Studies on the acute and sub-chronic toxicity of the essential oil of Ocimum gratissimum L. leaf

The Beneficial Impacts of Essential Oils Application against Parasitic Infestation in Fish Farm

Aquaculture is a growing sector due to the high rising demand for fish, shrimp, oysters, and other products, which is partially conflicted by various infectious diseases. The infectious diseases affecting the production and inducing high mortalities cause substantial economic losses in this sector. Also, parasitic infections may induce severe mortality and morbidity in fish farms. Therefore, most farmers apply several kinds of antibiotics to control the problems induced by bacterial diseases and, to some extent, parasitic infections. The extensive usage of antibiotics to control or prevent pathogens may lead to the development of pathogenic resistant strains that might cause hazards to human health. Besides, there is a global trend toward reducing the application of antibiotics in aquaculture farms. Thus, there is a great effort to discover new natural and safe products with pharmaceutical properties, such as natural essential oils (EO). Essential oils are secondary metabolites of many plants (roots, flowers, seeds, leaves, fruits and peels) and their molecular structures provide a high antimicrobial and antiparasitic efficiency against pathogens. Consequently, it is essential to provide sufficient knowledge about the mode of action of EO against fish parasites and its future applications and directions in aquaculture.

A Systematic Review of Medicinal Plants of Kenya used in the Management of Bacterial Infections

Kenya’s vision 2030 partly aims at ensuring adequate health care for all, and the integration of traditional healthcare practices into the national healthcare system would present a more rapid alternative towards the realization of universal health coverage in Kenya. Currently, research on Kenyan medicinal plants with potential antibacterial activity remains vastly fragmented across numerous literature studies and databases; thus, it is imperative to collate and appraise these data for the ease of future research and possible clinical application. Objective. This review aims at exploring and compiling research evidence on medicinal plants used in the management of bacterial infections in Kenya, with a focus on their efficacy and safety. Methodology. A comprehensive web-based systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was executed to highlight the Kenyan medicinal plants used for the management of bacterial infections in Kenya. This review includes studies published until January 2021 from the PubMed, Science Direct, AJOL, and Google Scholar databases. Results. A total of 105 Kenyan medicinal plants belonging to 43 families have their in vitro activity against various human pathogenic bacteria evaluated. Plants from the Lamiaceae, Rutaceae, and Fabaceae families were the most commonly studied. Aloe secundiflora, Toddalia asiatica, Senna didymobotrya, Warbugia ugandensis, Tithonia diversifolia, Fuerstia africana, Olea africana, and Harrisonia abyssinica were the plants frequently evaluated within Kenya. The plants with the strongest antimicrobial activities were Toddalia asiatica, Hagenia abyssinica, Ocimum gratissimum, Harrisonia abyssinica, Senna didymobotrya, Olea Africana, Camellia sinensis, and Tarmarindus indica. Conclusion. Based on a published work, it is evident that traditional medicine is seemingly an acceptable and efficient system among Kenyan communities in the management of bacterial infections. Kenya’s rich biodiversity with diverse secondary metabolites presents a promising source of new therapeutic alternatives with possibly different mechanisms of action against bacteria.

Toxicity Studies on Essential Oil from Phoenix dactylifera (L.) Seed in Wistar Rats

This study evaluated the toxicological effect of oral administration of Phoenix dactylifera seed essential oil (PDEO) in Wistar rats. PDEO was extracted through a steam-distillation technique. Acute toxicity study evaluated administration of a single dose of the oil in a group (n = 5) of rats followed by 24 h observation, for sub-acute toxicity evaluation, the animals were randomly divided into five groups (n = 3). Group 1 to 4 rats, respectively, received 62.5, 125, 250, and 500 mg/kg bw of PDEO for fourteen days, while the fifth group served as control. At the termination of the study, blood samples were obtained for biochemical and hematological analyses, while vital organs were histopathologically examined. Results from this study revealed no mortality or abnormal behavioral changes in the animals. A dose-related increase in bodyweight and hematological parameters was observed across the treated groups (p < 0.05). At a dosage of 500 mg/kg bw, PDEO caused slight elevation in biochemical marker levels and mild changes in histological architecture of liver and kidney of the test rats. This study revealed that PDEO exhibited significant hematopoietic attributes with no adverse effect on the experimental rats’ vital organs at concentrations below 500 mg/kg bw.

