Bioautographic screening for natural quinolone antimicrobial agents from Glycosmis pentaphylla (Retz.) DC., Ruta angustifolia (L.) Pers. and Lunasia amara Blanco
Background The quinoline alkaloids are a group of alkaloids with diverse structural types. The 4-oxygenated quinolone and 2-substituted 4-quinolone are the types of quinoline alkaloids that possess the chromophore structures which are similar to the pharmacophore of the conventional 4-quinolone a...
| Main Authors: | , , , , |
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| Format: | Conference or Workshop Item |
| Language: | English |
| Published: |
2009
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/8387/ http://irep.iium.edu.my/8387/ http://irep.iium.edu.my/8387/1/POSTER.pdf |
| Summary: | Background
The quinoline alkaloids are a group of alkaloids with diverse structural types. The 4-oxygenated quinolone and 2-substituted 4-quinolone are the types of quinoline alkaloids that possess the chromophore structures which are similar to the pharmacophore of the conventional 4-quinolone antimicrobial agents. Therefore it is presumed that these types of natural quinoline alkaloids could also share the same activity as the conventional quinolone antimicrobial agents. Although these conventional agents demonstrate an excellent treatment against so many infectious diseases, the emergence of quinolone resistance against some microbes has been a disturbing feature of microbial infection (Shigemura, et al., 2003).
Objectives
This study aims primarily to search for naturally occurring quinolone antimicrobial agents from three excellent plant sources of quinolone alkaloids, which are Glycosmis pentaphylla (Retz.) DC., Ruta angustifolia (L.) Pers. and Lunasia amara Blanco. It is aimed that the natural alkaloids will provide new structural types of quinolone antimicrobial agents in view to overcome microbial resistance towards the conventional agents.
Methods
The plant materials, which include the leaves and root barks of G. pentaphylla, and the leaves of R. angustifolia and L. amara were dried and powdered and subjected to extraction. Acid base extraction was employed following the continuous extraction by hexane and acetone to furnish the crude alkaloidal extracts. The extract was then fractionated by column chromatography. The fractions yielding major alkaloidal compounds were selected to be screened by using TLC Agar Overlay Bioautographic Assay for antimicrobial active quinolone alkaloids against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Candida albicans ATCC 90028.
Results
The column chromatography on the crude alkaloidal extracts has afforded two fractions containing major alkaloids from G. pentaphylla and one fraction each from
R. angustifolia and L. amara. TLC Agar Overlay Bioautographic screening for antimicrobial active alkaloids has revealed four antimicrobial active alkaloids. Two alkaloids, labeled as GP-3 and RA-3 which were active against S. aureus and C. albicans have been detected from the stem bark fraction of G. pentaphylla and the leaf fraction of R. angustifolia. Two major alkaloids such as GP-4 from the leaf fraction of G. pentaphylla and LA-4 from L. amara leaf fraction were found to be active against both S. aureus and E. coli.
Conclusion
The reported results of all three plant species therefore proved to have high potential in providing new structural types of lead compounds for synthesizing new drugs to overcome microbial resistance towards conventional quinolone antimicrobial agents.
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