Title : Antimicrobial potential of Solanum psychotrioides Dunal from Chocó against Staphylococcus aureus and Staphylococcus epidermidis
Abstract:
Antimicrobial resistance among skin-associated opportunistic pathogens, including Staphylococcus aureus and Staphylococcus epidermidis, limits the effectiveness of conventional treatments and highlights the need to identify new antimicrobial agents. In this context, Solanum psychotrioides, a Solanaceae species from the Colombian Chocó region, represents a promising source of bioactive compounds, supported by the region’s exceptional biological and ethnopharmacological diversity. This study aimed to evaluate the in vitro antimicrobial activity of an ethanolic extract of Solanum psychotrioides Dunal, collected in Chocó, Colombia, against reference strains of Staphylococcus aureus and Staphylococcus epidermidis, and to identify its major secondary metabolites. The crude extract was obtained by ethanolic maceration. Antibacterial activity against reference strains of S. aureus ATCC 25923 and S. epidermidis ATCC 12228 was evaluated by broth microdilution. Minimum inhibitory concentrations (MICs) were determined, and concentration–response data were used to calculate MIC?? values. The extract was fractionated by vacuum liquid chromatography (VLC) and flash chromatography, and isolated constituents were characterized by nuclear magnetic resonance spectroscopy. Our findings demonstrate that the ethanolic extract possesses moderate but notable inhibitory activity against both staphylococcal species exhibiting a MIC below 400 mg/L and a MIC50 inferior to 60 mg/L for each bacterium. Preliminary chemical analysis of the four fractions obtained from VLC indicated that dichloromethane fraction was the one with the highest activity against both strains. In this fraction, two saponin-like metabolites with a steroidal nucleus were predominant, which correlates with other reports of the presence of saponin-like metabolites in the family Solanaceae. This finding suggest that these compounds may be the bioactive candidates responsible for the observed antimicrobial effect of the extract. Collectively, these results position S. psychotrioides as a promising source of lead compounds for the development of novel anti-staphylococcal agents, warranting further investigation into its mechanism of action and in vivo applicability. Nevertheless, it is critical to acknowledge that these preliminary findings represent an early stage in a long translational pipeline, where future studies on cytotoxicity, pharmacokinetics, and formulation development will be essential to translate this promising bioactivity into tangible therapeutic solutions. This study was funded by the Sistema General de Regalías under project BPIN 2023000100047. The collection of plant material and access to genetic resources and their derived products were covered by Contract No. 121 of 22 January 2016 and Otrosí No. 21, signed between the Ministerio de Ambiente y Desarrollo Sostenible and the Universidad Nacional de Colombia, as well as by the amnesty established under Article 6 of Ley 1955 de 2019.
