Single Factor Effect of Natural Deep Eutectic Solvent Citric Acid-Glucose Based Microwave-Assisted Extraction on Total Polyphenols Content from Mitragyna speciosa Korth. Havil Leaves

Applying green chemistry principles in the exploration of an active secondary metabolite from natural products has continued to experience a significant increase in the last decade, mainly natural deep eutectic solvent (NADES) usage. Mitragyna speciosa (Korth.) Havil (Rubiaceae family) is a native of East Kalimantan, which is traditionally used as an herb to treat headaches and inflammation by drinking boiled water a few leaves. On the other hand, this plant has an addictive effect. This study aims to determine the single factor effect of NADES citric acid–glucose-based microwave-assisted extraction (MAE) to obtain the yield of total polyphenols content (TPC) from M. speciosa leaves. Dried powder of M. speciosa leaves was extracted using NADES citric acid-glucose based MAE method with some different conditions such as NADES (citric acid-glucose) ratio (4:1, 5:1, 6:1 g/g), solid-liquid ratio (10:1, 15:1, 20:1 mL/g), microwave power (90, 270, 450 Watts), and extraction time (15, 20, 25 min). The determination of TPC was performed using Folin-Ciocalteau reagent and gallic acid as a standard with different concentration levels. The absorbance measured using spectrophotometer UV-VIS at 746 nm to obtain a regression formula of Y = 0.0022X–0.00095, where R² = 0.9977. Based on the result, the best of single factor condition effect was obtained the TPC value including NADES ratio of 248.69 mg GAE/g sample (5:1 g/g citric acid-glucose), a solid-liquid ratio of 146.93 mg GAE/g sample (15:1 mL/g solvent-sample), microwave power of 192.20 mg GAE/g sample (270 Watts), and extraction time of 358.59 mg GAE/g sample (15 min). The single factor effect of NADES citric acid-glucose-based MAE shows a difference in TPC value based on various conditions of this method.