Antimicrobial Activity of Polycaprolactone Nanofiber Coated with Lavender and Neem Oil Nanoemulsions against Airborne Bacteria

The development of efficient, eco-friendly antimicrobial agents for air purification and disinfection addresses public health issues connected to preventing airborne pathogens. Herein, the antimicrobial activity of a nanoemulsion (control, 5%, 10%, and 15%) containing neem and lavender oils with polycaprolactone (PCL) was investigated against airborne bacteria, including Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. Various parameters such as the physicochemical properties of the nanoemulsion, pH, droplet size, the polydispersity index (PDI), the minimum inhibitory concentration (MIC), the minimum bacterial concentration (MBC), and the color measurement of the emulsion have been evaluated and optimized. Our results showed that the antimicrobial activity of PCL combined with neem and lavender oil was found to be the highest MIC and MBC against all tested bacteria. The droplet sizes for lavender oil are 21.86-115.15 nm, the droplet sizes for neem oil are 23.92-119.15 nm, and their combination is 25.97-50.22 nm. The range of pH and viscosity of nanoemulsions of various concentrations was found to be 5.8 to 6.6 pH and 0.372 to 2.101 cP. This study highlights the potential of nanotechnology in harnessing the antimicrobial properties of natural essential oils, paving the way for innovative and sustainable solutions in the fight against bacterial contamination.

Azadiradione, a Component of Neem Oil, Behaves as a Superoxide Dismutase Mimic When Scavenging the Superoxide Radical, as Shown Using DFT and Hydrodynamic Voltammetry

The neem tree, Azadirachta indica, belongs to the Meliaceae family, and its use in the treatment of medical disorders from ancient times to the present in the traditional medical practices of Asia, Africa and the Middle East is well-documented. Neem oil, extracted from the seeds of the fruit, is widely used, with promising medicinal benefits. Azadiradione, a principal antioxidant component of the seeds of A. indica, is known to reduce oxidative stress and has anti-inflammatory effects. To directly measure the antioxidant ability of neem oil, we used Rotating Ring Disk Electrode (RRDE) hydrodynamic voltammetry to quantify how it can scavenge superoxide radical anions. The results of these experiments show that neem oil is approximately 26 times stronger than other natural products, such as olive oil, propolis and black seed oil, which were previously measured using this method. Next, computational Density Functional Theory (DFT) methods were used to arrive at a mechanism for the scavenging of superoxide radical anions with azadiradione. Our work indicates that azadiradione is an effective antioxidant and, according to our DFT study, its scavenging of the superoxide radical anion occurs through a reaction mechanism in which azadiradione mimics the antioxidant action of superoxide dismutase (SOD). In this mechanism, analogous to the SOD enzymatic reaction, azadiradione is regenerated, along with the production of two products: hydrogen peroxide and molecular oxygen. This antioxidant process provides an explanation for azadiradione's more general and protective biochemical effects.

Antibacterial study of carbopol-mastic gum/silver nanoparticle-based topical gels with carvacrol/neem bark extract in vitro

BACKGROUND

Resistance to antimicrobial drugs as a result of prolonged use usually results in clinical failure, especially in wound infections. Development of effective antimicrobial therapeutics for the management of infected wounds from a natural source with improved therapeutic effects is a pressing need.

OBJECTIVE

In this study, carbopol-mastic gum-based topical gels were loaded with silver nanoparticles in combination with either neem bark extract or carvacrol oil. The effect of combining silver nanoparticles with neem bark extract or the essential oil carvacrol in the prepared gel formulations was investigated on selected bacterial strains.

METHOD

The prepared gels were characterised by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and ultraviolet-visible (UV-vis) spectroscopy, followed by antimicrobial analysis against selected strains of bacteria.

RESULTS

There was no interaction between the loaded natural extract or essential oil and the polymer used for the preparation of the formulations, which was visible from the FTIR spectra of the formulations. The gels were selective and effective against selected strains of bacteria. However, the combination of the silver nanoparticles with essential oil or natural extract in some of the gel formulations rendered the formulation ineffective against some of the bacterial strains.

