**Ekaterina V. Sokolova \*, Natalia I. Menzorova, Victoria N. Davydova, Alexandra S. Kuz'mich, Anna O. Kravchenko, Natalya P. Mishchenko and Irina M. Yermak**

G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far-East Branch of the Russian Academy of Sciences, Prospect 100-let Vladivostoku, 159, 690022 Vladivostok, Russia; menzor@piboc.dvo.ru (N.I.M.); vikdavidova@yandex.ru (V.N.D.); assavina@mail.ru (A.S.K.); Kravchenko\_89@mail.ru (A.O.K.); mischenkonp@mail.ru (N.P.M.); imyer@mail.ru (I.M.Y.)

**\*** Correspondence: eka9739@gmail.com; Tel.: +7-(423)2311430; Fax: +7-(423)2314050

Received: 9 October 2018; Accepted: 26 October 2018; Published: 1 November 2018

**Abstract:** Sea urchin pigment echinochrome A (Ech), a water-insoluble compound, is the active substance in the cardioprotective and antioxidant drug Histochrome® (PIBOC FEB RAS, Moscow, Russia). It has been established that Ech dissolves in aqueous solutions of carrageenans (CRGs). Herein, we describe the effects of different types of CRGs on some properties of Ech. Our results showed that CRGs significantly decreased the spermotoxicity of Ech, against the sea urchin *S. intermedius* sperm. Ech, as well as its complex with CRG, did not affect the division and development of early embryos of the sea urchin. Ech reduced reactive oxygen species production (ROS) in neutrophils, caused by CRG. The obtained complexes of these substances with pro- and anti-activating ROS formation properties illustrate the possibility of modulating the ROS induction, using these compounds. The CRGs stimulate the induction of anti-inflammatory IL-10 synthesis, whereas Ech inhibits this synthesis and increases the production of the pro-inflammatory cytokines IL-6 and TNFα. The inclusion of Ech, in the complex with the CRGs, decreases Ech's ability to induce the expression of pro-inflammatory cytokines, especially TNFα, and increases the induction of anti-inflammatory cytokine IL-10. Thus, CRGs modify the action of Ech, by decreasing its pro-inflammatory effect. Whereas, the Ech's protective action towards human epithelial HT-29 cells remains to be unaltered in the complex, with κ/β-CRG, under stress conditions.

**Keywords:** carrageenan; algae; echinochrome; reactive oxygen species; cytokines; HT-29
