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, , Ibrahim Arsyik, Rahayu Bakti Puji, Arifuddin M, Nur Yuspian, Prabowo Wisnu Cahyo,, Ambarwati Neneng Siti Silfi, Rijai Laode, and Ahmad Islamudin , Pharmacognosy Journal, September 2021, Volume 13, Issue 5, p.1109-1115, (2021)