Influence of medium pH, seasonal variation and subculture on in ivitro production of Rosmarinic acid in four Lamiaceae members [electronic resource].

Includes references.

Medicinal herbs are important sources of natural antioxidants. Conditions favoring oxidative stress such as drought, temperature, pH or light stresses cause the formation of high oxidized diterpenes. Rosmarinic acid (RA) is one ofthe most commonly occurring diterpenes and it is widely spread in family Lamiaceae. Since the influence of pH on the antioxidant activity is seldom taken into account, the main objective of this study was to investigate the influence of four different pH levels on RA accumulation in callus culture of four lamiaceae members through three successive subcultures, also the effect of seasonal variation on RA accumulation in vivo and in vitro. It was found that the highest RA accumulation in leaf tissues and in callus culture occurred during the summer and the second subculture in all four species, also it was found that the pH has a significant influence on RA accumulation in callus culture of the four species, the best pH was 6.8 in all species except in sage callus culture where the RA concentration increased significantly at pH 5.8. The highest Species in RA concentration in field production was the sage followed by the rosemary, thyme and oregano and was (0.048, 0.045, 0.035 and 0.026 mg RA/gm fw) respectively, while in vitro culture the highest RA accumulation occurred during the second subculture in the summer at pH 6.8 in Rosemary, Thyme and Oregano (0.086, 0.073, 0.069 mg RA/gm fw) respectively and the least accumulation occurred in sage in the second subculture during the summer at pH 5.8 (0.062 mg RA/gm fw).

Summary in Arabic.

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