New Aminonaphthoquinone from the Sea Urchins Strongylocentrotus pallidus and Mesocentrotus nudus

• Published in: Natural product communications 2016-06, Vol.11 (6), p.821-824
• Main Authors: Vasileva, Elena A., Mishchenko, Natalia P., Zadorozhny, Pavel A., Fedoreyev, Sergey A.
• Format: Article
• Language: English
• Subjects: Animals; Lipid Peroxidation; Molecular Structure; Naphthoquinones - chemistry; Sea Urchins - chemistry; Strongylocentrotus - chemistry
• ISSN: 1934-578X; 1555-9475
• DOI: 10.1177/1934578X1601100631

The aminonaphthoquinone, spinamine E (5), was isolated for the first time from the sea urchins Strongylocentrotus pallidus (Sars G.O., 1872) and Mesocentrotus nudus (A. Agassiz, 1864). The structure of 5 was elucidated as 2-amino-3,5,6,7,8-pentahydroxy-l,4-naphthoquinone using 1D 1H-, 13C- and 2D NMR procedures, and HR-ESI mass-spectrometric data of 5 and its trimethyl ether. Spinamine E, as well as two other aminonaphthoquinones of sea urchins, echinamines A (2) and B (3), along with their hydroxylated analogues, spinochrome E (4) and echinochrome A (1), were tested for their ability to scavenge the stable DPPH radical and to inhibit lipid peroxidation. All investigated naphthoquinones obtained from the sea urchins showed a high antiradical activity, which was up to 1.5 times higher than that of α-tocopherol. Echinamine B showed the highest scavenging effect (EC50 = 6.5-10−6 M); this effect decreases in the series 3>5>1>2>4>α-tocopherol. In a lipid peroxidation inhibition testing model, echinamine B and spinamine E showed the highest inhibitory effect. The stability of compounds 1-5 in weakly alkaline solutions was evaluated.