídicos, desempenhando um papel importante na prevenção de patologias relacionadas ao stress oxidativo, como doenças neurodegenerativas e cardiovasculares. O Alentejo é rico em plantas aromáticas autóctones, muitas utilizadas na medicina tradicional e também como condimentares na Dieta Mediterrânica. Neste estudo selecionaram-se quatro espécies aromáticas e condimentares da família Lamiaceae, Calamintha nepeta, Mentha cervina, Mentha spicata e Mentha pulegium, para preparação de extratos aquosos, caracterização do conteúdo fenólico, avaliação do potencial antioxidante e da letalidade em A. salina. Os extratos aquosos foram preparados da parte aérea da planta utilizando dois procedimentos distintos: a partir das águas de decocção resultantes da hidrodestilação da planta fresca (EHD) e a partir da solução aquosa resultante da trituração a frio da planta fresca (EPF). Para avaliação da varia ção sazonal da planta prepararam-se extratos EHD com plantas coletadas dois anos diferentes. Procedeu-se à caraterização química dos extratos EHD (obtidos de plantas de 2 anos diferentes, A e B, no mesmo estado vegetativo) e EPF com quanti cação dos fenóis totais, avonóides e taninos [2]. O potencial antioxidante foi avaliado in vitro por três mecanismos de ação diferentes, método do radical DPPH, sistema -caroteno/ácido linoleico e poder redutor do ferro. Procedeu-se também à avaliação dos mecanismos de atividade antioxidante dos extratos em sistemas enzimáticos envolvidos no stress oxidativo, com determinação do potencial inibitório da atividade de catalases e de glutationo-peroxidases, em homogenatos hepáticos

Essential oils of Portuguese flavouring plants: potential as green biocides in cultural heritage

Microbial biodeterioration is a growing problem in cultural heritage (CH). Many biocides used to control CH biodeterioration have toxic effects and risks of contamination for health and the environment. Essential oils (EOs) due to their antimicrobial potential and low toxicity represent a sustainable and safe alternative in the control of microbial growth in heritage assets. Nevertheless, EOs volatility is one of the main challenges for its use in bio-mitigation adapted to cultural heritage. The encapsulation of EOs may have an alternative strategy for the use of EOs as green biocides that promote a controlled release of EO. In this study, seven EOs of flavouring herbs were screened to evaluate their antimicrobial potential against filamentous fungi, yeast or bacteria strains, previously isolated from colonized artworks. Free EOs, namely L. luisieri and C. nepeta EOs, showed a large antimicrobial spectrum, with high activity for A. niger, Cladosporium spp., Penicillium spp., Rhodotorula sp. and Arthrobacter sp. strains. EO of T. vulgaris shows similar antifungal activity when encapsulated by co-precipitation with β-cyclodextrin, for an encapsulation efficiency higher than 50%. The results suggest the potential use of EO in the safeguard of cultural assets, as eco-friendly, biodegradable and non-toxic biocides, as a green and useful approach when compared to traditional biocides

Aqueous extracts of Origanum vulgare and Thymus spp. from Alentejo: Anti-inflammatory and Antioxidant Screening

Mediterranean diet, intangible cultural heritage of Humanity, is a fundamental pillar for sustainable development of populations. Alentejo is rich in indigenous aromatic plants in Montado cork oak forests, many of them used in traditional Medicine as well as food flavours in Mediterranean diet. Moreover, Medicinal, aromatic and flavouring plants (MAPs) and their extracts are rich in phenolic compounds and play an important role in prevention of pathologies related with oxidative stress, such as neurodegenerative, cardiovascular and cancer diseases. For this study, three autochthonous flavouring herbs from Lamiaceae family, widely distributed throughout Iberian Peninsula and used in Mediterranean cuisine, have been selected: Origanum vulgare L., Thymus capitellatus Hoffmanns. & Linkand and Thymus mastichina L. Freeze-drying decoction water extracts were performed to evaluate their chemical composition and antioxidant and anti-inflammatory potential. Antioxidant and anti-inflammatory proprieties were evaluated by several mechanisms including DPPH radical, reducing power and β-carotene/linoleic acid methods, as well as the ability to inhibit catalase activity in hepatic homogenates and to inhibit lipoxygenase activity

