LC-MS QUANTIFICATION OF ROSMARINIC ACID AND URSOLIC ACID IN THE<i>OCIMUM SANCTUM</i>LINN. LEAF EXTRACT (HOLY BASIL, TULSI)

Abstract

A simple, sensitive, and accurate liquid chromatography-mass spectrometry (LC-MS) using an atmospheric pressure chemical ionization (APCI) method for the determination of rosmarinic acid (RA) and ursolic acid (UA) in the leaves of ethanol extract of Ocimum sanctum (EEOS) Linn. (Holy Basil, an Indian traditional herb) has been developed for the first time and validated. The LC separation was carried out on a Phenomenex C18 (150 × 4 mm i.d., 5 µ) with single quadrupole MS analyzer. The mobile phase consisting of 0.5% formic acid–acetonitrile (75:25%) and ammonium acetate–acetonitrile (70:30%) were used for RA and UA, respectively, and delivered at a flow rate of 0.5 mL/min. The column temperature was maintained at 30°C. The assay was shown to be linear over the range of 100–1000 ng/mL (r 2 0.9997 and 0.9999 for RA and UA, respectively). The LOD and LOQ for RA and UA were found to be 1 and 3 ng/mL, and 2 and 6 ng/mL, respectively. The method was shown to be reproducible and reliable with intraday precision below 0.14% and 0.11% and interday precision below 0.71% and 0.46% and mean recovery excess of 94.38% and 92.92% for RA and UA, respectively. Using the optimized conditions, the quantity of RA and UA in EEOS was found to be 0.27 and 0.40% w/w, respectively. The method is simple, sensitive, reproducible, and ideally suited for rapid routine analysis.