New approaches for the standardization of the Monarda fistulosa herb

Objectives . The Monarda fistulosa herb of the Lamiaceae family is particularly interesting among essential oils from medicinal plants that have a wide spectrum of pharmacological activities. However, information regarding some of its flavonoids, which are found in the essential oil, is controversial. Inaccuracies in identification of the chemical composition of the herb have led to several different standardization approaches, which are cumbersome. To establish a uniform classification, here, we present confirmation for new approaches for the standardization of the Monarda fistulosa herb. Methods. Silica gel column chromatography was used to extract the flavonoids. Identification was based on ultraviolet spectroscopy, nuclear magnetic resonance spectroscopy, mass spectrometry, and acidic hydrolysis. The quality of the proposed quantitation methodology for total flavonoids was assessed by differential spectrophotometry at 394 nm, in isorhoifolin equivalent. Results. We have verified new approaches for the standardization of the Monarda fistulosa herb. The approaches can determine the authenticity of the herb by detecting monoterpene phenols and flavonoids that have diagnostic value. We also developed a technique for quantitation of the total flavonoids. Conclusions. We investigated the possibility of establishing the authenticity of the Monarda fistulosa herb based on the diagnostically significant flavonoids, isorhoifolin and linarin.