Background: Catha edulis Forsk is by far the most commonly cultivated shrub native to East Africa and Arabian Pennisula. The fresh leaves of this plant are chewed traditionally for feeling of wellness, mental alertness and euphoria by the people in Saudi Arabia. Studies demonstrated the cytotoxic and therapeutic effect of Catha edulis, however this study is first of its kind to demonstrate the solvent dependent antimicrobial activity in clinically isolated microbial strains.

Methodology and Results: The extract was prepared in three different polar solvents (Methanol, DMSO and Water) to determine their relative capacity to fish out the phytoconstituents with good antimicrobial, antioxidant and anti-inflammatory activity by performing a comparative phytoconstituent analysis using GC/MS. The antimicrobial activity of these extracts was tested against the clinical isolates such Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Klebseilla pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Candida albicans by agar well diffusion assay. For all the isolates, identification and antibiotic susceptibility was determined by Vitek-2 system. The results showed that out of three polar solvents, extract prepared in DMSO and methanol showed significant antimicrobial activity. Notably, the extract in DMSO was active against the multi-drug resistant isolates. This differential antimicrobial activity is concurrent with phytoconstituents detected by GC/MS.

Conclusion: The study unveils Catha edulis Forsk as a potential source of natural antimicrobial compound against both sensitive and MDR bacteria. Moreover, this is the first report to demonstrate the effect of solvent on the differential extraction of various phytoconstituents of Catha edulis by GC/MS.

Significance and impact of the study: Study distinct itself by corroborating observed differential antibacterial activity with the phytoconstituent detected by GC/MS analysis. Also, this is the first report to demonstrate the effect of solvent on differential extraction of phytoconstituent showing strong antimicrobial, anti-inflammatory and antioxidant activity of Catha edulis Forsk.