*Article* **Oxysterols from a Marine Sponge** *Inflatella* **sp. and Their Action in 6-Hydroxydopamine-Induced Cell Model of Parkinson's Disease**

**Sophia A. Kolesnikova 1,\*,†, Ekaterina G. Lyakhova 1,†, Anatoly I. Kalinovsky 1, Roman S. Popov 1, Ekaterina A. Yurchenko <sup>1</sup> and Valentin A. Stonik 1,2**


Received: 25 October 2018; Accepted: 19 November 2018; Published: 21 November 2018

**Abstract:** Four new oxysterols **1**–**4** along with previously known oxygenated sterols **5**–**14** were isolated from the sponge *Inflatella* sp., collected from the Sea of Okhotsk. Structures of **1**–**4** were elucidated by the detailed NMR spectroscopic and mass-spectrometric analyses as well as by comparison of the corresponding experimental data with those reported in literature. The influence of compounds **1**–**14** on the viability of neuronal Neuro2a cells treated by 6-hydroxydopamine and reactive oxygen species (ROS) formation in these cells was investigated.

**Keywords:** secondary metabolites; oxygenated steroids; marine sponge; *Inflatella*; NMR; ROS; Parkinson's disease; structure-activity relationship
