Essential Oil Of Ocimum Gratissimum Research Articles

Impact of Microencapsulation on Ocimum gratissimum L. Essential Oil: Antimicrobial, Antioxidant Activities, and Chemical Composition

Ocimum gratissimum (OG) is a species rich in essential oils (EO), which is known for its antimicrobial and antioxidant properties. This study aimed to encapsulate the essential oil of Ocimum gratissimum (OGE), determine its chemical composition, and evaluate its antioxidant and antimicrobial activities against six pathogenic bacteria, comparing it with the free essential oil (OGF). The EO was extracted by hydrodistillation using a Clevenger-type apparatus, and an oil-in-water emulsion was prepared using a combination of biopolymers: maltodextrin (MA), cashew gum (CG), and inulin (IN). The chemical profile was identified using gas chromatography–mass spectrometry (GC–MS). Antioxidant activity was assessed using the Oxygen Radical Absorbance Capacity with fluorescein (ORAC-FL) method, while the Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentrations (MBC) were determined by the microdilution method. Microparticles were formed using the spray-drying method, achieving an encapsulation efficiency of 45.2%. The analysis identified eugenol as the main compound both before and after microencapsulation. The OGE microparticles demonstrated high inhibitory and bactericidal effects against S. aureus, S. choleraesuis, and E. coli, with MIC values of 500 µg·mL−1 and MBC values of 1000 µg·mL−1, as well as antioxidant activity of 1914.0 µmol-TE·g−1. Therefore, it can be inferred that the EO of OG maintained its antimicrobial and antioxidant effects even after microencapsulation by spray-drying, making it a promising natural ingredient.

Oxidative responses in small juveniles of Colossoma macropomum anesthetized and sedated with Ocimum gratissimum L. essential oil.

This study evaluated the use of essential oil of Ocimum gratissimum (EOOG) for anesthesia and in transport of Colossoma macropomum. Experiment 1, Test 1, anesthesia induction and recovery times were determined using different EOOG concentrations (0, 20, 50, 100, 200, 300mg L-1), with two size classes: Juveniles I (0.86g) and Juveniles II (11.46g) (independent tests in a completely randomized design). Based on the results of Test 1, in Test 2 Juveniles II were exposed to EOOG concentrations: 0, 20, 100mg L-1. Tissue samples were collected immediately after induction and 1h post-recovery, to assess oxidative status variables. Experiment 2, Juveniles I (0.91g) and Juveniles II (14.76g) were submitted to transport in water with different concentrations of EOOG (0, 5, 10mg L-1) (independent tests in a completely randomized design). The effects on oxidative status variables were evaluated. Concentrations between 50 and 200mg L-1 EOOG can be indicated for Juveniles I, while concentrations between 50 and 100mg L-1 EOOG for Juveniles II. The concentration of 100mg L-1 EOOG was able to prevent oxidative damage in the liver. In Experiment 2, the concentrations of 5 and 10mg L-1 EOOG added to the transport water caused sedation for both studied size classes of juveniles and did not cause oscillations in water quality variables nor any mortality. The concentration of 10mg L-1 EOOG improved the oxidative status. It can be concluded that EOOG can be used for anesthesia and transport of C. macropomum.

In vitro antifungal activity of aqueous extract and essential oil of African basil (Ocimum gratissimum L.)

Background: Fruit and vegetables are threatened by several diseases. These diseases are mainly treated with chemicals representing a real danger to human health and the environment. Aims: This study aims to develop safe and non-polluting alternatives such as medicinal plants to control fungal phytopathogens. Material and Methods: In the present study, the aqueous extract and essential oil of the medicinal plant Ocimum gratissimum L. were tested in vitro against Botrytis cinerea, Colletotrichum gloeosporioides and Fusarium oxysporum. Results: The results show that the essential oil of Ocimum gratissimum L. has significant antifungal activity on the studied strains. It inhibits completely the growth of Botrytis cinerea and Colletotrichum gloeosporioides from the concentration of 500 ppm. While at least 750 ppm is required for complete inhibition of the growth of Fusarium oxysporum. Regarding the aqueous extract, total inhibition has been observed at the 60% concentration for Botrytis cinerea and Colletotrichum gloeosporioides. However, no concentration of aqueous extract completely inhibited the growth of Fusarium oxysporum. Conclusion: This study can be a starting point for research on a promising solution using the essential oil and aqueous extract of O. gratissimum L. as alternatives to chemicals to manage anthracnose (caused by C. gloeosporioides) and gray mold (caused by B. cinerea). Keywords: Antifungal activity, aqueous extract, essential oil, Ocimum gratissimum L.

