Phytochemical Investigation and Determination of Antibacterial Activity of Solvent Leave Extracts of Carissa spinarum

Abstract

Background

Among many traditionally used medicinal plants, Carissa spinarum (Agam) is a well-known indigenous plant in Ethiopia. It is used in its raw form to treat different diseases in different parts of the country. Therefore, the aim of this study is to investigate extraction, isolation, and determination of the antibacterial properties of the solvent leaf extract of Carissa spinarum.

Methods

In this study, 800 g of powdered leaves of Carissa spinarum were macerated with 2500 mL of methanol and yielded 58 g (7.25%, w/w) of gummy material. The extract was then further partitioned by using ethyl acetate and chloroform. The extracts were subjected to phytochemical screening test. The antibacterial activity of the three solvent leaf extracts of Carissa spinarum were evaluated using disc diffusion method. The methanol extract was subjected to column chromatography silica gel (60–200 mesh) by mixing methanol:petroleum ether (4:1). Then fractions were collected and investigated by TLC and finally identified using spectroscopy.

Results

The three extracts (methanol, ethyl acetate, and chloroform) of Carissa spinarum were presented to antimicrobial activity by disc diffusion method against four bacterial species using gentamycin and ampicillin discs as positive controls and DMSO as a negative control. All extracts had a relatively antibacterial effect with different extent zones of inhibition. However, the methanol extract showed superior antibacterial activity compared with DMSO and ethyl acetate and chloroform extracts. These could due to variation of the phytoconstituents. The most probable structure of the compound isolated was 5-(2’,3’,4’,6’-tetrahydroxy-5’-methoxycyclohexyloxy)-2,3,4 trihydroxypentanoic acid.

Conclusion

Data obtained from this study collectively indicated that the three solvent extracts of Carissa spinarum have a promising antimicrobial activity which supports the traditional claim of the plant for treatment of infection.

Keywords:

• antibacterial activity
• Carissa spinarum
• phytochemicals determination

Abbreviations

¹³C-NMR, carbon-13 nuclear magnetic resonance; ¹H-NMR, proton nuclear magnetic resonance; DEPT, distortionless enhancement by polarization transfer; DRC, Democratic Republic of Congo; IR, infrared spectroscopy; MHA, Mueller–Hinton agar; NMR, nuclear magnetic resonance; TA, trihydroxypentanoic acid; TLC, thin layer chromatography; TM, traditional medicine; TMPs, traditional medicinal practitioners; UoG, University of Gondar; WHO, World Health Organization; DMSO, dimethyl sulfoxide; PPM, parts per million; Rf, retention factor; MS, mass spectrometry; 2D-NMR, two-dimensional nuclear magnetic resonance.

Ethics Approval

Ethical clearance and permission was obtained from University of Gondar Research and Ethical Review Committee.

Acknowledgments

We are very grateful for University of Gondar for funding the study.

Author Contributions

All authors made a significant involvement to the work stated, that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agreed to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.

Additional information

Funding

University of Gondar provided all the required resources for conducting this research project.