CONCLUSION

The gel formulations were effective against bacterial strains such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis which are the common causes of wound infections. Incorporation of silver nanoparticles into the topical formulations with natural extracts is usually a good approach to overcome antibiotic-resistant infections. However, the combination of antibacterial agents must be managed carefully.

Efficacy and Safety of Neem Oil for the Topical Treatment of Bloodsucking Lice Linognathus stenopsis in Goats under Field Conditions

The aim of the present study was to evaluate the efficacy and safety of neem oil on caprine pediculosis and on kids' growth performances. The neem (Azadirachta indica) belongs to the Meliaceae family, and in Eastern countries it is mainly considered for the insecticidal activities of the kernel oil. The neem seeds contain bioactive principles, such as azadirachtin A, salannin, nimbin, and nimbolide. The trial was carried out on 24 kids, 120 days old, maintained in open yards. Animals were divided in 4 homogeneous groups (n = 6 animals/group) based on age, louse count, body condition score (BCS) and live body weight: Control Group (C, saline NaCl, 0.9%), Neem Group 1 (NO-100, 100 mL of neem oil per 10 kg), Neem Group 2 (NO-200, 200 mL/10 kg), Neem Group 3 (NO-300, 300 mL/10 kg). The treatments were performed by spraying the insecticide on the goat's body. The study lasted 56 days, and weekly, the kids underwent louse count, BCS and body weight determination, and FAMACHA score. Data were analyzed by ANOVA for repeated measures. The species of lice identified was Linognathus stenopsis. Kids belonging to NO-200 and NO-300 showed a stronger reduction of louse count throughout the study (>95%). The daily weight gain recorded was significantly higher (p < 0.05) in NO-300 than C. No differences were found for BCS and FAMACHA scores. The results of this trial showed that the administration of neem oil to control caprine pediculosis caused by sucking lice represents an alternative to synthetic compounds.

Neem oil against Aeromonas hydrophila infection by disrupting quorum sensing and biofilm formation

Aeromonas hydrophila is an opportunistic pathogen that can cause a number of infectious diseases in fish and is widely distributed in aquatic environments. Antibiotics are the main approach against A. hydrophila infections, while the emergence of resistant bacteria limits the application of antibiotics. Here, quorum-sensing (QS) was defined as the target and the inhibitory effects of neem oil against QS of A. hydrophila was studied. The results showed that neem oil could dose-dependently reduce aerolysin, protease, lipase, acyl-homoserine lactones (AHLs), biofilm and swarming motility at sub-inhibitory concentrations. Results of real-time PCR demonstrated that neem oil could down-regulate the transcription of aerA, ahyI and ahyR. Moreover, neem oil showed significant protections to A549 cells and a fish infection model. Taken together, these results indicated that neem oil could be chosen as a promising candidate for the treatment of A. hydrophila infections.

Comprehensive Dissipation of Azadirachtin in Grapes and Tomatoes: The Effect of Bacillus thuringiensis and Tentative Identification of Unknown Metabolites

Neem oil is a biopesticide normally applied together with Bacillus thuringiensis (Bt). However, neither its dissipation nor the influence of Bt has been previously evaluated. In this study, dissipation of neem oil was investigated when it was applied alone or together with Bt at 3 and 22 °C. A methodology involving solid-liquid extraction and liquid chromatography-high-resolution mass spectrometry was developed for that purpose. The method was validated obtaining recoveries from 87 to 103%, with relative standard deviations lower than 19% and limits of quantification from 5 to 10 μg/kg. Azadirachtin A (AzA) dissipation was fit to a single first order, being faster when neem oil was applied together with Bt and at 22 °C (RL₅₀ = 12-21 days) than alone and at 3 °C (RL₅₀ = 14-25 days). Eight related compounds were found in real samples with similar dissipation curves compared to AzA, and five unknown metabolites were identified in degraded samples, with increasing concentrations during parent compound degradation.

