Antibacterial and antibiotic-modifying activities of fractions and compounds from Albizia adianthifolia against MDR Gram-negative enteric bacteria

Abstract

Background Albizia adianthifolia (Schum.) is medicinally used in Cameroon to manage bronchitis and skin diseases. Our previous study documented the antibacterial potential of its roots’ methanol extract. In this study, methanol roots extract was subjected to chromatography techniques and fractions (AARa and AARb), sub-fractions (AARa1–4, AARb1–2 and AARb11–14) together with isolated phytochemicals were assessed for their antimicrobial as well as their antibiotic-potentiating effects towards Gram-negative multidrug resistant (MDR) bacteria. Methods The antibacterial activities of the samples (determination of Minimal Inhibitory « MIC » and Minimal Bactericidal Concentration « MBC ») were determined by the modified rapid p-iodonitrotetrazolium chloride (INT) colorimetric assay, as well as those of antibiotics in association with the compounds. Column chromatography was applied to isolate phytochemicals from roots extract and their chemical structures were determined using spectroscopic techniques. Results The phytochemicals isolated were stearic acid ( 1 ), a mixture (1:1) of stigmasterol and β -sitosterol ( 2 + 3 ), β -sitosterol 3- O - β - D -glucopyranoside ( 4 ), palmatin ( 5 ), homomangiferin ( 6 ) and mangiferin ( 7 ). Fraction AARa exhibited selective inhibitory effects whilst all tested bacteria were inhibited by AARb in MIC ranges of 8 to 1024 μg/mL. Sub-fractions AARb1–2 had MIC values between 8 μg/mL and 1024 μg/mL on all tested bacteria. Phytochemicals 4, 2 + 3 and 7 inhibited the growth of 54.54% (6/11), 45.45% (5/11) and 27.27% (3/11) tested bacterial strains, respectively. When tested with an efflux pumps inhibitor (Phenylalanine-Arginine- β -Naphthylamide or PAβN), the inhibitory effects of compounds 2 + 3 and 4 increased towards all the tested bacteria. In association with erythromycin (ERY), streptomycin (STR) and tetracycline (TET), compounds 2 + 3 and 4 had the most significant synergistic activity on the seven selected bacteria. Conclusion The present study provides information on the possible use of Albizia adianthifolia and its constituents in the control of Gram-negative infections including MDR phenotypes. Electronic supplementary material The online version of this article (10.1186/s12906-019-2537-1) contains supplementary material, which is available to authorized users.

Antimicrobial activity of medicinal plants used for urinary tract infections in pastoralist community in Ethiopia

“…Implausibly, both multidrug resistant and reference strains of E. coli were the most unresponsive strain of all tested bacteria species. These findings agreed with several reports [ 13 , 19 – 21 ] which demonstrated that gram positive ( S. aureus and E. faecalis ) bacteria to be more sensitive than gram negative ( E. coli and K. pneumonia ) bacteria for the plants’ phytochemical components being studied. Moreover, many studies have shown that medicinal plants contain different bioactive ingredients that inhibited the growth of human pathogenic bacteria [ 22 ].…”

“…gigantean had inhibitory potential on all tested human pathogenic bacteria and fungi except T. rubrum [ 16 ] . Another study conducted on extracts of Carum copticum and Albizia adianthifolia had exhibited good antimicrobial activities against E. coli, Proteus species, P. aeruginosa, P. neumoniae and Salmonellae species [ 18 , 19 ].…”

“…Another study conducted on the organic extracts of Phragmanthera capitat had comparative antimicrobial activities against ten pathogen bacteria with a MIC of 1.25–5 mg/ml and MBC of 2.5–10 mg/ml and fungi species with a MIC of less than 0.3125 to 1.25 mg/ml [ 17 ]. Likewise, the aqueous extracts of Carum copticum, and Albizia adianthifolia showed significant antibacterial effect against multidrug resistance gram negative human pathogen bacteria such as E.coli, Pseudomonas, K. pneumonia, Salmonella and Proteus species [ 18 , 19 ]. Several aqueous and hydro-alcoholic extracts obtained from different plants were screened for their antibacterial effects against human pathogenic bacteria and demonstrated remarkable antibacterial effects on multidrug resistant bacteria including MRSA and ESBL producing bacteria [ 20 – 24 ].…”

β-Sitosterol Attenuates High Grain Diet-Induced Inflammatory Stress and Modifies Rumen Fermentation and Microbiota in Sheep

“…In spite of a recent study indicate that rumen microorganisms may degrade several cyanotoxins [33], the threat from cyanotoxins cannot be ignored. Our results revealed that BSS might inhibit the growth of cyanobacteria, since its antibacterial activity has been documented [34,35].…”

Antimicrobial activity of Albizia tulearensis, an endemic Fabaceae from Madagascar

“…Indeed, in most of the countries where they grow, these plants are widely used in traditional medicine for the treatment of various diseases. As examples, Albizia adiantifolia was used for the treatment of syphilis [3] and bronchitis [4], Albizia schimperiana for the treatment of pneumonia [5] and diarrhea [6] and Albizia odoratissima for the treatment of dysentery and rhinitis [7]. Most research has shown that the antimicrobial activity of Albizia extracts [8,9] and several active ingredients were already isolated [10].…”