Neem (Azadirachta indica) is recognized as a medicinal plant well known for its antibacterial, antimalarial, antiviral, and antifungal properties. Neem nanoemulsion (NE) (O/W) is formulated using neem oil, Tween 20, and water by high-energy ultrasonication. The formulated neem NE showed antibacterial activity against the bacterial pathogen Vibrio vulnificus by disrupting the integrity of the bacterial cell membrane. Despite the use of neem NE in various biomedical applications, the toxicity studies on human cells are still lacking. The neem NE showed a decrease in cellular viability in human lymphocytes after 24 hours of exposure. The neem NE at lower concentration (0.7-1 mg/mL) is found to be nontoxic while it is toxic at higher concentrations (1.2-2 mg/mL). The oxidative stress induced by the neem NE is evidenced by the depletion of catalase, SOD, and GSH levels in human lymphocytes. Neem NE showed a significant increase in DNA damage when compared to control in human lymphocytes (P,0.05). The NE is an effective antibacterial agent against the bacterial pathogen V. vulnificus, and it was found to be nontoxic at lower concentrations to human lymphocytes. © 2015 Jerobin et al.

Amitava Mukherjee

Centre for Nanobiotechnology

Vellore Campus

Chandra Sekaran N

Jerobin J

Makwana P

Suresh Kumar R.S

Sundaramoorthy R

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Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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Antibacterial activity of neem nanoemulsion and its toxicity assessment on human lymphocytes in vitro

International Journal of Nanomedicine

Microemulsions are isotropic mixtures of oil and water stabilized by surfactant and excellent drug delivery carriers due to their typical properties. Their antimicrobial activity can be due to direct interaction with fungal cytoplasmic membrane. The present study aims to enhance the solubility of hydrophobic drug using formulated novel microemulsion system and check probable synergistic impact of oil system along with conventional drug against fungal strain of C. albicans. The worked out optimized formulation was achieved through oil: surfactant: water (5:20:70) which was subjected to physiochemical analysis. The rate of drug release was checked for drug loaded microemulsion compared to conventional drug (Ketoconazole). The drug loaded and unloaded optimized microemulsion formulations were checked for its antimicrobial activity against C. albicans, for its minimum inhibitory concentration (MIC) along with cytoplasmic leakage using membrane integrity assay. Kill kinetics study was carried out to check the time-based lethality of Ketoconazole based microemulsion against the fungal strain. In vitro toxicity was analyzed against human lymphocyte for microemulsion. The appearance of morphological distortion was observed using fluorescent staining and SEM. The results indicate promising delivery vehicle for the intended purpose and the optimized emulsion formulation was found to be non-toxic at lower concentration for oral usage. © 2018 Elsevier B.V.

Journal of Drug Delivery Science and Technology

Enhanced antifungal activity of Ketoconazole using rose oil based novel microemulsion formulation

The present study deals with the preparation and optimisation of neem oil nanoemulsion by microfluidization process and its application for the bacterial infection management in aquaculture. The effect of process parameters like surfactant concentration (Tween 20, Tween 80), homogenisation pressure and the number of cycles on the droplet size of neem oil nanoemulsion was investigated. The optimized pressure and number of cycles for the neem oil nanoemulsion preparation was found to be 20,000 psi and 25 cycles respectively. A significant decrease (p &lt; 0.05) in the particle size of neem oil nanoemulsion was observed as the pressure, number of cycles and concentration of surfactant increase. The neem oil nanoemulsion prepared using 1:3 ratio of neem oil and Tween 80 surfactant showed a good stability with a mean droplet size of 24.5 ± 1.33 nm. The concentration of Azadiractin, an active ingredient in neem oil nanoemulsion was found to be 21.187 ± 1.01 μg/mL. The 1:3 ratio of neem oil - Tween 80 formulated nanoemulsion showed good antibacterial activity against the fish pathogen, Aeromonas culicicola (MIC of 0.93 μl/mL). The morphological changes inflicted by the neem nanoemulsion treatment on bacterial cells were evident from the scanning electron microscopy and membrane integrity analysis. Further, the In-vivo bactericidal efficacy of the neem oil nanoemulsion was tested on Common carp (Cyprinus carpio). The neem oil nanoemulsion treatment exhibited protective action against Aeromonas culicicola infection and it improved the antioxidant defence system of fish. The above results envisage the use of neem oil nanoemulsion as a potential alternative for synthetic antibiotics in treatment of bacterial infection of the fish. Copyright © 2018 John Wiley &amp; Sons, Ltd.

Flavour and Fragrance Journal

Nanometric neem oil emulsification through microfluidization, and its therapeutic potential againstAeromonas culicicolainfection inCyprinus carpio

Presence of several biochemical constituents in neem makes it an efficient antimicrobial agent for pathogenic diseases. The current investigation was aimed to assess the therapeutic potential of neem nanoemulsion as a control measure for Pseudomonas aeruginosa infection in freshwater fish Labeo rohita. The median lethal concentration (LC50) for the neem oil and neem nanoemulsion was 73.9 and 160.3 mg/L, respectively. The biomarker enzymes of treated fish tissues showed a significant difference in the level of glutathione reductase, catalase, and lipid peroxidation in neem oil-treated samples than in neem nanoemulsion-treated samples at P &lt; 0.05. The results were corroborative with histopathology and ultrastructural analysis. The bacterial infection of P. aeruginosa treated using neem nanoemulsion was more effective in both in vitro and in vivo methods. Present findings suggest that neem-based nanoemulsion has negligible toxicity to Rohu fishes. This makes neem-based nanoemulsion as an efficient therapeutic agent against P. aeruginosa infection, leading to its possible usage in the aquaculture industry. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

