Iron(III) reducing and antiradical activities of three Sideritis from Turkey.

BACKGROUND

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.

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.

CONCLUSIONS

These results can be shown to have antioxidant activities of these Sideritis species and support the ethnopharmacological use of these Sideritis plants.