Essential oil composition of Senecio graciliflorus DC: comparative analysis of different parts and evaluation of antioxidant and cytotoxic activities

Effect of Industrial Pollution in Puchuncaví Valley on the Medicinal Properties of Senecio fistulosus Poepp. ex Les (Asteraceae): Content of Phytoconstituents and Their Antioxidant and Cytotoxic Activities

Senecio fistulosus, an endemic plant in Chile, is highly regarded for its medicinal properties and is popular in alternative medicine. It thrives even in polluted areas, like Puchuncaví Valley, Chile. Therefore, the study aimed to assess the impact of industrial pollution in Puchuncaví Valley, Chile, on the phytoconstituent content, as well as the antioxidant and cytotoxic activities, of S. fistulosus. Phenols, flavonoids, and anthraquinones content were measured, alongside the assessment of antioxidant activities. Additionally, a GC-MS analysis was conducted to profile the phytoconstituents, while the cytotoxic potential was evaluated in HT-29 and MCF-7 and cell line non-tumorigenic MCF-10. The Wild sample exhibited a greater concentration of phytoconstituents (0 to 169.48 mg·L-1) compared to the Commercial control (0 to 95.38 mg·L-1), directly correlating with its antioxidant activity. While the Wild species showed cytotoxic activity, the Commercial control demonstrated cytotoxic effects on MCF-10 and MCF-7. Noteworthy compounds identified were hexadecanoic acid (12.76 to 19.57% relative area) and (Z,Z,Z)-9,12,15-octadecatrienoic acid (18.36% relative area), with anticancer properties. In conclusion, the abiotic stress experienced by S. fistulosus led to higher phytoconstituent content and improved antioxidant activity when contrasted with the Commercial control. The Commercial species showed increased cytotoxic activity against both tumorigenic and non-tumorigenic cell lines.

Analysis of Streptomyces Volatilomes Using Global Molecular Networking Reveals the Presence of Metabolites with Diverse Biological Activities

Streptomyces species produce a wide variety of specialized metabolites, some of which are used for communication or competition for resources in their natural environments. In addition, many natural products used in medicine and industry are derived from Streptomyces, and there has been interest in their capacity to produce volatile organic compounds (VOCs) for different industrial and agricultural applications. Recently, a machine-learning workflow called MSHub/GNPS was developed, which enables auto-deconvolution of gas chromatography-mass spectrometry (GC-MS) data, molecular networking, and library search capabilities, but it has not been applied to Streptomyces volatilomes. In this study, 131 Streptomyces isolates from the island of Newfoundland were phylogenetically typed, and 37 were selected based on their phylogeny and growth characteristics for VOC analysis using both a user-guided (conventional) and an MSHub/GNPS-based approach. More VOCs were annotated by MSHub/GNPS than by the conventional method. The number of unknown VOCs detected by the two methods was higher than those annotated, suggesting that many novel compounds remain to be identified. The molecular network generated by GNPS can be used to guide the annotation of such unknown VOCs in future studies. However, the number of overlapping VOCs annotated by the two methods is relatively small, suggesting that a combination of analysis methods might be required for robust volatilome analysis. More than half of the VOCs annotated with high confidence by the two approaches are plant-associated, many with reported bioactivities such as insect behavior modulation. Details regarding the properties and reported functions of such VOCs are described. IMPORTANCE This study represents the first detailed analysis of Streptomyces volatilomes using MSHub/GNPS, which in combination with a routinely used conventional method led to many annotations. More VOCs could be annotated using MSHub/GNPS as compared to the conventional method, many of which have known antimicrobial, anticancer, and insect behavior-modulating activities. The identification of numerous plant-associated VOCs by both approaches in the current study suggests that their production could be a more widespread phenomenon by members of the genus, highlighting opportunities for their large-scale production using Streptomyces. Plant-associated VOCs with antimicrobial activities, such as 1-octen-3-ol, octanol, and phenylethyl alcohol, have potential applications as fumigants. Furthermore, many of the annotated VOCs are reported to influence insect behavior, alluding to a possible explanation for their production based on the functions of other recently described Streptomyces VOCs in dispersal and nutrient acquisition.

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.

Neuroprotective activity of natural products isolated from Senecio graciliflorus DC against corticosterone-induced impairment in SH-SY5Y cells

Senecio graciliflorus DC root extract was studied for secondary metabolite composition following the bioactivity-guided isolation technique. The ethyl acetate extract of Senecio graciliflorus root yielded nine chemical constituents: 3,4-di-tert-butyl toluene, stigmasterol, β-sitosterol, 2β-(angeloyloxy)furanoeremophilane, gallic acid, 2β-{[(Z)-2-hydroxymethylbut-2-enoyl]oxy}furanoeremophilane, 1-hydroxypentan-2-yl-4-methylbenzoate, sarcinic acid, and sitosterol 3-O-β-D-glucopyranoside. The structures of the chemical constituents were elucidated on the basis of spectral data analysis in the light of literature. All the compounds are being reported for the first time from this plant. The isolated constituents were screened for neuroprotective effects against corticosterone-induced impairment in neuroblastoma cell lines (SH-SY5S cells). The viability of SH-SY5S cells was determined using MTT assay. Among various isolated compounds, three natural products (sarcinic acid, gallic acid, and β-sitosterol) displayed robust neurotropic activity. The compounds increased neuronal cell survival in differentiated neuroblastoma cells (SH-SY5Y) from high-dose corticosterone (400 µM)-induced cell death. All the three constituents showed maximum AKT/ERK pathway activation at 20 µM concentration. The studies are aimed to explore small molecules for treating neurodegeneration underlying various neurological disorders to restore neuronal cell plasticity.

