Comparative analysis of total anthocyanin and antioxidant levels in anthocyanin-containing species Hibiscus sabdariffa L, Ocimum basilicum L. and endemic Ricotia carnosula Boiss. & Heldr under in vitro and in vivo conditions

This thesis aimed to investigate the in vitro production potential of anthocyanin and antioxidant compounds in three different anthocyanin-containing plant species (Hibiscus sabdariffa, Ocimum basilicum, and the endemic Ricotia carnosula) using tissue culture techniques in the field of plant biotechnology. Increasing secondary metabolite production is particularly important for the sustainable production of natural colorant and antioxidant sources. The study was conducted both in vitro and in vivo, and the experimental process consisted of three main stages: plant material production, callus induction, and metabolite analyses. Callus culture experiments carried out under in vitro conditions revealed the effects of medium components (basal medium, PGR type and concentration), culture conditions (light/dark) and explant type on callus formation, callus quality, rooting, anthocyanin and antioxidant production. In H. sabdariffa species, the highest callus proliferation occurred in the PGR combination of 0.5 mg/L 2,4-D + 0.25 mg/L Zeatin and this also supported anthocyanin production, albeit to a limited extent. Interestingly, the amount of antioxidants obtained from the in vitro callus sample was found to be higher compared to the in vivo sample. In O. basilicum species, it was determined that higher levels of anthocyanin were produced under dark conditions and in large leaf explants. The callus sample obtained from the PGR combination of 0.5 mg/L 2,4-D + 0.2 mg/L Zeatin provided the highest antioxidant activity. In R. carnosula, both anthocyanin amount and antioxidant capacity were higher in cotyledons collected from nature, while in in vitro samples the highest anthocyanin and antioxidant production was detected in the cotyledons of in vitro seedlings. The findings demonstrate that tissue culture techniques can be a powerful tool for secondary metabolite production, depending on the selected plant species. In vitro methods have shown promising results, particularly in terms of increasing antioxidant capacity. In this context, the study's findings have the potential to contribute to biotechnological applications for the sustainable production of natural bioactive compounds. Furthermore, future studies incorporating gene expression analysis and elicitor treatments have the potential to further increase production efficiency in this area.