Selection of the Most Suitable Solvent for Lovastatin Extraction from Natural Sources

Introduction Lovastatin (also known as monacolin K, mevinolin) is a competitive inhibitor of the hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase. It acts like synthetic statins and catalyzes the reduction of HMG-CoA to mevalonate, thereby inhibiting cholesterol synthesis. Also, lovastatin is the first drug approved by the Food and Drug administration (FDA) for dyslipidemia [1]. This drug can naturally occur in food products such as fermented Pu-erh tea, red yeast rice (cultivated with Monascus purpureus) and in many types of mushrooms [2,3]. Since there are many different sources of lovastatin it is important to determine the appropriate extraction conditions. The aim of this study is to select the most effective solvent for the extraction of lovastatin from natural sources. Materials and methods Red yeast rice was purchased in pharmacies. Supplements powder (0,1 g) was extracted with 10 ml of different solvents: acetonitrile, ethyl acetate, acetone, methanol, and ethanol (pure and acidified using acetic acid to pH 3). Extraction was performed in an ultrasonic bath for 30 min. Before HPLC analysis all samples were filtered through a 0.45 μm membrane filter. HPLC analysis was performed according to 04/2021:1538 Ph. Eur. monograph [4]. Results and discussion The study aimed to investigate which solvent is the most effective for the extraction of lovastatin. We determine that the samples contained between 1,594 – 4,361 mg/g lovastatin. The results showed that the optimal solvent is acetone. The difference was statistically significant (p<0,05). Using acetone, we determined that the content of lovastatin was 4,155±0,206 mg/g, expressed with the standard error. Acetonitrile also showed relatively good extraction efficiency (3,5765±0,073 mg/g). The extraction efficiencies for ethanol and methanol were comparable (ethanol: 3,577±0,027 mg/g; methanol: 4,0245±0,076 mg/g). Following the approach described by Yang et al. 2006, we examined the effect of acidification on the lovastatin concentration. Although a slight change was observed, the difference was not statistically significant (p>0,05). Conclusions In this study, the effect of different solvents on lovastatin extraction was investigated. The results indicated that acetone was the most effective solvents, while results obtained with ethyl acetate, methanol, acetonitrile and ethanol were less satisfactory. Acetone was chosen for subsequent analyses because of its suitability for the method and ability to solubilize dry materials better than other solvents.