Identification of Peptides in the Leaves of <i>Bauhinia rufescens</i> Lam (Fabaceae) and Evaluation of Their Antimicrobial Activities Against Pathogens for Aquaculture
Yves Oscar Ditchou Nganso, Lazare Sidjui Sidjui, Ange Gabrielle à Ngnoung Amang, Alex Doutsing Kahouo, Kombo Abah, Hermann Fomena, Mamoudou Hamadou
Abstract
Bauhinia rufescens Lam is a Cameroonian medicinal plant belonging to the Fabaceae family. It is used by indigenous people in the treatment of gout, diarrhea, dysentery, diabetes, malaria. It has antibacterial, antiparasitic, antifungal and antioxidant potential. The aim of this study is to identify peptides from the leaves of Bauhinia rufescens and assess their antimicrobial activities against certain pathogens in aquaculture. Previous studies have showed the antimicrobial properties of liquid extract on water against human pathogenic bacteria and the influenza virus. These properties have been mainly attributed to phenolic compounds. Phenolic compounds play an important role in human health due to their various pharmacological activities as anti-inflammatory, anti-allergic, antimicrobial, antiviral, and vasodilatory. However, other plant defense molecules, such as antimicrobial peptides (AMPs), may be present. In this work, we studied peptide extracts from the leaves of Bauhinia rufescens Lam. Mass spectrometry and analysis of peptides gave 3 to 3.6 kDa, among them, peptides rich in cysteine were identified with antimicrobial activity against various Gram-negative bacteria, including recurrent pathogens of Cameroonian aquaculture. In addition, membrane bleeding on the bacterial surface after exposure to the cyclotide was visualized by SEM microscopy and the SYTOX Green permeabilization test showed the ability to disturpt the bacterial membrane. The results obtained show that the peptides exert their action by destroying the bacterial membrane. Based on the results obtained, the medicinal value of this plant could be attributed to the presence of secondary metabolites.