separated and documented at UV 366 nm. The chromatogram neu-tralized with method 5 was subjected to the improved B. s. bioassay.After the MTT staining step, the plates were documented underwhite light illumination, and the absorbance was inversely mea-sured at 546 nm to define the minimum inhibition volume (MIV)of the extracts. The strongest antimicrobial effect in Salvia wasrelated to substance x (hRF50, Fig. 4b). Another adjacent com-pound x´ı (hRF54) also indicated a faint antimicrobial effect. BothMIVs were obtained for application of 0.8 L tincture per band,which equaled to a drug amount of Salvia leaves of 48 ng/bandor 60 mg/mL tincture (for a 1:17 drug extraction). All these visualresults were confirmed by densitometric measurements. The cor-responding peaks of substances x and x´ı were clearly separated at0.8 and 1 L/band (Fig. 4c, tracks 2 and 3), whereas substances x´ıwas evident as shoulder at higher concentrations or volumes (3 and4 L/band; Fig. 4c, tracks 4 and 5). The mean peak area of the inhi-bition zones of substance x over 3 days and 3 plates was 6817 AU(%RSD = 11%) per L Salvia tincture (Fig. 4c, track 3). The increasedresponse of compound x (overloaded at volumes > 4 L) led to apartial coelution with compound x´ı. Substances y and z showed aweak response at 3 and 4 L/band, respectively.