Simple colorimetric method to determine the in vitro antioxidant activity of different monoterpenes

Resveratrol against Echinococcus sp.: Discrepancies between In Vitro and In Vivo Responses

In an attempt to find new anti-echinococcal drugs, resveratrol (Rsv) effectiveness against the larval stages of Echinococcus granulosus and E. multilocularis was evaluated. The in vitro effect of Rsv on parasites was assessed via optical and electron microscopy, RT-qPCR and immunohistochemistry. In vivo efficacy was evaluated in murine models of cystic (CE) and alveolar echinococcosis (AE). The impact of infection and drug treatment on the mouse bone marrow hematopoietic stem cell (HSC) population and its differentiation into dendritic cells (BMDCs) was investigated via flow cytometry and RT-qPCR. In vitro treatment with Rsv reduced E. granulosus metacestode and protoscolex viability in a concentration-dependent manner, caused ultrastructural damage, increased autophagy gene transcription, and raised Eg-Atg8 expression while suppressing Eg-TOR. However, the intraperitoneal administration of Rsv was not only ineffective, but also promoted parasite development in mice with CE and AE. In the early infection model of AE treated with Rsv, an expansion of HSCs was observed followed by their differentiation towards BMCDs. The latter showed an anti-inflammatory phenotype and reduced LPS-stimulated activation compared to control BMDCs. We suggest that Rsv ineffectiveness could have been caused by the low intracystic concentration achieved in vivo and the drug's hormetic effect, with opposite anti-parasitic and immunomodulatory responses in different doses.

Essential Oil Composition, Antioxidant Activity and Leaf Micromorphology of Five Tunisian Eucalyptus Species

Eucalyptus species have been widely employed in the projects of reforestation in Tunisia. Although their ecological functions are controversial, these plants are indeed important to counteract soil erosion, and represent a fast-growing source of fuelwood and charcoal wood. In the present study, we considered five Eucalyptus species, namely Eucalyptus alba, E. eugenioides, E. fasciculosa, E. robusta, and E. stoatei cultivated in the Tunisian Arboreta. The aim was to carry out the micromorphological and anatomical characterization of the leaves, the extraction and phytochemical profile of the essential oils (EOs), and the evaluation of their biological properties. Four of the EOs showed the prevalence of eucalyptol (1,8-cineole) varying from 64.4 to 95.9%, whereas a-pinene predominated in E. alba EO (54.1%). These EOs showed in vitro antioxidant activity, and reduced the oxidative cellular stress as shown by their activity on reactive oxygen species (ROS) production, and modulation of the expression of antioxidant enzymes, such as glutamate-cysteine ligase (GCL) and heme oxygenase-1 (Hmox-1). Moreover, the EOs inhibited the production of nitric oxide (NO), showing anti-inflammatory activity. The data collected suggest that these EOs may be considered a promising therapeutic strategy for inflammation-based diseases and may represent an additional value for the economy of Tunisia.

Quantitative determination of voriconazole by thionine reduction and its potential application in a pharmaceutical and clinical setting

Voriconazole (VCZ) is a triazolic drug used to treat serious fungal infections and invasive mycosis and has also been more recently used as a generic antifungal treatment. However, VCZ therapies can cause undesirable side effects and doses must be carefully monitored before administration to avoid or reduce severe toxic effects. Analytical techniques used to quantify VCZ are mostly based on HPLC/UV and often associated with multiple technical steps as well as expensive equipment. The present work aimed to develop an accessible and affordable spectrophotometric technique in the visible range (λ = 514 nm) for the simple quantification of VCZ. The technique was based on VCZ-induced reduction of thionine (TH, red) to leucothionine (LTH, colorless) under alkaline conditions. The reaction showed a linear correlation over the range of 1.00 μg mL^-1 to 60.00 μg mL^-1 at room temperature, the limits of detection and quantification being 1.93 μg mL^-1 and 6.45 μg mL^-1, respectively. VCZ degradation products (DPs) according to ¹H and ¹³C-NMR spectrometric determinations not only showed good agreement with the ones previously reported (DP1 and DP2 - T. M. Barbosa, G. A. Morris, M. Nilsson, R. Rittner and C. F. Tormena, RSC Adv., 2017, DOI: 10.1039/c7ra03822d), but also revealed a new degradation product (DP3). Mass spectrometry not only confirmed the presence of LTH as a result of the VCZ DP-induced TH reduction, but also revealed the formation of a novel and stable Schiff base as a reaction product between DP1 and LTH. The latter finding became significant as it stabilizes the reaction for quantification purposes, by hindering LTH ↔TH redox reversibility. This analytical method was then validated according to the ICH Q2 (R1) guidelines, and additionally, it could be demonstrated as applicable for the reliable VCZ quantification in commercially available tablets. Importantly, it also represents a useful tool for detecting toxic threshold concentrations in human plasma from VCZ-treated patients, alerting when these risky limits are exceeded. In this way, this technique independent from sophisticated equipment, highly qualifies as a low-cost, reproducible, trustable, and non-laborious alternative method for VCZ measurements from different matrices.

