The genus Sida is used extensively in herbal medicine. A simple and specific analytical method for the quantitative determination of ecdysteroids in S. rhombifolia is reported. The ecdysteroids were separated with an acetonitrile (0.1% acetic acid)-water (0.1% acetic acid) gradient at a flow rate of 1.0 mL per minute. The HPLC separation was performed on a Synergi Polar-RP reversed phase column and operated at 35°C. Detection was performed at 247 nm. The method facilitated the quantification of seven ecdysteroids [20-hydroxyecdysone-3-O-β-D-glucopyranoside (1), 20-hydroxyecdysone (2), 2-deoxy ecdysone-3-O-β-D-glucopyranoside (3), pterosterone-3-O-β-D-glucopyranoside (4), ecdysone-3-O-β-D-glucopyranoside (5), ecdysone (6), and 20-hydroxy-(25-acetyl)-ecdysone-3-O-β-D-glucopyranoside (7)] in aerial parts of S. rhombifolia. The LOD and LOQ for compounds 1–7 were found to be in the range from 0.07-0.1 μg/mL and 0.3–0.5 μg/mL, respectively. In the present study, a micro-morphological description of S. rhombifolia is provided. The developed method was used for the determination of ecdysteroids in various other species of Sida, which were compared both micro-morphologically and chemically.
