Sequence characterized amplified region markers: A reliable tool for adulterant detection in turmeric powder

Abstract

Turmeric powder (Curcuma longa L.), an important medicinal spice product traded internationally, is subjected to adulteration by design or default with powders of related curcumin containing wild species like Curcuma zedoaria and Curcuma malabarica leading to toxicity and poor quality of the produce. The present study aims at development of specific, sensitive and reproducible Sequence Characterized Amplified Region (SCAR) markers to detect these adulterants in traded turmeric powder. Two putative RAPD markers, ‘Cur 01’ and ‘Cur 02’, generated by random primers OPA 01 and OPE 18 were identified as C. zedoaria/C. malabarica specific by comparative RAPD analysis of genuine turmeric and market samples of turmeric powder, C. zedoaria and C. malabarica. These specific RAPD markers were cloned and sequenced. Two pairs of SCAR primers were designed from the RAPD markers ‘Cur 01’ and ‘Cur 02’, respectively. Six market samples of turmeric powder and four simulated standards besides the genuine samples were analyzed using the specific SCAR markers. Both the SCAR markers detected the presence of C. zedoaria/C. malabarica adulteration in four market samples and all the simulated standards prepared in different concentrations. The two SCAR markers developed in the study would be potentially useful for the regulatory agencies to detect C. zedoaria/C. malabarica adulteration in traded turmeric powder. The analytical strategy being very simple could be used for large scale screening of turmeric powder samples intended for export and domestic uses.