The Effect of Storage Conditions on the Essential Oil of Ziziphora clinopodiodes

Ziziphora clinopodioides is an edible medicinal plant (belongs to the family Lamiaceae) that widespread all over Iran. In Iranian folklore, the dried aerial parts of this plant have been frequently used for culinary and also in cold and cough treatments. Present work aimed to evaluate the effect of storage conditions on essential oil composition, antimicrobial and antioxidant activities. Treatments were three levels of storage temperatures including room temperature (21°C), refrigerator temperature (4°C) and freezer temperature (-20°C) in 10 days. Essential oils after extraction with hydrodistillation were analyzed by GC-MS and their antioxidant and antibacterial activities were evaluated by DPPH and DISC diffusion methods. The results showed that in each of three storage temperatures, some compounds such as pulegone and menthone were main compounds in essential oil, but some of them were reduced in essential oil at room temperature. In antioxidant activity assay, freezing essential oil was stronger than other essential oils. The strongest antimicrobial activity against S. aureus, E. coli, and C. albicans was observed from room temperature essential oil; It can be due to the presence of a higher amount of 1,8-cineol, isomenthone and p-menth-4-en-3-one in this essential oil. In conclusion, the storage of secondary plant products especially essential oils, is an interesting research area which needs further studies with different aromatic plants essential oils.