An unusual 2-O-glyceryl-glycosyl-γ-pyrone from Erigeron annuus (L.) with potential antifungal activity: in-vitro and in-silico study.

Phytochemical characterisation of the polar fraction of Erigeron annuus extract led to the isolation of glycerylerigeroside (1), a unique γ-pyrone derivative. Structure of 1 was decided by intensive study of NMR and mass spectra as 3-O-[4'-((1,3-dihydroxypropan-2-yl)oxy)-ß-D-glucopyranoside)]-4H-pyran-4-one, with uncommon glyceroxy side chain attached to 4' position of pyromeconic acid ß-D-glucopyranoside. Antimicrobial potential of 1 was tested against Staphylococcus aureus, Salmonella enterica, and Candida albicans. Compound 1 strongly inhibited growth of Candida albicans (MIC = 17.24 µM/disc), compared to fluconazole (MIC = 16.33 µM/disc). Meanwhile, it moderately inhibited the growth of Staphylococcus aureus (MIC = 71.84 µM/disc) and Salmonella enterica (MIC = 71.84 µM/disc), as compared with thiophenicol (MIC = 14.05 µM/disc) and (MIC = 14.05 µM/disc), respectively. The binding mode of 1 with the active site of sterol 14α-demethylase (CYP51) from Candida albicans (PDB ID: 5TZ1), in combination with fluconazole, was predicted by molecular docking study and supported the antifungal activity.

Secondary Metabolites Generated from Saussurea lappa and Ligusticum sinensis Essential Oils by Microwave-Assisted Hydrodistillation: in Silico Molecular Docking and in Vitro Antibacterial Efficacy.

In the current study, both the essential oil composition and biological activity of Saussurea lappa and Ligusticum sinensis were investigated by means of microwave-assisted hydrodistillation (MAHD) and characterized by Gas chromatography/mass spectrometry (GC/MS), whereas the antimicrobial efficiency of MAHD essential oils was examined against four pathogens: Staphylococcus aureus, Escherichia coli, Aspergillus niger, and Candida albicans responsible for microbial infections. The goal was to spot synergy and a favorable method that gives essential oils to possibly use as alternatives to common antimicrobial agents for the treatment of bacterial infections using a microdilution assay. S. lappa's 21 compounds were characterized by MAHD extraction. Sesquiterpene lactones (39.7 % MAHD) represented the major components, followed by sesquiterpene dialdehyde (25.50 % MAHD), while L. sinensis's 14 compounds were identified by MAHD extraction. Tetrahydroisobenzofurans (72.94 % MAHD) was the predominant compound class. S. lappa essential oil collection showed the strongest antimicrobial activity with MIC values of 16 µg/ml against all pathogens tested, while L. sinensis showed strong antibacterial activity and moderate antifungal activity with MIC values of 32 µg/ml and 500 µg/ml, respectively. The principal components of both oils, (velleral, eremanthin and neocnidilide), were docked into the bacterial histidine kinase (HK) and the fungal heat shock protein 90 (Hsp90).