Antioxidant and anti-inflammatory properties of marmelosin from Bael (Aegle marmelos L.); Inhibition of TNF-α mediated inflammatory/tumor markers

Abstract

Oxidative stress and inflammation are important critical factors that are implicated in almost all life style disorders such as diabetes, cardiovascular disease, ulcer and cancer. Current study aimed at isolation and characterization of a furanocoumarin from Bael (Aegle marmelos L.) fruit that can modulate both oxidative stress and inflammation effectively. Ethyl acetate extract of Bael fruit (EAFB) was subjected to HPLC for identification, purified and characterized using FTIR, NMR and ESI-MS analysis. Predominant peak of EAFB at RT 12.54 min on HPLC was identified as marmelosin with molecular weight of m/z ∼ 271.2. Marmelosin was evaluated for antioxidant, antiproliferative, apoptotic, cancer (Tyrosinase & Galectin-3) and immunomodulatory (NO, TNF-α) potentials employing standard assay systems. Marmelosin possessed potent antioxidant activity with IC₅₀ of ∼ 15.4 ± 0.32 μM as opposed to standard - gallic acid (IC₅₀ 1.1 ± 0.08 μM), antiproliferative activity with IC₅₀ of ∼ 6.24 ± 0.16 μM as opposed to deferoxamine (∼10.8 ± 0.28 μM) and protected cells against cellular/DNA damage. Anti-inflammatory property was evident with significant reduction in the release of NO (∼3.9 fold) and TNF-α (∼3.4 fold), a pro-inflammatory cytokine, in addition to the inhibition of NFκB (∼2.7 fold), a transcription factor in Raw 264.7 cells. Marked down regulation of galectin-3 (∼5.5 folds) and tyrosinase (∼11.1 folds) by gene expression analysis substantiated by tyrosinase inhibition (IC₅₀ - 20.3 ± 1.26 μM Vs. Kojic acid - IC₅₀ - 24.1 ± 1.41 μM) and molecular docking studies strengthened the cancer modulatory property of marmelosin. In addition, marmelosin induced apoptotic bodies, chromatin condensation and nulcear blebbing in Raw 264.7 cells commending the apoptotic effect of marmelosin. Marmelosin thus displayed potential multi-potent antioxidant, anti-inflammatory and anticancer properties via TNF-α mediated Akt signaling pathway.

Keywords: Antioxidant; Cytotoxicity; Nitric oxide; Pro-inflammatory markers; Raw 264.7 cells; TNF-α.