Ocimum Gratissimum essential oil: A review of extraction methods, phytochemical constituents, pharmacological uses and formulation approaches

Ocimum gratissimum is a plant native to Africa. Its leaves have been used in local dishes over the years, with documented evidence of varying pharmacological uses of its essential oil. This review focuses on the extraction methods, phytochemical constituents, pharmacological uses and formulation approaches of Ocimum gratissimum essential oil. The traditional extraction methods that have been widely used include the solvent, cold press and hydrodistillation methods. However, newer methods such as steam distillation, ultrasound and microwave assisted hydrodistillation, supercritical fluid extraction, pressurized liquid extraction and pressurized hot water extraction methods have not been fully reported. These methods provide more yield of the essential oil compared with the traditional methods and their processes are less laborious. Furthermore, they are often limited to analytical applications as they cannot handle large quantities of samples. The phytochemical constituents of Ocimum gratissimum essential oil vary, based on location of the plant and the time of the season the plant parts were harvested for extraction. The African species have more thymol than eugenol. Other notable constituents are saponins, terpenes and flavonoids in both African species and others. The essential oil of Ocimum gratissimum bears the scent of the plant and other important properties such as protection of the plant from pests and to attract insects for cross-pollination. The essential oil of this plant has been noted to possess various pharmacological properties which explains its use in inflammatory conditions and the treatment of diarrhoeal disease, wound healing and cerebrovascular disorder, amongst others. The essential oil of Ocimum gratissimum has been embedded in gels, cream, silver nanoparticles and nanoemulsion to improve its pharmacological activity and bioavailability. This review article highlights the potentials of the essential oil of this ubiquitous plant as a therapeutic source for the treatment of different tropical diseases.

In-vitro Biocontrol of Sugarcane Stem Borer (Eldana saccharina Walker) with Essential Oils from Aromatic Plants

Study Design and Objectives: Sugar cane production is threatened by the devastating action of the larval populations of Eldana saccharina Walker. Faced with this situation, the search for sustainable control solutions is a major challenge for sugar producers. This study contributes to the control of the larval populations of the pest through the use of formulations based on essential oils of local aromatic plants.
 Methodology: Bioassays on the survival of the larvae were therefore conducted in the laboratory at the Sucrivoire site in Zuénoula. The larvae obtained from the eggs, incubated for 5 days were reared on a nutritional medium and then transferred to empty dishes after one week. Essential oils from the hydrodistillation of three aromatic plants (Cymbopogon citratus, Ocimum gratissimum and Zingiber officinale) were used. Five concentrations of these essential oils (1000, 2000, 4000, 8000 and 10000-ppm) were tested by direct contact on batches of 10 larvae for a total of 30 larvae/concentration. Dead larvae were counted daily and the mortality rate was calculated after 24, 48 and 72 hours of exposure.
 Results: As early as 24 hours, larval mortality was significant (P<0.001) from 2000-ppm for Cymbopogon citratus and Ocimum gratissimum essential oils. They caused larval mortality of 63.33 and 80% respectively. Zingiber officinale induced a significant mortality of 80% from 4000-ppm. After 72 hours of exposure of the larvae to the essential oils, the mortality rate increased significantly with the concentration (P<0.001). The lowest lethal concentrations for 50 and 90% (841.77 and 1905.06 ppm, respectively) were obtained with the essential oil of Ocimum gratissimum.
 Conclusion: The use of essential oils of Cymbopogon citratus, Ocimum gratissimum and Zingiber officinale can help to control Eldana saccharina Walker larval borers for better sugarcane production.