Hypericum and neem oil for dehisced post-surgical wounds: a randomised, controlled, single-blinded phase III study

OBJECTIVE

To evaluate the clinical efficacy of a hypericum and neem oil dressing, Primary Wound Dressing [ONE] (1PWD) (Kerecis AG, Switzerland), in a patient population with dehiscence of surgical wounds with critical colonisation/infection. Efficacy was defined as resolution of inflammatory/infective symptoms.

METHOD

A randomised, controlled, single-blinded, parallel-arms phase III study was conducted comparing the experimental medication to silver-based dressings. All patients were evaluated at enrolment, on days 7, 14, 21 and 28. Improvement of inflammatory/infective symptoms was measured by detecting seven items of the Bates-Jensen Wound Assessment Tool (BWAT). Pain was assessed using the Numeric Rating Scale (NRS).

RESULTS

The study enrolled 99 patients. Follow-up was completed in 49 patients in the experimental group and 48 patients in the control group. Overall BWAT evaluation demonstrated similar outcomes between the groups: t=0.23, p-value=0.81, 95% confidence interval (CI): -13.3-10.8. Furthermore, when evaluating the seven items of the BWAT relating to inflammatory signs, there was not a significant difference between the groups: t=0.38, p=0.35, 95% CI: -2.8-2.7. However, when an analysis using the NRS pain scale was performed, a statistically significant pain reduction was demonstrated in favour of the experimental group: t=7.8, p<0.0001, 95% CI: 2.918-4.8819.

CONCLUSION

This randomised controlled trial confirmed the efficacy of 1PWD, an investigational product, in the management of surgical dehiscence with critical colonisation or infection, with the added benefit of significant pain reduction when compared with a silver-based dressing.

The Influence of Neem Oil and Its Glyceride on the Structure and Characterization of Castor Oil-Based Polyurethane Foam

Neem (Azadirachta indica) oil is a non-edible oil that contains azadirachtin, which can be used as a biopesticide. This study synthesizes bio-based polyurethane (PU) foam from neem and castor (Ricinus communis L.) oil at normal temperature and pressure. Neem oil can be reacted to narrow-distribution polyol by transesterification of oil and glycerol. Neem oil glyceride (NOG) can be used as polyol for bio-based PU foams and can be blended with castor oil homogeneously to reduce the cost of production. The composition of polyol was castor oil and 0 to 20% molar ratios of NOG. Hexamethylene diisocyanate trimer (Desmodur N) was used as isocyanate. The molar ratios of NCO/OH were set as 1.0, 1.5 and 2.0. The average hydroxyl contents of castor oil, neem oil and NOG were 2.7 mmol/g, 0.1 mmol/g and 5.1 mmol/g, respectively. The reaction time of bio-based PU foam could be adjusted between 5 to 10 min, which is acceptable for manufacturing. The densities of PU foams were between 49.7 and 116.2 kg/m³ and decreased with increasing NCO/OH and NOG ratios and decreasing neem oil. The ranges of specific compressive strength of foams were from 0.0056 to 0.0795 kPa·m³/kg. Increasing the NOG and neem oil ratio significantly enhanced the specific compressive strength in the low NCO/OH ratio. The solvent resistance and thermogravimetric (TG) results showed that the foams have high water and thermal stability. NOG can help to increase solvent resistance. Adding neem oil reduces the solvent resistance. The results indicated that increasing NCO/OH and NOG ratios increases the cross-linking density and hard segment content of PU foams. This investigation demonstrated that castor oil-based PU foams are improved by adding NOG to the polyol mixture. PU foam has excellent properties. Neem oil can be used in manufacturing processes to produce high-performance foams via a green synthesis process.

