# First-Time Identification of the PPAT Protein as a Novel Antibacterial Target: Antimicrobial and Antioxidant Insights from E. purpurea

## TL;DR

This study identifies a new antibacterial target, PPAT, using Echinacea purpurea extracts and shows chlorogenic acid's potential as an antibiotic.

## Contribution

First-time identification of PPAT as a novel antibacterial target inhibited by chlorogenic acid from E. purpurea.

## Key findings

- Chlorogenic acid from E. purpurea showed strong binding to PPAT via hydrogen bonds.
- PPAT inhibition by chlorogenic acid suggests its potential as an antibacterial therapy target.
- E. purpurea petal methanol extract exhibited highest antimicrobial activity against Pseudomonas aeruginosa.

## Abstract

Echinacea purpurea (Asteraceae)
is a perennial medicinal herb with immune-stimulating and anti-inflammatory
properties. In this study, the antioxidant and antibacterial properties
of the organs of the E. purpurea plant
were investigated, and significant amounts of total phenolic and total
flavonoid contents were detected in flower extracts. It was determined
that the DPPH% values of the water extract were higher than the values
of methanol extracts. It was observed that Fe3+ reduction
capacity increased as the concentration increased in all plant extracts.
The highest antimicrobial activity was determined to be against Pseudomonas aeruginosa (35 mm) and Klebsiella pneumonia (20 mm) at the petal (EpP)–methanol extract. In HPLC analysis of component-based
phenolic substances, protocatechuic acid, caffeic acid, coumaric acid,
chlorogenic acid, and ferulic acid were determined in the extracts.
The lowest protein–ligand binding energy (kcal/mol) was found
to be −9.6 kcal/mol in chlorogenic acid. Chlorogenic acid can
bind with PPAT’s T10­(B)­OG1, W12­(b), I127­(B)­O, and S129­(B)­OG
and P88­(B)­HN2, T10­(B)­N, F11­(b)­N, D12­(B)­N, S129­(B)­N, and K12­(B)­NZ amino
acid residues via hydrogen bonds. The evidence collected indicates
that chlorogenic acid inhibits phosphopantetheine adenylyltransferase
(PPAT), validating PPAT as a potential target for antibacterial therapy
for the first time. The development of selective inhibitors such as
chlorogenic acid of bacterial PPAT is promising for the discovery
of new antibiotics.