Quantification of rosmarinic acid levels by near infrared spectroscopy in laboratory culture grown spearmint plantlets

ISSn: 0967-0335 © IM publications llp 2008 doi: 10.1255/jnirs.769 all rights reserved rosmarinic acid (ra) is caffeoyl ester phenolic from the phenylpropanoid pathway and is common among species of the Boraginaceae and Lamiaceae families.1,2 ra has been shown to have health promotive effects and may be employed for gastrointestinal disorders and urinary anti-inflammation and also has anti-HIV activity.1,3 In plant tissue culture, ra is constitutively expressed in cell suspensions and callus cultures,1,4–9 micro-shoots2,10 and cultured roots.11–13 In order to increase ra concentrations in sterile plantlets and micro-shoots a variety of nutritional and physical treatments have been employed.14,15 Microshoots and plantlets readily express the same secondary metabolites as found in plants grown in the soil.3,14–17 We have also examined the influence of co2 concentrations on ra production in vitro via this plant culture methodology.18,19 this research generates a large number of samples which require time and labour to process and analyse. consequently, they lead to delays in the experimental programme. as an alternative to conventional chromatographic analysis, we sought to employ nIr spectroscopy as a means for rapid ra analysis of dried samples to accelerate research efforts. nIr spectroscopy has been used to evaluate the general composition of a substance, detect impurities, determine differences in composition for substances and identifiy unknown substances.20,21 this technology has been expanded to evaluate a number of general parameters in plant samples including protein, moisture, fibre and lipid content.22 currently, protocols exist to determine the levels of essential oils, carotinoids, alkaloids and total phenolics in Quantification of rosmarinic acid levels by near infrared spectroscopy in laboratory culture grown spearmint plantlets