Simultaneous Natural Deep Eutectic Solvent-Based Ultrasonic-Assisted Extraction of Bioactive Compounds of Cinnamon Bark and Sappan Wood as a Dipeptidyl Peptidase IV Inhibitor.

Cinnamon bark (Cinnamomum burmannii) and sappan wood (Caesalpinia sappan) have been reported to be beneficial for Type-2 Diabetes Mellitus (T2DM) and the combination is commonly used by Indonesian herbal industries. In the present study, the simultaneous extraction of bioactive compounds from both plants was conducted using natural deep eutectic solvent (NADES), their content analyzed using high-performance liquid chromatography (HPLC), and their dipeptidyl peptidase IV (DPP IV) inhibitory activity evaluated. An additional in silico molecular docking analysis was conducted to ensure their activity. The results showed that NADES (with a composition of choline chloride-glycerol) extraction from cinnamon and sappan wood had DPP IV inhibitory activity of 205.0 and 1254.0 µg/mL, respectively. Brazilin as a marker substance from sappan wood was responsible for the DPP IV inhibitory activity, while none of the marker substances chosen for cinnamon bark (trans-cinnamaldehyde, coumarin, and trans-cinnamic acid) were found to have significant DPP IV inhibitory activity. These results were confirmed by molecular docking conducted in brazilin, trans-cinnamaldehyde, coumarin, and trans-cinnamic acid.

Optimization of choline chloride-glycerol based natural deep eutectic solvent for extraction bioactive substances from Cinnamomum burmannii barks and Caesalpinia sappan heartwoods.

Indonesian cassia (Cinnamomum burmannii Blume) is commonly used as a condiment. It reportedly contains a number of major phytochemical constituents such as trans-cinnamaldehyde and coumarin. Sappan wood (Caesalpinia sappan) is a native plant of Southeast Asia that contains brazilin, a widely known red pigment. This study aimed to determine the optimal extraction conditions using a choline chloride-glycerol (ChCl-glycerol)-based natural deep eutectic solvent (NADES) to obtain greater trans-cinnamaldehyde and brazilin levels from Indonesian cassia and sappan wood. The powders of Indonesian cassia and sappan wood were extracted using ChCl-glycerol-based NADES varied at three different levels: ratio of ChCl to glycerol, ratio of powder to NADES, and the amount of water in NADES. All variables were designed using the Box-Behnken design of response surface methodology to provide 15 extraction conditions. The extraction was performed using ultrasonication-assisted extraction for 30 and 50 min for Indonesian cassia and sappan wood, respectively. Determination of the active compound contents was performed using a high-performance liquid chromatography system equipped with a UV-VIS detector at λmax = 280 nm. The optimization results revealed that the highest levels of trans-cinnamaldehyde, coumarin, and brazilin in NADES extracts were 1907.32, 1735.68, and 368.67 µg/ml, respectively, whereas the lowest levels of these compounds were 453.59, 616.76, and 74.21 µg/ml, respectively. The maximal levels exceeded those obtained using a conventional extraction method, in which 5000 µg/ml Indonesian cassia reflux extract contained only 108.45 µg/ml trans-cinnamaldehyde. Similarly, 1000 µg/ml sappan wood contained only 124.64 µg/ml brazilin. ChCl-glycerol-based NADES was suitable for extracting active compounds from Indonesian cassia and sappan wood; moreover, this solvent is more effective than organic ethanolic coventional solvent.