Figure 7. Extracts are non-toxic to human cells and mouse skin at the concentration required for quorum quenching activity.

(a) Extracts were tested for cytotoxicity using a LDH assay against HaCaT cells at a concentration range of 6–734 μg mL⁻¹, with the vehicle (DMSO) not exceeding 1.5% of the well volume. The extracts were non-toxic at concentrations necessary for agr inhibition. The IC₅₀ values for 430, 430D, and 430D-F5 were 734, 367, and 184 μg mL⁻¹, respectively (data not shown). No IC₉₀ values were established at this concentration range. (b) There was no significant difference in weight gains or losses between mice injected with 50 μg of 430D-F5 or saline. (c) No skin irritation or injury were grossly apparent following a 50 μg injection of 430D-F5 into healthy mouse skin (ruler in cm). Photo taken on Day 1.