The antioxidant activity of Trachyspermum ammi essential oil and thymol in murine macrophages

Molecular insights into binding of bioactive compounds from essential oil of Trachyspermum ammi with human programmed cell death protein 1

The human programmed cell death protein 1 (PD-1) is expressed on the surface of T cells and contributes significantly to tumor immunity. Herein, six major compounds (carvacrol, thymol, β-phellandrene, α-terpinene, myrcene D, and α-pinene) from Trachyspermum ammi were studied for their intermolecular interactions and stability against PD-1. All tested compounds displayed docking energy (-4.2 to -3.7 kcal/mol) with PD-1. The highest docking scores of -4.2 and -4.1 kcal/mol were recorded for carvacrol and thymol, respectively. Also, a 100 ns molecular dynamics simulation predicted the stability of carvacrol- and thymol-docked PD-1 complex. Maximum of < 30 Å and < 12 Å root-mean-square deviation were observed for carvacrol and thymol at the end of the 100 ns simulation with respect to protein (Cα atoms), indicating retention and displacement of carvacrol and thymol from the initial binding pocket, respectively. Moreover, the endpoint binding free energies support the higher binding affinity of carvacrol (-22.87 ± 5.52 kcal/mol) than thymol (-16.83 ± 1.30 kcal/mol). The equicrural states of the respective ligands were supported by the respective root mean square fluctuation, where no significant deviations in the atoms of the ligands were observed. These findings suggest that carvacrol and thymol inhibit the PD-1/PD-L1 axis.Communicated by Ramaswamy H. Sarma.

Assessment of the in Vitro Antimelanoma Potential of Lippia microphylla Cham (Verbenaceae) Essential Oil

Essential oils stand out among natural products for their complex composition, frequently described in the literature with a range of biological effects. This study evaluated the cytotoxic activity against several human cancer cell lines of essential oils extracted from the leaves of Lippia microphylla (EO-LM) Cham. (Verbenaceae). The melanoma cell line SK-MEL-28 was the most sensitive to the EO-LM, presenting an IC50 of 33.38±1.16 μg/mL. Afterward, the effects of EO-LM on the cell cycle, induction of apoptosis, and production of reactive oxygen species (ROS) were evaluated. We stated a significant increase in the sub-G1 population, indicating apoptosis, later confirmed by an increase of SK-MEL-28 cells labeled with Annexin V-FITC and by the formation of apoptotic bodies and membrane blebs, observed by confocal microscopy. Additionally, EO-LM reduced the production of ROS, indicating antioxidant activity. Therefore, EO-LM exhibits anti-melanoma activity in vitro, suggesting its potential as an anticancer agent.

In-Depth Study of Thymus vulgaris Essential Oil: Towards Understanding the Antibacterial Target Mechanism and Toxicological and Pharmacological Aspects

Questions have been raised apropos the emerging problem of microbial resistance, which may pose a great hazard to the human health. Among biosafe compounds are essential oils which captured consumer draw due to their multifunctional properties compared to chemical medication drugs. Here, we examined the chemical profile and the mechanism(s) of action of the Thymus vulgaris essential oil (TVEO) against a Gram-negative bacterium Salmonella enterica Typhimurium ATTCC 10028 (S. enterica Typhimurium ATTCC 10028) and two Gram-positive bacteria Staphyloccocus aureus ATCC 6538 (S. aureus ATCC 6538) and Listeria monocytogenes ATCC 19117 (L. monocytogenes ATCC 19117). Findings showed that TVEO was principally composed of thymol, o-cymene, and γ-terpinene with 47.44, 16.55, and 7.80%, respectively. Molecular docking simulations stipulated that thymol and β-sesquiphellandrene (a minor compound at 1.37%) could target multiple bacterial pathways including topoisomerase II and DNA and RNA polymerases of the three tested bacteria. This result pointed plausible impairments of the pathogenic bacteria cell replication and transcription processes. Through computational approach, the VEGA quantitative structure–activity relationship (QSAR) model, we revealed that among twenty-six TVEO compounds, sixteen had no toxic effects and could be safe for human consumption as compared to the Food and Drug Administration (FDA) approved drugs (ciprofloxacin and rifamycin SV). Assessed by the SwissADME server, the pharmacokinetic profile of all identified TVEO compounds define their absorption, distribution, metabolism, and excretion (ADME) properties and were assessed. In order to predict their biological activity spectrum based on their chemical structure, all TVEO compounds were subjected to PASS (Prediction of Activity Spectra for Substances) online tool. Results indicated that the tested compounds could have multiple biological activities and various enzymatic targets. Findings of our study support that identified compounds of TVEO can be a safe and effective alternative to synthetic drugs and can easily combats hazardous multidrug-resistant bacteria.

Breaking the challenge of polyherbal quality control using UV and HPLC fingerprints combined with multivariate analysis

INTRODUCTION

Traditional herbal medicines are mostly composed of more than one herb which act synergistically; hence, there is high demand for proper quality control methods to ensure the consistent quality of polyherbal formulations.

AIMS

Proposing a simple, reliable, and efficient method for the qualitative and quantitative analysis of a polyherbal product using multivariate analysis of ultraviolet-visible (UV-Vis) spectroscopy or HPLC-PDA data.

METHODOLOGY

An antiobesity formula consisting of equal proportions of Trachyspermum ammi, Cuminum cyminum, and Origanum majorana was prepared as well as spiked with one of each herb simultaneously, representing accepted and unaccepted samples. Full factorial design (2^k ) was applied to study the effect of temperature, sonication, and stirring time for extraction optimisation. The HPLC and UV spectral fingerprints were separately subjected to multivariate analysis. The soft independent modelling of class analogy (SIMCA) and partial least squares (PLS) models were developed to segregate the accepted from the unaccepted samples and to predict the herbal composition in addition to the thymol content in each sample.

