Antibacterial Activity of Lavandula officinalis and Melissa officinalis Against Some Human Pathogenic Bacteria

Essential Oil of Lavandula officinalis: Chemical Composition and Antibacterial Activities

The purpose of this study was to determine the chemical composition of the essential oil of Lavandula officinalis from Morocco using the GC-MS technique and assess the antibacterial effects against seven pathogenic bacteria strains isolated from the food origins of Salmonella infantis, Salmonella kentucky, Salmonella newport, three serotypes of Escherichia coli (O114H8K11, O127K88ac, O127H40K11) and Klebsiella. Tests of sensitivity were carried out on a solid surface using the Disc Diffusion Method. Results showed that E. coli and S.newport were sensitive to Lavandula officinalis essential oil. Minimum inhibitory concentrations (MIC) were determined using the method of agar dilution. The antibacterial results showed that four strains (three serotypes of E. coli, and S. newport) were remarkedly sensitive to Lavandula officinalis essential oil, giving MIC values of 88.7 µg/mL and 177.5 µg/mL. The molecular docking of the main oil products with the E. coli target protein 1VLY, showed that eucalyptol and linalyl acetate bind efficiently with the active site of the target protein. In particular, eucalyptol showed a higher activity than gentamicin used as positive control with a binding energy of -5.72 kcal/mol and -5.55 kcal/mol, respectively.

The fabrication of a novel film based on polycaprolactone incorporated with chitosan and rutin: potential as an antibacterial carrier for rainbow trout packaging

ABSTRACT

Rutin and chitosan could be utilized in the food industry owing to their antioxidant and antibacterial properties. This study was carried out to fabricate novel films using polycaprolactone (PCL-sole), PCL and chitosan (PCL-CS), PCL and rutin (PCL-R), and PCL, chitosan, and rutin (PCL-CS-R) through electros pinning method. Physical properties, in vitro antibacterial and antioxidant properties of the films, and their antibacterial activity on rainbow trout were further investigated. The PCL-CS, PCL-R, and PCL-CS-R had smaller fiber diameter and film thickness and lower viscosity while they showed higher surface tension, water contact angle, and conductivity and better antibacterial and antioxidant properties compared with PCL-sole film (P < 0.05). The PCL-CS-R film respectively decreased 17.45%, 19.27%, and 18.39% more populations of L. monocytogenes, S. aureus, and E. coli compared to PCL-sole film in the fish samples. Therefore, the PCL-CS-R film can be potentially used in active packaging because of its antioxidant and antibacterial activities.

GRAPHIC ABSTRACT

Antioxidant, Antimicrobial and Antiviral Properties of Herbal Materials

Recently, increasing public concern about hygiene has been driving many studies to investigate antimicrobial and antiviral agents. However, the use of any antimicrobial agents must be limited due to their possible toxic or harmful effects. In recent years, due to previous antibiotics' lesser side effects, the use of herbal materials instead of synthetic or chemical drugs is increasing. Herbal materials are found in medicines. Herbs can be used in the form of plant extracts or as their active components. Furthermore, most of the world's populations used herbal materials due to their strong antimicrobial properties and primary healthcare benefits. For example, herbs are an excellent material to replace nanosilver as an antibiotic and antiviral agent. The use of nanosilver involves an ROS-mediated mechanism that might lead to oxidative stress-related cancer, cytotoxicity, and heart diseases. Oxidative stress further leads to increased ROS production and also delays the cellular processes involved in wound healing. Therefore, existing antibiotic drugs can be replaced with biomaterials such as herbal medicine with high antimicrobial, antiviral, and antioxidant activity. This review paper highlights the antibacterial, antiviral, and radical scavenger (antioxidant) properties of herbal materials. Antimicrobial activity, radical scavenger ability, the potential for antimicrobial, antiviral, and anticancer agents, and efficacy in eliminating bacteria and viruses and scavenging free radicals in herbal materials are discussed in this review. The presented herbal antimicrobial agents in this review include clove, portulaca, tribulus, eryngium, cinnamon, turmeric, ginger, thyme, pennyroyal, mint, fennel, chamomile, burdock, eucalyptus, primrose, lemon balm, mallow, and garlic, which are all summarized.