Evaluation of antibacterial and toxicological activities of essential oil of Ocimum gratissimum L. and its major constituent eugenol

The present study aimed to comparatively analyze the antibacterial activity, combined with antibiotics, and toxicological activity of the essential oil of O. gratissimum L. and its major compound, eugenol. The phytochemical analysis of the essential oil was performed by gas chromatography coupled with mass spectrometry. The minimum inhibitory concentration and combined antibiotic activity were performed by microdilution. Drosophila melanogaster was the model organism chosen to evaluate the toxicological response of substances. The chromatographic assay showed eugenol as the major compound of the essential oil of O. gratissimum L. The microbiological assays showed that in terms of antibacterial activity, both products showed similar activity, quite significant in Gram-negatives, such as those of strains of Pseudomonas aeruginosa. Similar results were verified in the modulatory activity, allowing the verification that the bioactivity performed by the essential oil of O. gratissimum L. is mainly influenced by its major constituent. Although the EC50 of the compounds varied subtly, the essential oil was less toxic compared to eugenol. The information obtained in the present study demonstrates that the essential oil of O. gratissimum L. is a promising antibacterial agent and better tolerated than its majority compound alone, in the model organism D. melanogaster.

Essential Oil of Ocimum gratissimum L. (Lamiaceae) as Biopreservative of Peanuts in Post-harvest: Application Model and Effects on Quality of Derived Products

The aim of this study was to investigate the use of essential oil extracted from leaves of African basil (Ocimum gratissimum L.) in post-harvest preservation of peanuts as well as the effects on the physicochemical, technological and organoleptic characteristics of derived peanut products. Preservation tests of peanuts with essential oil of Ocimum gratissimum at a concentration of 0.6 μl/g were carried out. Control was without essential oil. Evolution of the fungal flora as well as physicochemical, technological and organoleptic characteristics of preserved peanuts were evaluated. Results of microbiological analyses indicated a significant reduction (p <0.005) of the microbial quantum in peanut samples preserved with essential oil, when compared to the control. The results of physicochemical analyses revealed that preservation of peanuts using essential oil of Ocimum gratissimum had little effect on the physicochemical characteristics. However, results from evaluation of the technological aptitudes of preserved peanuts indicated that the essential oil has modified the functional properties of preserved peanut samples, with a particular impact on the elasticity of the pastes as well as the flavor and the texture of the peanut cakes. Organoleptic analyses revealed that preservation of peanuts with the essential oil of Ocimum gratissimum affected the aroma and flavor of derived products.

Effect of Drying the Chemical Composition of the Essential Oil of Ocimum gratissimum L (Lamiaceae) Harvested in the Tonkpi Region (Ivory Coast)

In this study, we were interested in the valuation of Ocimum gratissimum, an aromatic and medicinal plant of the Ivorian flora. The essential oils of the leafy branches of Ocimum gratissimum were extracted by hydrodistillation with a Clévenger-type device. The yield of the oils obtained increases from (0.05±0.01%) to (0.42±0.08%) depending on the drying time. The density of essential oils is almost constant at 0.80. The chemical composition of essential oils was identified after analysis of chromatograms and mass spectra. The number of phytocompounds also increases with the number of drying days from 32 to 37. These compounds are marked by the presence of hydrocarbon monoterpenes from (29.11% to 49.1%), and oxygenated from (40.33% to 50.02%) and the presence of hydrocarbon sesquiterpenes from (5.52% to 8.55%), and oxygenated from (0.80% to 2.16%). The number of major compounds is 5 on day 0 and decreases to 4 on the other days, and have the following proportions: thymol from (33.60% to 44.73%), β‑caryophyllene from (2.54% to 3.29%), para-cymene (12.32% to 25.60%), γ-terpinene (10.09% to 11.41%), Bis(2-ethylhexyl)phthalate (12.12% to 0.42%). bis (2-ethylhexyl) phthalate which is in the minority during the other drying days.

Inhibition of anthracnose symptoms in common bean by treatment of seeds with essential oils of Ocimum gratissimum and Syzygium aromaticum and eugenol

Inhibition of anthracnose symptoms in common bean by treatment of seeds with essential oils of Ocimum gratissimum and Syzygium aromaticum and eugenol

Application of Essential Oils of Ocimum gratissimum and Cymbopogon citratus as Bioinsecticides for the Management of Two Major Biting-Sucking Insects (Bemisia tabaci Gennadius and Jacobiella fascialis Jacobi) and the Improvement of Seed and Fiber Quality of Cotton Plants in Ivory Coast.

