In vitro antibacterial and antibiotic modifying activity of crude extract, fractions and 3′,4′,7-trihydroxyflavone from Myristica fragrans Houtt against MDR Gram-negative enteric bacteria

Abstract

BackgroundNutmeg is the seed kernel inside the fruit of Myristica fragrans Houtt. (Myristicaceae). It possesses various pharmacological activities but is used in Cameroon only for its flavor in making cakes. The present study thus aimed to investigate the in vitro antibacterial activity and antibiotic modifying activities of crude seed kernel methanol extract (MFS), fractions (MFSa-e) as well as 3′,4′,7-trihydroxyflavone from Myristica fragrans against a panel of multi-drug resistant (MDR) Gram-negative bacteria.MethodsThe modified rapid p-iodonitrotetrazolium chloride (INT) colorimetric assay was used to determine the Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) on the tested bacteria, as well as those of antibiotics in association with the extract and/or isolated compound. Column chromatography was used for the fractionation and purification of the seed kernel extract whilst the chemical structures of compounds were determined using spectroscopic techniques.ResultsPhytochemical investigations lead to the isolation of 3′,4′,7-trihydroxyflavone from the fraction MFSb. The crude extract showed antibacterial activity with MICs ranging from 32 to 1024 μg/mL on the majority of the 29 tested Gram-negative bacterial strains. Fraction MFSb inhibited the growth of 100% (29/29) of the tested bacterial strains, as well as the compound 3′,4′,7-trihydroxyflavone (12/12) with a MIC values ranging from 32 to 1024 μg/mL, and 4 to 128 μg/mL respectively. The lowest MIC value (4 μg/mL) was recorded with 3′,4′,7-trihydroxyflavone against Providencia stuartii ATCC299645 as well as the best MBC value (16 μg/mL) against the same strain. In the presence of Phenylalanine-Arginine-β-Naphthylamide (PAßN), an efflux pumps inhibitor, the activity of the extract increased on 73.33% (11/15) meanwhile that of 3′,4′,7-trihydroxyflavone increased on 100% tested bacteria. The compound 3′,4′,7-trihydroxyflavone potentiated the activity of antibiotics in the majority of the tested bacterial strains.ConclusionThe results of the present work provide additional information on the use of nutmeg and it major antibacterial component, 3′,4′,7-trihydroxyflavone, as a potential drug in the treatment of bacterial infections including multidrug resistant phenotypes.Electronic supplementary materialThe online version of this article (10.1186/s12906-018-2084-1) contains supplementary material, which is available to authorized users.

Flavonoids and Other Phenolic Compounds from Medicinal Plants for Pharmaceutical and Medical Aspects: An Overview

“…An obvious example is nutmeg or Myristica fragrans Houtt. ; this plant is mostly used traditionally as flavoring agent in Indonesia and other countries in South East Asia [ 24 , 25 ]. However, ethanolic extract of the nutmeg seed which contained 3′,4′,7-trihydroxyflavone showed effective potential against MDR gram-negative bacteria e.g., Providencia stuartii Ewing and Escherichia coli (Migula) Castellani and Chalmers.…”

“…However, ethanolic extract of the nutmeg seed which contained 3′,4′,7-trihydroxyflavone showed effective potential against MDR gram-negative bacteria e.g., Providencia stuartii Ewing and Escherichia coli (Migula) Castellani and Chalmers. [ 25 ]. Similarly, Pseudarthria hookeri Wight and Arn which has been used as traditional herbal medicine in Africa [ 26 , 27 ] for the treatment of pneumonia, abdominal pains, cough and diarrhea.…”

Characterization of Antibacterial Proanthocyanidins of Dalbergia monetaria, an Amazonian Medicinal Plant, by UHPLC-HRMS/MS

“…According to studies focusing on antibacterial activities of plant extracts, when the samples display a MIC below 100 µg/mL, the antimicrobial activity is considered good; from 100 to 625 µg/ mL, the antimicrobial activity is moderate; and over 625 µg/mL, the activity is weak [31]. So, the MIC of the crude extracts, fractions and subfractions that exhibited the lowest MIC (good and moderate) are shown in ▶ Table 1.…”

Flavonoids from the stem barks of Swintonia griffithii Kurz (Anacadiaceae) and their tyrosinase inhibitory activities

“…With these characteristic signals for a flavone derivative, the structure of 6 was concluded to be 3′,4′,7trihydroxyflavone. [5] The tyrosinase inhibitory activities of all isolated compounds were tested. Kojic acid, a cosmetic skinwhitening agent, was used as a positive control.…”

“…Our continued study on the screening of medicinal plants for tyrosinase inhibitory activity led to the finding that the MeOH-soluble extract of the stem barks of S. griffithii showed potent inhibitory effect with an IC50 value of 42.1 µg mL -1 . Thus, a further fractionation study was carried out to isolate six flavonoids (1)(2)(3)(4)(5)(6). Their isolation procedure and structural elucidation are described in this research.…”