Phenolic Antioxidant Compounds Produced by in Vitro. Cultures of Rosemary (Rosmarinus officinalis.) and Their Anti-inflammatory Effect on Lipopolysaccharide-Activated Microglia

Abstract

Different culture types (shoot culture, callus culture, and cell suspension culture) of Rosmarinus officinalis. L. were established and their ability to biosynthesize the phytochemicals carnosic acid, carnosol, and rosmarinic acid were assessed and compared with subcultures of the same stem plant over time. Furthermore, we examined the antioxidative effect of extracts from different culture types by measuring their scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals as well as their anti-inflammatory potential on neonatal microglial rat cells activated by means of the inflammogen lipopolysaccharide (LPS) taking nitric oxide (NO) as parameter. Our results show that during an investigation period of 17 months, the shoot culture accumulated varying amounts of carnosic acid and carnosol, which were also present in callus culture but about 20- to 80-fold lower than in the shoot culture. In suspension culture, only carnosic acid and no carnosol could be detected. The level of carnosic acid in suspension culture was threefold less than detected for the callus culture on average. The amount of rosmarinic acid produced in shoot culture and callus culture were comparable, whereas in suspension culture higher concentrations of rosmarinic acid could be measured than in shoot and callus culture. Thus, the content of carnosic acid, carnosol, and rosmarinic acid in the extracts depended on the differentiation grade of the cell culture type. The DPPH radical-scavenging activity of the extracts depended on the amount of all three phytochemicals, in particular of rosmarinic acid. The anti-inflammatory character of the extracts was mainly based on their carnosic acid content.

Keywords:

• Anti-inflammation
• carnosic acid
• carnosol
• microglia
• rosmarinic acid
• Rosmarinus officinalis