Development of a Lignin-Based Carrier - Citronella Oil Nanoemulsion and Its Utilization as an Herbicide against Specific Weed Species.

This research aims to create an emulsion formulation utilizing lignin as a carrier and citronella oil for its application as a herbicide. The formulation composition includes lignin solution 55-62 %v/v, Tween 80 25 %w/v, propylene glycol 10 %w/v, and citronella oil 3-10 %w/v. The preparation steps involve preparing the oil phase by mixing tween 80 surfactant, propylene glycol, and citronella oil; preparing the aqueous phase by mixing lignin into distilled water at pH 12 with stirring; mixing the oil phase and the water phase accompanied by stirring at 5000-10000 rpm for 1-5 minutes until a stable solution is formed as a natural herbicide. The application outcomes revealed that the formulation successfully eliminated specific weeds within two to three days at the maximum concentration of 10 %, leaving no detectable herbicide residue after 7 and 15 days of treatment. The result demonstrates how green technology has the capacity to replace herbicides derived from chemicals, especially in the agricultural sector.

Comparative Behavioral Responses of Pyrethroid-Susceptible and -Resistant Aedes aegypti (Diptera: Culicidae) Populations to Citronella and Eucalyptus Oils.

The objective of this study was to compare the behavioral responses (contact irritancy and noncontact spatial repellency) between susceptible and resistant populations of Aedes aegypti (L.) (=Stegomyia aegypti) to essential oils, citronella, and eucalyptus, Eucalyptus globulus, extracts, using an excito-repellency test system. N, N-diethyl-meta-toluamide (DEET) was used as the standard reference repellent. Mosquitoes included two long-standing insecticide susceptible colonies (U.S. Department of Agriculture and Bora Bora) and two pyrethroid-resistant populations recently obtained from Phetchabun and Kanchanaburi provinces in Thailand. Both DEET and citronella produced a much stronger excitation ("irritancy") and more rapid flight escape response in both pyrethroid-resistant populations compared with the laboratory populations. Noncontact repellency was also greater in the two resistant populations. Eucalyptus oil was found to be the least effective compound tested. Differences in responses between long-established pyrethroid-susceptible colonies and newly established and naturally resistant colonies were clearly demonstrated. These findings also demonstrate the need for further comparisons using natural pyrethroid-susceptible populations for elucidation of factors that might contribute to different patterns of escape behavior.

Effect of citronella essential oil on the inhibition of postharvest Alternaria alternata in cherry tomato.

BACKGROUND: Essential oils such as citronella oil exhibit antifungal activity and are potential alternative inhibitors to chemical synthetic fungicides for controlling postharvest diseases. In this study the antifungal activity of citronella oil against Alternaria alternata was investigated. RESULTS: In vitro, citronella oil showed strong inhibition activity against A. alternata. The minimum inhibitory concentration in potato dextrose agar and potato dextrose broth medium was determined as 1 and 0.8 µL mL(-1) respectively. In vivo the disease incidence of Lycopersicon esculentum (cherry tomato) treated with citronella oil was significantly (P < 0.05) reduced compared with the control after 5 days of storage at 25 °C and 95% relative humidity. The disease incidence at oil concentrations of 0.2-1.5 µL mL(-1) was 88-48%. The most effective dosage of the oil was 1.5 µL mL(-1), with 52% reduction, and the oil had no negative effect on fruit quality. Scanning electron microscopy observation revealed considerably abnormal mycelial morphology. CONCLUSION: Citronella oil can significantly inhibit A. alternata in vitro and in vivo and has potential as a promising natural product for controlling black rot in cherry tomato.

Safety and efficacy of a feed additive consisting of an essential oil derived from the leaves of Cymbopogon nardus (L.) Rendle (citronella oil) for use in all animal species (FEFANA asbl).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of citronella oil obtained from the leaves of Cymbopogon nardus (L.) Rendle, when used as a sensory additive for all animal species. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concluded that citronella oil from C. nardus is of low concern for long-living and reproductive animals at the use levels in complete feed of 3.5 mg/kg for laying hens and rabbits, 6 mg/kg for sows and dairy cows, 9.5 mg/kg for sheep/goats and horses, 2.0 mg/kg for cats and 10 mg/kg for dogs. For short-living animals (species for fattening), the additive was considered of no concern at concentrations of 18 mg/kg in chickens for fattening, 24 mg/kg in turkeys for fattening, 20 mg/kg for piglets, pigs for fattening, veal calves (milk replacer), cattle for fattening, sheep/goats for meat production, horses for meat production and rabbits for meat production, and 30 mg/kg for salmonids. The conclusions were extrapolated to physiologically related minor species. For any other species, the additive is considered of low concern at 2.0 mg/kg complete feed. The use of citronella oil in animal feed is expected to be of no concern for the consumers and for the environment. The essential oil under assessment should be considered as irritant to skin and eyes and as a dermal sensitiser. When handling the essential oil, exposure of unprotected users to methyleugenol may occur. Therefore, to reduce the risk, the exposure of the users should be minimised. Since the leaves of C. nardus and its preparations were recognised to flavour food and its function in feed would be essentially the same as that in food, no further demonstration of efficacy was considered necessary.

