İlkay ORHAN, F. Sezer ŞENOL, Ufuk KOCA, Tuğba ERÇETİN, Gülnur TOKER

Evaluation of the antioxidant and acetylcholinesterase inhibitory activities of Arnebia densiflora Ledeb.

Arnebia densiflora Ledeb. (Boraginaceae), a medicinal plant growing in Turkey, has been reported to contain a well-known red pigment, shikonin, a naphthoquinone derivative. In the current study, the acetylcholinesterase (AChE) inhibitory and antioxidant activities of the chloroform, ethyl acetate, methanol, and water extracts of the root, stem, and flowers of the plant, as well as shikonin, were investigated. AChE inhibition was tested using an ELISA microplate reader at 250, 500, 1000, and 2000 µg mL-1. Antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test and the Fe+2-ferrozine test system for metal chelating power. The results indicated that the methanol and water extracts of the roots had a moderate DPPH radical scavenging effect at 2000 µg mL-1, while the extracts exerted a better ferrous ion chelating effect as compared to the reference, butylated hydroxyanisole. Only the root chloroform extract showed mild inhibition against AChE at 62.5 µg mL-1 (49.6 ± 1.69%). Shikonin was inactive in all of the assays performed.

Anahtar Kelimeler:

Key words: Arnebia densiflora, Boraginaceae, shikonin, antioxidant activity, acetylcholinesterase inhibition

Evaluation of the antioxidant and acetylcholinesterase inhibitory activities of Arnebia densiflora Ledeb.

Keywords:

Key words: Arnebia densiflora, Boraginaceae, shikonin, antioxidant activity, acetylcholinesterase inhibition,

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1. The International Plant Names Index (2008). Published on the Internet: http://www.ipni.org [accessed 1 October 2009].
2. Davis PH (ed). Flora of Turkey and the East Aegean Islands, Vol. 6. Edinburgh University Press. Edinburgh; 1978: pp. 311-313.
3. Bozan B, Baser KHC, Kara S. Quantitative determination of naphthoquinones of Arnebia densiflora by TLC-densitometry. Fitoterapia 70: 402-406, 1999.
4. Singh B, Sharma MK, Meghwal PR et al. Anti-inflammatory activity of shikonin derivatives from Arnebia hispidissima. Phytomed 10: 375-380, 2003.
5. Nordberg A, Svensson AL. Cholinesterase inhibitors in the treatment of Alzheimer’s disease: a comparison of tolerability and pharmacology. Drug Safety 19: 465-480, 1998.
6. Ellman GL, Courtney KD, Andres V et al. A new and rapid colorimetric determination of acetylcholinesterase activity. Biochem Pharmacol 7: 88-95, 1961.
7. Blois MS. Antioxidant determinations by the use of a stable free radical. Nature 181: 1199-1200, 1958.
8. Deliorman Orhan D, Orhan N, Özçelik B et al. Biological activities of Vitis vinifera L. leaves. Turk J Biol 33: 341-348, 2009.
9. Orhan I, Kartal M, Naz Q et al. Antioxidant and anticholinesterase evaluation of selected Turkish Salvia species. Food Chem 103: 1247-1254, 2007.
10. Orhan I, Tosun F, Şener B. Coumarin, anthroquinone, and stilbene derivatives with anticholinesterase activity. Z Naturforsch 63: 366-370, 2008.
11. Kourounakis AP, Assimopoulou AN, Papageorgiou VP et al. Alkannin and shikonin: effect on free radical processes and on inflammation - a preliminary pharmacochemical investigation. Arch Pharm 335: 262-266, 2002.
12. Nishizawa M, Kohno M, Nishimura M et al. Presence of peroxy radicals in cigarette smoke and the scavenging effect of shikonin, a naphthoquinone pigment. Chem Pharm Bull 53: 796-799, 2005.
13. Weng XC, Xiang GQ, Jiang AL et al. Antioxidant properties of components extracted from puccoon (Lithospermum erythrorhizon Sieb. et Zucc.). Food Chem 69: 143-146, 2000.
14. Assimopoulou AN, Boskou D, Papageorgiou VP. Antioxidant activities of alkannin, shikonin, and Alkanna tinctoria root extracts in oil substrates. Food Chem 87: 433-438 2004.