Lina Lulu

Ethiopia

Anti-microbial effect of Khat (Catha edulis Forsk) on Neisseria gonorrhoeae and other organisms

Lina Alemayehu1
1. Department of General Public Health, St. Paul Hospital Millennium Medical College

Abstract

Background

Khat (Catha edulis Forsk), an East African stimulant containing the alkaloid cathinone, possesses a complex phytochemical profile suggesting antimicrobial potential. Given the continuous public health threat posed by Neisseria gonorrhoeae, this study was conducted to investigate and quantitatively determine the antimicrobial effects of C. edulis extracts against N. gonorrhoeae and select bacterial pathogens.

Methods

Standardized bacterial suspensions of N. gonorrhoeae, E. coli, and S. aureus ATCC were prepared to a 0.5 McFarland standard (≈ 1 x 10⁸ CFU/mL). The antibacterial efficacy of the two geographically distinct extracts (Sebeta and Gurage) was screened using the agar well diffusion method on respective agar plates. Extracts were tested at 100 mg/mL stock concentrations, with 50–75 µL placed in wells on inoculated plates. After 24-hour incubation, the zone of inhibition was measured to confirm activity, followed by quantitative determination of the Minimum Inhibitory Concentration (MIC) value for active extracts.

Results

Antimicrobial screening confirmed the anti-bacterial effects of Catha edulis extracts against N.gonorrhoeae and S. aureus, but showed minimal effect against E. coli. The highest zone of inhibition was observed against S. aureus (Gram-positive). Notably, the Gurage chat extract exhibited better inhibitory activity against N.gonorrhoeae than the Sebeta extract. (Yields were 25.9% for Sebeta and 28.8% for Gurage.)

Conclusions

This study confirms the anti-bacterial potential of Catha edulis extracts against clinically relevant strains. Susceptibility was highest in S. aureus and lowest in E. coli, suggesting cell wall components are crucial determinants of activity. The observed superior inhibition against N. gonorrhoeae by Gurage chat indicates significant chemical variation by source. Given the critical rise in antibiotic resistance and Ethiopia’s rich plant diversity, these findings strongly support the urgent need for quantitative research into medicinal plants as potential alternatives.