The essential oil from flowering aerial parts of Nepeta depauperata Benth., an endemic Iranian plant, obtained by steam distillation was analyzed by GC/MS. The constituents were identified by their mass spectra and Kovats* indices. Thirty-three compounds consisting 82.52% of the total components were identified from the oil obtained with a yield of 0.3%v/w. Among them, spathulenol (31.84%), beta caryophyllene (12.93%) and caryophyllene oxide (10.27%) were the major components of the oil.

Centaurea aucheri (DC.) Wagenitz is one of the species of Asteraceae that has not been the subject of many investigations. Different species of this genus have been used in traditional medicine. In this investigation C. aucheri was collected from Khanesorkh of Kerman and the essential oil of the aerial parts of plant was extracted by Clevenger apparatus and analyzed by GC-MS. Identification of the components of oils were based on their retention indices and mass spectra data in comparison with those reported in literatures. The amount of essential oil was 0.16% and 22 substances consisting 80.03% of the composition of the essential oil were identified. The main compounds were caryophyllene oxide (19.44%), β-caryophyllene (14%), Geremacrene-D (13.38%). The essential oil was rich in sesquiterpene oil.

Interest to natural medicines is increased for the sake of fewer side effects, microbial resistence and more compatibility to the human body. Centaurea depressa (commonly known "cornflower") belongs to compositeae family, which comprises more than 74 species in Iran. It has been claimed that it can be used in many cases, such as infections, cough, constipation, dermatitis, fever, jaundice, pain, water retention and cancer. Tannins, different salts, mucillage, cyanine are some of active compounds in this medicinal herb. In addition, lignanglycosides, sesquiterpenes, flavonoids and phytoecdysteroids have been found in different species of Centaurea. In this study Centaurea depressa was collected from Deilaman village in Gilan province in order to assay the antimicrobial activity, since it was used as an anticough and anticold remedy in those area. After collecting and drying the plants, extracts were made by perculation method in solvents with different polarity (hexane, chloroform and methanol). The agar diffusion method was used to assess the activity against five bacteria and one yeast: staphylococcus aureus, bacillus subtilis, escherchia coli, pseudomonas aeroginosa and candida albicans. The results, evaluated as the diameter of the inhibition zone of microbial growth, showed that methanolic extract was the most active extract against some gram-positive bacteria. Methanolic extract had more antimicrobial effect compared to nonpolar extracts. Therefore, the active compounds might have polar chemical structure that will be idetified by the research group.