Six Origanum species, Origanum acutidens (Hand. -Mazz.) Ietsw. (OA), Origanum brevidens (Bornm.) Dinsm. (OB), Origanum haussknechtii Boiss. (OC), Origanum husnucan-baseri H. Duman, Aytac & A. Duran (OHB), Origanum leptocladum Boiss. (OL), Origanum rotundifolium Boiss. (OR), belonging to sect. Brevifilamentum were analyzed for their essential oil and phenolic components. For the essential oil analyses, GC-MS and GC-FID were used. Phenolic contents of the aerial parts of the chloroform, acetone, and methanol extracts were analyzed using LC-MS/MS. Antioxidant activity of the species was investigated by three methods; DPPH free radical scavenging activity, beta-carotene linoleic acid assays and CUPRAC assays. Also, acetyl and butyrylcholinesterase inhibition of the extracts were investigated. While the essential oil contents of the section Brevifilamentum showed difference in chemotype, the phenolic contents were found to be coumaric acids and derivatives. These groups were the most abundant components of the extracts. Especially rosmarinic acid was detected in high amounts in acetone and methanol extracts. OA had the best activity both in antioxidant and anticholinesterase assays.