CHEMICAL COMPOSITION AND ANTIMICROBIAL ACTIVITY OF ESSENTIAL OILS OF LAVANDULA SPP.

Lavenders belong to the family Labiatae and represent some of the most popular medicinal plants of great economic importance. Their essential oils are important for the perfume, cosmetic, flavouring and pharmaceutical industries. However, despite its popularity, and the long tradition of use, biological properties of the various Lavandula species are not yet been well sustained by scientific or clinical studies and some available data being inconclusive and controversial [1]. Although Lavandula spp. have similar ethnobotanical properties, however, chemical composition and therapeutic uses differ from different species and main composition of essential oils showed differences with species and with the region were they grow [1,2,3]. L. stoechas L. subsps. luisieri (Rozeira) Rozeira. L. pedunculata (Mill.) Cav. and L. viridis L’Hér are endemic to the Iberian Peninsula, widespread in the South of Portugal, namely in Alentejo and Algarve. In our work, essential oils from the stems or leaves from wild grown plants of L. luisieri (Alentejo), L. pedunculata (Alentejo) and L. viridis (Algarve), were extracted by hydrodistillation and analyzed by GC-FID. Antimicrobial activity was evaluated by solid diffusion disk assay and minimal inhibitory concentration (MIC) against pathogenic Gram-positive and Gram-negative bacteria and food spoilage fungi.

Antimicrobial activity of Brazilian propolis extracts for Staphylococcus aureus of sheep and goats mastitis origin

Twenty-four S. aureus isolates were analysed. From those, 22 were isolated from milk of goats and sheep with clinical and subclinical mastitis, from the region of Vale do São Francisco in the Brazilian Sertão and S. aureus ATCC 25923 plus a MRSA strain were added. Alcoholic extracts were produced from several batches of green, red and brown propolis consisting of 300 g of raw propolis in 700 mL of 70 % ethanol. Four genes related to antimicrobial resistance were assessed: blaZ that determines the resistance to β-lactam antibiotics, and genes icaA, icaD and bap that influence the production of biofilm. For the tests of susceptibility to different types of propolis the microdilution method was used, in triplicate, and dilutions between 0.003672 and 15% were tested, 70 % ethanol consisted of a negative control. The gene blaZ was found in 15 isolates; icaA gene was present in 3 isolates, icaD gene in 2 and bap gene was detected in 6 isolates. All the propolis tested exhibited antimicrobial activity, ranging from 44 to 100 % of susceptible isolates depending on different propolis batches. According to the results of this experiment the green and red propolis appear to have better antimicrobial activity than the brown variety.

Antioxidant,antimicrobial and toxicological properties of Schinus molle L. essential oils

Ethnopharmacological relevance: Schinus molle L. has been used in folk medicine as antibacterial, antiviral, topical antiseptic, antifungal, antioxidant, anti-inflammatory, anti-tumoural as well as antispasmodic and analgesic; however, there are few studies of pharmacological and toxicological properties of S. molle essential oils. Aim of the study: The aim of this study was to evaluate the antioxidant and antimicrobial activities of S. molle leaf and fruit essential oils, correlated with their chemical composition and evaluate their acute toxicity. Materials and methods: The chemical composition of S. molle leaf and fruit essential oils were evaluated by GC-FID and GC-MS. Antioxidant properties were determined using the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical and β-carotene/linoleic acid methods. Antimicrobial properties were evaluated by the agar disc diffusion method and minimal inhibitory concentration assay. Toxicity in Artemia salina and acute toxicity with behavioural screening in mice were evaluated. Results: The dominant compounds found in leaf and fruit essential oils (EOs) were monoterpene hydrocarbons, namely -phellandrene, β-phellandrene, β-myrcene, limonene and α-pinene. EOs showed low scavenging antioxidant activity by the DPPH free radical method and a higher activity by the β-carotene/linoleic acid method. Antimicrobial activity of EOs was observed for Gram+, Gram– pathogenic bacteria and food spoilage fungi. EOs showed cytotoxicity for Artemia salina and lower toxicity in Swiss mice. Conclusions: The result showed that EOs of leaves and fruits of S. molle demonstrated antioxidant and antimicrobial properties, suggesting their potential use in food or pharmaceutical industries.