RESULTS

The SIMCA^uv and SIMCA^hplc models showed correct discrimination between the accepted and unaccepted samples with excellent selectivity and sensitivity. The PLS^uv , PLS^hplc , and PLS^thym models showed excellent linearity and accuracy with R²  > 0.98, slope close to 1, intercept close to 0, low root mean square error of calibration (RMSEC), and root mean square error of prediction (RMSEP) (close to 0). On validation, the PLS models correctly predicted the quantity of the three herbs and thymol content with ±5% accuracy.

CONCLUSION

This study demonstrates the reliability and efficiency of HPLC and UV spectroscopy coupled with multivariate statistical analysis (MVA) for ensuring the consistency of polyherbal preparations.

Chemical Composition, Antioxidant, and Anti-Inflammatory Activity of Essential Oil from Omija (Schisandra chinensis (Turcz.) Baill.) Produced by Supercritical Fluid Extraction Using CO2

Schisandra chinensis (Turcz.) Baill., which is known as omija in South Korea, is mainly cultivated in East Asia. The present study aimed to investigate the chemical composition of essential oil from the omija (OMEO) fruit obtained by supercritical fluid extraction using CO₂ and to confirm the antioxidant and anti-inflammatory activity of OMEO using HaCaT human keratinocyte and RAW 264.7 murine macrophages. As a result of the chemical composition analysis of OMEO using gas chromatography-mass spectrometry, a total of 41 compounds were identified. The detailed analysis results are sesquiterpenoids (16), monoterpenoids (14), ketones (4), alcohols (3), aldehydes (2), acids (1), and aromatic hydrocarbons (1). OMEO significantly reduced the increased ROS levels in HaCaT keratinocytes induced by UV-B irradiation (p < 0.05). It was confirmed that 5 compounds (α-pinene, camphene, β-myrcene, 2-nonanone, and nerolidol) present in OMEO exhibited inhibitory activity on ROS production. Furthermore, OMEO showed excellent anti-inflammatory activity in RAW 264.7 macrophages induced by lipopolysaccharide. OMEO effectively inhibited NO production (p < 0.05) by suppressing the expression of the iNOS protein. Finally, OMEO was investigated for exhibition of anti-inflammatory activity by inhibiting the activation of NF-κB pathway. Taken together, OMEO could be used as a functional food ingredient with excellent antioxidant and anti-inflammatory activity.

Drying Effects on Chemical Composition and Antioxidant Activity of Lippia thymoides Essential Oil, a Natural Source of Thymol

Leaves of Lippia thymoides (Verbenaceae) were dried in an oven at 40, 50 and 60 °C and the kinetic of drying and the influence of the drying process on the chemical composition, yield, and DPPH radical scavenging activity of the obtained essential oils were evaluated. The composition of the essential oils was determined with gas chromatography-mass spectrometry and gas chromatography-flame ionization detection analyses. The influence of drying on the chemical composition of the essential oils of L. thymoides was evaluated by multivariate analysis, and their antioxidant activity was investigated via the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The Midilli model was the most appropriate to describe the behavior of drying kinetic data of L. thymoides leaves. Thymol was the major compound for all analyzed conditions; the maximum content was obtained from fresh leaves (62.78 ± 0.63%). The essential oils showed DPPH radical scavenging activity with an average of 73.10 ± 12.08%, and the fresh leaves showed higher inhibition (89.97 ± 0.31%). This is the first study to evaluate the influence of drying on the chemical composition and antioxidant activity of L. thymoides essential oils rich in thymol.

In vitro antioxidant and antidiabetic activity of essential oils encapsulated in gelatin-pectin particles against sugar, lipid and protein oxidation and amylase and glucosidase activity

The in vitro antioxidant and antidiabetic activities of Oliveria decumbens, Thymus kotschyanus, Trachyspermum ammi, and Zataria multiflora essential oils incorporated into gelatin-pectin composite were investigated. The gas chromatography-mass spectrometry characterization revealed that thymol (1.2%-86.4%), carvacrol (3.2%-52.4%), gamma-terpinene (0.0%-12.7%), para-cymene (3.2%-5.2%), geraniol (0.0%-14.5%), and spathulenol (0.0%-13.6%) are the major constituents of the essential oils. Gelatin-pectin composite incorporated with the essential oils exhibited acidic pH (2.40-3.04), low conductivity (265-278 µS/cm), low surface tension (19.0-23.5 mN/m), low Newtonian viscosity (23.7-28.5 mPa.s), negative zeta-potential (14.2-16.9 mV), and nanoscale particle size (313-336 nm). These rheological properties result in the production of globular gelatin-pectin nanoparticles with a size range of 500-700 nm. The FTIR spectra of gelatin-pectin and gelatin-pectin-essential oils to some extent were similar, suggesting the noncovalent interactions between them. Gelatin-pectin composite incorporated with the essential oils displayed antiglucose oxidation (130-150 µg/ml) antilipid peroxidation (120-130 µg/ml), antiprotein oxidation (150-168 µg/ml), and antiprotein glycation (145-170 µg/ml) as well as antiamylase (216-230 µg/ml), and antiglucosidase (212-238 µg/ml) activity. The essential oils strongly improved the antioxidant capacity of the gelatin-pectin composite so strongly which can be recommended as a natural compound for oxidative stress management.