The Effect of Extraction Method on Phenolic and Flavonoid Compounds and Antioxidant Activity of Satureja avromanica Maroofi

Satureja avromanica Maroofi is a medicinally perennial herb which is native to Iran, exclusively restricted to Uramanat mountains of Kurdistan province. It has various pharmaceutical and biological activities such as antibacterial, antifungal, antioxidant, anti-inflammatory, antiviral, anticancer and antiprotozoal properties. The experiment was conducted to study the biochemical characteristics of S. avromanica Maroofi extract by two extraction methods as solvent and solvent-ultrasonic.

The study was carried out as a factorial based on a completely randomized design. The investigated factors were the type of solvent (water, 75% water, 50% water, 75% methanol and methanol) and extraction method (solvent and solvent-ultrasonic). For this purpose, the plant samples were collected from Uraman Mountains of Kurdistan province in July of 2016. Samples were immediately transferred to Herbarium of Agricultural Research Center and Natural Resources of Kurdistan province. The samples were dried in shade for 15 days, and then crushed into pieces of 0.5 to 1 cm by a laboratory mill (Molyneux, Spain). The content of phenol and flavonoid as well as antioxidant activity was measured. Besides, the components of phenol and flavonoid for the best treatment were determined by HPLC apparatus.

The results showed that the compounds extracted by water-ultrasonic were significantly more than those extracted by water. Inhibition percent in water-ultrasonic and water treatments were 16.62% and 11.92%, respectively. The content of phenol (45.36 mg/g, 40.29 mg/g) in water-ultrasonic was higher than that obtained in water treatment (40.29 mg/g). The flavonoid content (15.33 mg/g) in water-ultrasonic was more than that in water treatment (13.29 mg/g). Therefore, water-ultrasonic treatment was more efficient in extracting S. avromanica Maroofi compared to water treatment. On the other hand, the 75% water treatment had more compounds compared to other solvents. The chromatogram of essential ingredient revealed that S. avromanica Maroofi had more Caffeic acid, Gallic acid, Chlorogenic acid, Quercetin, p-Coumaric acid, Ferulic acid. Also, Rutin as the highest amount was obtained in Ferulic acid to be 9.12 mg/g.

We found that water is the best solvent for biochemical extraction of S. avromanica Maroofi. We found a 12% increase of phenol and 14 % increase of flavonoid in water-ultrasonic relative to water treatment. Due to the wide structure of hydrogen bonds, water is a very polar solvent with a dielectric constant at room temperature and atmospheric pressure. Ultrasonic is a type of ultrasound that increases the polarity of the liquid phase. Ultrasonic waves cause mechanical fluctuations in the liquid medium. The mechanical effect of ultrasound improves the penetration of solvent into cellular materials and mass transfer. Hence, ultrasonic waves are more efficient for producing the biochemical compounds like phenol and flavonoid.