Management of Onion Thrips (Thrips tabaci) in Organic Onion Production Using Multiple IPM Tactics

Simple Summary

Onion thrips (Thrips tabaci) is a major pest in organic onion production and effective integrated pest management strategies are lacking. Our objective was to evaluate pest management programs consisting of several different tactics: (1) two onion plant cultivars with semi-glossy leaves (“Rossa di Milano” and B5336AxB5351C) and one with waxy leaves (“Bradley”), (2) silver reflective and white plastic mulches, and (3) with or without an application of a biopesticide (spinosad + neem oil tank mix). Thrips densities were counted weekly and bulbs weighed at harvest. The application of the biopesticide had the most significant reduction in thrips densities and increase in yield. The cultivar “Rossa di Milano” had lower thrips densities compared with “Bradley” and B5336AxB5351C, but also had the lowest yield. Reflective mulch had lower thrips densities than white mulch but had no effect on yield. None of the other tactics provided any significant additional benefits to thrips management. While biopesticides will still be a key component to onion thrips management programs, their application frequency should be further optimized.

Abstract

Onion thrips (Thrips tabaci Lindeman) is a major pest in organic onion production and effective integrated pest management strategies are lacking. Our objective was to evaluate combinations of semi-glossy (“Rossa di Milano” and B5336AxB5351C) and waxy (“Bradley”) onion cultivars with reflective mulch, with or without biopesticides (spinosad + neem oil tank mix), to manage T. tabaci in organic onion production. Thrips densities were assessed weekly and bulbs graded and weighed at harvest. Onions sprayed with spinosad + neem oil had fewer T. tabaci (adults: 74% (2019); larvae: 40% (2018), 84% (2019) and produced higher yields (13% (2018), 23% (2019)) than onions that were unsprayed, regardless of mulch type or onion cultivar. “Rossa di Milano” had relatively fewer adult and larval thrips populations compared with “Bradley” (21% (2018), 32% (2019)) and B5336AxB5351C. However, “Rossa di Milano” had the lowest marketable yield in both years. Reflective mulch reduced densities on certain dates in both years compared to white mulch, but the largest and most consistent reduction only occurred in 2019. Reflective mulch had no impact on bulb yield. While spinosad + neem oil reduced thrips numbers and increased yield alone, none of the treatment combinations were effective at suppressing populations of thrips. Future T. tabaci management in organic onions will require optimization of the available effective biopesticides.

Renewable Aromatics from Tree-Borne Oils over Zeolite Catalysts Promoted by Transition Metals

Despite the ever-growing demand for benzene-toluene-xylene (BTX), the alternative route of production from tree-borne oils is rarely investigated and poorly understood. Here, we have synthesized a Zn-loaded Y-zeolite catalyst for the continuous production of bio-BTX from tree-borne oils (nonedible seed oil), e.g., neem oil. Our approach involves low-temperature selective cracking-dehydrogenation-aromatization of neem oil over metal-supported catalysts to xylene-rich aromatics. The physicochemical properties of the prepared catalyst were characterized using powder XRD, N₂ physisorption, TEM, NH₃-TPD, XPS, Py-FTIR, solid-NMR, and TG analyses. Mesoporous Y-zeolites with a pore diameter of 7.4 Å showed better selectivity toward aromatics and were found to be the most effective catalyst for the aromatization process, especially for BTX. The aromatic yield was found to increase with the addition of Zn, and the highest conversion of 90-94% with an ∼75% BTX yield was achieved with the ZnY catalyst. During aromatization, a sizable number of short alkanes and olefins were also obtained on acidic Y-zeolites. The off-gas composition shows the presence of ∼45% C₂-C₄ olefins with 8.9% H₂. The incorporation of Zn species can promote the dehydrogenation activity, and the subsequent aromatization required a suitable pore network. The optimized ZnY catalyst inspires the formation of toluene and xylenes, inhibiting the formation of benzene and gaseous alkanes.

Use of Neem oil and Hypericum perforatum for treatment of calcinosis-related skin ulcers in systemic sclerosis

Objective

This study evaluated Neem oil and Hypericum perforatum (Holoil®) for treatment of scleroderma skin ulcers related to calcinosis (SU-calc).

Procedure: We retrospectively analyzed 21 consecutive systemic sclerosis (SSc) patients with a total of 33 SU-calcs treated daily with Holoil® cream compared with a control group of 20 patients with 26 SU-calcs. Holoil® was directly applied to skin lesions, while the control group received only standard medication.

