Antioxidant and Anti-Inflammatory Activities from Optimum Formula of Spatholobus littoralis Hassk. and Sauropus androgynus L.: In Vitro and In Silico Studies

This study aimed to optimize a formulation of <i>Spatholobus littoralis</i> Hassk. stems and <i>Sauropus androgynus</i> L. leaves using Simple Lattice Design (SLD). In this context, the response variable was DPPH (2,2-Diphenyl-1-picrylhydrazyl) antioxidant activity, while the optimum extract concentration of the two plants served as the experimental factor. Subsequently, the optimum formula was investigated for its in vitro anti-inflammatory activity against COX-2 (cyclooxygenase-2) and through in silico study. Molecular docking on the COX-2 receptor (PDB ID: 5IKQ) from the secondary metabolite profile was validated for the optimum formula. The formulation recommended by SLD comprised a 1:1 mixture of 70% ethanol extract of <i>S. littoralis</i> Hassk. stems and <i>S. androgynus</i> L. leaves. This optimum formula had an IC₅₀ value of 108.70 µg/mL for the DPPH antioxidant with a synergistic effect due to the production of higher COX-2 inhibitory activity (73.05 ± 2.36%) than the single extract at 100 µg/mL. Daidzein (-8.514 kcal/mol), (10E,12Z)-9-Hydroperoxy-10,12-octadecadienoic acid (-7.604 kcal/mol), arteannuic acid (-7.114 kcal/mol), L-Proline,4-hydroxy-5-oxo-4-(tetrahydro-2,3,4-trihydroxy-2-furanyl)- (-6.480 kcal/mol), and Androst-2-en-17-amine,4,4-dimethyl-N-(2-phenylethyl)-, (5.alpha.)- (-5.440 kcal/mol) were the five compounds from the 70% ethanol extract of <i>S. littoralis</i> Hassk. stems and <i>S. androgynus</i> L. leaves that strongly bound 5IKQ. These compounds were obtained from five groups of compounds, namely flavonoids, fatty acids, terpenoids, amino acid derivatives, and amine derivatives. The formulation of <i>S. littoralis</i> Hassk. and <i>S. androgynus</i> L. extract has potential as an antioxidant and anti-inflammatory agent.