In recent years, in all cotton production areas in Ivory Coast, whitefly (Bemisia tabaci) and jassid (Jacobiella facialis), two biting sucker insects were causing depreciation of quality of the cottonseed and fiber obtained at harvest. However, the excessive use of synthetic chemical insecticides against these pests presents a danger for the sustainability of the production system. This study aims to evaluate the insecticidal efficacy of essential oils of Ocimum gratissimum and Cymbopogon citratus on B. tabaci and J. fascialis and on the technological parameters of the cottonseed and fiber. A field experiment was conducted in which essential oils of O. gratissimum and C. citratus were applied to cotton plants every two weeks from day 45 to 115 after emergence using a backpack sprayer. The effects of these extracts were compared to those of a synthetic chemical insecticide composed of acetamiprid and alphacypermethrin known under the trade name IBIS A 52 EC (positive control). After 160 days of cultivation where entomological data were collected, the seed cotton samples were harvested, ginned and submitted for analysis. O. gratissimum essential oil at concentrations of 1 and 5 % gave to the cotton plants better protection against whiteflies and jassids. In addition to the synthetic chemical, these cotton plants received a better proportion of healthy cottonseed, fat and a fiber with very good reflectivity. The essential oil of O. gratissimum could therefore be integrated into the phytosanitary protection programs of the cotton plant.

Treatment of Girolando cattle dermatophilosis using a combination of different plant extracts in the municipality of Abomey-Calavi, Republic of Benin.

Background and Aim:Dermatophilosis is a bacterial infection of the skin of animals. It is prevalent worldwide and is caused by Dermatophilus congolensis. The study aimed to assess the therapeutic efficacy of different mixtures prepared with indigenous phytogenetic extracts from Benin in the management and treatment of Girolando cattle that showed high sensitivity to the disease compared to any other known cattle breed in Benin.Materials and Methods:Consequently, two types of extact mixtures (extract mixture 1=Elaeis guineensis kernel oil + essential oil of Ocimum gratissimum + sap of Jatropha multifidi; extract mixture 2= O. gratissimum + sap extract of J. multifida) of 20% concentration were prepared and tested on eight Girolando cattle. Two different parts of the affected skin with acute lesions of dermatophilosis were debrided, and 0.5 mL of each of the extract mixture was applied per square centimeter of a single zone of the affected skin.Results:Both extracts mixtures were found to possess significant wound healing properties compared to the control (procaine G penicillin). However, the extract mixture 1, which was made up of Elaeis guineensis kernel oil, essential oil of O. gratissimum and sap of J. multifida (Linn), showed a better result. This was evident by increase in the rate of wound contraction and healing without recurrence 2 weeks after the end of the experiment and the subsequent immediate manifestation of hair or hair growth at the affected area.Conclusion:The preliminary findings of this study are very promising. Extract mixture 1 could serve as an alternative in the treatment or management of bovine dermatophilosis in Benin and other dermatophilosis endemic areas of the world. However, in vitro testing and sensitivity against isolated D. congolensis organism using extract mixture 1 as well as cost implications should be studied.

Repellent and Insecticidal Effects of Basil Essential Oil (Ocimum gratissimum) from Kabylie (Algeria) on Rhyzopertha dominica F. (Coleoptera: Bostrichydae): Impact of Treatment on the Physicochemical and Rheological Qualities of Common Wheat Flour (Triticum aestivum)

In Algeria, grain-based products occupy a huge place, both in terms of nutrition and economy. Common wheat (Triticum aestivum) is the second most cultivated cereal after durum wheat (Triticum durum), the latter being often subject to attack from various storage pests. To address this issue, phosphine fumigations are used most of the time. Unfortunately, these types of conventional pesticides have caused the emergence of resistant insect populations, and represents a real danger for the environment and human health. The objective of this study is the introduction of a sustainable biological solution to control Rhyzopertha dominica F. (Coleoptera: Bostrychidae) populations using the essential oil of Ocimum gratissimum. To this end, O. gratissimum essential oil was extracted by steam distillation, then chemically characterised by CGMS. A preliminary study was conducted to demonstrate its insecticidal effects on adults of R. dominica. The impact of the extracted essential oil was also estimated on the mineral fraction and the physicochemical and rheological properties of healthy soft wheat flour, R. dominica infested flour, and treated wheat. After 30 days of incubation, the results showed that the essential oil is active by fumigation. The LD50 is 14.36 (µl/l air) for a TL50 of 153.690 h. The repellent effect was estimated at 64.44 %. The essential oil does not affect the rheological and physicochemical characteristics of the flour, which remain compliant with ISO standards. The mineral fraction showed no significant differences at P-values < 0.05.

