Chemical constituents and antioxidant activities of waste liquid extract from Apostichopus japonicus Selenka processing

Apos tichopus japonicus Selenka is an ideal tonic food that is used traditionally in many Asian countries, and it contains many bioactive substances, such as antioxidant, antimicrobial, and anticancer materials. To convert waste liquid generated during production into a useful resource, extract from waste liquid was isolated by column chromatography and studied by the pyrogallol autoxidation and 1,10-phenanthroline-Fe²⁺ oxidation methods. Results show that the extract scavenged about 91% of the superoxide anion radical at a concentration of 1.4 mg/mL and 24% of the hydroxyl radical at 3.3 mg/mL. Four compounds were isolated and identified from the extract: 2,4-dihydroxy-5-methyl-1,3-azine; 2,4-dihydroxy-1,3-diazine; 3-O-[β-D-quinovopranosyl-(1→2)-4-O-sodium sulfate-β-D-xylopranosyl]-holosta-9(11)-ene-3β,12α,17α-triol; and 24-ethyl-5α-cholesta-7-ene-3β-O-β-D-xylopyranoside. All of these compounds are known in A. japonicus, and were found in the waste liquid for the first time.