Design and Characterization of Citronella Oil-Loaded Micro-Emulgel for the Treatment of Candida Albicans Infection.

The purpose of the current study was to prepare and evaluate a citronella oil-loaded microemulsion-based micro-emulgel for the treatment of Candida albicans. The primary objective was to use the skin to transfer hydrophobic medications into the bloodstream. The formulation included cinnamon oil as an antifungal oil and citronella oil as an active pharmaceutical ingredient, respectively. Tween 80 and PEG 200 were used as the surfactant and co-surfactant, respectively, to create phase diagrams. Carbopol 940, one of the frequently used polymers, was investigated for its ability to prepare gel formulations. The optimized (F3) batch contained the highest percentage (87.05 ± 0.03%) of drug content and, according to the statistics provided, had the highest drug release rate of around 87.05% within 4 h. The Korsmeyer-Peppas model with n value of 0.82, which is in the range 0.5-1, had the highest r2 value, indicating that release following non-Fickian/anomalous diffusion provided a better dimension for all of the formulations. The optimized (F3) formulation had stronger antifungal activity in comparison to other formulations. This leads to the conclusion that citronella oil can be made into a micro-emulgel, which may improve its release in aqueous systems while maintaining a high level of drug release at the target site.

Development of a Nanotechnology Matrix-Based Citronella Oil Insect Repellent to Obtain a Prolonged Effect and Evaluation of the Safety and Efficacy.

Mosquito-borne diseases affect millions of people worldwide each year, and the use of a topically applied insect repellent is an economically viable preventative health practice. The general objective of this work was to encapsulate citronella oil (CO) in a nanostructured lipid carrier (NLC) to formulate a topical repellent with a long duration of efficacy on the skin and a good safety profile based on minimizing skin penetration. In the studied CO, the main chemical constituents of geraniol, citronellal, and citronellol were identified and subsequently used as markers for the in vitro skin permeation testing (IVPT). An optimal NLC encapsulating CO formulation was developed and had an average particle size of 350 nm. The NLC was then formulated in combination with CO at ratios of 2:1, 1:1, and 1:2 CO:NLC-CO as oil-in-water (O/W) emulsions and compared to CO in the same O/W emulsion base (all at 10% CO in the final O/W topical formulation). The markers geraniol, citronellol, and citronellal were detected in all samples tested F1 (10% CO in O/W emulsion) and F3 (10% CO/NLC-CO 1:1 in O/W emulsion). Even the percentages of F3 markers were higher than F1. The recovery of the percentage balance (based on the total remaining on the skin surface, on the skin, and penetrated through the skin to the receptor) of geraniol, citronellol, and citronellal markers for F1 and F3 was 7.70% and 11.96%; 25.51% and 31.89%; and 5.09% and 4.40%, respectively. The nanoparticle lipid solid forms a repellent reservoir on the skin surface, releasing the active ingredients slowly through volatilization, extending the repellent action, and reducing permeation through the skin. It is possible to assume that the remaining 92.30% and 88.03%; 74.49% and 68.11%; and 94.10% and 95.60% of geraniol, citronellol, and citronellal markers of F1 and F3, respectively, were lost to evaporation. In the in vivo efficacy test carried out with the Aedes aegypti mosquito, F3 was the optimal formulation, providing the greatest repellent action compared to free oil in O/W emulsion. Thermal analysis showed that the NLC-CO raised the boiling point of the encapsulated CO compared to the free oil, suggesting that the controlled release of the CO was a possible mechanism for its prolonged effect. We concluded that the nanocarriers developed with CO were stable and provided improved mosquito-repellent efficacy with minimal skin penetration of the CO actives over 24 h. Indeed, regardless of whether the CO was applied as free oil, a 1:1 mixture of CO (pure/free oil) or NLC-CO applied in an O/W emulsion can be considered safe for topical application due to minimal skin penetration.

Topical Mosquito Repellent Formulations for Enhanced Repellency Time and Reduced Toxicity.