Secondary metabolites (essential oils) from sand-dune plants induce cytotoxic effects in cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Despite advances in modern therapeutic strategies, cancer remains the second leading cause of death worldwide. Therefore, there is a constant need to develop more efficient anticancer targeting strategies. The anticancer therapeutic proprieties of medicinal plants and their bioactive compounds have been reported for several years, making natural extracts and/or compounds derived from these a promising source of novel anticancer agents. Sand dune plants are subjected to severe environmental stresses, leading to the development of adaptations, including the production of secondary metabolites with a wide range of bioactivities, such as: anti-inflammatory, analgesic, antiseptic, hypoglycaemic, hypotensive, antinociceptive, antioxidant and anticancer.

AIM OF THE STUDY

The anticancer potential of sand dune plants remains under-investigated, so this research describes the characterisation of the composition of bioactive EOs from sand-dune plants of Peniche (Portugal), and assessment of their activity in vitro and potential mechanism of action.

MATERIALS AND METHODS

EOs were extracted from six sand-dune species of plants from Peniche sand dunes: Crithmum maritimum L., Seseli tortuosum L., Artemisia campestris subsp. maritima (DC.) Arcang., Juniperus phoenicea var. turbinata (Guss.) Parl., Otanthus maritimus (L.) Hoffmanns. & Link, and Eryngium maritimum L.. EOs composition was fully characterised chemically using Gas Chromatography-Mass Spectrometry (GC-MS). The assessment of anticancer activity and mechanism of action was performed in vitro using breast and colorectal cancer 2D and 3D spheroid cell line models, through cell proliferation assay, western blotting analysis, and cell cycle analysis.

RESULTS

EOs from the majority of the species tested (S. tortuosum, A. campestris subsp. maritima, O. maritimus, and E. maritimum) were mainly composed by hydrocarbon compounds (sequisterpenes and monoterpenes), showing antiproliferative activity in both 2D and 3D models. EO extracted from S. tortuosum and O. maritimus were identified as having the lowest IC₅₀ values for both cell lines when compared with the other species tested. Furthermore, this antiproliferative activity was associated with increased p21 expression and induction of apoptosis.

CONCLUSIONS

The present study suggests that EOs extracted from S. tortuosum and O. maritimus present promising cytotoxic properties. Further evaluation of the extracts and their key components as potential anticancer agents should therefore be explored.

Senecio brasiliensis impairs eclosion rate and induces apoptotic cell death in larvae of Drosophila melanogaster

Senecio brasilienis (Spreng) Less., is a species native from Brazil, popularly known as "Maria mole", and known to induce hepatotoxicity due to its high content of Pyrrolizidine alkaloids. Despite its toxicity, this plant is widely used in Brazilian folk medicine. Considering the antagonizing effects described for S. brasiliensis, we describe here molecular markers involved in the toxicity of hydroalcoholic extract from leaves of S. brasiliensis (HESB) in Drosophila melanogaster. Phytochemical analysis of HESB revealed the presence of phenolic acids and flavonoids. A significant antioxidant potential against ABTS⁺ and DPPH radical was found in parallel. Ingestion of extract did not alter the survival and locomotor activity of adult flies. However when ingested along the larval developmental phase, the eclosion rate of flies was interrupted at higher concentration of extract. To comprehend this phenomenon several analysis were conducted in larvae. HESB stimulated activity of antioxidant enzymes SOD and GST, and increased GSH/GSSG ratio and ROS production. Additionally, HESB caused a significant decrease of cell viability. The mRNA expression of Nrf2, TrxR, CAT, Drice and Dilp6 were also significantly up-regulated. HESB caused significant decrease on the phosphorylation of MAPKs and AKT. In parallel, PARP cleavage and caspases 3/7 activity were stimulated. In addition, glucose, glycogen and triglycerides levels were decreased. Taken together our study depicts a disruption in the eclosion of D. melanogaster possibly attributed to the inhibition of kinases implied in developmental process, energetic demand and induction of apoptotic cell death process.

Pharmacological Potential of Phylogenetically Diverse Actinobacteria Isolated from Deep-Sea Coral Ecosystems of the Submarine Avilés Canyon in the Cantabrian Sea

Marine Actinobacteria are emerging as an unexplored source for natural product discovery. Eighty-seven deep-sea coral reef invertebrates were collected during an oceanographic expedition at the submarine Avilés Canyon (Asturias, Spain) in a range of 1500 to 4700 m depth. From these, 18 cultivable bioactive Actinobacteria were isolated, mainly from corals, phylum Cnidaria, and some specimens of phyla Echinodermata, Porifera, Annelida, Arthropoda, Mollusca and Sipuncula. As determined by 16S rRNA sequencing and phylogenetic analyses, all isolates belong to the phylum Actinobacteria, mainly to the Streptomyces genus and also to Micromonospora, Pseudonocardia and Myceligenerans. Production of bioactive compounds of pharmacological interest was investigated by high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) techniques and subsequent database comparison. Results reveal that deep-sea isolated Actinobacteria display a wide repertoire of secondary metabolite production with a high chemical diversity. Most identified products (both diffusible and volatiles) are known by their contrasted antibiotic or antitumor activities. Bioassays with ethyl acetate extracts from isolates displayed strong antibiotic activities against a panel of important resistant clinical pathogens, including Gram-positive and Gram-negative bacteria, as well as fungi, all of them isolated at two main hospitals (HUCA and Cabueñes) from the same geographical region. The identity of the active extracts components of these producing Actinobacteria is currently being investigated, given its potential for the discovery of pharmaceuticals and other products of biotechnological interest.