Evaluation of phytochemical markers characterising cultivated and wild mullein flowers (Verbascum phlomoides L.)

Verbasci flos, the drug of mullein is officinal in numerous national pharmacopoeias. Most important compounds of the herb are flavonoids, iridoids, mucilaginous polysaccharides and saponins [1,2,3,4]. Due to its expectorant and diaphoretic activity Verbasci flos has been used in folk medicine in cases of cold [1]. The aim of our study was to reveal the chemical composition of flower drugs from the annual cultivated variety 'Napfény' and from a wild biennial Verbascum phlomoides population. Further purpose was to compare the two drugs. Active substance assays were performed from representative drug samples, with triple repeats according to the instructions of the European Pharmacopoeia as well as with TLC, TLC-densitometry, HPLC, HPLC/MS, GC and GC/MS methods. Identification of representative compounds was carried out with standard additon and comparison with mass spectra from spectral libraries. We have found that in the accumulation of polar compounds characteristic of flower drugs there could not be detected any significant distinction between wild and cultivated stands. Contents of wild and cultivated stands are as follows: swelling index was 8,2–10,2ml and 8,0–11,0ml; total flavonoid content was (expressed as hyperoside) 0,97g/100g and 1,05g/100g; total tannin content was (expressed as pyrogallol) 4,12g/100g and 3,80g/100g, respectively. At valuation of flavonoid/phenolic composition tamarixetin, rutoside, rutin, isoquercitrin, quercitrin and chlorogenic acid contents have been studied and proportional differences have been found. We have observed significant differences in occurence of iridoid and apolar compounds of inflorescence drugs, accordingly in essential oil composition (occurence and proportion of α and β isophorone, minor compounds) and in accumulation of phytosterols and triterpenoids.

References: [1] Wichtl M. (1997) Teedrogen und Phytopharmaka. Wissenschaftliche Verlagsgesellschaft. Stuttgart. [2] Kraus, J. et al. (1987) Deutsche Apotheker Zeitung. 127: 665–669. [3] Klimek B. et al. (1996) Phytochemistry. 43: 1281–1284. [4] Papay, V. et al. (1980) Pharmazie 35: 334–335.