Comparative study of acute oral toxicity of essential oils of Ocimum gratissimum, Hyptis suaveolens and Psidium guajava in wistar rats

The essential oils from Ocimum gratissimum, Hyptis suaveolens (Lamiceae) and Psidium guajava (Myrtaceae) have biological properties. The aim of this work is to compare the effect of essential oils of these three medicinal plants on weight growth, hematological and biochemical parameters of treated rats through the procedure of acute toxicity evaluation on Wistar rats. The doses applied are 100, 250 and 500mg/Kg bw for each of the essential oils From the results obtained, the effects of essential oils of Ocimum gratissimum, Hyptis suaveolens and Psidium guajava leaves on biochemical, hematological parameters and weight growth of rats are dose dependent. At the dose of 500mg/Kg bw, they significantly increased the rate of white blood cells, urea, creatinemia, transaminases and reduced the weight growth of rats by more than 10% (p

Comparative Preservative Potential of Essential Oils of Ocimum gratissimum from Bambili of the North West and Mbonge of the South West Regions of Cameroon on Scomber scombrus

Essential oils serve as a natural alternative to chemical or synthetic antimicrobials and antioxidants to fight against food borne pathogens or spoilage organisms, inhibiting lipid peroxidation and extending the shelf life of fish and other seafood. This study examines the antibacterial properties of essential oils from leaves of Ocimum gratissimum L. from two localities of the North West and South West of Cameroon on some pathogenic spoilage gram negative and positive bacteria isolated from mackerel, and their antimicrobial and antioxidant effectiveness on the fish quality during preservation for one month at -18oC. The plant materials were harvested from Bambili, the North West Region of Cameroon and from Mbonge, the South West Region of Cameroon and the essential oils extracted by hydro-distillation using Clevenger-type apparatus. Escherichia coli, Salmonella typhi and Staphylococcus aereus were isolated from mackerel by culture techniques and their susceptibility to the essential oils determined by well diffusion method. Psychrophilic bacteria and Enterobacteraceae counts were used to evaluate the microbiological quality of the fish during storage. Total volatile basic nitrogen and thiobarbituric acid reactive substance assays were used as indices to assess the biochemical quality of the fish during storage. Antibacterial susceptibility test showed that essential oils of O. gratissimum from the North West and South West Regions were active on all the tested microorganisms with different degree.The inhibitory diameters for essential oil from the South West Region were 28.0 mm, 27.2 mm and 26.0 mm while that for essential oil from the Bambili were 24.1 mm, 20.4mm and 21.9 mm for Staphylococcus aereus, Escherichia coli and Salmonella typhi respectively. At the end of storage periods, the values of Psychrotrophs plate counts, total volatile base nitrogen and thiobarbituric acid reactive substances for fish samples treated with essential oil from the Mbonge were 2.71log10cfu/g, 12.88 mgN/100g and 0.88 mgMDA/Kg, while that treated with North West essential oil were 3.00 log10cfu/g, 16.24 mgN/100g and 1.26 mgMDA/Kg respectively. From the obtained results, essential oil of O. gratissimum from the Mbonge was the most effective in preserving Atlantic mackerel.

Molecular Docking of Compounds in the Essential Oil of Ocimum gratissimum Leaf against PIM-1 Kinase of Escherichia coli

The activity of the phytochemical compounds in the essential oil of Ocimum gratissimum against PIM-1 kinase of Escherichia coli was studied using computer simulation. The essential oil was extracted by hydrodistillation, and the components identified using a gas chromatography-flame ionization detector (GC-FID) instrument. The quantity of the compounds in the essential oil was in the order isobornyl acetate (64.3 %) &gt; Octamethylhexadecan-1-ol (12.2 %) &gt; nonadecanal (11.5 %) &gt; decanal (8.7 %) &gt; undecanal (2.8 %) &gt; α-selinene (0.5 %) &gt; drimenin (&lt; 0.1 %). The results from the in silico studies showed that α-selinene had good binding affinity on the PIM-1 kinase target and therefore, could be a promising drug candidate for prostate cancer.