Colloidal delivery of vitamin E into solid lipid nanoparticles as a potential complement for the adverse effects of anemia treatment

Vitamin E (VitE) is one of the most important antioxidants and plays a key role in decreasing the inflammatory effects of oxidative stress caused by recurrent doses of iron administration in anemia treatment. However, VitE is poorly soluble in aqueous environments. Here, VitE encapsulation into solid lipid nanoparticles (SLN) composed of myristil myristate to improve its bioavailability was proposed. A 99.9 ± 0.1% encapsulation efficiency with a drug/lipid ratio of 500 µg/mg and 478 higher VitE solubility was obtained. The antioxidant properties of VitE after encapsulation were maintained. SLN-VitE showed a 228.2 nm mean diameter with low polidispersitivity (0.335), and negative Z potential (ζ ≈ -9.0 mV). The SLN were well-dispersed, displayed spherical and homogeneous morphology by TEM. A controlled release of VitE from SLN was found. The XRD and FTIR analyses revealed the presence of a nanostructured architecture of SLN after VitE incorporation. We probed the safety of SLN-VitE after contact with three in vitro cell models: erythrocytes, lymphocytes and HepG2 cells. The cell viability in presence of SLN, SLN-VitE, and their combinations with iron was not affected. The comet assay demonstrated that the DNA damage caused by iron administration was decrease in presence of SLN-VitE.

Antibacterial and Oxidative Stress-Protective Effects of Five Monoterpenes from Softwood

Volatile organic compounds (VOC) affect the quality of indoor air. Terpenes and especially monoterpenes are the main molecules emitted from softwood material (coniferous species), which is widely used in construction. The corneal epithelium is one of the first human membranes to encounter VOCs in the air. Moreover, the industrial use of pleasant-scented monoterpenes in cosmetics, food, and detergents exposes people to monoterpenes in their daily lives. In the present study, the health effective properties of five monoterpenes from softwood were tested; cytotoxicity and oxidative stress-protective effects of α- and β-pinenes, R- and S-limonene, and 3-carene were tested in a human corneal epithelial (HCE) cell model system and with two additional in vitro antioxidant tests: oxygen radical absorbance capacity (ORAC) and hydrogen peroxide (H₂O₂) scavenging. Antibacterial efficacies were tested with two bioluminescent bacterial biosensor strains (Escherichia coli K12+pcGLS11 and Staphylococcus aureus RN4220+pAT19) and with minimum inhibitory concentration (MIC) test against Escherichia coli. Only very high concentrations of monoterpenes (0.3–0.5 mg/mL) demonstrated cytotoxicity against HCE cells. Contrary to the original hypothesis, monoterpenes did not exhibit strong antioxidant properties in tested concentrations. However, biosensors and MIC tests indicated clear antibacterial activities for all tested monoterpenes.

