Antibacterial activity of flavonoids and triterpenoids isolated from the stem bark and sap of Staudtia kamerunensis Warb. (Myristicaceae)

Jordan L. Tonga; Michael H.K. Kamdem; Julio I. M. Pagna; Thierry Y. Fonkui; Charlotte M. Tata; Marthe C.D. Fotsing; Ephrem A. Nkengfack; Edwin M. Mmutlane; Derek T. Ndinteh

Arabian Journal of Chemistry (Oct 2022)

Antibacterial activity of flavonoids and triterpenoids isolated from the stem bark and sap of Staudtia kamerunensis Warb. (Myristicaceae)

Jordan L. Tonga,
Michael H.K. Kamdem,
Julio I. M. Pagna,
Thierry Y. Fonkui,
Charlotte M. Tata,
Marthe C.D. Fotsing,
Ephrem A. Nkengfack,
Edwin M. Mmutlane,
Derek T. Ndinteh

Affiliations

Jordan L. Tonga: Drug Discovery and Smart Molecules Research Laboratory, Department of Chemical Sciences, University of Johannesburg, P.O. Box 17011, Doornfontein, Johannesburg 2028, South Africa; Centre for Natural Product Research (CNPR), Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa; Research Centre for Synthesis and Catalysis, Department of Chemical Sciences, University of Johannesburg-Kingsway Campus, Auckland Park 2008, South Africa
Michael H.K. Kamdem: Drug Discovery and Smart Molecules Research Laboratory, Department of Chemical Sciences, University of Johannesburg, P.O. Box 17011, Doornfontein, Johannesburg 2028, South Africa; Centre for Natural Product Research (CNPR), Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa; Research Centre for Synthesis and Catalysis, Department of Chemical Sciences, University of Johannesburg-Kingsway Campus, Auckland Park 2008, South Africa
Julio I. M. Pagna: Department of Organic Chemistry, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
Thierry Y. Fonkui: Department of Biotechnology and Food Technology, Faculty of Science, University of Johannesburg, Doornfontein Campus, Johannesburg 2028, South Africa
Charlotte M. Tata: Centre for Natural Product Research (CNPR), Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa; Department of Biochemistry, University of Bamenda, P.O. Box 39, Bambili, Cameroon
Marthe C.D. Fotsing: Drug Discovery and Smart Molecules Research Laboratory, Department of Chemical Sciences, University of Johannesburg, P.O. Box 17011, Doornfontein, Johannesburg 2028, South Africa; Centre for Natural Product Research (CNPR), Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa
Ephrem A. Nkengfack: Department of Organic Chemistry, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
Edwin M. Mmutlane: Centre for Natural Product Research (CNPR), Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa; Research Centre for Synthesis and Catalysis, Department of Chemical Sciences, University of Johannesburg-Kingsway Campus, Auckland Park 2008, South Africa; Corresponding authors.
Derek T. Ndinteh: Drug Discovery and Smart Molecules Research Laboratory, Department of Chemical Sciences, University of Johannesburg, P.O. Box 17011, Doornfontein, Johannesburg 2028, South Africa; Centre for Natural Product Research (CNPR), Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa; Corresponding authors.

Journal volume & issue: Vol. 15, no. 10
p. 104150

Abstract

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The chemical investigation of the ethyl acetate extract of the stem bark of Staudtia kamerunensis and sap led to the isolation of six compounds which included three isoflavonoids: biochanin A (1), formononetin (2) and 3-(1,3-benzodioxol-5-yl)-5,6,7-trimethoxy-4H-1-benzopyran-4-one (3), one flavonoid: (-) epicatechin (4) and two pentacyclic triterpenoids (oleanan-12-ene-2α,3β -diol (5) and 2α,3β-dihydroxylup-20-ene (6). They were characterized by HREIMS (High Resolution Electron Ionisation Mass Spectrometry), NMR spectroscopy (1D and 2D) and comparison with existing data in literature. The crude extract and isolates were tested against twelve bacterial strains namely; Bacillus subtilis, Staphylococcus epidermidis, Enterococcus faecalis, Mycobacterium smegmatis, Staphylococcus aureus, Enterobacter cloacae, Klebsiella oxytoca, Pseudomonas aeruginosa, Proteus vulgaris, Escherichia coli, Proteus mirabilis and Klebsiella pneumonia. Streptomycin, nalidixic acid and ampicillin were used as standard antibacterial drugs. The results revealed significant antibacterial activity for both the ethyl acetate partition and for the tested compounds, with the lowest MIC value being 15.625 μg/mL. A synergistic activity of the isolated triterpenoids was evaluated with interesting results. On a general note, the antibacterial activity of compound 5 was doubled specifically against Gram-negative bacterial strains. This could be a therapeutic antimicrobial pathway in face of the rising bacterial resistance. To the best of our knowledge, it is the first time that flavonoids and triterpenoids are isolated from this genus and species. It is also the first report of antibacterial studies on this species.

Published in Arabian Journal of Chemistry

ISSN: 1878-5352 (Print)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Science: Chemistry
Website: http://www.journals.elsevier.com/arabian-journal-of-chemistry/

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