Essential oil of Ocimum gratissimum (Linnaeus, 1753): efficacy for anesthesia and transport of Oreochromis niloticus.

This study aimed to evaluate the essential oil of Ocimum gratissimum L. (EOOG) for anesthesia and in the transport of Oreochromis niloticus. Experiment I determined the time of anesthesia induction and recovery during anesthesia of O. niloticus exposed to different concentrations of EOOG (0, 30, 90, 150, and 300mgL-1). Based on data from Experiment I, Experiment II evaluated the effect of 0, 30, and 90mgL-1 EOOG on blood parameters and oxidative stress immediately after anesthesia induction and 1h after recovery. Experiment III evaluated the effect of 0, 5, and 10mgL-1 EOOG on blood variables immediately after 4.5h of transport of juveniles. Concentrations between 90 and 150mgL-1 EOOG were efficient for anesthesia and recovery. The use of 90mgL-1 of EOOG prevented an increase in plasma glucose. Other changes in blood parameters and oxidative stress are discussed. The use of 10mgL-1 EOOG in transport increased plasma glucose and decreased hematocrit values immediately after transport. It is concluded that the use of 90 and 150mgL-1 EOOG causes anesthesia and recovery in O. niloticus within the time intervals considered ideal. The use of 90mgL-1 EOOG favored stable plasma glucose soon after anesthesia induction and 1h after recovery, but caused changes in the antioxidant defense system by increasing hepatic and kidney ROS. The transport of 12g O. niloticus for 4.5h can be performed with concentration of 5mgL-1 of EOOG.

The use of Ocimum gratissimum L. essential oil during the transport of Lophiosilurus alexandri: Water quality, hematology, blood biochemistry and oxidative stress

This study evaluated the effects of the essential oil of Ocimum gratissimum L. (EOOG) on water quality, blood characteristics and tissue damage during transport of Lophiosilurus alexandri. One hundred and sixty juveniles of L. alexandri (123.44 ± 1.95 g and 23.71 ± 1.95 cm) were fasted for 24 h before transportation. Fish were then submitted to one of three treatments of transport water with five replicates each: 0 (control), 5 and 10 mg/L EOOG. The animals were transported for 4 h in plastic bags at a density of 1 juvenile/L and 10 animals per bag. The ventilatory frequency of one fish from each bag was determined after 3 h of transport by direct observation and counting of opercular beats. Blood, brain and liver samples were collected prior to (basal group) and at the end of transport from 10 animals each. Blood aliquots were used to determine hematocrit and hemoglobin, total plasma protein, glucose, aspartate aminotransferase and alanine aminotransferase levels. Samples of liver and brain were used to determine parameters and oxidative stress (reactive oxygen species, glutathione peroxidase, superoxide dismutase, glutathione S-transferase, lipid peroxidation and protein carbonyl formation). No mortality was observed 24 h after transport. The addition of EOOG to transport water appeared to reduce animal metabolism, thus ensuring higher dissolved oxygen and lower ammonia levels. Juveniles transported with 10 mg/L EOOG also had reduced opercular beats, lower levels of hemoglobin and blood aspartate aminotransferase and glucose. This concentration also reduced lipid and protein oxidation levels in tissues, thereby avoiding lipid peroxidation and the formation of carbonyl protein. The use of 10 mg/L EOOG during transport promotes a sedative effect in L. alexandri, with reduced oxygen consumption, ammonia excretion and biochemical changes and enhanced protection against oxidative damage.

Essential oil of Ocimum gratissimum (Linnaeus, 1753) as anesthetic for Lophiosilurus alexandri: Induction, recovery, hematology, biochemistry and oxidative stress

