Immunotoxicological Evaluation of Schinus molle L. (Anacardiaceae) Essential Oil in Lymphocytes and Macrophages

Evidence for the efficacy of anti-inflammatory plants used in Brazilian traditional medicine with ethnopharmacological relevance

ETHNOPHARMACOLOGICAL RELEVANCE

When exacerbated, inflammatory processes can culminate in physical and emotional disorders and, if not stopped, can be lethal. The high prevalence of inflammation has become a public health problem, and the need for new drugs to treat this pathology is imminent. The use of medicinal plants has emerged as an alternative, and a survey of data that corroborates its application in inflammatory diseases is the starting point. Furthermore, Brazil harbors a megadiversity, and the traditional use of plants is relevant and needs to be preserved and carefully explored for the discovery of new medicines.

AIM OF THE STUDY

This review sought to survey the medicinal plants traditionally used in Brazil for the treatment of inflammatory processes and to perform, in an integrative way, a data survey of these species and analysis of their phytochemical, pharmacological, and molecular approaches.

MATERIALS AND METHODS

Brazilian plants that are traditionally used for inflammation (ophthalmia, throat inflammation, orchitis, urinary tract inflammation, ear inflammation, and inflammation in general) are listed in the DATAPLAMT database. This database contains information on approximately 3400 native plants used by Brazilians, which were registered in specific documents produced until 1950. These inflammatory disorders were searched in scientific databases (PubMed/Medline, Scopus, Web of Science, Lilacs, Scielo, Virtual Health Library), with standardization of DECS/MESH descriptors for inflammation in English, Spanish, French, and Portuguese, without chronological limitations. For the inclusion criteria, all articles had to be of the evaluated plant species, without association of synthesized substances, and full articles free available in any of the four languages searched. Duplicated articles and those that were not freely available were excluded.

RESULTS

A total of 126 species were identified, culminating in 6181 articles in the search. After evaluation of the inclusion criteria, 172 articles representing 40 different species and 38 families were included in the study. Comparison of reproducibility in intra-species results became difficult because of the large number of extraction solvents tested and the wide diversity of evaluation models used. Although the number of in vitro and in vivo evaluations was high, only one clinical study was found (Abrus precatorius). In the phytochemical analyses, more than 225 compounds, mostly phenolic compounds, were identified.

CONCLUSION

This review allowed the grouping of preclinical and clinical studies of several Brazilian species traditionally used for the treatment of many types of inflammation, corroborating new searches for their pharmacological properties as a way to aid public health. Furthermore, the large number of plants that have not yet been studied has encouraged new research to revive traditional knowledge.

Acute and developmental toxicity of embelin isolated from Embelia schimperi Vatke fruit: In vivo and in silico studies

Background

Embelin is a hydroxybenzoquinone constituent of the Embelia species that has anti-disease properties. However, its toxicity, particularly the in silico, acute, and developmental toxicity profiles, has yet to be thoroughly investigated. Hence, this study aims to assess these toxicity profiles.

Materials and Methods

In silico and in vivo experimental studies were conducted on embelin isolated from the fruits of Embelia schimperi Vatke. In silico toxicity predictions were computed using the ProTox model. The in vivo experiment was done by administering 5000 mg/kg of embelin to a single female albino Wistar rat, followed by three female rats in the absence of death, to determine the mean lethal dose (LD50). Afterwards, three groups of pregnant rats were treated with embelin at doses of 250 mg/kg, 500 mg/kg, and 1000 mg/kg for the developmental toxicity test. Vehicle and ad libitum control groups were used to compare the acute and developmental toxicity variables.

Results

In silico toxicity predicted that embelin is free from hepatotoxic, carcinogenic, mutagenic, and cytotoxic effects. No inhibitory effect on hERG channels was observed. It has an immunotoxic property and an inhibitory effect on the CYP2D6 enzyme. Since mortality and signs of toxicities were not observed after treatment with 5000 mg/kg, the mean lethal dose (LD₅₀) is determined to be > 5000 mg/kg. There was no significant difference in the morphological scores or number of somites among experimental animals. None of the embryonic systems possessed developmental delays. Nevertheless, the crown-rump length of the high-dose group became significantly shorter. Maternal food intake and weight gain exhibited significant dose-dependent differences between embelin-treated animals and controls. The number of implantations was significantly low in the treatment group, accompanied by a higher frequency of prior resorption.

