Obtaining and antimicrobial characterization of extracts from Tusca or Vachellia aroma located in Santiago del Estero.

CASTELLI, MARÍA VICTORIA; CARRERAS R.; PAEZ K.; DEPOMPA S.; HOLLMANN, AXEL; LÓPEZ, SILVIA NOELÍ; ANDREA C. CUTRÓ

Rosario

Congreso; LIX Reunion Annual de la Sociedad argentina de Invetsigaciones en Bioquímica y Biología Molecular (SAIB 2023); 2023

Sociedad de Bioquimica y Biología Molecular SAIB

Medicinal plants are still used in traditional and alternative medicine. They contain bioactive secondary metabolites such as alkaloids, flavonoids, steroids, terpenes, sesquiterpenes, diterpenes, phenolics and saponins. These substances are crucial in helping plants adjust to their changing environment and biotic and abiotic stressors. In this sense, plants represent a potential natural source of chemicals with pharmacological value, including potential antimicrobial agents. In the latter situation, they represent an alternative to traditional antibiotics for the treatment of clinical infections with pathogenic bacteria, resistant bacteria, multi-resistant bacteria and resistant forms such as biofilms that represent a serious health problem worldwide. In this context, Vachellia aroma (former name Acacia aroma Gill ex Hook. & Arn.) also known as Tusca, is a small and robust tree with alternate leaves, yellowish flowers whose fruit is made up of a legume found in the northwest, Cuyo and northeast regions of Argentina. The infusions and juices of this plant were reportedly used as an antiseptic, among other things. In this sense, previous in vitro studies have reported the antibacterial activity of its extracts. In this framework, ethanolic extracts were obtained from the leaves and flowers of different specimens located in Santiago del Estero, with a yield of 5–10%. Chemical profiles were determined by thin layer chromatography; as well as its antibacterial activity against Gram positive and Gram negative model bacteria. Bioautography assays of said flower and leaf extracts have shown chromatographic bands with antibacterial activity against Staphylococcus aureus and not against Escherichia coli. In addition, the minimum inhibitory and bactericidal concentrations (MIC and MBC) against S. aureus were determined. Most of the leaf extracts showed a MIC value of 2 mg/mL; except for one, which showed an MIC of 0.5 mg/mL and a MBC of 2 mg/mL. The latter was also able to inhibit the development of S. aureus biofilm from 72 h of formation at a sub-MIC concentration (0.25 mg/mL). However, the chemical profile of the leaf extracts were very similar to each other under the conditions evaluated. This would suggest that the variation in activity observed is probably due to different relative abundances of the main metabolites present. On the other hand, all of the flower extracts obtained from the different specimens have been shown to have a MIC value of 1 mg/mL. The findings suggest that the extracts obtained from Tusca or V. aroma located in Santiago del Estero represent a potential source of antimicrobial compounds, and further research into this matter is required.Key words: Tusca, Vachellia aroma, biofilm, antibacterial, extracts