ANTIBACTERIAL ACTIVITY OF RUBIA TINCTORUM LINN. ROOT EXTRACTS

This research aimed to determine the antibacterial activity of methanolic, aqueous, chloroformic and petroleum ether extracts of Rubia tinctorum roots against two gram positive and two gram negative bacteria using agar well-diffusion method. The minimum inhibitory concentration (MIC) was determined using microdilution method. Extracts were dissolved in DMSO to obtain a concentration of 10% (w/v), and the density of bacterial suspension was 1.5 × 10⁸ cfu/ml.  Results showed that methanolic extract showed antibacterial activity against both gram negative and gram positive bacteria with minimum inhibitory concentration ranging from 0.1562 to 0.3125 mg/ml, while aqueous extract showed no activity against the tested bacteria. However, chloroformic extract showed antibacterial activity only against Escherichia coli with minimum inhibitory concentration value of 2.5 mg/ml. But petroleum ether extract showed antibacterial activity against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus with minimum inhibitory concentration ranging from 0.3125 to 1.25 mg/ml. But in conclusion, methanolic extract was the most effective against all tested bacteria. Further studies are needed for pharmaceutical purposes.