In vitro 5-lipoxygenase inhibition and anti-oxidant activity of Eriocephalus L. (Asteraceae) species

The genus Eriocephalus (Asteraceae) is endemic to South Africa where some of the species are used traditionally to treat dermal infections, gastro-intestinal disorders, and upper respiratory tract infections. In vitro screening for the presence of anti-oxidants was carried out on acetone leaf extracts of 22 species (80 samples) collected from wild populations using the 2,2, diphenyl-1-picryhydrazyl (DPPH) radical scavenging method. The extracts showed moderate activity with the IC50 values ranging between 21.5 μg ml− 1 (E. punctulatus) and 79 μg ml− 1. The hydrodistilled essential oils were also tested but did not show activity at the starting concentration of 100 μg ml− 1. Essential oils of seventeen species were screened for the presence of inhibitors of 5-lipoxygenase enzyme. The IC50 values ranged between 19 μg ml− 1 (E. africanus) and 98.9 μg ml− 1. Variation between and within natural populations with respect to the activities tested is also documented.