The resazurin assay utilising microtitre-plate, described by Drummond and Waigh in 2000, has been modified to achieve more accuracy in the determination of the minimum inhibitory concentration (MIC) values of natural products, including crude extracts, chromatographic fractions or purified compounds against various bacterial strains. This modified resazurin method is simple, sensitive, rapid, robust and reliable, and could be used successfully to assess antibacterial properties of natural products.

From a consideration of ethnobotanical and taxonomic information, seeds of 45 Scottish plant species encompassing 23 different families were obtained from authentic seed suppliers. The n-hexane, dichloromethane (DCM) and methanol (MeOH) extracts were assessed, both qualitatively and quantitatively, for free radical scavenging activity in the DPPH assay. The MeOH extracts of 37 species exhibited low to high levels of free radical scavenging activity (RC50 values ranging from 2.00 to 4.7 x 10(-4) mg/mL), and Alliaria petiolata, Prunus padus and Prunus spinosa were the most potent antioxidant extracts. The DCM extracts of 17 species showed similar levels of activity, and among those, Prunus padus and Prunus spinosa extracts were the most active with RC50 values of 2.5 x 10(-4) and 5.0 x 10(-4) mg/mL, respectively. The n-hexane extracts were much less active than the MeOH and DCM extracts, and 17 species, with the exception of Glechoma hederacea (RC50 = 1.94 x 10(-4)) displayed low to moderate levels of free radical scavenging property (RC50 values ranging from 2.00 to 8.7 x 10(-3) mg/mL).

No abstract

No abstract

The antioxidant and antibacterial properties of moschamindole (1), an indole alkaloid isolated from the methanol extract of the seeds of Centaurea moschata, have been assessed. General toxicity of this compound has also been determined by the brine shrimp lethality bioassay.