Volatile compounds in the stem bark of Sclerocarya birrea (Anacardiaceae) possess antimicrobial activity against drug-resistant strains of Helicobacter pylori

C. Njume, A. J. Afolayan, E. Green, R. N. Ndip

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)

Abstract

The aim of this study was to isolate and identify phytochemicals with anti-Helicobacter pylori activity from the stem bark of Sclerocarya birrea. The plant crude extract was fractionated by silica gel column and thin layer chromatography techniques, initially with ethyl acetate (EA) and subsequently with a combination of ethyl acetate/methanol/water (EMW). Further fractionation and identification of the phytoconstituents was achieved by gas chromatography and mass spectrometry (GC/MS) analysis. The antimicrobial activity of the fractions and compounds was evaluated against five metronidazole- and clarithromycin-resistant strains of H. pylori as well as a reference strain ATCC 43526 using the microbroth dilution technique. Amoxicillin was included in the experiments as a positive control antibiotic. Of the 18 fractions collected, 16 demonstrated anti-H. pylori activity with 50% minimum inhibitory concentration (MIC 50) values ranging from 310 μg/mL to 2500 μg/mL. Two of the fractions (EMW fraction 6 and EA fraction 1) revealed the presence of 5 and 24 compounds, respectively, representing 40.5% and 86.57% of the total composition. Most of the compounds were essential oils, with terpinen-4-ol being the most abundant agent (35.83%), followed by pyrrolidine (32.15%), aromadendrene (13.63%) and α-gurjunene (8.77%). MIC 50 ranges for amoxicillin, terpinen-4-ol and pyrrolidine were 0.0003-0.06 μg/mL, 0.004-0.06 μg/mL and 0.005-6.3 μg/mL, respectively. The inhibitory activities of terpinen-4-ol and pyrrolidine were similar to amoxicillin (P > 0.05). Most of these compounds are being reported in this plant for the first time and may represent new sources of therapeutically useful compounds against H. pylori.

Original languageEnglish
Pages (from-to)319-324
Number of pages6
JournalInternational Journal of Antimicrobial Agents
Volume38
Issue number4
DOIs
Publication statusPublished - Oct 2011
Externally publishedYes

Keywords

  • Antibiotic resistance
  • Essential oils
  • Helicobacter pylori
  • Medicinal plant
  • Pyrrolidine
  • Sclerocarya birrea
  • Terpinen-4-ol

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases
  • Pharmacology (medical)

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