Optimized Antibacterial Effects in a Designed Mixture of Essential Oils of Myrtus communis, Artemisia herba-alba and Thymus serpyllum for Wide Range of Applications

Nowadays, the combination of molecules influences their biological effects, and interesting outcomes can be obtained from different component interactions. Using a mixture design method, this research seeks to simulate the efficacy of essential oil combinations against various bacteria and forecast the ideal combination. The chemical compositions of Myrtus communis, Artemisia herba-alba and Thymus serpyllum essential oils were analyzed using CG/MS. Then, the combined antibacterial effects were evaluated by testing mixture design formulations using the microdilution bioassay. The main compounds detected for M. communis essential oil were myrtenyl acetate (33.67%), linalool (19.77%) and 1,8-cineole (10.65%). A. herba-alba had piperitone as a chemotype, representing 85%. By contrast, the T. serpyllum oil contained thymol (17.29%), γ-terpinene (18.31%) and p-cymene (36.15%). The antibacterial effect of the essential oils studied, and the optimum mixtures obtained were target strain-dependent. T. serpyllum alone ensured the optimal inhibition against S. aureus and E. coli, while a ternary mixture consisting of 17.1%, 39.6% and 43.1% of M. communis, A. herba-alba and T. serpyllum respectively, was associated with optimal inhibitory activity against B. subtilis. The outcome of this research supports the idea of the boosting effect of essential oil combinations toward better activities, giving better understanding of the usefulness of mixture designs for food, cosmetics, and pharmaceutical applications.

Enhanced Spontaneous Antibacterial Activity of δ-MnO2 by Alkali Metals Doping

Recently, the widespread use of antibiotics is becoming a serious worldwide public health challenge, which causes antimicrobial resistance and the occurrence of superbugs. In this context, MnO2 has been proposed as an alternative approach to achieve target antibacterial properties on Streptococcus mutans (S. mutans). This requires a further understanding on how to control and optimize antibacterial properties in these systems. We address this challenge by synthesizing δ-MnO2 nanoflowers doped by magnesium (Mg), sodium (Na), and potassium (K) ions, thus displaying different bandgaps, to evaluate the effect of doping on the bacterial viability of S. mutans. All these samples demonstrated antibacterial activity from the spontaneous generation of reactive oxygen species (ROS) without external illumination, where doped MnO2 can provide free electrons to induce the production of ROS, resulting in the antibacterial activity. Furthermore, it was observed that δ-MnO2 with narrower bandgap displayed a superior ability to inhibit bacteria. The enhancement is mainly attributed to the higher doping levels, which provided more free electrons to generate ROS for antibacterial effects. Moreover, we found that δ-MnO2 was attractive for in vivo applications, because it could nearly be degraded into Mn ions completely following the gradual addition of vitamin C. We believe that our results may provide meaningful insights for the design of inorganic antibacterial nanomaterials.

In Vitro Antibacterial Susceptibility of Different Pathogens to Thirty Nano-Polyoxometalates

Due to their unique properties, nano-polyoxometalates (POMs) can be alternative chemotherapeutic agents instrumental in designing new antibiotics. In this research, we synthesized and characterized “smart” nanocompounds and validated their antibacterial effects in order to formulate and implement potential new drugs. We characterized thirty POMs in terms of antibacterial activity–structure relationship. The antibacterial effects of these compounds are directly dependent upon their structure and the type of bacterial strain tested. We identified three POMs that presented sound antibacterial activity against S. aureus, B. cereus, E. coli, S. enteritidis and P. aeruginosa strains. A newly synthesized compound K6[(VO)SiMo2W9O39]·11H2O (POM 7) presented antibacterial activity only against S. aureus (ATCC 6538P). Twelve POMs exerted antibacterial effects against both Gram-positive and Gram-negative strains. Only one POM (a cluster derivatized with organometallic fragments) exhibited a stronger effect compared to amoxicillin. New studies in terms of selectivity and specificity are required to clarify these extremely important aspects needed to be considered in drug design.

Discovery of a novel class of small-molecule antibacterial agents against Staphylococcus aureus

Background: With constantly increasing resistance against the known antibiotics, the search for novel antibacterial compounds is a challenge. The number of synthetic antibacterial agents is limited. Materials & methods: We discovered novel small-molecule antibacterial agents that are accessible via a simple two-step procedure. The evaluation against Staphylococcus aureus showed antibacterial effects depending on the substituent positioning at the residues of the molecular scaffold. Additionally, we investigated the potential of the compounds to increase the antibacterial activity of tetracycline. Results: The most effective antibacterial compounds possessed a 3-methoxy function at an aromatic residue. In combination with tetracycline, we found a strong effect for a few compounds in boosting the antibacterial activity, so the first promising lead compounds with dual activities could be identified.

