Phenolic antioxidant compounds produced by in vitro shoots of sage ( Salvia officinalis L.)

Abstract

In vitro shoots of sage ( Salvia officinalis L.) were established under four different cytokinin supplementations by culturing nodal segments excised from aseptically germinated seedlings. The highest rates of shoot proliferation and linear shoot growth occurred with the supplementation of 1.5 mg/l benzyladenine and 0.05 mg/l dichlorophenoxyacetic acid. However, under these conditions, the specific production of total antioxidant phenolics was the lowest. Variation in kinetin (KIN) concentration (1.5; 2.0; 4.0 mg/l), in the presence of 0.05 mg/l 2,4-D, did not influence significantly the rates of shoot proliferation and linear shoot growth but influenced the production of antioxidant phenolics and biomass. Seventeen compounds were identified in the antioxidant phenolic extracts from shoots: gallic acid, 3- O-caffeoylquinic acid, 5- O-caffeoylquinic acid, caffeic acid, and rosmarinic acid, as phenolic acids; hesperetin, apigenin, hispidulin, cirsimaritin, and genkwanin, as flavonoids; epirosmanol, epirosmanol methyl ether, carnosol, epiisorosmanol ethyl ether, rosmadial, carnosic acid, and methyl carnosate, as phenolic diterpenes. With exception of carnosic acid and methyl carnosate, all the other phenolic compounds (15) were also identified in a commercial sample of this species. Rosmarinic acid and carnosol were the main compounds in all the antioxidant phenolic extracts. The increase in concentration of KIN decreased the accumulation of the most of phenolic diterpenes, particularly that of carnosol.