Influence of the extraction technique on yield and chemical composition of Vitex agnus castus L. essential oil

Abstract

Ekstrakcija pomoću superkritičnog CO2 kao nova zelena tehnologija razmatra se intenzivno posljednjih godina jer se CO2 pokazao kao vrlo poželjno otapalo u separacijskim procesima budući da je neotrovan, nezapaljiv, bez okusa i mirisa, jeftin i lako dostupan u većim količinama, kao i zbog toga što je ekološki prihvatljivo otapalo. Stoga su ciljevi ovoga rada sljedeći: (1) proizvodnja ekstrakata iz ploda konopljike (Vitex agnus castus L.) pomoću superkritičnog CO2 pri različitim procesnim parametrima (tlak, temperatura, protok otapala, veličina čestica), (2) dobivanje eteričnog ulja konopljike postupkom vodene destilacije, (3) ispitivanje kemijskog sastava dobivenih ekstrakata primjenom plinske kromatografije, (4) proizvodnja suhih ekstrakata postupkom liofilizacije i formuliranje tableta. Promjena uvjeta ekstrakcije značajno utječe na prinos ekstrakta. Najveći prinos ekstrakta 12,27% ostvaren je pri tlaku od 225 bar, temperaturi od 60°C, protoku CO2 od 1,95 kg/h i veličini čestica 0,393 mm. Utvrđeno je da ekstrakt ploda konopljike ima veoma kompleksan kemijski sastav. Sastav eteričnog ulja se bitno razlikuje od sastava ekstrakta dobivenog superkritičnim CO2, posebice u količini pojedinih spojeva poput viridiflorola, koji je glavni sastojak eteričnog ulja i α-humulena, koji također dominira u eteričnom ulju, dok je u superkritičnom ekstraktu zastupljen u znatno manjoj količini. Pronađena je i potencijalna primjena dobivenog ekstrakta u farmaceutske svrhe budući da sadrži brojne bioaktivne komponente.Supercritical CO2 extraction as a new green technology is discussed extensively in recent years and it has proven that CO2 is highly desirable solvent in the separation process since it is non-toxic, non-flammable, odorless, tasteless, it is cheap and readily available in large quantities, thus being an environmentally friendly solvent. The aims of this work were as follows: (1) production of extracts from Vitex agnus-castus fruit by supercritical CO2 extraction, under different process parameters (pressure, temperature, solvent flow rate, particle size), (2) production of essential oil of Vitex agnus-castus fruit by hydrodistillation, (3) investigation of chemical composition of obtained extracts applying gas-chromatography, (4) production of dry extracts using freeze drying and formulation of tablets. Extraction conditions change significantly affects the extraction yield. The highest extraction yield of 12.27% was achieved at pressure of 225 bar, temperature of 60 °C, CO2 flow rate of 1.95 kg /h and particle size of 0.393 mm. It was found that an extract of the fruit of Vitex agnus castus L. has a very complex chemical composition. Obvious differences were found between the composition of essential oil and extracts obtained by supercritical CO2 in the amount of certain compounds such as viridiflorol, which is the main component of essential oil and α-humulene, which also dominates in essential oil, while in supercritical extract it is present in much lower quantities. Resulting extracts have found potential application as a pharmaceuticals since they contain a number of bioactive components