Kosger, Ozturk, Sokmen, Bulut, Ay observed. Subepithelial healing was evident than that of control group (Figure 2). After 14 days in the control group, subepithelial healing accelerated and it was seen that collagen fibers were marked. Wound healing was favorable in incision areas treated with extract during 14 days than that of controls. However, mononuclear cell infiltration was present in incision areas (Figure 3). Twenty-one days after incision made with scalpel, it was observed that the incision area was entirely closed; and epithelium and subepithelium were normal in appearance (Figure 4). dISCuSSIoN A. densiolfra is one of the four species of genus Arnebia (Boraginaceae). Previous studies showed antibacterial, anti-tumoural and wound healing activities of napthaquinone isolated from Arnebia.7- 11 Aktan found that application of ointment containing 10% A. densiolfra root extract to full- thickness skin incision in rats for 7 days decreased the oedema, while collagen fibre development and epithelium regeneration accelerated thus epithelium thickness increased.12 In this study, we histologically evaluated effect of A. densiolfra root extract on scalpel wounds in rat palatal tissue model. Rats treated with A. densiolfra showed rapid healing than the control group. Wound closure and collagen production were faster and healing occurred on the 14th day after wounding, however, in the control group healing was occurred on the 21st day. A. densiolfra root extract improved healing, especially wound closure and collagen fibre production stages. However, this outcome may also show differences in human wound healing models. CoNCLuSIoNS In the limits of this study, A. densiolfra root extract seems to improve healing of scalpel wounds in rat palatal mucosa. Also, as our study used A. densiflora root extract instead of isolated napthaquinone derivatives, further studies using isolated napthaquinone derivatives would be much informative. ACKNoWLEdGEMENtS Financial support from Cumhuriyet University (number: DIS-007) is gratefully acknowledged. April 2009 - Vol.3 REFERENCES 1. Cragg GM, Newman DJ, Snader KM. Natural products in drug discovery and development. J Nat Prod 1997;60:52- 60. 2. Davis PH. Flora of Turkey and East Aegean Islands. Vol 6. University Press, Edinburgh, 1988: p. 311. 3. Sokmen A, Jones BM, Erturk M. The in vitro antibacterial activity of Turkish medicinal plants. J Ethnopharmacol 1999;67:79-86. 4. Dulger B, Gonuz A, Aysel V. Inhibition of clotrimazole- resistant Candida albicans by some endemic Sideritis species from Turkey. Fitoterapia 2006;77:404-405. 5. Baytop T. A dictionary of vernacular names of wild plants of Turkey, vol. 578. Turkish Language Society, Ankara, 1997: p. 131. 6. Bozan B, Baser KHC, Kara S. Quantitative determination of naphthoquinones of Arnebia densiflora by TLC- densitometry. Fitoterapia 1999;70:402-406. 7. Yao XS, Ebizuka Y, Noguchi H, Kiuchi H, Shibuya M, Iitaka Y, Seto H, Sankava U. Biologically active constituents of Arnebia euchroma: Structure of arnebinol, an ansa- type monoterpenylbenzenoid with inhibitory activity on prostaglandin biosynthesis. Chem Pharm Bull 1991;39:2956- 2961. 8. Kaith BS, Kaith NS, Chauhan NS. Anti-inflammatory effect of Arnebia euchroma root extract in rats. J Ethnopharmacol 1996;55:77-80. 9. Sidhu GS, Singh AK, Banaudha KK, Gaddipati JP, Patnaik GK, Maheswari RK. Arnebin-1 accelerates normal and hydrocortisone-induced impaired wound healing. J Invest Dermatol 1999;113:773-781. 10. Gaddipati JP, Mani H, Shefali, Raj K, Mathad VT, Bhaduri AP, Maheshwari RK. Inhibition of growth and regulation of IGFs and VEGF in human prostate cancer cell lines by shikonin analogue 93/637 (SA). Anticancer Res 2000;20:2547-2552. 11. Ogurtan Z, Hatipoglu F, Ceylan C. The effect of Alkanna tinctoria Tausch on burn wound healing in rabbits. Dtsch Tierarztl Wochenschr 2002;109:481-485. 12. Aktan Y. Analgesic, anti-inflammatory, wound healing activities and effects on liver of Arnebia densiflora (Nordm.) Ledeb. root extract. Institute of Health Sciences, Master Thesis, 1994, Osmangazi University, Eskisehir, Turkey (in Turkish). 99 European Journal of Dentistry