Aldulaimi, O, Drijfhout, F, Uche, FI, Horrocks, P and Li, W-W (2019) Discovery, synthesis and antibacterial evaluation of phenolic compounds from Cylicodiscus gabunensis. BMC Complementary and Alternative Medicine, 19 (1). 183 -?. ISSN 1472-6882

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Cylicodiscus gabunensis Harms (Family Leguminosae) (CG) is an African medicinal plant used as a treatment of various ailments including malaria, liver diseases, and gastrointestinal disturbances. Its extracts showed potent in vitro antibacterial activity. However, the antibacterial components are unknown.

In this study, the stem bark of the CG plant was extracted and its antibacterial property against a panel of Gram-negative and Gram-positive bacterial strains assessed using the disk diffusion assay method. Bioassay-guided fractionation of the bioactive extracts was employed to identify bioactive constituents using both gas and liquid chromatography mass spectrometry. Chemical synthesis was used to make the analogues of gallic acid. Microplate dilution assays and scanning electron microscopy (SEM) were used to evaluate the antibacterial properties and mechanism of action of the active fractions and pure compounds.

The most bioactive sub-fractions derived from CG comprised of ethyl gallate, gallic acid and polyphenols. Five alkyl/alkenyl gallates were synthesized. A preliminary structure-activity relationship of gallic acid derivatives was obtained using the synthetic analogues and a series of commercially available phenolic compounds. Increasing the length of alkyl chains generally increases the potency of the alkyl gallates. Introducing a double bond with restricted conformations of the C-5 side chain has little effect on the antibacterial property. SEM analysis of the effect of alkyl gallates on Staphylococcus aureus indicates that they appear to interrupt S. aureus bacterial cell wall integrity.

The results of this research rationalise the ethnobotanical use of C. gabunensis and suggest that gallate derivatives may serve as promising antibacterial agents for the treatment of infectious diseases.

Item Type: Article
Additional Information: This is the final published version of the article (version of record). It first appeared online via BioMed Central at - please refer to any applicable terms of use of the publisher.
Uncontrolled Keywords: Alkyl gallates, Antibacterial activity, Cylicodiscus gabunensis, Leguminosae, Scanning electron microscopy
Subjects: R Medicine > RS Pharmacy and materia medica
Divisions: Faculty of Medicine and Health Sciences > School of Pharmacy and Bioengineering
Related URLs:
Depositing User: Symplectic
Date Deposited: 08 Aug 2019 13:03
Last Modified: 08 Aug 2019 13:16

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