Essential oils of Calamintha nepeta, Origanum vulgare and Thymus mastichina of Alentejo (Portugal): a pharmacological approach

Alentejo, in the south of Portugal, is rich in endemic aromatic plants, that are used as condiments and food additives by the local population. The aim of this study was to evaluate the antioxidant, antimicrobial and antiproliferative activities of EOs of autochthones Calamintha nepeta (L.) Savi (syn. Clinopodium nepeta (L.) Kuntze), Origanum vulgare L., and Thymus mastichina L. EOs were extracted from the aerial part of the plants by hydrodistillation and the chemical composition was analyzed by GC-FID and GC-MS. Antioxidant potential of the oils was evaluated by three different assays: DPPH radical, β-carotene/linoleic acid and reducing power methods. Antimicrobial activity of the oils was evaluated by a solid disk diffusion assay and minimal inhibitory concentrations (MIC) were determined by a microdilution broth method. Toxicity of the EOs was screened by the brine shrimp lethality test (LC50) and the oral lethal doses (DL50) were determined for mice. Cell viability was assessed by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay using MDAMB231 breast cancer cells

Toxicological and pharmacological properties of essential oils of Calamintha nepeta, Origanum virens and Thymus mastichina of Alentejo (Portugal)

Three autochthonous flavouring herbs from Alentejo (Portugal), Calamintha nepeta (syn. Clinopodium nepeta), Origanun virens and Thymus mastichina, were selected to evaluate toxicological, antioxidant, antiproliferative and antimicrobial potential of their essential oils (EOs). C. nepeta and T. mastichina EOs showed a high content of oxygenated monoterpenes (86–91%) while O. virens had similar content of oxygenated and hydrocarbon monoterpenes (45%). Toxicological assessment suggests high activity against A. salina (31.8 < CL50 < 128.4 mg/L) and very low toxicity in Swiss mice (DL50≥1500 mg/kg). EOs showed high antioxidant ability by DPPH radical scavenging assay (0.1–0.6 mg QE/mL EO), total reducing power method (0.2–1.7 mg QE/mL EO) and β-carotene/ linoleic acid system (11–501 mg QE/mL EO). An important antiproliferative effect against human breast tumour cell line was observed (88.9 < EC50 < 108.5 mg/L). Moreover, EOs presented a large antibacterial spectrum. Results point out the low toxicity and high antioxidant, antiproliferative and antimicrobial activities of EOs of these endemic aromatic plants, suggesting their potential use in biotechnological, food and/or pharmaceutical industries

Antioxidant and Antimicrobial Activities of Arylamide-Acetals derivates: Potential Drugs for Neurodegenerative Diseases

Antioxidants behave as major defense agents against reactive oxygen species (ROS) which are prominent in many serious illnesses, including neurodegenerative diseases such as: Alzheimer’s and Parkinson’s diseases [1]. It is thought that some of the symptoms are due to the imbalance between pro-oxidant and antioxidant homeostasis. Antioxidant defense mechanisms are responsible for the removal of O2, scavenging of reactive oxygen species or inhibition of reactive oxygen species formation [2]. Therefore the discovery of small molecules with antioxidant properties is important in the fight against neurodegenerative diseases and microbial infections [2]. In the present study a small library composed by diazepine and quinolinone derivatives and their precursors (arylamide-acetals) were screened for their antioxidant and antimicrobial properties. Antioxidant activities were evaluated either by free radical DPPH method and -carotene/linoleic acid system. The antimicrobial activities were screened against Gram -positive and Gram- negative pathogenic bacteria by disc diffusion assay, and the minimal inhibitory concentration (MIC) was determined for sensitive strain