Effect of Aging on the Main Active Ingredients in the Volatile Oil and Crude Methanolic Extract from Achillea santolina

Achillea santolina is an important plant in traditional medicine in Jordan. To utilize the herb throughout the year, the storage process seems to be inevitable. This study investigates the effect of aging for one year on the main active ingredients of the volatile oil and some predominant polar compounds in a methanolic extract of the aerial parts of the plant. Fresh and old samples were evaluated and compared for their antioxidant activity and content of the phenolic and flavonoid compounds. The antioxidant activity of A. santolina was weaker than ascorbic acid (IC50 values for the old, fresh samples, and ascorbic acid: 185.6, 171.4, and 61.3, respectively). Plant storage did not affect the antioxidant capacity and the total phenolic and flavonoid content. Semiquantitative analysis using GC-MS showed that the storage process significantly affected the volatile oil content. Several monoterpenoid and sesquiterpenoid compounds significantly diminished or were even absent in the old sample. Conversely, the content of the polar compounds was not affected by the storage process. The polar compounds derived from azulene, naphthalene, and anthracene dominated the fresh and old samples. The azulene compound achillicin was noticeably abundant in both samples. In conclusion, the volatile oil content seemed to play a pivotal role in the activity of A. santolina, and consequently, storage for one year adversely affected its activity.