Aerial parts of creeping thistle (C. arvense), marsh thistle (C.
palustre), spear thistle (C. vulgare), prickly sow thistle (S. asper),
common knapweed (C. nigra), greater knapweed (C. scabiosa), and
lesser burdock (A. minus) were collected locally in Dublin, Ireland.
Dandelion (T. officinale) roots were collected and purchased from
Irish Organic Herbs Ltd., Leitrim, Ireland. A representative sample
of each plant was identified at the National Botanic Gardens (Dublin,
Ireland). All plants were washed and cleaned prior to freeze
drying using an A12/60 Freeze Dryer (Frozen In Time Ltd., York,
England). Each plant was then ground into a fine powder with the aid of a Waring Commerical Blender (Christison Particle
Technologies, Gateshead, UK) and stored at 20 C.