Abietane diterpenoid salvipisone: Structure elucidation, conformational analysis, and antimicrobial activity

• Published in: Journal of molecular structure 2025-02, Vol.1321, p.139807, Article 139807
• Main Authors: Dekić, Milan S., Gusinac, Amina M., Jeremić, Svetlana R., Jakovljević, Violeta D., Plojović, Samira A., Jovanović, Dijana, Radulović, Niko S.
• Format: Article
• Language: English
• Subjects: Antimicrobial activity; Conformational analysis; Molecular docking; Salvia aethiopis L; Salvipisone; Structure elucidation
• ISSN: 0022-2860
• DOI: 10.1016/j.molstruc.2024.139807

•Salvipisone, an abietane diterpenoid, was isolated from Salvia aethiopis L.•Its structure was elucidated using a combination of spectroscopic methods.•An analysis revealed discrepancies with previously reported NMR data of salvipisone.•Salvipisone demonstrated significant efficacy against tested Gram-positive bacteria.•In silico studies suggested significant potential for inhibiting the enzyme gyrase. Salvipisone, an abietane diterpenoid, was isolated from the roots of Salvia aethiopis L. using a combination of chromatographic separation techniques. Its structure was elucidated employing a variety of spectroscopic methods, including ultraviolet (UV), infrared (IR), 1D and 2D nuclear magnetic resonance (NMR), and mass spectrometry. A comprehensive analysis of experimental 1D and 2D NMR data, incorporating 1H iterative full spin analysis and higher-order multiplet simulation, revealed discrepancies with previously reported NMR data for this compound. Detailed examination of the 1H NMR spectrum's spin-spin coupling structure provided insights into the relative populations of the three staggered conformers around the C12–C13 bond at room temperature. The conformer populations were determined using the relationship between the experimental values for vicinal coupling constants and the estimated ones for the preferred staggered conformers, yielding a ratio of approx. 80:4:16 for anti, gauche, and gauche′-conformers, respectively. Possible reasons for the observed unevenly populated staggered conformers were also discussed. The antimicrobial activity of salvipisone was evaluated using in vitro and in silico methods. In vitro antimicrobial assays demonstrated that salvipisone exhibited the highest inhibitory effect against Staphylococcus aureus ATCC and Enterococcus faecalis ATCC (MIC = 3.125 μg/mL), followed by Bacillus subtilis ATCC (MIC = 6.25 μg/mL). In contrast, concentrations above 100 μg/mL were necessary to inhibit Escherichia coli ATCC and Klebsiella pneumoniae ATCC. In silico studies suggested that salvipisone, particularly its keto form, has significant potential for inhibiting the enzyme gyrase, highlighting its mechanism of antimicrobial action. Our findings highlight the promising antimicrobial and inhibitory properties of salvipisone, particularly against Gram-positive bacteria such as S. aureus. [Display omitted]