In vitro Antimicrobial Activity of Agents from Spilanthes filicaulis and Laportea ovalifolia against Some Drug Resistant Bacteria
Jane-Francis Tatah Kihla Akoachere
Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Cameroon and Laboratory for Emerging Infectious Diseases, Faculty of Science, University of Buea, Cameroon.
Yvonne Suylika
Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Cameroon.
Ajeck James Mbah
Department of Chemistry, Faculty of Science, University of Buea, Cameroon.
Aponglen Godfred Ayimele
Department of Chemistry, Faculty of Science, University of Buea, Cameroon.
Jules Clement Nguedia Assob
Department of Biomedical Sciences, Faculty of Health Sciences, University of Buea, Cameroon.
Siméon Pierre Chegaing Fodouop
Department of Biomedical Sciences, Faculty of Science, University of Ngaoundéré, Cameroon and Department of Biochemistry, Faculty of Science, University of Dschang, P.O.Box 67 Dschang, Cameroon.
Norbert Kodjio
Department of Biochemistry, Faculty of Science, University of Dschang, P.O.Box 67 Dschang, Cameroon.
Donatien Gatsing *
Department of Biochemistry, Faculty of Science, University of Dschang, P.O.Box 67 Dschang, Cameroon.
*Author to whom correspondence should be addressed.
Abstract
Aims: In a search for natural substances with potential for the treatment of typhoid fevers and urinary tract infections (UTI), extracts and compounds obtained from S. filicaulis and L. ovalifolia were tested for antibacterial activity.
Study Design: Extraction, fractionation, isolation and identification of compounds, antibacterial evaluation.
Place and Duration of Study: University of Buea and University of Dschang, Cameroon, between February 2012 and December 2013.
Methodology: The most active extracts were fractionated by column and thin layer chromatographic (TLC) techniques, and tested for antibacterial activity, using agar diffusion and broth dilution methods. The structures of pure compounds obtained were elucidated by NMR spectroscopy, physical data and by comparing these values with published data.
Results: Methylene chloride extract of S. filicaulis was the most active (diameters of 12-15 mm). Methylene chloride (12-16 mm) and methanol (13-16 mm) extracts of L. ovalifolia were active against all isolates. MIC values ranged from 0.08 - 1.25 mg/ml for the fractions of S. filicaulis and 0.16 - 1.25 mg/mL for L. ovalifoliafractions. Streptococcus sp was the most sensitive microbial agent (MIC = 0.08 mg/mL) for fraction IS of S. filicaulis. Staphylococcus aureus and Streptococcus sp recorded the lowest MIC for fraction ML of L. ovalifolia. Two compounds isolated from S. filicaulis were identified as β-stigmasterol (1) and hexadecanoic acid (2) while one from L. ovalifolia was identified as β-sitosterol (3). These three compounds and two other secondary metabolites not yet identified (GL2 and GL3) showed antibacterial activity. The in vitro activity of β-stigmasterol against Klebsiella pneumoniae and Salmonella Typhimurium is reported herein for the first time.
Conclusion: These plants may contain lead molecules for the formulation of drugs useful for the management of UTI and typhoid fevers caused by resistant pathogens.
Keywords: Urinary tract infection, typhoid fevers, drug resistance, natural substances, antibacterial activity