Exploring of bioactive compounds in essential oil acquired from the stem and root derivatives of Hypericum triquetrifolium callus cultures

Profile and in silico analysis of metabolite compounds of the endophytic fungus Alternaria alternata K-10 from Drymoglossum piloselloides as antioxidants and antibacterials

Endophytic fungi are known for producing secondary metabolites with valuable biological activities, including antiviral, anticancer, antibacterial, and antioxidant properties. This study aims to evaluate an endophytic fungus from Dragon Scales leaves (Drymoglossum piloselloides) and analyze its metabolites as antioxidants and antibacterials. In this study, an endophytic fungus was isolated from the leaves of Dragon Scales (D. piloselloides) and identified using molecular analysis of the Internal Transcribed Spacer (ITS) ribosomal RNA locus. The fungus was authenticated as Alternaria alternata strain K-10. Crude extracts were obtained using n-hexane and ethyl acetate and analyzed via GC-MS Shimadzu-QP 2010 Ultra with NIST spectral library. Antibacterial activity was observed against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa using the paper disc method, showing inhibition zones of 8.7-9.3 mm and 8.8-9.4 mm for ethyl acetate and n-hexane extracts, respectively. Ethyl acetate and n-hexane extracts exhibited strong antioxidant potential against 2,2-diphenyl-1-picrylhydrazil (DPPH) radical (IC50 values of 50.99 μg mL-1 and 74.44 μg mL-1, respectively). GC-MS analysis revealed 40 compounds in both extracts, some of which, including 2-ethylhexyl ester benzoic acid, benzo-b-dihydropyran-6-hydroxy-4-4-5-7-8-pentamethyl, diethyl phthalate, and octadecanoic acid, were identified through in silico analysis and found to possess antioxidant properties. These findings hold implications for potential applications of the plant and its biological constituent to be developed as lead compounds in the medical sector.

Identification of terpenoids as potential inhibitors of SARS-CoV-2 (main protease) and spike (RBD) via computer-aided drug design

The scientific community has been faced with a major challenge in the fight against the SARS-CoV-2 virus responsible for the COVID-19 pandemic, due to the lack of targeted antiviral drugs. To address this issue, we used an in silico approach to screen 23 natural compounds from the terpenoid class for their ability to target key SARS-CoV-2 therapeutic proteins. The results revealed that several compounds showed promising interactions with SARS-CoV-2 proteins, specifically the main protease and the spike receptor binding domain. The molecular docking analysis revealed the importance of certain residues, such as GLY143, SER144, CYS145 and GLU166, in the main protease of the SARS-CoV-2 protein, which play a crucial role in interactions with the ligand. In addition, our study highlighted the importance of interactions with residues GLY496, ARG403, SER494 and ARG393 of the spike receptor-binding domain within the SARS-CoV-2 protein. ADMET and drug similarity analyses were also performed, followed by molecular dynamics and MM-GBSA calculations, to identify potential drugs could be repurposed to combat COVID-19. Indeed, the results suggest that certain terpenoid compounds of plant origin have promising potential as therapeutic targets for SARS-CoV-2. However, additional experimental studies are required to confirm their efficacy as drugs against COVID-19.Communicated by Ramaswamy H. Sarma.

Hypericum Essential Oils—Composition and Bioactivities: An Update (2012–2022)

Hypericum genus, considered to comprise over 500 species that exhibit cosmopolitan distribution, has attracted human interest since ancient times. The present review aims to provide and summarize the recent literature (2012–2022) on the essential oils of the title genus. Research articles were collected from various scientific databases such as PubMed, ScienceDirect, Reaxys, and Google Scholar. Scientific reports related to the chemical composition, as well as the in vitro and in vivo pharmacological activities, are presented, also including a brief outlook of the potential relationship between traditional uses and Hypericum essential oils bioactivity.

Analysis of Microbial Community, Volatile Flavor Compounds, and Flavor of Cigar Tobacco Leaves From Different Regions

Despite the booming international trade in cigar tobacco leaves (CTLs), the main characteristics of tobacco leaves from different producing areas are rarely reported. This study aimed to characterize the microbial community, volatile flavor compounds (VFCs), and flavor of CTLs from four famous cigar-producing areas, including Dominica, Brazil, Indonesia, and China. High-throughput sequencing results showed that the dominant genera in CTLs were Staphylococcus, Pseudomonas, Aspergillus, Sampaiozyma, and Alternaria. Sensory analysis revealed that Indonesian and Chinese CTLs were characterized by leathery, peppery, and baked aroma. Brazilian CTLs were dominated by caramel and herb aroma. Dominican CTLs had aromas of milk, fruity, sour, cream, flower, nutty, and honey. Supplemented with the determination of volatile flavor compounds (VFCs), the flavor of CTLs could be scientifically quantified. Most of these VFCs were aldehydes and ketones, and 20 VFCs showed significant differences in CTLs from different regions. The microbial community, VFCs, and flavor of CTLs vary widely due to geographic differences. Network analysis revealed the microbial community was closely related to most VFCs, but the relationships between the fungal community and VFCs were less than the bacterial community, and most of them were negative. Furthermore, it also found that the bacterial community had a greater contribution to the flavor of CTLs than the fungal community. This study obtained essential information on CTLs, which laid a foundation for deeply excavating the relationship between microbes and VFCs and flavor, and establishing a tobacco information database.

Production of isoquinoline alkaloids from the in vitro conserved Fumaria parviflora and their in vitro wound healing activity

Fumaria parviflora Lam. is a rare herbaceous annual plant, with a well-known richness of isoquinoline alkaloids. It is threaten due to expansion on construction in the Mediterranean coastal region. We established callus culture protocol aiming at in vitro conservation of this plant. Murashige and Skoog medium fortified with a combination of 0.5 mg/l 1-naphthaleneacetic acid (NAA) and 1 mg/l 6-benzylaminopurine (BAP) showed optimal callus initiation. UPLC-MS/MS profiling revealed that calli induced on the tested media were able to produce isoquinoline alkaloids. Eight alkaloids were isolated from aerial parts of the cultivated plant and their cytotoxicity against Human skin fibroblast (HF) and wound healing activity using in vitro scratch assay were determined. Structural similarity between the isolated alkaloids enabled structure activity relationship (SAR) study. Sanguinarine displayed the potent activity compared to the other alkaloids. Iminium ion and methylenedioxy potentiated the activity.