Structure Elucidation of Ostreocin D, a Palytoxin Analog Isolated from the Dinoflagellate Ostreopsis siamensis

High Resolution LC-MSn Fragmentation Pattern of Palytoxin as Template to Gain New Insights into Ovatoxin-a Structure. The Key Role of Calcium in MS Behavior of Palytoxins

“…Summing-up, on the basis of the above results, ovatoxina, compared with palytoxin, (1) lacks three hydroxyl groups, one at C-17, one at C-44 or C-45, and one in the region C-53 to C-78, respectively; (2) presents an additional hydroxyl group at C-42, similarly to 42-hydroxy palytoxin and ostreocin-D [6,7]; (3) presents the same structural features as palytoxin in the regions ranging from the A-side terminal to C-16, from C-18 to C-41, from C-46 to C-52, and from C-79 to the B-side terminal.…”

“…The A-side fragment of cleavage #4 was also fragmented within MS 3 (precursor m/z 906.89327.1) and MS 4 (precursor m/z 906.8 9327.1 9309.1) experiments. The fragments obtained due to cleavages #1+#4, #2, and #3 (Table 2, Figure 1) provided information on the part structure ranging from C-8 to the A-side terminal of palytoxin which is a further region of the molecule where structural differences among palytoxin and most of its congeners (ostreocin-D, homo, bishomo-, neopalytoxin, ovatoxin-b, -c, and -e) occur [5,6,10,18]. Alternative fragmentation modes, namely pulsed Q collision induced dissociation (PQD) and high energy collision dissociation (HCD) were also investigated.…”

“…A number of palytoxin analogues have been so far isolated either from soft corals (Palythoa genus) or dinoflagellates (Ostreopsis spp. ): homo, bishomo-, neo-, and 73-deoxy-palytoxin [5], ostreocin-D (namely 42-hydroxy-3,26-didemethyl-19,44-dideoxypalytoxin) [6], and 42-hydroxy-palytoxin [7]. Structure elucidation of these compounds was carried out by extensive NMR analyses and in most cases through the use of degradation/derivatization reactions [1,5,8].…”

Developmental Biology of Neoplastic Growth

“…The differences (squares) between ostreocin-D and palytoxin are reported in the inset from the benthic dinoflagellate Ostreopsis siamensis which also produce PTX and ostreocin D (42-hydroxy-3, 26-didemethyl-19, 44-dideoxypalytoxin) (Fig. 4), a PTX analog (Rhodes et al 2002;Taniyama et al 2003;Ukena et al 2001;. Recently, PTX and a new analogue, Ovatoxin-a have been identified in the Mediterranean Sea during a massive bloom of the dinoflagellate Ostreopsis ovata (Ciminiello et al 2006;Ciminiello et al 2008).…”

Sanitary problems related to the presence of Ostreopsis spp. in the Mediterranean Sea: a multidisciplinary scientific approach

“…Globally, attention shifted toward Ostreopsis in 1995, when Dr. Takeshi Yasumoto's group isolated and characterized PLTX-like compounds from O. siamensis [26][27]. Until this time, the origin of palytoxins was thought to be soft corals of the genus Palythoa [28].…”