Optimization of Extraction Process of Flavonoid-Rich Extract From Glochidion Littorale Leaves With Anti-Inflammatory and Cytotoxic Activities Against Selected Cancer Cell Lines

The extraction conditions for a flavonoid-rich extract derived from the leaves of Glochidion littorale, evaluated for its anti-inflammatory potential and cytotoxicity against selected cancer cell lines, were optimized using response surface methodology (RSM) with the Box-Behnken design. The optimal conditions included an ethanol concentration of 68%, an ultrasonic extraction duration of 25 minutes, and a temperature of 60 °C. The total flavonoid content (TFC) obtained from the prepared extract was 198.18 ± 1.13 mg quercetin equivalents (QE)/g of extract, which closely aligned with the model-predicted value of 197.38 mg QE/g. Anti-inflammatory activity was assessed based on nitric oxide (NO) scavenging capacity—NO being a signaling molecule associated with inflammation. Results showed a dose-dependent reduction in NO levels, with the lowest NO concentration (31.39 ± 0.95 µM, corresponding to approximately 61% inhibition) observed at a sample concentration of 200 µg/mL. Regarding cytotoxic activity, half-maximal inhibitory concentration (IC₅₀) values were determined to be 133.48 ± 4.61 µg/mL for SK-LU-1 (lung cancer cells), 102.14 ± 0.35 µg/mL for HepG2 (liver cancer cells), and 144.20 ± 5.41 µg/mL for MKN7 (gastric cancer cells). The study concludes that the optimized flavonoid-rich extract of Glochidion littorale exhibited potent anti-inflammatory and cytotoxic potentials against lung, liver, and gastric cancer cell lines in vitro.