Objective      To determine the in vitro antibacterial activities of R- and S-linalool.       Methods      The in vitro antibacterial activities were determined by agar-diffusion method and micro-dilution assay

including MIC

MBC

B/I

inhibition curves

IC

50

time-kill curves.       Results      R- and S-linalool inhibited the growth of bacteria

including strains of S. aureus (ATCC29213

ATCC25923)

S. epidermidis (ATCC12228

ATCC35984)

and E. coli (ATCC25922). All the MIC values of sensitive bacteria were between 1.024 and 4.096 mg/mL. The antibacterial activities of R-linalool were slightly better than those of S-linalool in terms of some bacteria.

The ratio range of B/I was from 1 to 2.The MIC values of P. aeruginosa (ATCC27853) wasn’t obtained (MIC 8.192 mg/mL). When linalool was used to inhibit S. aureus (ATCC29213

ATCC25923)

the IC

50

of R isomer was smaller than those of S isomer (P0.05). Effect curves of two isomers showed a dose- and time-dependent manner.       Conclusion      R- and S-linalool effectively inhibit the growth of bacteria. And the subtle difference may be present between them.