Linalool as a Therapeutic and Medicinal Tool in Depression Treatment: A Review

Depression is a prevalent disease worldwide, limiting psychosocial functioning and thequality of life. Linalool is the main constituent of some essential oils from aromatic plants, representing about 70% of these volatile concentrates. Evidence of the linalool activity on the central nervous system, mainly acting as an antidepressant agent, is increasingly abundant. This review aimed to extend the knowledge of linalool's antidepressant action mechanisms, which is fundamental for future research, intending to highlight this natural compound as a new antidepressant phytomedication. A critical analysis is proposed here with probable hypotheses of the synergic mechanisms that support the evidence of antidepressant effects of the linalool. The literature search has been conducted in databases for published scientific articles before December 2020, using relevant keywords. Several pieces of evidence point to the anticonvulsant, sedative, and anxiolytic actions. In addition to these activities, other studies have revealed that linalool acts on the monoaminergic and neuroendocrine systems, inflammatory process, oxidative stress, and neurotrophic factors, such as BDNF, resulting in considerable advances in the knowledge of the etiology of depression. In this context, linalool emerges as a promising bioactive compound in the therapeutic arsenal, capable of interacting with numerous pathophysiological factors and acting on several targets. This review claims to contribute to future studies, highlighting the gaps in the linalool knowledge, such as its kinetics, doses, routes of administration, and multiple targets of interaction, to clarify its antidepressant activity.

Design of magnetic hybrid nanostructured lipid carriers containing 1,8-cineole as delivery systems for anticancer drugs: Physicochemical and cytotoxic studies

The development of versatile carriers to deliver chemotherapeutic agents to specific targets with establishing drug release kinetics and minimum undesirable side effects is becoming a promising relevant tool in the medical field. Magnetic hybrid nanostructured lipid carriers (NLC) were prepared by incorporation of 1,8-cineole (CN, a monoterpene with antiproliferative properties) and maghemite nanoparticles (MNPs) into a hybrid matrix composed of myristyl myristate coated with chitosan. Hybrid NLC characterized by DLS and TEM confirmed the presence of positively charged spherical nanoparticles of around 250 nm diameter and +10.2 mV of Z-potential. CN encapsulation into the lipid core was greater than 75 % and effectively released in 24 h. Modification of the crystalline structure of nanoparticles after incorporation of CN and MNPs was observed by XRD, DSC, and TGA analyses. Superparamagnetic NLC behavior was verified by recording the magnetization using a vibrating scanning magnetometer. NLC resulted in more cytotoxic than free CN in HepG2 and A549 cell lines. Particularly, viability inhibition of HepG2 and A549 cells was increased from 35 % to 55 % and from 38 % to 61 %, respectively, when 8 mM CN was incorporated into the lipid NPs at 24 h. Green fluorescent-labeled NLC with DIOC18 showed an enhanced cellular uptake with chitosan-coated NLC. Besides, no cytotoxicity of the formulations in normal WI-38 cells was observed, suggesting that the developed hybrid NLC system is a safe and good potential candidate for the selective delivery and potentiation of anticancer drugs.

α-Phellandrene exhibits antinociceptive and tumor-reducing effects in a mouse model of oncologic pain

Medical reports indicate a prevalence of pain in 50% of patients with cancer. In this context, this article investigated the antinociceptive activity of α-PHE using in vivo Sarcoma-180-induced hypernociception in mice to detail its mechanism(s) of antinociception under different conditions of treatment and tumor progression. Firsty, in vitro cytotoxic action was assessed using melanoma B-16/F-10 and S-180 murine cells and colorimetric MTT assays. For in vivo studies, acute treatment with α-PHE (6.25, 12.5, 25 and 50 mg/kg orally by gavage) was performed on the 1st day after S-180 inoculation. Subacute treatments were performed for 8 days starting on the next day (early protocol) or on day 8 after S-180 inoculation (late protocol). For all procedures, mechanical nociceptive evaluations were carried out by von Frey's technique in the subaxillary region peritumoral tissue (direct nociception) and in right legs of S-180-bearing mice (indirect nociception). α-PHE showed in vitro cytotoxic action on B-16/F-10 and S-180 (CI₅₀ values of 436.0 and 217.9 μg/mL), inhibition of in vivo tumor growth (ranging from 47.3 to 82.7%) and decreased direct (peritumoral tissue in subaxillary region) and indirect (right leg) mechanical nociception in Sarcoma 180-bearing mice with early and advanced tumors under acute or subacute conditions of treatment especially at doses of 25 and 50 mg/kg. It improved serum levels of GSH as well as diminished systemic lipid peroxidation, blood cytokines (interleukin-1β, -4, -6, and tumor necrosis factor-α). Such outcomes highlight α-PHE as a promising lead compound that combines antinociceptive and antineoplasic properties. Its structural simplicity make it a cost-effective alternative, justifying further mechanistic investigations and the development of pharmaceutical formulations. Moreover, the protocols developed and standardized here make it possible to use Sarcoma-180 hypernociception model to evaluate the capacity of new antinociceptive molecules under conditions of cancer-related allodynia.

