Apigenin extraction from fresh Elsholtzia ciliata herb

Abstract

Background. Polyphenols have gained a significant importance as bioactive compounds with substantial health benefits. The main properties of polyphenols are anti-diabetic, cardioprotective, anti-aging, neuroprotective, anti-inflammatory, antioxidative effects. The genus Elsholtzia from Lamiaceae family is rich in phenolic compounds. Elsholtzia ciliata is an annual aromatic plant used as a spice in cuisine and as a remedy in folk medicine. Aim. The aim of this study was to increase the extraction efficiency of apigenin from E. ciliata fresh herb. Methods. Extracts of fresh E. ciliata herb were produced using 96, 90 and 70% ethanol by ultrasound-assisted (UAE) (10 min, 25 °C), heat-reflux (HRE) (6 h, 95°C), continuous stirring (CSE) (24 h, 25 °C), percolation (PE) (48 h, 25 °C) and maceration (ME) (48 h, 25 °C) methods. HPLC analyses have been carried out using Waters 2695 chromatography system (Waters, Milford, CT), equipped with Waters 996 PDA detector. For analysis an ACE 5 C18 250 x 4.6 mm (Waters, Milford, USA) column was used. The mobile phase consisted of solvent A (phosphoric acid/acetonitrile/ water) (1:19:80 V/V/V) and solvent B (phosphoric acid/methanol/acetonitrile) (1:40:59 V/V/V). The linear gradient elution profile was as follows: 100 % A – at 0 min, 55 % A/45% B – at 20 min, 100 % B at 25 – to 26 min, 100 % A – at 30 – to 31 min. The flow rate was 1.2 mL/min and injection volume was 10 μL. Absorption was measured at 330 nm. Quantification of apigenin was performed using reference standard of apigenin. The linear calibration curve were constructed (R2 ==0.999979). Results. The lowest content of apigenin was obtained by ME and PE using 96% ethanol (141.06±1.7 and 161.51±1.43 μg/g, respectively). The highest content of apigenin (855.54±5.75 μg/g) was obtained by UAE, using 70% ethanol. During CSE, the content of apigenin depended on the solvent concentration used: 96 % ethanol w[...].