Methanol Extracts from Manilkara zapota with Moderate Antibacterial Activity Displayed Strong Antibiotic-Modulating Effects against Multidrug-Resistant Phenotypes

Abstract

Background: The emergence and persistence of multidrug-resistant (MDR) bacteria appears today as a serious threat of growing concern to human health. The aim of this present study was to investigate the antibacterial and antibiotic-modulating activity of the methanol extracts of Manilkara zapota (L.) P. Royen (Sapotaceae) against pathogenic strains belonging to Gram-positive bacterium, Staphylococcus aureus, and Gram-negative bacteria.

Methods: The antibacterial activity as well as the interactions between the plant extracts and the antibiotics was determined based on the minimum inhibitory concentration (MIC) using the microdilution method. The phytochemical screening of the various extracts was carried out according to the standard qualitative methods.

Results: Phytochemical analysis of the extracts revealed the presence of steroids and the absence of saponins in all the extracts. The other phytochemical classes were selectively distributed in the extracts. The extracts showed significant to moderate antibacterial activities (256 μg/mL ≤ MIC ≤ 1024 μg/mL) against the tested bacteria strains. Therefore, the leaves extract was more active. Furthermore, the leaves and seeds extract of M. zapota (at their MIC/2 and MIC/4) strongly potentiated, 2 to 16 folds the activity of tetracycline (TET), kanamycin (KAN), ciprofloxacin (CIP), and chloramphenicol (CHL) on 70% (7/10) to 80% (8/10) of the tested MDR bacteria. They can be sources of products with antibiotic modifying activity.

Conclusions: This study demonstrates that, the leaves extract of Manilkara zapota has moderate antibacterial and antibiotic modulatory activities, and therefore could be an interesting weapon against MDR bacteria.