Two new sesquiterpene isonitriles from the nudibranch, phyllida pustulosa

Chemical Defenses: From Compounds to Communities

“…Phyllidiid nudibranchs can be brightly colored (aposematic coloration), and many of them contain isocyanide compounds (Fusetani et al, 1990a(Fusetani et al, , 1991, often the same isocyano terpenes as their prey sponges, suggesting a trophic transfer of these compounds (Chang and Scheuer, 1993;Avila, 1995;Garson et al, 2000). On Guam, Phyllidiella granulatus was observed feeding on the sponge Acanthella cavernosa, and both the nudibranch and its mucus contained the same isocyano diterpenes as the sponge (Ritson-Williams and Paul, 2007).…”

“…Phyllidiid nudibranch extracts (which often contain isocyano terpenes derived from their sponge diets) were toxic against common bacteria, fungi, and the mosquitofish Gambusia affinus (Gunthorpe and Cameron, 1987). The isolated isocyano terpene, 2-isocyanoallopupukeanane, was tested for its toxicity against the killifish Oryzias latipes and was found to have an LC 50 of 10 g/ml (Fusetani et al, 1991). Many laboratory organisms such as mosquitofish and killifish are not encountered in the same habitat as the sponges and nudibranchs that contain isocyanide compounds, and therefore experiments using these organisms can only suggest a likely ecological function.…”

Marine isocyano compounds

“…As mentioned previously, it usually is the same carbon that bears the -NC, -NCS, or -NHCHO function. Commonly encountered in sesqui-and diterpenes are 4~ [57] [43] 3.…”

“…From the nudribranch, Phyllidia pustulosa, the cis-decalin 35, an analog of 31, was one of seven isonitriles isolated [43]. In 1989 an unusual thiocyanate 36, mp 67-68 °C, was reported to occur in a Palauan sponge, Axinyssa (= Trachyopsis) aptysinoides, from which several other marine isonitriles were obtained [44].…”

“…In 1989 an unusual thiocyanate 36, mp 67-68 °C, was reported to occur in a Palauan sponge, Axinyssa (= Trachyopsis) aptysinoides, from which several other marine isonitriles were obtained [44]. The corresponding isonitrile, which was not present in the sponge, was later obtained from P. pustulosa [43]. Amorphanes 38-40 were also isolated from Acanthella cannabina.…”