Ornamental “Drumstick Onions“ of Allium Subgenus Melanocrommyum Used as Medicinal Plants in Southwest and Central Asia

Many members of Allium subg. Melanocrommyum are cultivated as ornamentals in European and North American gardens. Most of these species occur naturally in Southwest and Central Asia where they are collected in nature and used as vegetable, spice, and medicinal plants by native populations. Between 2002 and 2006, Allium samples were collected in the republics of Iran, Turkmenistan, Uzbekistan and Tajikistan. Eighteen species reportedly used as medicinal plants were morphologically and taxonomically characterized. Most of these species were chemically analyzed by means of HPLC and also screened for radical scavenger activity by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Our data verified relatively large amounts (>0.25%) of cysteine sulphoxides (the main medicinally relevant sulphur compounds of garlic and common onion) to be present in ten species. However, some highly valued species showing also a very high radical scavenger activity contained only traces of cysteine sulphoxides but significant amounts of the newly detected sulphur pyrrole. This compound is apparently responsible for the high radical scavenger activity of A. motor, A. komarowii, A. jesdianum, A. rosenorum, and possibly also A. karataviense. Unexpectedly, some species showed high scavenger activity but did contain neither remarkable amounts of cysteine sulphoxides nor of sulphur pyrroles (e.g., A. alaicum, A. chelotum). These data underlined that another bioactive principle might be present, and more species of subg. Melanocrommyum than hitherto used may represent valuable medicinal plants.

Acknowledgements: The authors are greatly indebted to organizers and local scientists supporting the field-work in Iran, Tajikistan and Uzbekistan, especially to Dr. Mehrdad Abbasi, Prof. Dr. Hikmat Hisoriev, and Dr. Furkat Khassanov. Funding by VolkswagenStiftung (Hannover, Germany) under the general funding theme “Zwischen Europa und Orient – Mittelasien/Kaukasus im Fokus der Wissenschaft“ is gratefully acknowledged.