Elucidation of anthocyanidins of Thymus praecox Opiz subsp. caucasicus var. caucasicus by HPLC-UV

Phenolic compounds, found naturally in many fruits and vegetables, draw attention due to they have important biological activities such as antioxidant, antiviral and antitumor. Phenolic compounds are examined as phenolic acids and flavonoids into two parts. Anthocyanidins are colorful compounds placed in the group of flavonoids. Phenolic compounds are synthesized by plants, as secondary metabolites. Anzer tea (Thymus praecox Opiz subsp. caucasicus var. caucasicus), as a type of thyme, is in a herbs constituting Anzer honey and being used as a healing source by local people. Plant with colorful flowers was analyzed by HPLC-UV for its anthocyanidins in this thesis. An appropriate method has been developed primarily for HPLC-UV analysis of anthocyanidins. Suitable extraction method was chosen to isolate anthocyanidins from Anzer tea and three different methods were used, including acid hydrolysis. Also the stability of anthocyanidins as unstable compounds, was investigated with cyanidin standard into two different concentrations 1 mg.l-1 and 10 mg.l-1 and two different anzer tea extracts prepared in pH 1, 50 days during at -18 ? C for the time-dependent changes in the amount, using HPLC-UV analysis. Cyanidin and pelargonidin were detected in the Anzer tea extracts. Comparing non-hydrolyzed extracts with hydrolyzed one, while 11 different peaks were observed before hydrolysis, they have dropped to 3 peaks including cyanidin after hydrolysis. The amount of cyanidin was greater than the cyanidin equivalent of the other two peaks 2.28 and 10.55 times in the hydrolyzed extract. In the light of these datas, it is concluded that the plant has the main content being rich of cyanidin glycosides. According to the result of stability test of cyanidin standard, at -18?C and pH 1 after 50 days, it is observed that the standards analyzed sequentially in every analysis day at 1 mg.L-1 and 10 mg.L-1 concentrations were decreased 60% and 90% consequently. It is observed that the concentrations of the standards, at the concentrations of 1mg.L-1 and 10mg.L-1 and analyzed only one single day, were decreased around 20%. The loss of concentration was observed around 85% at the hydrolyzed and non-hydrolyzed two Anzer tea extracts at the end of 50 days. Anahtar kelimeler: Anthocyanidin, Anzer tea, HPLC-UV, the stability of cyanidine.