Chemometric Profile of Curcuma longa L. Towards Standardization of Factors for High Essential Oil Yield and Quality

Abstract

The quality of an herbal drug is indomitable by its important secondary metabolites. The secondary metabolites present in turmeric plant vary in quantity and phyto-constituent proportion at different growing locations. In spite of ever increasing demand of turmeric essential oil it is still not clear how the soil nutrients and environmental factors influence the quality of turmeric essential oil. The present work was conducted by cultivating a high yielding turmeric cultivar i.e., Roma at 9 different agroclimatic zones to analyse the effect of soil nutrients and environmental factors on its essential oil production and quality. Gas chromatography and mass spectrometry analysis showed wide variation in quality of leaf and rhizome essential oil across all the studied zones. Leaf and rhizome essential oil yield at different experimental zones varied from 0.37 to 1 and 0.39 to 0.7%, respectively. In leaf oil alpha phellandrene content varied from 39 to 82.35% and in rhizome oil tumerone it varied from 12.6 to 71%. Phosphorous content was the most sensitive factor for leaf and rhizome essential oil yield. Nitrogen and organic carbon were the key factors for tumerone content. Euclidian distance matrix analysis showed highest distance coefficient between zone 2 and zone 3 for leaf oil (0.92) and zone 7 and zone 9 for rhizome oil (0.91). The result suggests that essential oil yield and quality in turmeric are greatly controlled by environmental factors and soil nutrients. Thus, yield with volatile constituents can be improved through selection of growing location and proper nutrient management.