Yarrow (Achillea mille folium, L.) plant, Fam. Asteraceae, locally known as
"Thousand leaves", is an important medicinal and aromatic plant that contain high
quality essential oil of deep blue color which is rich in chamazulene. A study was
carried out during two successive seasons 200012001 and 2001/2002, at the
Experimental Station of Medicinal and Aromatic plants, Fac. of Agric., Mansoura Univ.
The research aimed to study the effect of length of the storage period on essential oil
percentage of the dried flowers collected from two consequent harvests from spring
and autumn plantings and the changes that took place during storage in the
composition and the relative percentage of its constituents. The physical and chemical
properties of the oil were determined and are included in this study. The results showed that increasing the storage period of the dried flowers
significantly decreased the essential oil percentage of the flowers by an average of
0.06% every two months. The planting date or the interaction between planting date
and the storage period did not significantly affect the essential oil percentage of the
dried flowers.               ,        Gas Liquid Chromatography analysis of oil samples revealed ten identified compounds. Chamazulene was the major constituent of the oil forming from 18.42%
to 47.32%. The other constituents were p-pinene, thujone, limonene,1-8 cineol,
bisabolol, camphor, a _pinene, borneol, terpeinol, and caryophyllene. Increasing
length of storage period decreased the percentage of (borneol, terpinol, 1-8
cineol,camphor, thujone and bisabolol) and increased the percentage of (a,p-pinene,
Iimonene and caryophylene). While chamazulene percentage increased after two
months of storage and decreased thereafter. Oil of autumn planting was higher in
chamazulene, 0- and p-pinene, but lower in limonene, caryophylene, 1-8 cineol,
Bisabolol, Terpinol, camphor and bomeol than spring. The oil of the 1 st cut of both
plantings contained higher percentages of a -pinene, camphor, borneol, thujone,
terpinol and chamazulene, but lower p-pinene and bisabolol than the comparable
ones of the 2nd cut.