ANTIOXIDANT, ANTIMICROBIAL AND TOXICOLOGICAL PROPERTIES OF SCHINUS MOLLE L. ESSENTIAL OILS

Schinus molle L. is commonly known as pink pepper or American pepper, of Anacardiaceae family, from subtropical regions of South America, introduced and naturalized in South Europe, including Portugal. In folk medicine, plant extracts and essential oil has related as having antibacterial, antiviral, antifungal, anti-inflammatory, antitumoral, antispasmodic, analgesic and antidepressive properties. The aim of present study was to evaluate the chemical composition and biological activities of essential oil extracted from leaves and fruits of S. molle. For this purpose, the essential oils were analyzed by gas chromatography (GC/FID) and antioxidant properties were evaluated by the free radical DPPH and by system β-carotene/linoleic acid methods. The antimicrobial activities were screened against pathogenic bacteria and fungi and food spoiling fungi by the disc diffusion assay and minimal inhibitory concentration (MIC) was determined for sensitive strains. Toxicity of essential oils were carried out by the brine shrimp mortality test (EC50) and acute lethal dose (DL50) determination after oral administration in Swiss mice The major components in leaf essential oil were α-phellandrene, β-phellandrene and limonene, while myrcene, α-phellandrene and 1,8-cineole are the main components in the fruit essential oil. The essential oils of leaf and fruit of S. molle showed antioxidant activity through the two mechanisms: the ability to capture free radicals and protection of lipid peroxidation. These oils exhibited also a broad microbial activity spectrum, against pathogenic bacteria Gram-positive and Gram-negative and Candida spp. The fruit essential oil showed high cytotoxicity against Artemia salina. Essential oils of leaves and fruits of S. molle showed significant antioxidant and microbial properties, so the studies continue to clarify more in deep its toxicity, including hepatotoxicity and nephrotoxicity, and to evaluate its medicinal or nutraceutical potential.

Propolis components accountable for bactericidal accomplishment and antibiofilm activity

This study aimed at evaluating antimicrobial and antibiofilm activity of phenolic compounds present in propolis ethanol extracts (PEE). Seventy per cent ethanol extracts from seven types of propolis, one Green, two Red and four Brown collected in four Brazilian States were prepared and total phenolics, flavonoids, tannins and anthocyanins were assessed by high-performance liquid chromatography (HPLC). Minimum bactericidal concentration (MBC) and inhibitor effect on Staphylococcus aureus biofilm formation and capacity to disrupt established biofilms were assessed towards eight S. aureus isolates from milk of small ruminants with mastitis, one methicillin-resistant S. aureus (MRSA) and S. aureus ATCC 25923. To evaluate different propolis components accountability for bactericidal accomplishment and antibiofilm activity, the results were analysed by the non-parametric Spearman coefficient. Results of phenolic compounds were 216,21 to 312,08 gallic acid milligram equivalent per extract gram (mg EGA/g) of total phenolics, 55,08 to 140,6 quercetin milligram equivalent per extract gram (mg EQ/g) of flavonoids, 118,51 to 3766,16 catechin milligram equivalent per extract gram (mg EC/g) of tannins and 1,03 to 8,39 milligram per extract gram (mg/g) of anthocyanins. Red1 and Red2 showed higher tannin contents, while Red2 exhibited superior amount of anthocyanins and total phenolics. Brown3 presented higher flavonoid quantity. Green, Red1 and Red2 PEE showed the lowest levels of flavonoids, but the higher antimicrobial activity. Most PEE exhibit bactericidal activity at a concentration of 1.6 mg/mL. Brown4 PEE showed the worst capacity to inhibit S. aureus. Green PEE showed to be the most efficient in both preventing and disrupting biofilm. All PEE studied exhibited a better inhibitory activity prior-to than post-biofilm formation. According to non-parametric Spearman correlation analysis, there seems to be a significant negative correlation between the ability to disrupt biofilm and both tannins and anthocyanins contents.

Seasonal variation, Chemical composition and antioxidante and antimicrobial proprieties of Calamintha nepeta

The aim of this study is to evaluate the chemical composition and the antioxidant and antimicrobial activities of EOs of C. nepeta collected in two different seasons, spring (leaves) and autumn (leaves and flowers) and to understand the relationship between seasonality composition and these biological activities. EOs were extracted by hydrodistillation of aerial parts of the plants wild grown in Évora (Alentejo) and their chemical composition was evaluated by GC-FID and GC-MS. Antioxidant activity was determined by β -carotene/linoleic acid system, total reducing power assay and DPPH radical methods [1]. Antimicrobial activity was assessed against Gram-negative and Gram-positive clinical isolates and food spoilage fungi [2,3].

Estudo preliminar sobre a ação antimicrobiana de óleos essenciais sobre agentes etiológicos de mastite em ovelhas

The control of mastitis is currently reliant on antibiotic utilization. Nevertheless antibiotics overuse and use without criteria leads to the development of resistant strains with negative consequences both in animal and public health. Essential oils (EOs) are classified as GRAS (generally recognized as safe), are provided with antimicrobial properties and no resistance has been reported after use. The aim of this study was to evaluate the antimicrobial activity of EOs of aromatic herbs, growing wild in Alentejo region and widely used in Mediterranean food, against microorganisms isolated from ovine mastitic milk.

