[Chemical Study of essential oil of Syrian oregano Origanum Syriacum, and testing its efficiency in the integrated pestes management]

In this work several samples of Origanum Syriacum had been collected during different during different periods of growing (growing, flowering, after flowering) from three Syrian regions which differ in its height from the see level, climate, samples were dried and oil was extracted by water distillation, chemical composition was identified by GC-MS. Results show that the oil yield and composition is related to the region where it grow, and related to the period of growing, this implicate the choice of the period of collection to obtain the desired chemical with the higher percent to get the economical or medical benefit. The best oil yield was obtained during flowering period. On the other hand, the study of natural conditions (topography, climate, biology) showed a positive relation between humidity and oil yield, and the percent of phosphor and potassium in the soil has a positive relation with the oil yield. The oil yield increases when the direction of mountain slope is more oriented to the north. By analysing the oil of Origanum Syriacum 23 chemicals were identified, the percent of these chemicals together is 92% of the oil. Thymole, carvacrol, para-cymene, and gamma-terpinene form 84% of the oil. Percent of every chemical change as the period and region of collection change. Quantitative analyses of thymole, carvacrol , para cymene and gamma terpinene was done. thymol, carvacrol and gamma terpinene reach their maximum concentration during the flowering period excluding the sample collected from the region of Messiaf, gamma terpinene reachs its maximum concentration during the the growing period, para cymene reachs its minimum concentration during the growing period and its concentration increases to attain its maximum after flowering and becomes dominant. Antifungal activity of the water aqueous emulsion of Origanum Syriacum against Alternaria alternanta and Trichothecium roseum was tested, aqueous emulsion was prepared using several different samples of dried plant, all samples showed high efficiency of inhibition of the mycelial growth of the two fungis, the percent inhibition of Trichothecium roseum was more than 90% for a concentration of dried plant of 0.125g /L. on the other hand, the percent inhibition Alternaria alternanta was more than 75% for a concentration of dried plant of 2g /L, and it attained 60% when the concentration was 0.5g/L. The water aqueous emulsion of origanum syriacum against feve aphis was also tested, results showed high mortality between aphis due to effect of monotrepines in the oil which prevent the feeding of aphis.