The Effect of Ocimum basilicum L. and Its Main Ingredients on Respiratory Disorders: An Experimental, Preclinical, and Clinical Review

Ocimum basilicum L. (O. basilicum) and its constituents show anti-inflammatory, immunomodulatory, and antioxidant effects. The plant has been mainly utilized in traditional medicine for the treatment of respiratory disorders. In the present article, effects of O. basilicum and its main constituents on respiratory disorders, assessed by experimental and clinical studies, were reviewed. Relevant studies were searched in PubMed, Science Direct, Medline, and Embase databases using relevant keywords including “Ocimum basilicum,” “basilicums,” “linalool,” “respiratory disease,” “asthma,” “obstructive pulmonary disease,” “bronchodilatory,” “bronchitis,” “lung cancer,” and “pulmonary fibrosis,” and other related keywords.The reviewed articles showed both relieving and preventing effects of the plant and its ingredients on obstructive pulmonary diseases such as chronic obstructive pulmonary disease (COPD), asthma, and other respiratory disorders such as bronchitis, aspergillosis tuberculosis, and lung cancer. The results of the reviewed articles suggest the therapeutic potential of O. basilicum and its constituent, linalool, on respiratory disorders.

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.

Acute and repeated-dose toxicity of Echinops kebericho Mesfin essential oil

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No mortality was observed up to 2000 mg/kg dose in acute toxicity study of Echinops kebericho essential oil.

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On repeated-dose toxicity study, essential oil treated groups and controls did not show significant variations.

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No significant variation was observed in food consumption, body and organ weight, and histopathology between treated and control groups.

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Urea, albumin, aspartate aminotransferase, andorgan weight of kidney significantly varied between some treated groups compared to control.

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Significant variations were observed between male and female in many parameters.

Echinops kebericho Mesfin is used for the management of various diseases and fumigation during child birth. This study investigated acute and repeated-dose toxicity of E. kebericho M. essential oils (EOs). The study was conducted in Swiss albino mice. Organ weight, histopathology and clinical chemistry were analyzed. The dose and duration of treatment were defined in accordance with Organization for Economic Co-operation and Development (OECD) guideline.

No mortality was observed in acute oral dose toxicity study up to 2000 mg/kg per body weight. Compared to control group, treated groups did not show significant abnormalities in body weight and most parameters of clinical chemistry parameters and relative organ weight in repeated-dose toxicity study. However, urea, albumin, aspartate aminotransferase, and relative organ weight of right kidney showed variations in treated groups compared to control group. All treated groups and control group showed normal histology except lymphocytic infiltrates observed on the kidney with 200 mg/kg treated female group. The current study revealed that EO of E. kebericho M. could be considered well tolerated in acute and repeated-dose exposure. Further, teratogenic, mutagenic, carcinogenic, and sub-chronic and chronic toxicity studies are warranted.

Members of the family <i>Lamiaceae</i> Lindl. as sources of medicinal plant raw materials to obtain neurotropic drugs

The aim of this work is to review and analyze the data published in the modern scientific literature obtained in pharmacological, pharmacognostic and pharmacotechnological studies of various types of raw materials obtained from members of the family Lamiaceae L., which were sources of biologically active substances, pharmaceutical substances, total extracts and the drugs – with a neurotropic activity.

Materials and methods. For the review, we used the information of scientific literature from open and accessible sources of the last twenty years, located in the scientific and technical libraries of institutions, as well as in electronic databases: Elibrary, PubMed, Scopus, Cyberleninka, GoogleAcademy, J-Stage. The search inquiries were: the species of the family Lamiaceae (Russian and Latin), the samples of medicinal plant materials based on them as well as the names of the drugs and biologically active substances obtained from these raw materials.

Results. When working with the sources of scientific information, the main attention was paid to pharmacologic tests performed during the studies on laboratory animals and proving the presence of neurotropic activity in the studied objects – essential oils and extracts from plant raw materials: aqueous, aqueous alcoholic, and methanol ones. It has been established that the potential of the therapeutic and preventive application of pharmaceutical substances and drugs based on the medicinal plant materials obtained from 30 genera members of the Lamiaceae family, remains unrealized despite the close attention of various researchers.

Conclusion. This review comprised 71 species from 30 genera. Despite the significant level of the previous study presented in the analysis of this publication, an enormous potential of this family’s species remains unexplored. In the future, they can be of both – pharmacognostic and practical interest, in particular, in creation of new medicinal preparations of the neurotropic action based on them.

