Antioxidative oxygenated terpenoids with bioactivities against pro-inflammatory inducible enzymes from Indian squid, Uroteuthis (Photololigo) duvaucelii

Abstract

Cephalopod squid, Uroteuthis (Photololigo) duvaucelii is consumed as culinary delicacy along the southwest part of Asian continent. Ethyl acetate:methanol extract of U. duvaucelii was chromatographically fractionated to yield C19 furano-norditerpenoid (1) along with irregular C15 sesquiterpenoid (2) and C20 diterpenoid compounds (3). In vitro anti-inflammatory and antioxidant analyses were utilised to evaluate their bio-potentials. The C19 furano-norditerpenoid was reported for significantly effective 2,2-diphenyl-1-picrylhydrazyl radical inhibition (IC50 0.60 mg/mL) than other compounds and α-tocopherol (IC50 ≥ 0.64 mg/mL). The 2,2’-azino-bis-3-ethylbenzothiozoline-6-sulfonic acid inhibition and ferrous ion chelating potentials were higher for compounds 1 and 2 (IC50 ∼ 0.69 and ∼0.84 mg/mL, respectively) compared to α-tocopherol (IC50 0.76–0.95 mg/mL). The studied compounds displayed comparable inhibitory activities with synthetic ibuprofen against pro-inflammatory inducible 5-lipoxygenase (IC50 ∼ 0.92 mg/mL). The lower hydrophobicity and steric variables were directly correlated with their antioxidative and anti-inflammatory properties. The studied compounds could be utilised as natural antioxidants and anti-inflammatory functional food ingredients.