Antibacterial constituents of Rumex nepalensis spreng and its emodin derivatives

Ruland Tchuinkeu Nguengang; Billy Toussie Tchegnitegni; Joel Eddy Terence Ateba; Georges Bellier Tabekoueng; Angelbert Fusi Awantu; Jean Jules Kezetas Bankeu; Jean Rodolphe Chouna; Celine Nguefeu Nkenfou; Norbert Sewald; Bruno Ndjakou Lenta

doi:10.1080/14786419.2022.2162894

Antibacterial constituents of Rumex nepalensis spreng and its emodin derivatives

Nat Prod Res. 2023 Nov-Dec;37(23):3935-3946. doi: 10.1080/14786419.2022.2162894. Epub 2022 Dec 30.

Affiliations

¹ Department of Organic Chemistry, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon.
² Department of Chemistry, Higher Teacher Training College, University of Yaoundé 1, Yaoundé, Cameroon.
³ Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon.
⁴ Department of Process Engineering, National Polytechnique School, University of Douala, Douala, Cameroon.
⁵ Department of Chemistry, Faculty of Science, The University of Bamenda, Bambili, Cameroon.
⁶ Department of Biology, Higher Teacher Training College, University of Yaoundé 1, Yaoundé, Cameroon.
⁷ Organic and Bioorganic Chemistry, Faculty of Chemistry, Bielefeld University, Bielefeld, Germany.

PMID: 36584290
DOI: 10.1080/14786419.2022.2162894

Abstract

The CH₂Cl₂-MeOH (1:1) extract of roots of Rumex nepalensis (Polygonaceae) displayed significant antibacterial activity against five bacterial strains with MICs (62.5-31.2 μg.mL^-1). The EtOAc soluble fraction displayed a significant activity against the same strains with MICs (31.2-3.9 μg.mL^-1). The purification of the EtOAc fraction yielded one new phenylisobenzofuranone derivative, berquaertiide (1), along with 19 known compounds (2-20). Their structures were elucidated based on the analysis of their NMR and MS data. All the isolated compounds were assessed for their antibacterial activity. Compound 2 was the most active against all the tested strains (15.7 to 1.9 μg.mL^-1), while compounds 3-7 displayed good activities on at least one of the tested strains. In addition, seven analogues (21-27) of compound 2 were prepared and further assessed for their antibacterial activity. Compounds 26 and 27 were most active than 2 against Salmonella enterica and Klebsiella pneumoniae with MIC (125 and 15.6 μg.mL^-1, respectively).

Keywords: Rumex nepalensis; antibacterial activity; emodin; phenylbenzofuranone; polygonaceae.

MeSH terms

Anti-Bacterial Agents / chemistry
Anti-Bacterial Agents / pharmacology
Bacteria
Emodin* / pharmacology
Microbial Sensitivity Tests
Plant Extracts / chemistry
Rumex* / chemistry

Substances

Emodin
Plant Extracts
Anti-Bacterial Agents