Evaluation of Secondary Metabolites in Various Stages of Okra Seed Development and Their Anti-Inflammatory Potential Against IL-1ß

Okra is a flavonoid-rich food known to confer a variety of health benefits and have extensive therapeutic characteristics. In this study, okra seeds at five stages of development (youngest, young, intermediate, mature and fully mature) were assessed for secondary metabolite content using 70% methanol. Extracts from mature seeds were found to contain the highest accumulation of total polyphenol content (TPC) (536.65 ± 80.13 mg GAE/g), total flavonoid content (TFC) (234.73 ± 45.58 mg ISE/g), DPPH scavenging activity (70.11%) and ABTS+ activity (75.19%). High-performance liquid chromatography (HPLC) analysis revealed that in fully mature seed extracts, quercetin (148.14 ± 11.01 mg/kg) is abundant, while isoquercetin and quercertin-3-O-gentibiose are respectively abundant in the youngest (5205.02 ± 48.54 mg/kg) and mature seeds (12,396.48 ± 77.54 mg/kg). Mature seed extracts also exhibited the highest activity against nitric oxide (NO) production and the pro-inflammatory cytokine interleukin-1 beta (IL-1β) in lipopolysaccharide-induced (LPS) RAW 264.7 cells. The findings from this study showed that secondary metabolite accumulation in okra seeds varies at different stages of development. Thus, determining the bioactive compounds at different levels of seed development is considered essential for potential pharmacological advancements in biologically significant plants.