Using Medicinal Plants in Valmalenco (Italian Alps): From Tradition to Scientific Approaches

This ethnobotanical survey was carried out in Caspoggio (Valmalenco, SO, Italy) with the purpose of investigating the traditional uses of medicinal plants. Moreover, a bibliographic research meant to validate or refute the uses, focusing on the potentially responsible compounds, was performed. Fifty-nine species, attributable to 30 families (Asteraceae, Pinaceae, Malvaceae, and Lamiaceae the most cited), were mentioned. Arnica montana, anti-inflammatory for traumas and musculoskeletal pains; Pinus mugo, expectorant; Malva sylvestris, anti-inflammatory and soothing; Achillea moschata, digestive. The compounds, responsible for the therapeutic activities, are often polyphenols and terpenoids: helenanin in A. montana, α-pinene, δ-3-carene, and limonene in P. mugo, gossypin and malvin in M. sylvestris, luteolin and apigenin in A. moschata. Scientific evidence for at least one of the traditional activities described was found for 50 species but only in 26 out of 196 works consulted, it is possible to make a comparison between investigated extracts and traditional preparations. This study is thus a stimulus to new phytochemical investigations, mimicking as much as possible the traditional preparations. This work is part of the European Interreg Italy-Switzerland B-ICE project, aimed at creating a management model for the ongoing climate change and searching for new sources of territory valorization as attractions for tourists.

Agro-ecological cultivation, secondary metabolite characteristics and microbiological tests of lemon balm (Melissa officinalis) – the variety Citronella

Lemon balm (Melissa officinalis L.) is a native of the eastern Mediterranean region southward to Israel and Syria and eastward through the Crimea, the Caucasus, and Northern Iran to the Tien Shan and the Pamirs. It appears to have been naturalized in the Central Europe including the Carpathian Ukraine and Eastern Slovakia. The objective of this study was characterization of the chemical composition and antimicrobial activity of essential oils from Melissa officinalis L. variety Citronella in the conditions of cultivation in a lowland region of the Ukrainian Carpathians. Plant material, balm dry leaves and leafy tops of the shoots, were grown in a small-scale cultivation ground at the Zakarpatian Institute of Agroindustrial Production in Velikaja Bakta, Carpathian-Ukraine. The Citronella variety is used for herb production. Essential oil from balm parts (herb and leaves) was isolated by distillation with boiled water. Hydro-distillation lasted for 4 hours, sample weights were 10 g of dry drug matter. A modified Coocking & Middleton distillation apparatus was used. Identification and evaluation of balm essential oil were carried out using the selected analytical method of HPLC-DAD analysis. The final balm extract was analyzed directly on a Dionex UltiMate 3000 system. The analysis of balm essential oil was carried out using a gas chromatograph Varian 3090, connected to a MS Saturn 2100T integrator. The sensitivity of microorganisms to plant extracts was determined by the disk diffusion test (with disk diameter of 6 mm). The quantitative and qualitative characteristics of balm essential oil (0.05–0.12% v/w) and its composition show very high content of α-citrale (geranial) (44%), β-citrale (neral) (29%) and citronellal (9%). Rosmarinic acid can be extracted from leaves and its content equals up to 1.7 ± 0.1%. Composition of the natural substances depends on the balm taxon, origin, soil and climatic growing conditions, and methods of harvest and isolation and effective weed control which are used. Antibacterial effect of the oil showed low activity against all bacterial strains. Our results confirmed higher activity of EOs against Gram-positive bacteria than Gram-negative. The balm essential oil displayed antimitotic effect especially towards Candida glabrata clinical strain. Thus, studies have shown that Melissa officinalis variety of Citronella in the conditions of cultivation in the lowland region of Carpathian-Ukraine according to biochemical characteristics and microbiological properties corresponds to world analogues.