Caracterização química e actividade biológica dos óleos essenciais e extractos aquosos de algumas Lavandula spp. do Sul de Portugal

No presente trabalho estudaram-se três espécies do género Lavandula, do sul de Portugal: L. luisieri e L. pedunculata (Alentejo) e L.viridis (Algarve), com vista caraterizar a composição química dos óleos essenciais das diferentes espécies, parte vegetativa (folha) e espiga floral, e dos respetivos extratos de hidrodestilação, e avaliar as propriedades antioxidante, antimicrobiana, toxicológica, analgésica e antiinflamatória de alguns dos seus óleos essenciais e extratos aquosos, mais promissores. Os resultados mostraram importantes diferenças na composição química dos óleos essenciais, quanto à diversidade e à proporção dos seus constituintes. Os óleos essenciais e hidrolatos, em estudo, apresentaram importantes propriedades antioxidantes e antimicrobianas. Os estudos toxicológicos e farmacológicos mostraram que os óleos apresentaram citotoxicidade em Artemia salina, apresentaram valores de DL50 muito superiores a 2000 mg/kg em ratinhos Swiss, e que possuem importantes propriedades analgésicas e anti-inflamatória. Estes resultados sugerem o seu potencial uso para aplicações farmacológicas como agentes nutracêuticos e/ou fitoterapêuticos; ABSTRACT:The aim of present work was to develop a set of studies of three species of the genera Lavandula, at the South of Portugal: L. luisieri e L. pedunculata (Alentejo) e L.viridis (Algarve), in order to characterize the chemical composition of the essential oils (leaves and flowers) and to evaluate the antioxidant, antimicrobial, toxicological and pharmacological properties of selected essential oils and aqueous extracts. Results show important differences in chemical composition of essential oils, both in diversity as the proportion of their constituents. Essential oils and aqueous extracts of different Lavandula spp. showed important antimicrobial and antioxidant properties. Pharmacological studies have shown that essential oils showed cytotoxicity against Artemia salina, low acute toxicity, with LD50 >> 2000 mg/kg for mice, and important analgesic and anti-inflammatory properties. These results suggest their potential use for pharmacological applications as nutraceutical and/or phytotherapeutic agents.

Pesquisa de fungos endofíticos presentes em videira (Vitis vinifera L.) com capacidade para inibir o crescimento do agente causal da podridão negra (Guignardia bidwellii)

Neste trabalho testou-se o potencial antagonista de 16 fungos endofíticos isolados de videiras (Vitis vinifera L.), de castas representativas do Alentejo produzidas em modo de proteção integrada e em modo biológico, contra Guignardia bidwellii. Os isolados identificados após ITS-PCR e sequenciação pertencem aos géneros Epicoccum, Alternaria, Botrytis, Athelia, Phoma e Gibberella. Os isolados testados mostraram atividade antagonista contra G. bidwellii quer por inibição direta, quer através da produção de compostos voláteis, à exceção dos dois isolados de B. cinerea. No entanto, todos os isolados produziram alguns compostos voláteis com reconhecida atividade antimicrobiana, tais como benzaldeído, 3-metil-1-butanol e derivados de ácido propanoico. Foi ainda observado que seis dos isolados produziram também metabolitos não voláteis com capacidade de inibir o crescimento de G. bidwellii. Os resultados obtidos vêm mostrar o potencial dos fungos endofíticos como agentes de luta biológica no controlo de G. bidwellii, podendo constituir novas alternativas no âmbito de Proteção de Plantas; ABSTRACT: Endophytic fungi present in grapevines (Vitis vinifera L.) with the ability to inhibit the growth of the causal agent of black rot (Guignardia bidwellii) In this work the antagonistic potential of 16 endophytic grapevine fungi isolates (Vitis vinifera L.), from representative cultivars of the Alentejo region produced either under integrated pest management or organic mode, was tested against Guignardia bidwellii. Isolates were identified through ITS-PCR and sequencing, as belonging to the genera Epicoccum, Alternaria, Botrytis, Athelia, Phoma and Gibberella. Isolates showed antagonist activity against G. bidwellii either by direct inhibition or through the production of volatile compounds, with the exception of two isolates of B. cinerea. Nevertheless, all isolates produced volatile compounds with known antimicrobial activity such as benzaldehyde, 3-methyl-1-butanol and propionic acid derivatives. Additionally, six isolates produced non-volatile metabolites with the ability to inhibit G. bidwellii growth. These results show the potential that endophytic fungi have as agents for biological control of G. bidwellii, opening new options in the field of Plant Protection.