Mosquito-borne diseases such as dengue, malaria, yellow fever, chikungunya and Zika virus affect millions of people worldwide each year. Vector control and personal protection are very important to minimize the spread of diseases, and the use of repellent is an economic practice to prevent them. The application of repellent, which acts on the skin to form a vapor layer with a repellent odor to mosquitos, is recommended as an economic prevention and practice. The natural botanical product Citronella is an effective mosquito repellent due to the high concentrations of active chemical constituents present, notably terpenic alcohols. However, citronella tends to evaporate quickly from the skin surface, resulting in a rapid loss of activity. Strategies to increase repellency time, while at the same time minimizing toxicity, are major focuses of research and development in natural repellent products. Here we highlight the role of extended-release systems (ERS) of citronella oil in this approach.

Design, development and assessment of an essential oil based slow release vaporizer against mosquitoes.

Mosquitoes (Diptera; Culicidae) are a biting nuisance and are of economic and health importance, especially for people living in tropical countries like India. Given the environmental concerns and health hazards of synthetic insecticides, development of natural products for the control of mosquito and mosquito-borne diseases are needed. In view of this, an essential oil based novel liquid vaporizer formulation with citronella and eucalyptus oils has been developed using a computer aided Artificial Neural Network and Particle Swarm Optimization (ANN-PSO) algorithm approach, aiming to predict the best optimized formulation (OF). Following the development, OF was characterized by Fourier Transform-Infra Red (FT-IR) spectroscopy and gas chromatography-mass spectroscopy (GC-MS). The efficacy of the OF was assessed against two major mosquito vectors viz. Anopheles stephensi and Aedes albopictus using a Peet-Grady chamber. Finally, toxicological impacts of the OF following its inhalation were investigated as per the Organization for Economic Co-operation and Development (OECD) guidelines. The results revealed all the ideal characteristics of the OF which were found to provide a slow release of up to 450 h at room temperature. Most importantly, the OF, exhibited 50% mosquito knock down (KT50) within 11.49±1.34 and 14.15±2.15 min against An. stephensi and Ae. albopictus respectively. Toxicity assessment showed a non toxic nature of the OF following inhalation. Thus the present development would be beneficial for controlling both An. stephensi and Ae. albopictus without any associated health hazards.

Forcasting of an ANN model for predicting behaviour of diesel engine energised by a combination of two low viscous biofuels.

This study is focused on artificial neural network (ANN) modelling of non-modified diesel engine keyed up by the combination of two low viscous biofuels to forecast the parameters of emission and performance. The diesel engine is energised with five different test fuels of the combination of citronella and Cymbopogon flexuous biofuel (C50CF50) with diesel at precise blends of B20, B30, B40, B50 and B100 in which these numbers represent the contents of combination of biofuel and the investigation is carried out from zero to full load condition. The experimental result was found that the B20 blend had improved BTE at all load states compared with the remaining biofuel blends. At 100% load state, BTE (31.5%) and fuel consumption (13.01 g/kW-h) for the B20 blend was closer to diesel. However, the B50 blend had minimal HC (0.04 to 0.157 g/kW-h), CO (0.89 to 2.025 g/kW-h) and smoke (7.8 to 60.09%) emission than other test fuels at low and high load states. The CO2 emission was the penalty for complete combustion. The NOx emission was higher for all the biodiesel blends than diesel by 6.12%, 8%, 11.53%, 14.81% and 3.15% for B20, B30, B40, B50 and B100 respectively at 100% load condition. The reference parameters are identified as blend concentration percentage and brake power values. The trained ANN models exhibit a magnificent value of 97% coefficient of determination and the high R values ranging between 0.9076 and 0.9965 and the low MAPE values ranging between 0.98 and 4.26%. The analytical results also provide supportive evidence for the B20 blend which in turn concludes B20 as an effective alternative fuel for diesel.

Therapeutic Potential of Citronella Essential Oil: A Review.

Mosquito-borne diseases such as malaria, filariasis, chikunguniya, yellow fever, dengue and Japanese encephalitis are the major cause of remarkable morbidity and mortality in livestock and humans worldwide. Since ancient times, aromatic plants are used for their medicinal value. Essential oils derived from these plants may be used as effective alternatives/adjuvants in pharmaceuticals, biomedical, cosmetic, food, veterinary and agriculture applications. These oils have also gained popularity and interest for prevention and treatment of various disorders. However, several reports on adverse effects including skin eruption, contact artricaria or toxic encephalopathy in children are available for synthetic repellent in the literature. Thus, natural insect repellents like essential oils have been explored recently as an alternative. One such essential oil studied widely, is citronella oil, extracted mainly from Cymbopogon nardus. This essential oil has exhibited good efficacy against mosquitoes. It is a mixture of components including citronellal, citronellol, geraniol as major constituents contributing to various activities (antimicrobial, anthelmintic, antioxidant, anticonvulsant antitrypanosomal and wound healing), besides mosquito repellent action. Citronella essential oil is registered in US EPA (Environmental protection agency) as insect repellent due to its high efficacy, low toxicity and customer satisfaction. However, poor stability in the presence of air and high temperature limits its practical applications. Since specific knowledge on properties and chemical composition of oil is fundamental for its effective application, the present review compiles and discusses biological properties of citronella oil. It also sheds light on various formulations and applications of this essential oil.