Results

Application of Holoil® either resulted in crushing and complete resolution of calcium deposits or facilitated sharp excision of calcinosis during wound care sessions in 27/33 cases (81.8%). Complete healing of SU-calc occurred in 15/33 (45%) of cases within a time period of 40.1 ± 16.3 (mean ± SD) days, while 18/33 (55%) of lesions improved in terms of size, erythema, fibrin and calcium deposits. Patients reported a reduction of pain (mean numeric rating scale 7.3 ± 1.9 at baseline versus 2.9 ± 1.4 at follow-up) The control group had longer healing times and a higher percentage of infections.

Conclusions

The efficacy of local treatment with neem oil and Hypericum perforatum suggest that Holoil® could be a promising tool in the management of SSc SU-calc.

Azadirachta indica (Sapindales: Meliaceae) Neem Oil as a Repellent Against Aedes albopictus (Diptera: Culicidae) Mosquitoes

Increased concerns regarding the safety of many chemicals used as insecticides or repellents, together with the development of resistance by insects to various insecticides, have led to the search for new active natural ingredients. For what we believe is the first time, that is monitored the efficiency of neem oil (Azadirachta indica) as a repellent against adult Aedes albopictus directly in the field. To test the efficacy of repellency against adults, treatments were performed (5 ml/l) in six different locations. For each location, two closed gardens distance between them 200 m were chosen (one where the treatment was performed, consisting in spraying a mixture of water and Neem oil 5 g/l and one which was used as a control where only water with emulsifier was used). To monitor the treatment efficacy, six ovitraps were used (for each location three for the treated garden and three for the control garden). Data (n° mosquito eggs trapped in each ovitrap) were collected weekly for 6 mo (from May to October) for a total of 900 samplings. Daily temperature and daily rainfall were monitored throughout the trial. The treatment was most effective in June and July. Very high temperatures and high rainfall reduced the efficacy of neem oil over time.

Polyesteramide of Neem Oil and Its Blends as an Active Nanomaterial for Tissue Regeneration

Neem oil gained importance due to its antibacterial properties. Therefore, it is extensively being used for various applications. Oils can be polymerized as a polyesteramide to extend their utility as biomaterials. In our studies, we synthesized polyesteramide from neem oil and various compositions of blends were prepared with the drug, chlorohexidine digluconate (CH) to develop a nanomaterial for tissue regeneration. The studies such as cytotoxicity, biodegradable, antibacterial, in vitro drug release, in vivo wound healing, and histopathological studies were performed to identify their potential for tissue regeneration. In vivo wound healing studies of the nanofiber mats with and without CH recorded a faster healing rate as compared to the commercial cream (povidone-iodine). Most importantly, there was no requirement of repeated application of nanofiber mats during the treatment. The histopathology studies also suggested the re-epithelialization of the wounds. Hence, these nanomaterials are considered to be environmentally safe scaffolds for efficient tissue regeneration applications.

Neem oil-loaded cross-linked biodegradable polymeric capsules: Its larvicidal activity against Culex quinquefasciatuss larvae

Background:

Pesticide delivery system has been formulated in the form of emulsifiable concentrates, water solutions, aerosols, or spray formulations. However, such formulations showed health hazards. Encapsulation technique is the more suitable method to reduce health hazard and to deliver and release the pesticides. Natural biopolymers have been widely studied for encapsulation of pesticide compounds, as they are biodegradable, biocompatible, and low toxic to mammalian. Neem oil has been reported for controlling of the mosquitoes and more eco-friendly insecticide than synthetic insecticides. The present study was designed to prepare a cross-linked polymeric network capsules loaded with neem oil as effective controlled release formulation against Culex quinquefasciatus larvae.

Materials and Methods:

Neem oil-loaded chitosan/alginate/gelatin capsules were prepared by cross-linking method. Neem oil-loaded capsules were characterized with respect to their capsule size, scanning electron microscopy (SEM) analysis, and swelling property. In vitro larvicidal activity of neem oil-loaded polymeric capsules was studied against C. quinquefasciatus larvae.

