A comparative study between the effect of aqueous and alcoholic extracts of cloves on inhibiting the growth of some gram-positive and gram-negative bacteria

Abstract

Background: Clove (Syzygium aromaticum) shows broad spectrum antibacterial effects, it works on both Gram-positive and Gram-negative microorganisms too. Because of this, its usefulness as a natural antimicrobial is worth a more careful, step by step study using consistent solvent extraction procedures… like the standardized ones. Objective: The aim was to see how strongly aqueous and alcoholic clove extracts can slow, or inhibit, bacterial growth when the concentration is set at 5% and 10%. Focus was on Gram-positive as well as Gram-negative bacteria. Methods: In total, 80 bacterial samples were taken. They included Gram-positive and Gram-negative isolates, plus another 20 control samples. Clove was processed into two kinds of extracts: aqueous, meaning water based, and alcoholic, meaning 96% ethanol based. Each extract type was made at 5% and at 10%. For the Gram-positive side, 20 samples were exposed to each extract type at both concentrations. For the Gram-negative side, 40 samples were treated the same way, using aqueous and alcoholic extracts at 5% and 10%. After treatment, antibacterial effects were checked by observing bacterial growth inhibition across all groups. Results: Both aqueous and alcoholic clove extracts had clear inhibitory action against Gram-positive and Gram-negative bacteria at 5% and 10%. In general, the 10% concentration was more effective than 5% for both bacterial groups, and this held up for both solvent types. Also, there was no obvious, standout advantage of aqueous over alcoholic, or vice versa. Conclusion: Overall, clove plant extracts can produce measurable antimicrobial activity across a wide set of bacteria, and the effect is concentration dependent. These results also hint that clove-derived compounds could be considered later, as potential antibiotic alternatives for handling microbial infections, although more work is still needed, both in the lab and in clinical settings.