# Inhibitory effect of deltorphin-II on development of malaria in Plasmodium berghei-infected mice

## TL;DR

This study shows that deltorphin-II, a peptide, can inhibit malaria development in mice, likely by activating the δ2 receptor.

## Contribution

The study demonstrates deltorphin-II's anti-malarial effect and suggests its mechanism via δ2 receptor activation.

## Key findings

- Deltorphin-II at 0.8 mg/kg/day significantly reduced parasitaemia in Plasmodium berghei-infected mice.
- The effect of deltorphin-II was blocked by pre-treatment with naltriben, indicating δ2 receptor involvement.
- Deltorphin-II shows potential as a new strategy for malaria treatment.

## Abstract

Drug resistance has been one of the main obstacles in the fight against vector-borne infectious diseases. Among these diseases, malaria represents a serious public health challenge, mainly in the tropics, where vector-favourable climates are a crucial factor. Each of the various anti-malarial drugs currently used against this disease, such as quinolones, sulphonamides and artemisinins are inadequate and new strategies are required. Peptides are known to have a huge number of biological effects. Antimicrobial peptides (AMPs) have been proven to be effective against bacterial, fungal and viral infections. This study explored the effect of the peptide ‘deltorphin-II’ in Plasmodium berghei-infected mice.

Mean percentage parasitaemia was calculated by studying infected erythrocytes after microscopic examination of 104 erythrocytes from infected mice on days 4, 7, 10, 14 and 21 after infection in all groups. Results. Deltorphin-II shows maximum activity at a dose of 0.8 mg/kg/day from day 4 to day 21. Pre-treatment of infected mice with naltriben abrogates the deltorphin-II-mediated effect.

Deltorphin-II inhibits the development of malaria, most probably via activation of the δ2 receptor.