Extraction of Faloak Stem Bark (Sterculia quadrifida R. Br) Using Microwave-Assisted Extraction Method And LC-HRMS Profiling of the Extract

The extraction of bioactive plants is an essential step in isolating the targeted bioactive compounds. Microwave-assisted extraction (MAE) offers a green technology extraction that can minimize energy, time, and solvent and is a suitable method for extracting thermolabile plant bioactive compounds. The study aims to find out the optimal time and temperature for isolating the total phenolic content (TPC), total flavonoid (TF), and antioxidant activity (AO) of faloak stem bark (FSB) (Sterculia quadrifida R. Br) and to profile the phytochemicals in the FSB extract using sophisticated of LC-HRMS (Liquid Chromatography High-Resolution Mass Spectrometry). The research used the Randomized Block Design (RBD) method with two factors. The factors were the extraction time (5, 15, and 25 min) and temperature variation (50, 60, and 70°C). The data of observed parameters were calculated using Analysis of Variance (ANOVA) and followed by a further test with a 95% confidence interval. The results showed an interaction between temperature and time of extraction on TPC, TF, and AO activity. The best MAE condition for extracting FSB was achieved at 60°C for 25 min. The FSB extract had a TPC of 81.2 mg GAE/g, TF of 70.30 mg QE/g, and AO activity of 67.8%. LC-HRMS revealed the newly identified phenolic compounds such as methyl cinnamate, vanillin, apocynin, scopoletin, L(-)-pipecolinic acid, arecoline, δ-valerolactam, 3,4-dihydroxybenzaldehyde, 4-hydroxybenzaldehyde; flavonoids such as epicatechin and rutin and some fatty acids and its derivatives. Future research could focus on developing new therapies for promoting human health using extract FSB.