Blood biochemical parameters and melanomacrophage centers in Nile tilapia fed essential oils of clove basil and ginger

Nile tilapia (Oreochromis niloticus) is the most farmed freshwater fish in the world, however, disease outbreaks are the main cause of losses in production. Due to this, there is an increasing interest in natural products for enhancing disease resistance, without causing physiological impairment. The aim of this study was to verify the effect of the essential oils of clove basil (Ocimum gratissimum) and ginger (Zingiber officinale) on physiological and immunological parameters of nile tilapia. After 35 and 55 days of supplementation (0.5%, 1.0% and 1.5%), blood collection was performed for determination of metabolites (glucose, cholesterol, triglycerides, serum total protein and immunoglobulins) and lysozyme activity. Spleen tissue was also collected at 55 days for analyzing melanomacrophages centers. At 35 days, cholesterol showed significant reduction in the treatments 0.5% and 1.5 ginger and 1.5% clove basil. The serum triglycerides showed significant reduction in these same treatments, in addition to 1.0% clove basil. At 55 days all the supplemented groups showed significant reduction for both parameters. The lysozyme activity at 35 days was significantly higher in fish supplemented with 1.0% ginger and showed no difference among the treatments at 55 days. Regarding the melanomacrophage centers, at 35 days increased number in fish supplemented with 0.5% clove basil was observed but with no significant difference in the total percent area of spleen occupied by centers. The levels of glucose, total serum protein and immunoglobulins did not show significant differences in both sampling times. The addition of essential oils showed to be useful for improving physiological status of the fish, without excessive activation of defense mechanisms.

Linalool-rich essential oils from the Amazon display antidepressant-type effect in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

The essential oils of the leaves of Aniba rosaeodora (pau-rosa), Aniba parviflora (macacaporanga) and Aeollanthus suaveolens (catinga-de-mulata), rich in linalool, are used in the traditional medicine of the Brazilian Amazon for its effects on the central nervous system, such as sedative, anticonvulsant and antidepressant, among other therapeutic properties.

AIM OF THE STUDY

To analyze the chemical composition of these oils and to evaluate their neurobehavioral effects in rodents, based on different and established behavioral tests.

MATERIAL AND METHODS

The oils were distilled and analyzed by GC and GC-MS. Male Wistar rats received intraperitoneal doses of the oils of pau-rosa (3.5 and 35mg/kg), macacaporanga (8.5 and 85mg/kg) and catinga-de-mulata (7.5 and 75mg/kg), in addition to a linalool standard (30mg/kg). The neurobehavioral effects were evaluated using the tests: Open Field (spontaneous locomotion activity), Elevated Plus Maze (anxiolytic- type activity), Splash and Forced Swimming (antidepressive-type activity) and the Inhibitory Avoidance (memory retention).

RESULTS

The three oils (highest dose) and standard linalool presented significant antidepressant activity in rodents. Linalool was identified as the major constituent of the oils (pau-rosa, 88.6%, macacaporanga, 45%, catinga-de-mulata, 49.3%). The standard linalool used was 97.0%.

CONCLUSION

The pau-rosa, macacaporanga, and catinga-de-mulata oils presented antidepressant activity due to the presence of linalool, which, by the final synergistic action of other constituents found in oils, may have contributed to the increase or reduction of this behavioral effect in the treated animals. A relevant fact is that there was no compromise of spontaneous locomotion and the memory retention in the rodents.

Chemical composition, toxicological aspects and antifungal activity of essential oil from Lippia sidoides Cham

OBJECTIVES

The aims of this study were to test the essential oil from Lippia sidoides Cham. for antifungal activity, in vitro, against Candida spp. and Microsporum canis, to evaluate its acute and subchronic toxicological effects, in vivo, and to determine its chemical constituents.

METHODS

The antifungal activity, in vitro, was initially evaluated by the agar-well diffusion technique, and the MIC and minimum fungicidal concentration (MFC) were determined by the broth microdilution method. The acute and subchronic toxicological effects were determined in mice and rats, respectively. The chemical composition of the essential oil was determined by gas chromatography coupled to mass spectroscopy.

RESULTS

The essential oil obtained from L. sidoides was effective against all tested strains by the agar-well diffusion method. The MICs of L. sidoides essential oil for strains of M. canis ranged from 4 to 70 mg/L and the MFCs ranged from 9 to 150 mg/L. The MICs for strains of Candida spp. ranged from 620 to 2500 mg/L and the MFCs ranged from 1250 to 5000 mg/L. The main constituents of L. sidoides essential oil were thymol (59.65%), E-caryophyllene (10.60%) and p-cymene (9.08%). The acute administration of the essential oil up to 3 g/kg by the oral route to mice was devoid of overt toxicity. The 30 day oral administration of L. sidoides oil (117.95 mg/kg/day) to rats did not induce any significant histopathological, haematological or serum biochemical alterations.

CONCLUSIONS

The essential oil from L. sidoides may be a promising source in the search for new antifungal drugs due to its efficacy and low toxicity.