Production of eco-friendly fuel with the help of steam distillation from new plant source and the investigation of its influence of fuel injection strategy in diesel engine.

The primary intention of this experiment is to abate the harmful emissions of imported petroleum fuel by approach of novel citronella emulsified fuel. The study is emphasized by evaluating the influence of alteration in IT (injection timing) and IP (injection pressure) in diesel engine when utilizing B20 emulsion fuel of 5% water, 1% surfactant, 14% citronella oil and 80% diesel. The IT and IP are speckled in the array of 21 degCA bTDC, 23 degCA bTDC and 25 degCA bTDC and 180, 200, 220 and 240 bar correspondingly. It is found that retarding the IT and increasing the IP along with emulsified fuel lead to increase in the brake thermal efficiency by 1.16% and minimal in the brake-specific fuel consumption by 4.86% at top load state when correlated with diesel. Exhaust emissions carbon monoxide, NOx and smoke were considerably reduced by 35%, 0.8% and 34% respectively, but slight increase in HC was observed by 5.26%; heat release rate and cylinder pressure had a considerable improvement. From the determination of these values, the optimum values of IT and IP are inferred as 21° bTDC and 200 bar. Graphical abstract.

Citronella oil-loaded electrospun micro/nanofibrous matrices as sustained repellency systems for the Asian tiger mosquito Aedes albopictus.

BACKGROUND: Mosquitoes are hematophagous insects of major public health concern, serving as vectors of many diseases. Available products for personal protection against mosquitoes lack adequate efficacy and in most cases need to be reapplied or replaced frequently. In recent years, the encapsulation of the active repellents in various matrices has arisen as an alternative method for the development of new-generation repellent systems. The aim of the present study was to explore the potential of functional micro/nanofibrous matrices as systems for the sustained release of the highly volatile insect-repellent citronella oil. RESULTS: Micro/nanofibrous single- and triple-layer systems incorporating citronella oil as the active agent were developed via the electrospinning technique using the low-cost, non-toxic, biodegradable polymers cellulose acetate and polyvinylpyrrolidone. All the micro/nanofiber systems produced exhibited prolonged release of citronella oil and a high repellent activity in laboratory bioassays against the mosquito Aedes albopictus for at least 4 weeks. CONCLUSION: Considering the high volatility of the embedded repellent, the present study demonstrates the strong potential of the micro/nanofibrous matrices to act as carriers of highly volatile repellents for an effective and sustained protection from mosquitoes. © 2019 Society of Chemical Industry.

Sustained release formulations of citronella oil nanoemulsion using cavitational techniques.

Nanoemulsion synthesis has proven to be an effective way for transportation of immobile, insoluble bioactive compounds. Citronella Oil (lemongrass oil), a natural plant extract, can be used as a mosquito repellent and has less harmful effects compared to its available market counterpart DEET (N, N-Diethyl-meta-toluamide). Nanoemulsion of citronella oil in water was prepared using cavitation-assisted techniques while investigating the effect of system parameters like HLB (Hydrophilic Lipophilic Balance), surfactant concentration, input energy density and mode of power input on emulsion quality. The present work also examines the effect of emulsification on release rate to understand the relationship between droplet size and the release rate. Minimum droplet size (60nm) of the emulsion was obtained at HLB of 14, S/O1 ratio of 1.0, ultrasound amplitude of 50% and irradiation time of 5min. This study revealed that hydrodynamic cavitation-assisted emulsification is more energy efficient compared to ultrasonic emulsification. It was also found that the release rate of nanoemulsion enhanced as the droplet size of emulsion reduced.

Biological activities and acute oral toxicity of citronella and lemongrass oil / 대한수의학회지

This study was performed to investigate the antibacterial, antioxidant, and termite repellent effects of citronella oil (CiO) and lemongrass oil (LO). When the antibacterial activity against Staphylococcus (S.) aureus with various levels of antibacterial resistance were tested, a 0.05% concentration of CiO and LO completely inhibited the growth of all tested S. aureus strains. Evaluation of the antioxidant effect demonstrated that the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of CiO was 2~3 times greater than that of LO. Among trial products made with various combinations of CiO and LO, a CiO : LO ratio of 6 : 4 had the most potent termite repellent effects. Assessment of acute toxicity of the trial product showed that the LD50 was more than 2,000 mg/kg. Based on the above results, CiO and LO have antibacterial, antioxidant, and termite repellent activities. Therefore, both compounds could be potential termites repellent reagents.