Abstract:
Abiotic and biotic elicitors that activate the defense mechanisms of plants can be a good strategy for increasing bioactive compounds in plant tissue culture systems (cell, callus, hairy root, and organ cultures). The aim of this study was to determine the effects of cadmium chloride (CdCl2), silver nitrate (AgNO3) and yeast extract (YE) treatments applied at different concentrations to Ocimum bacilicum L. cell suspension cultures on the cell growth (cell dry weight and number), cell viability (%), total phenolic content (TPC) and flavonoid content (TFC) and pharmaceutical active ingredients. The TPCs and TFCs were determined by Folin-Ciocalteu and aluminum chloride colorimetric assays, respectively. Antioxidant capacities were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay. Polyphenols and terpenoids were identified by reversed phase-high-performance liquid chromatography (RP-HPLC) and headspace solid-phase microextraction-gas-chromatography-mass-spectrometry (HS-SPME-GC/MS), respectively. Antioxidant activity, TPCs, and TFCs were the highest in the treatment of 200 mg/L YE among the tested elicitors. The analysis (RP-HPLC) showed that the highest accumulation of chicoric acid (6.45 mg/g DW, 50 mg/L treatment) and rosmarinic acid (21.28 mg/g DW, 200 mg/L treatment) were obtained in yeast extract treatment which was 0.92 and 1.25 times greater than the control. The optimum biosynthesis of rutin and isoquercetin was obtained in the treatment of 50 mg/L yeast extract compared with the control culture, with an increase of 1.91 times (6.54 mg/g DW) and 1.86 times (3.72 mg/g DW), respectively. The highest values of linalool and estragole compared with the control culture were obtained from AgNO3 as 4.37 mu g/g DW (25 mu M treatment) and 3.30 mu g/g DW (5 mu M treatment), respectively. These results show that CdCl2, AgNO3 and YE treatments may be a good strategy for increasing pharmaceutical active ingredients in O. basilicum cell suspension cultures.