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Comparison of HPLC and ATR-FTIR Methods for the Determination of Rosmarinic acid in Aqueous Leaf Extract of Orthosiphon stamineus.



Rosmarinic acid (RA) is an important natural bioactive compound widely distributed in food plants. ATR-FTIR and HPLC methods for comparative determination of RA in aqueous methanolic extracts of Orthosiphon stamineus leaf samples are described.



The quantitative determination of RA was performed by using HPLC with UV detection at 340 nm and ATR-FTIR based on peak height location at 1712.29 cm-1.



The mean recovery of RA was 99.54 ± 1.23% by the HPLC method and 105.48 ± 2.76 by the ATR-IR method. The relative standard deviation for the intra-day and inter-day precision were less than 5% for the HPLC method and less than 8% for the ATR-FTIR method. The limit of detection and limit of quantification values for the HPLC method were 2 ng/ml and 10 ng/ml, respectively. The limit of detection and limit of quantification values for the ATR-FTIR method were 0.14% and 0.83% w/w, respectively. The validated methods were used for the quantification of RA in leaf samples of O. staminues. The results of HPLC and ATR-FTIR methods were comparable.



ATR-FTIR method is suitable for the routine determination of RA in herbal medicinal products of O. stamineus.
