Effect of Fractioning on Antibacterial Activity of Enantia chlorantha Oliver (Annonaceae) Methanol Extract and Mode of Action

Abstract

Infectious diseases caused by bacteria constitute the main cause of morbidity and mortality throughout the world and mainly in developing countries. In this work, the influence of fractioning and the mode of action of stem barks methanol extract of Enantia chlorantha were investigated. The aim was to optimize the antibacterial activity of the methanol extract. The extract was prepared by maceration of barks powder in methanol. Fractioning was done using increasing solvents polarity. Standard phytochemical methods were used for phytochemical screening. Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentration (MBC) of the methanol extract and fractions were determined using broth microdilution method. The studied mode of action of both methanol extract and n-butanol fraction included antibiofilm activity, H+-ATPase-mediated proton pumping assay, salt tolerance, and cells cycle. The methanol extract of E. chlorantha stem barks was found to be active on all the bacteria tested (32 ≤ MIC ≤ 512 μg/mL), its activity being significant (MIC < 100 μg/ml) out of 5 of the 28 clinical isolates used. Salmonella enterica serovar paratyphi A was the most sensitive (32 μg/mL). Compared to the extract and other fractions, the n-butanol fraction was found to be more active (32 ≤ MIC ≤ 256). Significant antibacterial activity of this fraction was observed out of 10 of the 28 bacterial isolates and 3 out of 7 bacterial strains. Lowest MIC values (32 μg/ml) of this fraction were obtained with Escherichia coli (136), Pseudomonas aeruginosa (CIP 76110), and Salmonella enterica serovar typhi 9. The methanol extract of E. chlorantha and its n-butanol fraction revealed several modes of action including the prolongation of the latency phase of the bacterial growth, the inhibition of the pump with protons H+ - ATPases bacterial, the loss of the salt tolerance of the Staphylococcus aureus, and inhibition of the formation of the bacterial biofilm. The present results showed that the n-butanol fraction of the methanol stem barks extract of E. chlorantha possess the essential antibacterial components and could best be used to fight against bacterial infections as compared to methanol extract.

Large-Scale Screening of 239 Traditional Chinese Medicinal Plant Extracts for Their Antibacterial Activities against Multidrug-Resistant Staphylococcus aureus and Cytotoxic Activities

“…In addition, these active compounds are commonly targeted at multiple sites rather than one specific site of antibacterial action [27,28]. For example, Ebelle et al [29] reported that the methanolic extract of Enantia chlorantha had several modes of antibacterial action including the extension of the bacterial latency period, the deactivation of H+ -ATPases activity in cell membrane, the loss of the salt tolerance of the S. aureus, and inhibition of the biofilm formation. Since TCMP extracts contain diverse chemical substances, they probably influence the bacteria cell constituents or molecular targets by various mechanisms.…”

Evaluation of the anti-inflammatory and antioxidant potential of the stem bark extract and some constituents of Aidia genipiflora (DC.) dandy (rubiaceae)

“…Though the exact mechanism of anti-inflammatory action is unknown, the percentage inhibition of total oedema over the 6 h-period of observation suggests that the extracts may have inhibited the release or action of one or more of these inflammatory mediators. From the results, the whole extract of A. genipiflora (AG) had a higher anti-inflammatory effect than its MeOH (AGM), EtOAc (AGEt), and petroleum ether (AGPE) fractions implying a possible synergistic effect of constituents in the whole extract that were lost during fractionation ( Ebelle-Etame et al., 2018 ). Among the fractions, AGEt and AGM showed similar anti-inflammatory activity better than AGPE.…”

Antimicrobial properties of various solvents combinations for phytochemical fraction derived from Uncaria gambier extract against Enterococcus faecalis ATCC 29212

“…Solvents can also affect the antimicrobial activity of herbal plants. 22,23 The chemical ingredients in gambier that are most widely used are catechins and tannins. Catechins are oligomeric procyanidin (OPC) tannin compounds classified as flavonoids.…”

“…This result is influenced by the content of bioactive compounds found in each solvent. 23 The polarity of the solvent plays an important role in increasing the solubility of the bioactive compound. 10,11,24,25 The difference in the polarity of the solvent determines the difference in the type and composition of the phytochemical compounds.…”