Results:

The cross-linking method produced spherical shape of neem oil-loaded capsules. Ultraviolet spectroscopy analysis indicated that 10% of neem oil was loaded with capsule. A swelling study indicated that swelling of the loaded capsules tends to be more stable. SEM analysis showed that loading of the neem oil with the capsules fills all pores and capsules were found with good compatibility between chitosan, alginate, and gelatin due to the uniform shape of the capsule. Formulated neem oil-loaded capsules showed potential larvicidal activity (100% of mortality) against C. quinquefasciatus larvae in an in vitro model.

Conclusion:

Formulated neem oil-loaded capsules showed a simple method of preparation and eco-friendly. These polymeric capsule containing neem oil exhibited potential larvicidal activity against C. quinquefasciatus larvae.

Utilizing larvicidal and pupicidal efficacy of Eucalyptus and neem oil against Aedes mosquito: An approach for mosquito control

Background and Objectives:

Plant-based products can provide safe and biodegradable mosquito control agents. The essential oils have a strong odor due to complex secondary metabolites and exhibit lower density than that of water, which renders them suitable to form a thin layer above the water surface. The present study was designed to evaluate the larvicidal, pupicidal activity of Eucalyptus and neem oils against Aedes aegypti and Aedes albopictus.

Materials and Methods:

We evaluated the activity of commercially available Eucalyptus (Eucalyptus globulus) and neem (Azadirachta indica) oils against larvae and pupae of A. aegypti and A. albopictus for their larvicidal and pupicidal activity, stability in different water types, dependence on volume and surface area of the water body, and residual efficacy.

Results:

Eucalyptus oil was found to be more effective against larvae and pupae at lower concentrations, i.e., concentration at which 50% is observed (LC50) for larvae and pupae was 93.3 and 144.5 parts per million (ppm) and concentration at which 90% is observed (LC90) was 707.9 and 741.3 ppm, respectively, while for neem oil, LC50 for larvae and pupae was 7852 and 19,054 ppm and LC90 was 10,092 and 19,952 ppm, respectively. The efficacy of Eucalyptus oil depended on surface area rather than volume of water, and the residual efficacy of Eucalyptus oil was up to 8 days.

Conclusions:

Eucalyptus oil was more effective against mosquito larvae at lower concentration as compared to neem oil. It can, therefore, be utilized in the community in artificial and small temporary water bodies as an eco-friendly vector control measure in the era of increasing resistance to chemical insecticides.

Preparation and characterization of neem oil nanoemulsion formulations against Sitophilus oryzae and Tribolium castaneum adults

This study aimed to improve the efficacy of azadirachtin (Azadirachta indica. A. Juss) against two serious pest species of stored products, Sitophilus oryzae (L.) and Tribolium castaneum (Herbst), through nano-emulsion formulations. Pseudoternary phase diagrams were constructed consisting of an emulsion system of an active ingredient (neem oil), surfactant (polysorbate or alkylpolyglucoside), and water. Isotropic regions were formed in the pseudoternary phase diagrams, and four formulations were selected from the isotropic regions and characterized according to particle size, particle aging, zeta potential, stability and thermostability, surface tension, viscosity, and pH. The selected formulations showed particle sizes of 208-507 nm in diameter. The result of contact toxicity demonstrated excellent mortality of S. oryzae and T. castaneum adults, with a mortality range of 85-100% and 74-100%, respectively, at a 1% azadirachtin concentration after only 2 days of exposure. Compared to non-formulated neem oil, the nano-emulsion formulations significantly increased the mortality of the tested species.

Neem Oil and Crop Protection: From Now to the Future

A major challenge of agriculture is to increase food production to meet the needs of the growing world population, without damaging the environment. In current agricultural practices, the control of pests is often accomplished by means of the excessive use of agrochemicals, which can result in environmental pollution and the development of resistant pests. In this context, biopesticides can offer a better alternative to synthetic pesticides, enabling safer control of pest populations. However, limitations of biopesticides, including short shelf life, photosensitivity, and volatilization, make it difficult to use them on a large scale. Here, we review the potential use of neem oil in crop protection, considering the gaps and obstacles associated with the development of sustainable agriculture in the not too distant future.

