The bioprofiling of antibacterials in olive leaf extracts via thin layer chromatography-effect directed analysis (TLC-EDA)

Snezana Agatonovic-Kustrin; Vladimir Gegechkori; David W Morton; Joseph Tucci; Ehtesham U R Mohammed; Heng Ku

doi:10.1016/j.jpba.2022.114916

The bioprofiling of antibacterials in olive leaf extracts via thin layer chromatography-effect directed analysis (TLC-EDA)

J Pharm Biomed Anal. 2022 Sep 20:219:114916. doi: 10.1016/j.jpba.2022.114916. Epub 2022 Jun 27.

Authors

Snezana Agatonovic-Kustrin¹, Vladimir Gegechkori², David W Morton³, Joseph Tucci⁴, Ehtesham U R Mohammed⁴, Heng Ku⁴

Affiliations

¹ Department of Pharmaceutical and Toxicological Chemistry named after Arzamastsev of the Institute of Pharmacy, I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow 119991, Russia; Department of Pharmacy and Biomedical Sciences, La Trobe University, Edwards Rd, Bendigo 3550, Australia. Electronic address: s.kustrin@latrobe.edu.au.
² Department of Pharmaceutical and Toxicological Chemistry named after Arzamastsev of the Institute of Pharmacy, I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow 119991, Russia.
³ Department of Pharmaceutical and Toxicological Chemistry named after Arzamastsev of the Institute of Pharmacy, I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow 119991, Russia; Department of Pharmacy and Biomedical Sciences, La Trobe University, Edwards Rd, Bendigo 3550, Australia.
⁴ Department of Pharmacy and Biomedical Sciences, La Trobe University, Edwards Rd, Bendigo 3550, Australia.

PMID: 35809514
DOI: 10.1016/j.jpba.2022.114916

Abstract

In this study, effect-directed analysis (EDA) (i.e. TLC hyphenated with an in situ MTT (3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide) antimicrobial assay), was used for screening and identification of antimicrobials in olive leaf extract. EDA detected that the same compounds exhibited significant antimicrobial activity against bacterial species of the genera Enterococcus (E. faecalis), Escherichia (E. coli), Streptococcus (S. mutans) and Staphylococcus (S. aureus). Flash chromatography-fractionation was used to isolate antimicrobial compounds in olive leaf extract. The active compounds were identified as maslinic acid and oleanolic acid by comparing R_F values of the detected active bands with the standard reference materials, with identity confirmed with NMR and ATR-FTIR spectroscopy. Maslinic and oleanolic acids were tested on the E. faecalis strain (which displayed the highest sensitivity in the MTT assay) to determine their inhibiting concentration 50% (IC₅₀) and minimum bactericidal concentrations.

Keywords: Antimicrobial; Maslinic acid; Oleanolic acid; Olive leaf extracts.

MeSH terms

Anti-Bacterial Agents / chemistry
Anti-Bacterial Agents / pharmacology
Anti-Infective Agents*
Chromatography, Thin Layer
Escherichia coli
Microbial Sensitivity Tests
Olea
Oleanolic Acid* / chemistry
Plant Extracts / chemistry
Staphylococcus aureus

Substances

Anti-Bacterial Agents
Anti-Infective Agents
Plant Extracts
Oleanolic Acid
olive leaf extract