Antibacterial activity of Barbatimão (Stryphnodendron adstringens) against Staphylococcus aureus: in vitro and in silico studies.

We evaluated the activity of the aqueous fraction and the ethyl acetate fraction of Stryphnodendron adstringens against Staphylococcus aureus and proposed their mechanism of action. The antibacterial activity of S. adstringens fractions was evaluated against S. aureus and the cell targets were rated by docking. The fractions showed moderate antibacterial activity against S. aureus without toxicity on two mammalian cell lines. They also showed synergistic antibacterial activity with tannic acid (TA). In silico assays indicated FabG, FabZ and FabI as probable targets. The metabolic pathway for fatty acid biosynthesis in S. aureus was affected by components of S. adstringens. The synergistic effect when combining TA with S. adstringens fractions suggests a natural alternative to S. aureus control. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study describing the possible targets of action of Stryphnodendron adstringens on Staphylococcus aureus. Molecular dynamics simulations showed that the components of S. adstringens affected the metabolic pathway for fatty acid biosynthesis (FAS II) in S. aureus, inhibiting the FabI, FabG and FabZ enzymes. As tannic acid (TA) is a known inhibitor of some targets identified, we showed synergistic antibacterial activity of S. adstringens in combination with TA. This combination did not show toxicity against HaCaT and Vero cells and based on all these results we suggest that S. adstringens can be a natural and sustainable alternative to S. aureus control.

Conserved baculoviral ORFs 10 and 14 from Bombyx mori multiple nucleopolyhedrovirus.

ORFs 10 and 14 from Bombyx mori multiple nucleopolyhedrovirus (BmMNPV) were amplified, cloned and sequenced. Nucleotide analysis of these genes and those of other baculoviruses showed that these genes are highly conserved. The p10 protein from BmMNPV ORF10 has 70 amino acid residues similar to that of the four other known BmNPV strains. The BmMNPV ORF14 alignment showed a higher identity with the nucleopolyhedrovirus ORF14 from the baculovirus BmNPV and from Autographa californica multiple nucleopolyhedrovirus. The BmMNPV ORF14 protein has a putative transmembrane domain in the C-terminal region, which is similar to that of other baculoviruses. A phylogenetic analysis showed that BmMNPV ORF14 protein has higher similarity with BmNPV ORF14 and ORF23 of A. californica multicapsid nucleopolyhedrovirus (Ac23). We conclude that proteins produced by ORFs 10 and 14 from BmNPV and BmMNPV are highly conserved in NPVs and MNPVs. The high degree of conservation among members of these genera indicates the importance of these proteins, which could mean an important function that is active throughout the infection cycle.