Flavonoid-Decorated Nano-gold for Antimicrobial Therapy Against Gram-negative Bacteria Escherichia coli

Nano-gold (Aunps) have emerged as promising options that exhibit unique features discrete from traditional materials suited for biomedical applications. Aunps were synthesized using flavonoid quercetin (Q) as reducing agent, and resultant nanoparticles were further conjugated with the flavonoid. The resultant nano-system was expected to perform a dual role as antibacterial and as antioxidant agent. Nano-gold surface plasmon peaks were recorded at 560 nm with size around 62 nm and having slim distribution pattern. Spherical particle with smooth surface was observed under TEM and AFM studies. TEM micrographs confirmed a homogeneous particle population of size around 30 nm. Quercetin association to nano-gold was corroborated through FTIR and EDAX analysis. Antioxidant nature of nano-gold prevented rapid oxidation of brilliant cresyl blue dye, in presence of sodium hypochlorite. Antimicrobial action of QuAunp was tested against Gram-negative bacteria Escherichia coli. Nano-gold designed produced a minimum inhibitory concentration of 7.6 μg/ml and minimum bactericidal concentration 10.5 μg/ml against E. coli. Further TEM analysis and membrane permeability studies revealed the impact of QuAunps on bacterial membrane leading to cell damage.

Effect of α-tocopherol on the physicochemical, antioxidant and antibacterial properties of levofloxacin loaded hybrid lipid nanocarriers

Non-toxic hybrid lipidic nanoparticles become a promising tool for enhanced lung delivery of levofloxacin in combination with antioxidant properties.

α-Phellandrene attenuates tissular damage, oxidative stress, and TNF-α levels on acute model ifosfamide-induced hemorrhagic cystitis in mice

Hemorrhagic cystitis (HC) is the major dose-limiting adverse effect of the clinical use ifosfamide (IFOS). The incidence of this side effect can be as high as 75%. Mesna has been used to reduce the risk of HC, although 5% of patients who get IFOS treatment may still suffer from HC. In previous studies, our group demonstrated that α-phellandrene (α-PHE) possesses anti-inflammatory activity, which opens the door for its study in the attenuation of HC. The objective of this study was to investigate the potential uroprotective effect of the α-PHE in the mouse model of IFOS-induced HC. In order to analyze the reduction of the urothelial damage, the bladder wet weight, hemoglobin content, and the Evans blue dye extravasation from the bladder matrix were evaluated. To investigate the involvement of neutrophil migration and lipid peroxidation and involvement of enzymatic and endogenous non-enzymatic antioxidants, the tissue markers myeloperoxidase (MPO), malondialdehyde, nitrite/nitrate (NOx), superoxide dismutase (SOD), and reduced glutathione (GSH) were evaluated. TNF-α and IL-1β were measured by ELISA immunoassay technique. The results show that pretreatment with α-PHE significantly reduced urothelial damage that was accompanied by a decrease in the activity of MPO, MDA, and NOx levels and prevention of the depletion of SOD and GSH in bladder tissues. In the assessment of cytokines, α-PHE was able to significantly reduce TNF-α level. However, it does not affect the activities of IL-1β. These data confirm that α-PHE exerts potent anti-inflammatory properties and demonstrates that α-PHE represents a promising therapeutic option for this pathological condition.