This study tested the use of essential oil of Ocimum gratissimum (EOOG) as an anesthetic for juvenile Lophiosilurus alexandri and its efficiency in mitigating the effects of handling stress. Two experiments were performed. Experiment 1 determined the time for anesthesia induction and recovery and the ventilatory frequency of juveniles exposed to different concentrations of EOOG (0, 10, 30, 90, 150 and 300 mg L−1). Based on the results of Experiment 1, Experiment 2 evaluated the effects of 0, 10 and 90 mg L−1 of EOOG on blood parameters and oxidative stress in liver and brain immediately after induction and one hour after recovery. No mortality was observed in any experiment. In Experiment 1, times for anesthesia induction were shorter, and recovery times longer, with increased EOOG concentrations. Compared to the animals anesthetized with 0, 10 and 30 mg L−1 of EOOG, higher ventilatory frequencies were observed during induction for animals anesthetized with 90, 150 and 300 mg L−1. In experiment 2, variations on hematological variables derived from EOOG exposition were determined, but parameters returned to baseline levels one hour after recovery. The use of 90 mg L−1 EOOG prevented increased plasma glucose and cortisol levels one hour after handling. However, animals anesthetized with 90 mg L−1 EOOG had higher concentrations of ROS (hepatic and brain) after induction and one hour after recovery. The increase in ROS for animals anesthetized with 90 mg L−1 was not matched by the antioxidant defense system, which showed a reduction in brain GST activity one hour after recovery. Juveniles anesthetized with 10 mg L−1 EOOG only presented an increase in hepatic ROS one hour after recovery from anesthesia, however, there was a response from the antioxidant defense system, with an increase in brain and hepatic GST. The increase in ROS in treatments submitted to handling under the effect of anesthesia did not cause tissue damage. It is concluded that the use of 90 and 150 mg L−1 EOOG cause anesthesia in L. alexandri within the ideal intervals of induction and recovery. The use of 90 mg L−1 EOOG prevented higher levels of plasma glucose and cortisol one hour after handling, and induced changes to the antioxidant defense system, increasing the concentration of liver and brain ROS, and reducing the activity of brain GST one hour after recovery.

Modulation of antibiotic resistance by the essential oil of Ocimum gratissimum L. in association with light-emitting diodes (LED) lights.

This study aimed to evaluate the antibacterial and antibiotic-enhancing effects of the essential oil obtained from Ocimum gratissimum L. (OEOg) alone or in association with light-emitting diodes (LED) lights. The essential oil was obtained by hydrodistillation and its chemical composition analysed by gas chromatography coupled to mass spectrometry. The antibacterial and antibiotic-enhancing activities against multiresistant strains of Staphylococcus aureus and Escherichia coli were evaluated by the gaseous contact method. The analysis of the photoinductive effect on the antibacterial activity of the OEOg and antibiotics was assessed through exposure to different LED lights (red, blue and yellow). The phytochemical analysis identified five compounds, including eugenol, as the major constituent. The OEOg caused a significant inhibition of the halo, indicating a direct antibacterial effect. Exposure to the LED lights significantly enhanced the activity of the OEOg against E. coli. On the other hand, the action of the essential oil against S. aureus was enhanced by exposure to both blue and yellow lights. The effects of LED light exposure on the activity of conventional antibiotics varied significantly according to the drug and the bacterial strain. However, most combinations of LED lights and the OEOg presented synergistic effects against resistant bacterial strains, indicating enhanced antibacterial activity. Thus, these in vitro findings suggest that both OEOg and LED lights have promising antibacterial effects. Nevertheless, further research is required to evaluate in vivo the potential of these therapies for the treatment of infectious skin diseases.

Repellence and fumigant toxicity of essential oils of Ocimum gratissimum and Ocimum kilimandscharicum on Tuta absoluta (Lepidoptera: Gelechiidae).

Tuta absoluta Meyrick originates in South America and is now one of the most important insect pests of Solanaceae in different parts of the world, including Africa. Its control has relied primarily on chemical insecticides, which are associated with negative ecological effects. In the present study, essential oils of Ocimum gratissimum and O. kilimandscharicum were tested for repellence and fumigant toxicity on the adult stages under laboratory conditions. The oil of O. gratissimum was more repellent, but its toxicity was comparable with that of O. kilimandscharicum. The major constituents of O. gratissimum were methyl eugenol (39.5%) and eugenol (29.7%). Those of O. kilimandscharicum were camphor (47.1%) and 1.8-cineole (19.3%). Eugenol (LC50 of 0.24μl/ml, 83.3%, RI50 = 0.15) and camphor (LC50 of 0.23μl/ml, 89.5%, RI50 = 0.13) were more toxic (at 1μl/ml for 24h) and repellent than the other constituents. The results show potential of the essential oils for use in integrated management of the tomato pest.