Describing auxin solid state intermolecular interactions using contact descriptors, shape property and molecular fingerprint: comparison of pure auxin crystal and auxin-TIR1 co-crystal

This work reports for the first time, the analysis of intermolecular interactions in crystal structures of auxin (Indole-3-acetic acid) crystallized as pure sample (Aux-A) or co-crystallized with transport inhibitor response 1 (Aux-B). Using crystal packing of pure auxin and a cluster of residues in a radius of 6 Å around this ligand in the transport inhibitor response 1 binding domain, various properties were calculated and mapped on the Hirshfeld surface (HS). The HSs of the two molecules are characterized by close parameters of volume, area, globularity, and asphericity revealing the efficiency of the considered cluster. The HS mapped over descriptors like de, di and dnorm showed red spots corresponding to hydrogen bonds contacts. In addition to the shape index and curvedness descriptors, the results highlight weak interactions stabilizing the auxin structures. The analyses of electrostatic potential, electron density, and deformation density maps confirm the slightly change in the electron donor and acceptor groups localization. Furthermore, the molecular fingerprint analyses revealed a notable discrepancy in the shape and percentage value of the various contacts. Decomposition of the fingerprint shows that the contributions of important contacts (H···H, H···O, and O···O) are higher in Aux-B than in Aux-A. Finally, the quantitative approach by the determination of the molecular interaction energies of the two structures in their respective crystallographic environment revealed that Aux-A is slightly more stabilized than Aux-B

Preliminary Phytochemical Screening and Antimicrobial Activity of the Hydroethanolic Extract of the Fruits of Solanum torvum (Swartz) (Solanaceae) Use as Vegetable in Togo

The fruits of Solanum torvum (Swartz), a vegetable-fruit, are used in traditional medicine in Togo in the treatment of infectious diseases and as an anti-anemic. This study then focused on the antimicrobial activity assessment of the hydroethanolic extract of these fruits in the interest of contributing to the valorization of this Togolese flora’s species. A hydroethanolic extraction (50 % - 50 %: v/v) was performed followed by preliminary phytochemical tests. Antimicrobial activity was determined on fourteen bacterial strains using the agar diffusion method. Qualitative phytochemical screening revealed the presence of alkaloids, reducing compounds, tannins, cardiac glycosides, flavonoids, coumarins, triterpenes, saponins, total carbohydrates and free quinones. The extract was active on the reference strains of S. aureus, E. coli, S. pneumoniae and P. aeruginosa. However, this activity was only observed on clinical strains of S. pneumoniae and P. aeruginosa. The extract showed MICs of 25 and 50 mg/ml and BMCs of 50 and 100 mg/ml respectively for S. pneumoniae and P. aeruginosa. The MBC/MIC ratio for these two strains was 2. These fruits would then have bacteriostatic activity on S. pneumoniae and P. aeruginosa. The antibacterial properties of the extract on these germs could justify the use of this plant in traditional medicine for the treatment of certain bacterial infections. Keywords: Solanum torvum, fruits, phytochemical compounds, antimicrobial activit