In vitro antioxidant and antimicrobial activities, and in vivo anti-inflammatory activity of crude and fractionated PHNQs from sea urchin (Evechinus chloroticus)

Abstract

This study investigated the bioactivities of polyhydroxyl-1,4-naphthoquinone (PHNQ) extracts from Evechinus chloroticus shell waste. PHNQs were extracted from E. chloroticus shells and spines using different solvents and the crude extracts were fractionated by HPLC. The antioxidant activity of the PHNQ extracts were evaluated by the DPPH, ABTS, ORAC and FRAP assays. Ethyl acetate was the best extraction solvent and spine extracts showed better antioxidant activity than shell extracts (p < 0.05). The HPLC fraction containing spinochrome E showed the highest antioxidant activity (p < 0.05). The Minimum Inhibitory Concentration of the PHNQ crude extracts and the HPLC fractions ranged from 250 to 2500 µg/mL depending on the PHNQ extract and microbial species tested. Treatment by PHNQ extracts resulted in alteration of the morphology of the microbial cell wall as observed by transmission electron microscopy. PHNQ extracts also exhibited anti-inflammatory activity in rats (ED₅₀ = 8.26 ± 0.22 µg), comparable to that of Celecoxib (6.12 ± 0.18 µg).

Keywords: 4-naphthoquinone (PHNQ); Anti-inflammation; Anti-microbial; Antioxidant; Evechinus chloroticus; Polyhydroxyl-1.