Abstract
Context: Sideritis species (Lamiaceae) are widely used as herbal tea and have been used in folk medicine for their anti-inflammatory, anti-rheumatic, digestive, and antimicrobial activities in Turkey. Sideritis dichotoma Huter., Sideritis erythrantha Boiss. var. cedrotorum, and Sideritis vuralii H. Duman et Başer are available as commercial products in Turkey.
Objective: The antiradical activities of the various solvent extracts of Sideritis species are investigated here for the first time.
Materials and methods: Plant samples were sequentially extracted with n-hexane, dichloromethane, methanol, and aqueous methanol (50%, v/v) in Soxhlet apparatus. The extracts of Camellia sinensis (L.) Kuntze (Theaceae) were also prepared for use as a positive control. Total phenolics, iron(III) reductive effects, and 1,1-diphenyl-2-picrylhydrazyl (DPPH
*
) radical scavenging activities of the all extracts were measured colorimetrically.
Results: The aqueous MeOH and MeOH extracts contained the highest amount of total phenols, whereas the n-hexane extract contained the lowest amounts. The polar extracts of C. sinensis showed higher antiradical activity and also iron(III) reductive effects than the Sideritis species; however, the non-polar extracts of Sideritis species were found to be more active than those from C. sinensis in the iron(III) reductive assay and in the DPPH
*
assay as well. But none of the extracts was found to be as active as with positive controls, viz., ascorbic acid, butylated hydroxyanisole (BHA), and Trolox.
Discussion and conclusion: These results can be shown to have antioxidant activities of these Sideritis species and support the ethnopharmacological use of these Sideritis plants.