In vitro screening of natural feed additives from crustaceans, diatoms, seaweeds and plant extracts to manipulate rumen fermentation

BACKGROUND

Eight natural products from animal, unicellular algae, brown seaweed and plant origins were chosen according to their theoretical antimicrobial activity: Diatomaceous earths (DE), insoluble chitosan (ICHI), soluble chitosan (CHI), seaweed meal (SWM), Ascophyllum nodosum (ASC), Laminaria digitata (LAM), neem oil (NOIL) and an ivy fruit extract rich in saponins (IVY). Dose-response incubations were conducted to determine their effect on rumen fermentation pattern and gas production, while their anti-protozoal activity was tested using (14) C-labelled bacteria.

RESULTS

DE, SWM, NOIL and ICHI had very small effects on rumen function when used at inclusion rate up to 2 g L(-1) . ASC had anti-protozoal effects (up to -23%) promoting a decrease in gas production and methanogenesis (-15%). LAM increased VFA production (+7%) and shifted from butyrate to acetate. CHI also shifted fermentation towards propionate production and lower methane (-23%) and protozoal activity (-56%). IVY decreased protozoal activity (-39%) and ammonia concentration (-56%), as well as increased feed fermentation (+11% VFA concentration) and shifted from acetate to propionate production.

CONCLUSIONS

ASC, LAM, CHI and IVY showed promising potential in vitro as feed additives to improve rumen function, thus more research is needed to investigate their mode of action in the rumen microbial ecosystem. © 2015 Society of Chemical Industry.

Physical and Antimicrobial Properties of Starch-PVA Blend Films as Affected by the Incorporation of Natural Antimicrobial Agents

In this work, active films based on starch and PVA (S:PVA ratio of 2:1) were developed by incorporating neem (NO) and oregano essential oils (OEO). First, a screening of the antifungal effectiveness of different natural extracts (echinacea, horsetail extract, liquid smoke and neem seed oil) against two fungus (P. expansum and A. niger) was carried out. The effect of NO and OEO incorporation on the films’ physical and antimicrobial properties was analyzed. Only composite films containing OEO exhibited antibacterial and antifungal activity. Antibacterial activity occurred at low OEO concentration (6.7%), while antifungal effect required higher doses of OEO in the films. Incorporation of oils did not notably affect the water sorption capacity and water vapor barrier properties of S-PVA films, but reduced their transparency and gloss, especially at the highest concentrations. The mechanical response of the S-PVA films was also negatively affected by oil incorporation but this was only relevant at the highest oil ratio (22%). S-PVA films with 6.7% of OEO exhibited the best physical properties, without significant differences with respect to the S-PVA matrix, while exhibiting antibacterial activity. Thus, the use of OEO as a natural antimicrobial incorporated into starch-PVA films represents a good and novel alternative in food packaging applications.

Organic neem compounds inhibit soft-rot fungal growth and improve the strength of anthracite bricks bound with collagen and lignin for use in iron foundry cupolas

AIMS

To examine organic neem compounds for their effective growth inhibition of saprotrophic soft-rot fungi on anthracite bricks bound with collagen and lignin for use in iron foundry cupolas as an alternative fuel source.

METHODS AND RESULTS

Azadirachtin, crude neem oil (NO), and clarified neem oil extract (CNO) were combined with copper to inhibit the growth of the soft-rot fungus, Chaetomium globosum. A synergistic interaction was observed between CNO and a low dose of copper on nutrient media (two-factor anova with triplicate replication: P < 0·05). Interaction was confirmed on lab-scale collagen-lignin-anthracite briquettes by measuring their unconfined compressive (UC) strength. The effective collagen strength of the briquettes was enhanced by applying CNO to their surface prior to inoculation: the room temperature UC strength of the briquettes was 28 ± 4·6% greater when CNO (0·4 mg cm(-2) ) was surface-applied, and was 43 ± 3·0% greater when CNO plus copper (0·14 μg cm(-2) ) were surface-applied.