Conclusion

Embelin is predicted to have a high probability of immunotoxicity potential and affect drug metabolism by inhibiting CYP2D6. In addition, it affects food intake, weight gain, and the number of implantations in pregnant rats. Therefore, it is highly recommended not to take embelin and embelin-rich plants during pregnancy. Further in vitro and in vivo studies need to be conducted to understand the mechanism behind the toxicity of embelin.

Much More Than a Pleasant Scent: A Review on Essential Oils Supporting the Immune System

The augmenting acceptance and application of herbal medicine in prevention and treatment of diseases also involve the use of plant essential oils (EOs) through different routes of administration (aromatherapy). Scientific data supporting the efficacy of certain herbal products are continuously growing; however, the cumulative evidence is not always sufficient. The anti-inflammatory properties of EOs have been investigated more extensively and also reviewed in different settings, but so far, our review is the first to summarize the immune-supporting properties of EOs. Our aim here is to synthesize the currently available data on the immune function enhancing effects of EOs. An online search was conducted in the PubMed database, which was terminated at the end of July 2019. Other articles were found in the reference lists of the preselected papers. Studies that applied whole EOs with known components, or single EO constituents under in vitro or in vivo laboratory conditions, or in human studies, and de facto measured parameters related to immune function as outcome measures were included. Two specific fields, EO dietary supplementation for livestock and fish, and forest bathing are also explored. Some EOs, particularly eucalyptus and ginger, seem to have immune function enhancing properties in multiple studies.

Essential Oils as a Feed Additives: Pharmacokinetics and Potential Toxicity in Monogastric Animals

Essential oils (EOs) are now a hot topic in finding modern substitutes for antibiotics. Many studies have shown positive results and confirmed their high antibacterial activity both in vitro and in vivo. Deservedly, there is an attempt to use EOs as a substitute for antibiotics, which are currently limited by legislation in animal breeding. Given the potential of EOs, studies on their fate in the body need to be summarized. The content of EO's active substances varies depending on growing conditions and consequently on processing and storage. Their content also changes dynamically during the passage through the gastrointestinal tract and their effective concentration can be noticeably diluted at their place of action (small intestine and colon). Based on the solubility of the individual EO's active substances, they are eliminated from the body at different rates. Despite a strong antimicrobial effect, some oils can be toxic to the body and cause damage to the liver, kidneys, or gastrointestinal tissues. Reproductive toxicity has been reported for Origanum vulgare and Mentha arvensis. Several publications also address the effect on the genome. It has been observed that EOs can show both genoprotective effects (Syzygium aromaticum) and genotoxicity, as is the case of Cinnamomum camphor. This review shows that although oils are mainly studied as promising antimicrobials, it is also important to assess animal safety.

Fluconazole induces genotoxicity in cultured human peripheral blood mononuclear cells via immunomodulation of TNF-α, IL-6, and IL-10: new challenges for safe therapeutic regimens

Context: Fluconazole (FNZ) is a drug used in antifungal therapy. However, the minimum FNZ dose to interfering with immune responses or inducing DNA damage is still unknown. Objective: This study investigated the toxicological profile of FNZ on cultured human peripheral blood mononuclear cells (PBMCs) treated with different concentrations of this azole. Materials and methods: Cultured PBMCs were exposed to FNZ (6, 12, 30, 60 and 120 μg/mL) and the toxicological profile was assessed by the following parameters: cytotoxic and nuclear division index (necrotic, apoptotic and viable cells), DNA damage (alkaline comet test), mutagenic potential (micronucleus test), cytokine modulation (IL-1, IL-6, IL-10, TNF-α, IFN-γ), and predictive toxicity (Osiris^® and LAZAR^® programs). Results: Our results demonstrated that FNZ induced cellular DNA damage and mutagenicity at concentrations above the plasma peak (>30 μg/mL) and 6 μg/mL, respectively, which was associated with increased TNF-α, and decrease IL-6 and IL-10 concentrations. These effects may be related to increased apoptosis and cytotoxic nuclear division index in the cultured PBMCs. In silico results indicated potential mutagenic, tumorigenic, irritant, and carcinogenic effects, which were partially confirmed by the above assays. Discussion and conclusions: Together, these findings suggest the need to rationalize the use of FNZ, especially if it is used for long periods or with concomitant pathologies requiring azole therapy that may increase FNZ's plasma concentration.