Oregano (Origanum vulgare L.) Essential Oil Feed Supplement Protected Broilers Chickens against Clostridium perfringens Induced Necrotic Enteritis

Oregano (Origanum vulgare L.) is a well-known traditional medicine and a cooking spice. Recent practice has also applied the essential oil from oregano (OEO) in poultry due to its great potential for an antibiotic alternative. Our objective was to evaluate the potential effects of OEO (with carvacrol and thymol as the main active ingredient) on preventing necrotic enteritis (NE) caused by Clostridium perfringens (Cp) in chickens. In the feeding trial, a total of 450 one-day-old commercial Arbor Acres broilers were randomly assigned in 5 experimental groups during a 26-day production period (d19 to d 26 was the Cp challenge stage), and each group consisted of 6 replicate pens (15 birds each pen). All treatments were: basal diet (control group); basal diet and Cp challenge (model group); Cp challenge and 10 mg/kg enramycin (positive control group); Cp challenge and 200 mg/kg OEO product (OEO low dosage group, OEOL); Cp challenge and 300 mg/kg OEO product (OEO high dosage group, OEOH). OEO feed supplement at both dosages had significant effects on increasing the body weight gain (BWG) and reversing the dropped feed intake (FI) induced by Cp challenge. Histopathological changes in the ileums of broiler chickens with NE induced by Cp were alleviated by OEO, which was mutually confirmed by the intestinal lesion scores. Dosage did not influence the protective effect of OEO on intestinal lesion scores. Furthermore, OEO was found to have limited effects on tight junction-related gene expressions (Occludin and ZO-1). The broilers of the OEOL and OEOH groups significantly decreased the expression of TNF-α mRNA in the ileum and only the OEOH group was found to inhibit the IFN-γ expression of IFN- induced by Cp challenge. Finally, despite the fact that in vitro antibacterial effects by OEO were observed, considering its high minimum inhibitory concentration (MIC) value, we inferred that the protective effects by OEO against Cp challenge were not attributable to its direct antibacterial effects. We proposed OEO as a promising substitute for antibiotics against NE induced by Cp during poultry production.

In Vivo Antibacterial Efficacy of Nanopatterns on Titanium Implant Surface: A Systematic Review of the Literature

Background: Bionic surface nanopatterns of titanium (Ti) materials have excellent antibacterial effects in vitro for infection prevention. To date, there is a lack of knowledge about the in vivo bactericidal outcomes of the nanostructures on the Ti implant surfaces. Methods: A systematic review was performed using the PubMed, Embase, and Cochrane databases to better understand surface nanoscale patterns’ in vivo antibacterial efficacy. The inclusion criteria were preclinical studies (in vivo) reporting the antibacterial activity of nanopatterns on Ti implant surface. Ex vivo studies, studies not evaluating the antibacterial activity of nanopatterns or surfaces not modified with nanopatterns were excluded. Results: A total of five peer-reviewed articles met the inclusion criteria. The included studies suggest that the in vivo antibacterial efficacy of the nanopatterns on Ti implants’ surfaces seems poor. Conclusions: Given the small number of literature results, the variability in experimental designs, and the lack of reporting across studies, concluding the in vivo antibacterial effectiveness of nanopatterns on Ti substrates’ surfaces remains a big challenge. Surface coatings using metallic or antibiotic elements are still practical approaches for this purpose. High-quality preclinical data are still needed to investigate the in vivo antibacterial effects of the nanopatterns on the implant surface.

A Mini- review : Effect of Phyllantus niruri L. on Growth and Health of Fish

Phyllanthus niruri L. is one of the herbal ingredients that has been widely used to treat various diseases in humans such as intestinal infections, kidney stones, chronic liver disease, diabetes, hepatitis B, asthma, gonorrhea, bronchitis, syphilis and boost the immune system. The ability of P. niruri in overcoming various diseases is based on its phytochemical content and pharmacological properties. Based on these properties, the plant may possibly be used as a drug to treat diseases in fish. So the purpose of writing this article is to review the extent to which P. niruri can be used as an alternative medicine to treat disease and maintain fish health. Secondary metabolites and phyllanthine as specific compounds present in P. niruri have antibacterial effects for types of bacteria that usually attack fish such as Aeromonas hydrophila, Edwardsiella tarda, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa. In addition, it has the effect of being an antioxidant, immunostimulant and can be used for treatment and to increase fish growth. So it can be concluded that P. niruri can be used as an alternative material to maintain health and help fish growth.