High-Performance Liquid Chromatographic Analysis of Flavones from the Anti-inflammatory Fraction of Orthosiphon stamineus Chloroform Extract

Abstract: orthosiphon (o.) stamineus is a popular medicinal herb which has gained its popularity by the name of misai kucing (cat's whiskers) in malaysia. it has been used traditionally as diuretic and for the treatment of rheumatism, diabetes, hypertension and inflammation. studies have been carried out to screen the anti-inflammatory activity of o. stamineus extract on animals. sub-fraction cf2b from the crude chloroform extract of o. stamineus was found to be most active in inhibiting carrageenan-induced hind paw oedema in mice thus indicating the most active anti-inflammatory fraction of the extract to be sub-fraction cf2b. two compounds were isolated and identified from this active sub-fraction, namely 5,3'-dihydroxy-6,7,4'-trimethoxyflavone 1 and 5,6,7,3',4'- pentamethoxyflavone 2. compounds i and 2 are flavones commonly known as eupatorin (eu) and sinensetin (si) respectively. both compounds were identified and elucidated through spectroscopic methods. a simple, rapid and accurate high-performance liquid chromatographic (hplc) method was developed for the assessment of these two flavones. in the quantitative determination, the concentrations of eu and si are found to be 0.0505 mg/ml (5.05%) and 0.0286 mg/ml (2.86%) respectively in 1 mg/ml of cf2b active sub-fraction. the method is precise with relative standard deviations for these two constituents ranging between 1.27-4.52%) (intra-day) and 2.17-4.52%) (inter-day).