Background: Thai traditional remedy called Kabpi (KP) has long been used for oral and throat infection. It composed with four herbs Syzygium aromaticum (L.) Merr. et Perry, Nigella sativa L., Limonia acidissima L. and Achasma sphaerocephalum Holtt.
Objective: To investigate antimicrobial activity of KP remedy extracts and its plant components.
Material and Method: The extract procedures were maceration method with 95% ethanol, 50% ethanol and dried by evaporator, and boiling in water, filtrated dried by lyophilizer. The residue from the maceration in 95% ethanol and 50% ethanol were boiled in water and dried by lyophilizer. In the preliminary studied, all extracts were evaluated antimicrobial activity by disc diffusion method. All extracts were tested against one type of gram positive bacteria Staphylococcus aureus (ATCC 25923) and one type of yeast Candida albicans (ATCC 90028). The active plant extracts were diluted to determine the minimum inhibitory concentration (MIC) values by microtiter plate-based assay.
Results: The 95% ethanol extract of KP remedy showed antimicrobial activity against S. aureus (ATCC 25923) and
C. albicans (ATCC 90028) (MIC = 0.625, 0.625 mg/ml, respectively). The zone of inhibition of all extracts were in the range of 7.33 to 23.33 mm. The 95% ethanol extract of Achasma sphaerocephalum Holtt. showed the highest inhibition zone against S. aureus 21.00 mm (MIC = 0.625 mg/ml). The 95% ethanol extract of Syzygium aromaticum (L.) Merr. et Perry exhibited the best antimicrobial activity against C. albicans the inhibition zone with inhibition zone of 23.33 mm (MIC = 0.156 mg/ml).
Conclusion: The present study demonstrated that the extracts of KP remedy and its plant components had an antimicrobial effect against oral and throat infection such as S. aureus and C. albicans. These results support using this remedy of Thai traditional medicine called Kabpi for oral and throat infection.

Keywords: Kabpi, Thai traditional medicine, Antimicrobial activity