CONCLUSION

Surface application of CNO and copper synergistically prevents fungal growth on bindered anthracite briquettes and increases their room temperature strength.

SIGNIFICANCE AND IMPACT OF THE STUDY

This novel organic fungicidal treatment may increase the storage and performance of anthracite bricks in iron foundries, thereby saving 15-20% of the energy used in conventional coke production.

Neem (Azadirachtaindica A. Juss) Oil: A Natural Preservative to Control Meat Spoilage

Plant-derived extracts (PDEs) are a source of biologically-active substances having antimicrobial properties. The aim of this study was to evaluate the potential of neem oil (NO) as a preservative of fresh retail meat. The antibacterial activity of NO against Carnobacterium maltaromaticum, Brochothrix thermosphacta, Escherichia coli, Pseudomonas fluorescens, Lactobacillus curvatus and L. sakei was assessed in a broth model system. The bacterial growth inhibition zone (mm) ranged from 18.83 ± 1.18 to 30.00 ± 1.00, as was found by a disc diffusion test with 100 µL NO. The bacterial percent growth reduction ranged from 30.81 ± 2.08 to 99.70 ± 1.53 in the broth microdilution method at different NO concentrations (1:10 to 1:100,000). Viable bacterial cells were detected in experimentally-contaminated meat up to the second day after NO treatment (100 µL NO per 10 g meat), except for C. maltaromaticum, which was detected up to the sixth day by PCR and nested PCR with propidium monoazide (PMA™) dye. In comparison to the previously published results, C. maltaromaticum, E. coli, L. curvatus and L. sakei appeared more susceptible to NO compared to neem cake extract (NCE) by using a broth model system.

Efficacy of a Combined Treatment of Neem Oil Formulation and Endosulfan against Helicoverpa armigera (Hub.) (Lepidoptera: Noctuidae)

Efficacy of the combined treatment of a neem oil formulation and endosulfan on feeding and midgut enzyme activities of Helicoverpa armigera larvae was studied. The antifeedant activity was recorded at 24 h after treatment and the activities of midgut digestive (total serine protease and trypsin) and detoxifying (esterase and glutathione-S-transferase) enzymes were estimated at 72 h after treatment. The antifeedant activity in endosulfan + neem oil formulation (endosulfan 0.01% and neem oil formulation 1% at 1:1 ratio) was 85.34%, significantly greater than in individual treatments. Midgut digestive enzymes and EST activities were significantly reduced and the GST activity significantly increased in the combined treatment of endosulfan + neem oil formulation, thus showing increased effect of the combined treatment of the two pesticides. These results suggest that neem oil can be used in combination with endosulfan to reduce its quantity.

A 90-day subchronic toxicity study of neem oil, a Azadirachta indica oil, in mice

To determine the no-observed-adverse-effect level (NOAEL) of exposure and target organs of neem oil for establishing safety criteria for human exposure, the subchronic toxicity study with neem oil in mice was evaluated. The mice (10 per sex for each dose) was orally administered with neem oil with the doses of 0 (to serve as a control), 177, 533 and 1600 mg/kg/day for 90 days. After the treatment period, observation of reversibility or persistence of any toxic effects, mice were continuously fed without treatment for the following 30 days. During the two test periods, the serum biochemistry, organ weight and histopathology were examined. The results showed that the serum biochemistry and organ coefficient in experimental groups had no statistical difference compared with those of the control group. At the 90th day, the histopathological examinations showed that the 1600 mg/kg/day dose of neem oil had varying degrees of damage on each organ except heart, uterus and ovarian. After 30-day recovery, the degree of lesions to the tissues was lessened or even restored. The NOAEL of neem oil was 177 mg/kg/day for mice and the target organs of neem oil were determined to be testicle, liver and kidneys.