Biotechnology and Applied Biochemistry

Study on antimicrobial potential of neem oil nanoemulsion againstPseudomonas aeruginosainfection inLabeo rohita

The plant derived essential oil nanoemulsion was prepared using a mixture of components containing eucalyptus oil as organic phase, water as continuous phase, and non ionic surfactant, Tween 80, as emulsifier at a particular proportion of 1:1 v/v%. The ultrasonication was applied for varied processing time from 0 to 30 min to study the effect of time on the formation of nanoemulsion and physical stability of formulation by this method. The transparency and stability of emulsion was enhanced when the sonication time was increased compared to hand blender emulsion. The most stable nanoemulsion was obtained in 30 min sonication having the mean droplet diameter of 3.8 nm. The antibacterial studies of nanoemulsion against Staphylococcus aureus by time kill analysis showed complete loss of viability within 15 min of interaction. Observations from scanning electron microscopy of treated bacterial cells confirmed the membrane damage compared to control bacteria. Furthermore, the wound healing potential and skin irritation activity of the formulated nanoemulsion in Wistar rats, suggested non-irritant and higher wound contraction rate with respect to control and neomycin treated rats. These results proposed that the formulated system could be favourable for topical application in pharmaceutical industries. © 2013 Elsevier B.V. All rights reserved.

Ultrasonics Sonochemistry

Ultrasonic emulsification of eucalyptus oil nanoemulsion: Antibacterial activity against Staphylococcus aureus and wound healing activity in Wistar rats

The current study deals with the formulation and characterization of bio-based oil in water nanoemulsion and its potential antibacterial activity. A typical v/v% of eucalyptus oil (16.66%), Tween 80 (16.66%), and water (68.68%) was prepared by ultrasonication method. The mean droplet size was 17.1nm as confirmed by dynamic light scattering. Different concentrations of the formulation ranging from undiluted to 10-, 100-, and 1000-fold dilutions were used to check the antibacterial activity in three different microorganisms, namely, Bacillus cereus, Staphylococcus aureus (Gram-positive), and Escherichia coli (Gram-negative). All three species showed a 100% bactericidal at the 10-fold dilution of the nanoemulsion formulation in the following order: B. cereus at 0th min, S. aureus at 15min and E. coli at 1h, respectively. A 10-fold dilution of the nanoemulsion showed that, the cytoplasmic content leakage from the bacterial species was high for S. aureus when compared to B. cereus and E. coli as determined by UV-Vis spectroscopic method. Fluorescence microscopic technique further confirmed this study. © 2013.

Journal of Basic Microbiology

Bio-based nanoemulsion formulation, characterization and antibacterial activity against food-borne pathogens

Clarias batrachus (Linn) is a species of catfish of the family claridae. Pathogenecity of Aeromonas salmonicida was studied in healthy fish. The inoculum was injected into healthy fingerlings through intramuscular injection and immersion challenge. Histopathological investigation of the infected organs was also studied. The bacterial infection was treated using neem nanoemulsion by in vitro and in vivo analysis and was found to be effective. © 2013 Elsevier B.V.

Aquaculture

Studies on pathogenecity of Aeromonas salmonicida in catfish Clarias batrachus and control measures by neem nanoemulsion

The growing commercial applications had brought aluminium oxide nanoparticles under toxicologists' purview. In the present study, the cytotoxicity of two different sized aluminium oxide nanoparticles (ANP1, mean hydrodynamic diameter 82.6±22nm and ANP2, mean hydrodynamic diameter 246.9±39nm) towards freshwater algal isolate Chlorella ellipsoids at low exposure levels (≤1μg/mL) using sterile lake water as the test medium was assessed. The dissolution of alumina nanoparticles and consequent contribution towards toxicity remained largely unexplored owing to its presumed insoluble nature. Herein, the leached Al3+ ion mediated toxicity has been studied along with direct particulate toxicity to bring out the dynamics of toxicity through colloidal stability, biochemical, spectroscopic and microscopic analyses. The mean hydrodynamic diameter increased with time both for ANP1 [82.6±22nm (0h) to 246.3±59nm (24h), to 1204±140nm (72h)] and ANP2 [246.9±39nm (0h) to 368.28±48nm (24h), to 1225.96±186nm (72h)] signifying decreased relative abundance of submicron sized particles (&lt;1000nm). The detailed cytotoxicity assays showed a significant reduction in the viability dependent on dose and exposure. A significant increase in ROS and LDH levels were noted for both ANPs at 1μg/mL concentration. The zeta potential and FT-IR analyses suggested surface chemical interaction between nanoparticles and algal cells. The substantial morphological changes and cell wall damage were confirmed through microscopic analyses (SEM, TEM, and CLSM). At 72h, significant Al3+ ion release in the test medium [0.092μg/mL for ANP1, and 0.19μg/mL for ANP2] was noted, and the resulting suspension containing leached ions caused significant cytotoxicity, revealing a substantial ionic contribution. This study indicates that both the nano-size and ionic dissolution play a significant role in the cytotoxicity of ANPs towards freshwater algae, and the exposure period largely determines the prevalent mode of nano-toxicity. © 2013 Elsevier B.V.

Journal	International Journal of Nanomedicine
Publisher	Informa UK Limited
ISSN	11769114
Open Access	Yes