Identification of the Active Principle Conferring Anti-Inflammatory and Antinociceptive Properties in Bamboo Plant.

Early plants began colonizing earth about 450 million years ago. During the process of coevolution, their metabolic cellular pathways produced a myriad of natural chemicals, many of which remain uncharacterized biologically. Popular preparations containing some of these molecules have been used medicinally for thousands of years. In Brazilian folk medicine, plant extracts from the bamboo plant Guadua paniculata Munro have been used for the treatment of infections and pain. However, the chemical basis of these therapeutic effects has not yet been identified. Here, we performed protein biochemistry and downstream pharmacological assays to determine the mechanisms underlying the anti-inflammatory and antinociceptive effects of an aqueous extract of the G. paniculata rhizome, which we termed AqGP. The anti-inflammatory and antinociceptive effects of AqGP were assessed in mice. We identified and purified a protein (AgGP), with an amino acid sequence similar to that of thaumatins (~20 kDa), capable of repressing inflammation through downregulation of neutrophil recruitment and of decreasing hyperalgesia in mice. In conclusion, we have identified the molecule and the molecular mechanism responsible for the anti-inflammatory and antinociceptive properties of a plant commonly used in Brazilian folk medicine.

Antimicrobial peptide selection from Lippia spp leaf transcriptomes.

Antimicrobial resistance is considered a health issue worldwide. This public health problem underscores the importance of searching for new antimicrobial molecules with different mechanisms of action. Leaf transcriptomes were used to search and develop synthetic antimicrobial peptides derived from mRNA sequences. The in silico search for new AMPs from the L. rotundifolia and L. alba transcriptomes allowed the identification of 120 putative peptide mRNA sequences. Eight of them fitted into optimal parameters and were translated and chemically synthesized antimicrobial peptides. Their biological activity was tested in both Gram-positive and Gram-negative bacteria against which they exhibited antibacterial activity. However, they showed an important hemolytic effect. Afterwards, two active peptides showing bactericidal activity isolated from each plant transcriptome tested were modified and modeled in 11 new variants to increase their antimicrobial activity and stability and to reduce or eliminate their hemolytic effect from their original peptides. The La-AMP1 (MSLLERKLLMHFLRV) the original peptide from L. alba showed a 52% hemolytic effect while the derived peptide La-AMP1a (GLMKLLRELLHMFSRVG) had its hemolytic effect reduced to 0.5% at 128 µg.mL-1. Similarly, we observed that the original peptide from L. rotundifolia, Lr-AMP1 (MRIGLRFVLM), displayed a 71.5% hemolytic effect, while its derived peptide Lr-AMP1f (GSVLRAIMRMFAKLMG) showed 0% hemolysis at 128 µg.mL-1, tested with fresh human erythrocytes. Our results indicate a promising method for the search for novel antimicrobial agents with reduced or zero hemolytic effect, as well as prediction and optimization of their activity from plant mRNA libraries.