Chemical Composition, Preliminary Toxicity, and Antioxidant Potential of Piper marginatum Sensu Lato Essential Oils and Molecular Modeling Study.

The essential oils (OEs) of the leaves, stems, and spikes of P. marginatum were obtained by hydrodistillation, steam distillation, and simultaneous extraction. The chemical constituents were identified and quantified by GC/MS and GC-FID. The preliminary biological activity was determined by assessing the toxicity of the samples to Artemia salina Leach larvae and calculating the mortality rate and lethal concentration (LC50). The antioxidant activity of the EOs was determined by the DPPH radical scavenging method. Molecular modeling was performed using molecular docking and molecular dynamics, with acetylcholinesterase being the molecular target. The OES yields ranged from 1.49% to 1.83%. The EOs and aromatic constituents of P. marginatum are characterized by the high contents of (E)-isoosmorhizole (19.4-32.9%), 2-methoxy-4,5-methylenedioxypropiophenone (9.0-19.9%), isoosmorhizole (1.6-24.5%), and 2-methoxy-4,5-methylenedioxypropiophenone isomer (1.6-14.3%). The antioxidant potential was significant in the OE of the leaves and stems of P. marginatum extracted by SD in November (84.9 ± 4.0 mg TE·mL-1) and the OEs of the leaves extracted by HD in March (126.8 ± 12.3 mg TE·mL-1). Regarding the preliminary toxicity, the OEs of Pm-SD-L-St-Nov and Pm-HD-L-St-Nov had mortality higher than 80% in concentrations of 25 µg·mL-1. This in silico study on essential oils elucidated the potential mechanism of interaction of the main compounds, which may serve as a basis for advances in this line of research.

Variation in the Chemical Composition of Endemic Specimens of Hedychium coronarium J. Koenig from the Amazon and In Silico Investigation of the ADME/Tox Properties of the Major Compounds.

Four species of the genus Hedychium can be found in Brazil. Hedychium coronarium is a species endemic to India and Brazil. In this paper, we collected six specimens of H. coronarium for evaluation of their volatile chemical profiles. For this, the essential oils of these specimens were extracted using hydrodistillation from plant samples collected in the state of Pará, Brazil, belonging to the Amazon region in the north of the country. Substance compounds were identified with GC/MS. The most abundant constituent identified in the rhizome and root oils was 1,8-cineole (rhizome: 35.0-66.1%; root: 19.6-20.8%). Leaf blade oil was rich in ß-pinene (31.6%) and (E)-caryophyllene (31.6%). The results from this paper allow for greater knowledge about the volatile chemical profile of H. coronarium specimens, in addition to disseminating knowledge about the volatile compounds present in plant species in the Amazon region.

Phytochemical Profile and Herbicidal (Phytotoxic), Antioxidants Potential of Essential Oils from Calycolpus goetheanus (Myrtaceae) Specimens, and in Silico Study.

The essential oil (EO) of Calycolpus goetheanus (Myrtaceae) specimens (A, B, and C) were obtained through hydrodistillation. The analysis of the chemical composition of the EOs was by gas chromatography coupled with mass spectrometry CG-MS, and gas chromatography coupled with a flame ionization detector CG-FID. The phytotoxic activity of those EOs was evaluated against two weed species from common pasture areas in the Amazon region: Mimosa pudica L. and Senna obtusifolia (L.) The antioxidant capacity of the EOs was determined by (DPPH•) and (ABTS•+). Using molecular docking, we evaluated the interaction mode of the major EO compounds with the molecular binding protein 4-hydroxyphenylpyruvate dioxygenase (HPPD). The EO of specimen A was characterized by ß-eudesmol (22.83%), (E)-caryophyllene (14.61%), and γ-eudesmol (13.87%), while compounds 1,8-cineole (8.64%), (E)-caryophyllene (5.86%), δ-cadinene (5.78%), and palustrol (4.97%) characterize the chemical profile of specimen B's EOs, and specimen C had α-cadinol (9.03%), δ-cadinene (8.01%), and (E)-caryophyllene (6.74%) as the majority. The phytotoxic potential of the EOs was observed in the receptor species M. pudica with percentages of inhibition of 30%, and 33.33% for specimens B and C, respectively. The EOs' antioxidant in DPPH• was 0.79 ± 0.08 and 0.83 ± 0.02 mM for specimens A and B, respectively. In the TEAC, was 0.07 ± 0.02 mM for specimen A and 0.12 ± 0.06 mM for specimen B. In the results of the in silico study, we observed that the van der Waals and hydrophobic interactions of the alkyl and pi-alkyl types were the main interactions responsible for the formation of the receptor-ligand complex.

Chemical Composition and Preliminary Toxicity Evaluation of the Essential Oil from Peperomia circinnata Link var. circinnata. (Piperaceae) in Artemia salina Leach.

Peperomia Ruiz and Pav, the second largest genus of the Piperaceae, has over the years shown potential biological activities. In this sense, the present work aimed to carry out a seasonal and circadian study on the chemical composition of Peperomia circinata essential oils and aromas, as well as to evaluate the preliminary toxicity in Artemia salina Leach and carry out an in silico study on the interaction mechanism. The chemical composition was characterized by gas chromatography (GC/MS and GC-FID). In the seasonal study the essential oil yields had a variation of 1.2-7.9%, and in the circadian study the variation was 1.5-5.6%. The major compounds in the seasonal study were ß-phellandrene and elemicin, in the circadian they were ß-phellandrene and myrcene, and the aroma was characterized by the presence of ß-phellandrene. The multivariate analysis showed that the period and time of collection influenced the essential oil and aroma chemical composition. The highest toxicity value was observed for the essential oil obtained from the dry material, collected in July with a value of 14.45 ± 0.25 µg·mL-1, the in silico study showed that the major compounds may be related to potential biological activity demonstrated by the present study.

Chemical composition, antimicrobial and antifungal activity of Lippia Thymoide essential oil in oral pathogens

Aim: This study evaluated the chemical composition of Lippia thymoides (Lt) essential oil and its antimicrobial activity against fungal strains of Candida albicans (Ca) and Gram-negative bacteria Prevotella intermedia (Pi) and Fusobacterium nucleatum (Fn). Methods: Lt essential oil was obtained by hydrodistillation apparatus with a modified Clevenger extension. The chemical analysis was analyzed by gas phase chromatography and mass spectrometry on Shimadzu QP 2010 plus. Sample sensitivity evaluation was performed by ABHb-inoculum and culture plates were developed with triphenyltetrazolium chloride, also Fn and Pi samples analysis were in anaerobic environment and Ca sample analysis was performed in aerobic environment. The minimum inhibitory concentration (CIM) was determinated by microdilution in eppendorfs tubes. Results: The chemical analysis showed that Thymol (59,91%) is the main compound found in Lt essential oil, also other antifungal and antimicrobial agents were present γ-terpinene (8.16%), p-cymene (7.29%) and ß-caryophyllene (4.49%), Thymol is a central ingredient of many medicinal plants and has a potent fungicidal, bactericidal and antioxidant activity, it has been previously shown to have anti-inflammatory activity against Periodontal Disease (PD) cause can reduces prostanoids, interleukins, leukotrienes levels in periodontium. CIM result Pi was 6.5 µg/mL, Fn was 1.5 µg/mL and Ca was 0.19 µg/mL. Conclusion: The antimicrobial activity of L. thymoides, through the compound Thymol, has been shown promising potential against gram-negative periodontopathogenic bacteria and fungi whose therapeutic arsenal is still very restricted