Cytotoxic activity and antioxidative properties of Sideritis scardica extracts

Sideritis scardica Griseb., Lamiaceae (mountain tea) is endemic plant of Balcan peninsula. Traditionally, mountain tea has known for its anti-inflammatory and gastroprotective properties [1]. The dried aerial parts of the mountain tea were extracted using ethanol, diethyl ether, ethyl acetate, and n-butanol. The total phenolics content was determined by the Folin-Ciocalteu method [2]. The extracts were tested for their antioxidant activity measuring the reduction of DPPH absorption to indicate the capacity to scavenge free radicals, independent of any enzymatic activity. Antioxidant capacity of investigated extracts was expressed as EC₅₀. Cytotoxic activity was studied by Kenacid Blue R dye binding method on three different tumor cell lines: HeLa, B16 and FemX [3]. The results are presented in Table. IC₅₀ values for 48 and 72 hours of continual extracts action were determined from cell survival diagrams. The results indicate that, as shown by IC₅₀ values, ethyl-acetate extract have highest dose-dependent cytotoxic activity on all investigated lines. n-Butanolic extract induced strong dose-dependent cytotoxic activity only on HeLa and FemX cell lines after prolonged time of incubation. Diethyl ether extract was not tested for cytotoxic activity.

Extracts	Total phenolics	DPPH activity EC50±σ	Cytotoxicity results for 48 and 72h extracts action IC50±σ (µg/ml)
	±σ (mg GA/g)	(µg/ml)	HeLa		B16		FemX
			48h	72h	48h	72h	48h	72h
Ethanolic	188.45 ±12.91	31.50 ±0.36	86.50 ±3.28	93.59 ±1.33	>100	>100	>100	77.96 ±6.96
Diethyl ether	84.20 ±7.29	147.27±1.76	n.t.	n.t.	n.t.	n.t.	n.t.	n.t.
Ethyl acetate	345.61 ±21.70	20.07±0.41	67.65 ±0.99	68.25 ±0.56	35.03 ±6.34	91.70 ±2.14	57.16 ±5.46	46.51 ±0.5
n-Butanolic	300.2 ±13.39	5.67±0.37	>100	41.99 ±2.01	>100	>100	>100	37.73 ±1.36

Acknowledgements: The authors wish to thank Serbian Ministry of Science for financial support.

References: 1. Gabrieli, C.N. et al. (2005)J. Ethnopharnacol. 96:423–428. 2. Velioglu, Y. S et al. (1998)J. Agric. Food Chem. 46:4113–4117. 3. Clothier, R. H. (1995) Met. Mol. Biol. 43: 109–118.