Ultrasound-assisted extraction of peanut shell by-product: Chemical properties, antioxidant, and anti-inflammatory effects

Abstract

Peanut shell by-products have been explored for their pharmacological potential, particularly through applications developed from their utilization. This study aimed to investigate the effects of peanut shell extract (UPE) obtained via ultrasound-assisted extraction (UAE) on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. High-performance liquid chromatography analysis revealed elevated levels of luteolin in the ultrasound-extracted peanut shell extract (UPE). UPE demonstrated significant in vitro antioxidant activity, as evidenced by its ability to scavenge 1,1-diphenyl-2- picrylhydrazyl (DPPH) and 2,2?-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals. The anti-inflammatory effects of UPE were assessed using the nitric oxide (NO) Griess assay, prostaglandin E2 (PGE2), and interleukin-6 (IL-6) enzyme-linked immunosorbent assay (ELISA). Western blot analysis and reverse transcription polymerase chain reaction (RT-PCR) were used to evaluate the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). UPE significantly reduced NO, PGE2, and IL-6 levels in LPS-treated RAW 264.7 cells, suggesting potent anti-inflammatory properties. Furthermore, UPE downregulated the expression of iNOS and COX-2, thereby suppressing NO and PGE2 production. These findings indicate that peanut shell extracts obtained through UAE have therapeutic potential due to their enhanced antioxidant and antiinflammatory effects, likely attributed to increased levels of luteolin.