Rubia davisiana ehrend, bitkisinin antrakinonlarının izolasyonu, identifikasyonu ve boyacılıkta kullanımı

Abstract

102 ÖZET Bu çalışmada yalnız ülkemizde yetişen (endemik) R. davisiana Ehrend. bitkisinin köklerindeki antrakinonlar ve boyama nitelikleri incelendi. Rubiaceae familyasından bir bitki olan Rubia davisi ana Ehrend. Temmuz 1985 te Antalya'dan toplandı. Kurutularak kaba toz edilen R. davisiana kökleri soks- let apa reyinde etanol ile ektre edildi, vakumda uçurulduktan sonra sulandırılan bakiye benzenle tüketildi. Benzen ekstre- sinin bir kısmı silikajel sütun kromatograf isi ile fraksi- yonlandırılarak 10 ana grupta toplandı. Elüsyon işlemine pet rol eteri ve benzenle başlandı, benzene artan oranlarda klo roform ilave edilerek devam edildi ve alkol ile tamamlandı. Bu fraksiyonlardan dört antrakinon bileşiği preparatif sili kajel plâklar kullanarak çok az miktarlarda ve saf kristal halde izole edildi. Maddelerin yapısı spektral yöntemler (İR, UV, NMR, MS), renk reaksiyonları, sulu NaOH ve Na CO, çözeltilerindeki çözünürlük testleri, standart örnekle ince tabaka kromatograf isi ve erime derecesi kıyaslamaları yapı larak aydınlatıldı. Antrakinonların yapısı l-hidroksi-2-me- tilantrakinon (A,), 1,4-dihidroksiantrakinon (quinizarin ) (A.,), l,6-dihidroksi-3-metilantrakinon (phomarin) (A,), 1, 6-dihidroksi-2-metil-8-metoksiantrakinon (veya izomerle ri) (A.) olarak belirlendi.- 103 - Benzen ekstresinin ikinci kısmı asidik silikajel sü tundan fraksiyonlandırıldı. Benzenle yapılan elüsyonlarda B,B,B,B. maddeleri karışım halde elde edildi. Maddeler bu karışımdan preparatif silikajel plaklar kullanılarak i- zole edildi. Bu maddelerin yapıları renk reaksiyonları, sulu NaOH ve Na_CO, çözeltilerindeki çözünürlükleri, standart örnekle ince tabaka kromatograf isi ve erime dereceleri kıyaslamaları ve ayrıca İR, UV gibi spektral yöntemler vasıtasıyla 1,3- dihidroksiantrakinon-2-karboksilik asit(munjistin) (B^) ; 1,2-dihidroksiantrakinon (alizarin) (B

104 - SUMMARY In this study anthraquinones of the roots and dyeing properties of Rubia davisiana Ehrend. which is an endemic species, were investigated. Rubia davisiana Ehrend. is a plant from Rubiaceae family, collected from Antalya in July 1985. Air-dried and crudely powdered roots of R. davisiana was extracted in a soxhlet apparatus with ethanol. After evaporation in vacuo, the aqueous residue was extracted with benzene. A part of benzene extract was separated into ten main fractions using a silicagel column. The eluation started with petroleum ether, then with benzene, increasing amounts of chloroform were added into benzene and the elua tion completed with alcohol. From the fractions four anthraquinones were isolated as pure crystals in very small amount by preparative silicagel TLC. The identifica tion and structure determination of the compounds were done by spectral methods (IR, UV, NMR, MS), colour reactions, solubility tests in aqueous NaOH and in Na.CO, solutions, thin layer chromatographic comparison with authentic sample and by melting point. The structure of the anthraquinones were determined as l-hydroxy-2- methylanthraquinone (A, ), 1,4-dihydroxyanthraquinone (quinizarin ) (A,), 1, 6-dihydroxy- 3-methylanthraquinone (phomarin) (A3), 1,6-dihydroxy-2-methyl- 8-methoxyanthraquinone (or its isomers) (A4).- 105 - The second part of benzene extract was fractionated on an acidic silicagel column. The benzene elutions yielded four compounds B^BjjB, and B4 as mixtures. The compounds were isolated by preparative silicagel plates from this mixture. The structure of these compounds were determined as l,3-dihydroxyanthraquinone-2-carboxylic acid (munjistin) (B1), 1,2-dihydroxyanthraquinone (alizarin) (B?), 1,2,4- trihydroxyanthraquinone (purpurin) (B ) and 1,2,4-trihydrox- yanthraquinone-3-carboxylic acid (pseudopurpurin) (B.) by colour reactions, solubility tests in aqueous NaOH and in Na2C03 solutions, thin layer chromatographic comparison with authenic sample, melting point measurement and spectral methods such as IR, UV. Therefore, in this first chemical investigation of R. davisiana we have isolated and identified eight anthraqu i- nones. According to the literature four of these compounds, B,,B,B, and B. are natural and mordant dye and metal complex of A, and B are pigment dye. In the second part of this study, wool and cotton were dyed with R. davisiana roots using traditional mordant dyeing methods and fastness properties were determined. According to the fastness properties R. davisiana roots which dyes the wool into a brown-red colour could be an advisable natural mordant dye for wool, but it could be a good mordant dye for cotton with special receipts on dyeing methods.