Development and validation of a simple,sensitive and reproducible method for simultaneous determination of six polyphenolic bioactive markers in Dendrobium plants

Dendrobium is a large genus of orchid plants containing several bioactive polyphenols, including bibenzyls, phenanthrenes, and flavanones that have been used as antioxidants in nutraceutical and pharmaceutical products. Several polyphenols including (2S)-eriodictyol, (2S)-homoeriodictyol, moscatilin, gigantol, chrysotoxine and crepidatin are primarily found in Dendrobium species and can serve as bioactive markers of orchid plants. In the present study, a simple UPLC-UV method for the simultaneous determination of six polyphenols was developed for evaluating the distribution of bioactive phytochemicals in orchid plants and validated according to the ICH Q2 (R1) guidance. The sample was prepared by extracting dendrobium powder with methanol and the supernatant was analyzed using the Waters ACQUITY UPLC^TM H-Class system on an ACQUITY UPLC^TM BEH C18 column (2.1 × 50 mm, 1.7 μm) with gradient elution of water and acetonitrile, containing 1% v/v trifluoroacetic acid (TFA) each, at a flow rate of 0.2 mL/min and UV detection at 280 nm. The chromatographic condition provided good peak shape and resolution. The method was linear over the specific ranges with the coefficient of determination (r²) > 0.995. Accuracy of the method expressed as %recovery ranged from 80 to 110%. The precision of the method demonstrated as %CV was < 7.3%. The method is simple, accurate, precise and robust and is recommended for routine quality control analysis of orchid plants containing the six polyphenols as the main principles in the herb. The proposed method was successfully applied for simultaneous quantification of the 6 polyphenolic compounds in 11 samples from 3 Dendrobium species, suggesting that the method was suitable for quality assessment of orchid herbal raw materials.