Phytochemical comparison of essential oils in five species of Stachys L. in Khorramabad agronomic conditions

Stachys L. belonging to Lamiaceae family is one of the most important medicinal and aromatic herbs that is found in different regions of Iran. This research was aimed to compare the chemical composition of essential oils in five species of Stachys (S. lavandulifolia, S. laxa, S. inflata, S. germanica and S. byzantina), so their seeds were planted and propagated in a research farm in Khorramabad in 2018. Plants were sampled at full flowering stage. The samples were dried and ground in the shade. Essential oil extraction was performed using Clevenger apparatus and water distillation method and their compositions were determined by GC and GC / MS. The essential oil compounds were detected using GC and GC/MS. The results showed that the highest and lowest essential oil yields (w/w) with average values of 2.0 and 0.8% were obtained in S. lavandulifolia and S. byzantina, respectively. The highest amount of α-pinene with values of 6.13 and 9.9%, and the highest amount of β-phellandrene with values 19.2% and 25.1%, were obtained in S. laxa and S. inflata, respectively. The highest amount of Linalool with values of 9.9 and 3.9% were observed in S. germanica and S. inflata, respectively. Similarly, the highest amount of caryophyllene with a value of 15.6% was obtained in S. laxa species. The amount of germacrene-D in S.byzantina, S.laxa, S. lavandulifolia and S.inflata was 33.8%, 4.4%, 3.1% and 2.7%, respectively. In S. lavandulifolia, the main compounds were Bicyclogermacrene (4.6%), δ-Cadinene (6.5%), Spathulenol (6.8%), δ-Cadinol (3.1%), α-Cadinol (8.7%), respectively. As a result, due to its wide distribution in Iran, this species is introduced as one of the important species of Stachysfor cultivation and domestication.