Efflux transporters as a novel herbivore countermechanism to plant chemical defenses

The recent discovery of efflux transporters in the gut has revolutionized our understanding of the absorption and bioavailability of pharmaceuticals and other xenobiotics in humans. Despite the celebrity of efflux transporters in the areas of pharmacology and medicine, their significance is only beginning to be realized in the area of plant-herbivore interactions. This review integrates reports on the importance of gut efflux transporters to diet selection by herbivores. The diets of herbivores are laden with toxic plant secondary metabolites (PSMs) that until recently were thought to be processed almost exclusively by detoxification enzymes in the liver. We describe how efflux transporters in the gut may play a critical role in regulating the absorption of PSMs in herbivores and dictating diet selection. Recent studies suggest that the role of efflux transporters in mediating diet selection in herbivores may be as critical as detoxification enzymes. In addition to diet selection, gut efflux transporters have implications for other aspects of plant-animal interactions. They may be significant components of the evolutionary arms race that influences chemical diversity in plants. Furthermore, in agricultural systems, gut efflux transporters may play an important role in the effectiveness of pesticides. This synthesis paper introduces a new direction in plant-herbivore interactions by providing a complementary mechanism, regulated absorption, to detoxification that may define tolerance to PSMs by herbivores.

Effects of seasonal variation on the central nervous system activity of Ocimum gratissimum L. essential oil

Ocimum gratissimum L. (Lamiaceae) and other species of the same genus are used as medicines to treat central nervous system (CNS) diseases, commonly encountered in warm regions of the world. The chemical composition of Ocimum gratissimum essential oil varies according to their chemotypes: timol, eugenol or geraniol. In this study, the essential oil type eugenol was extracted by hydrodistillation in each of the four seasons of the year. Activity upon CNS was evaluated in the open-field and rota-rod tests; sleeping time induced by sodium pentobarbital (PBS, 40 mg/kg, intra-peritoneally, i.p.) and anticonvulsant activity against seizures induced by both pentylenetetrazole (PTZ; 85 mg/kg, s.c.) and maximal electroshock (MES, 50 mA, 0.11 s) were determined. Essential oils obtained in each season were effective in increasing the sleeping duration and a preparation obtained in Spring was able to protect animals against tonic seizures induced by electroshock. In each season, eugenol and 1,8-cineole were the most abundant compounds, and in Spring the essential oil presented the greatest relative percentage of sesquiterpenes, suggesting that these compounds could explain the differences observed in the biological activity in essential oils obtained in different seasons of the year.

The antimutagenic activity of Lavandula angustifolia (lavender) essential oil in the bacterial reverse mutation assay

Essential oils from Melaleuca alternifolia (tea-tree oil) and Lavandula angustifolia (lavender oil) are commonly used to treat minor health problems. Tea-tree oil possesses broad-spectrum antimicrobial activity, and is increasingly used for skin problems. Lavender oil, traditionally used as an antiseptic agent, is now predominantly used as a relaxant, carminative, and sedative in aromatherapy. Despite their growing use no data are available on their mutagenic potential. In this study, after determining the chemical composition of tea-tree oil and lavender oil, by gas-chromatography and mass spectrometry, we investigated their mutagenic and antimutagenic activities by the bacterial reverse mutation assay in Salmonella typhimurium TA98 and TA100 strains and in Escherichia coli WP2 uvrA strain, with and without an extrinsic metabolic activation system. Neither essential oil had mutagenic activity on the two tested Salmonella strains or on E. coli, with or without the metabolic activation system. Conversely, lavender oil exerted strong antimutagenic activity, reducing mutant colonies in the TA98 strain exposed to the direct mutagen 2-nitrofluorene. Antimutagenicity was concentration-dependent: the maximal concentration (0.80 mg/plate) reduced the number of histidine-independent revertant colonies by 66.4%. Lavender oil (0.80 mg/plate) also showed moderate antimutagenicity against the TA98 strain exposed to the direct mutagen 1-nitropyrene. Its antimutagenic property makes lavender oil a promising candidate for new applications in human healthcare.

Evaluation of antinociceptive and antiinflammatory activities of the essential oil (EO) ofOcimum micranthum Willd. from Northeastern Brazil

The EO of Ocimum micranthum was studied for a possible analgesic effect on the acetic acid induced writhing and formalin test in mice and antioedema activities on the carrageenan and dextran induced paw oedema in rats. The EO demonstrated antinociceptive effects, and pretreatment with naloxone did not reverse the antinociception, indicating that the opioid system is not involved. On the other hand, pretreatment with L-arginine (L-arg) reversed the antinociception, suggesting involvement of the nitric oxide (NO) system. The EO did not present an antioedematogenic effect in the carrageenan and dextran models.