3P-Hydroxy-sterols

In addition to A -3p-hydroxy-sterols Stellata clarella also contains 5a-cholestanol (147), 5a-ergostanol (256), and 5a-poriferastanol (257). The latter two must be counted as new to Porifera. 

Figure 2.12 Charge tagging with the GP reagent to an oxysterol. Oxidation of an oxysterol with a 3p-hydroxy-5-ene function (e.g., 24S,25-epoxycholesterol, C -3p-ol-24S,25-epoxide) to the analogous sterol with a 3-oxo-4-ene function (24S,25-epoxycholest-4-en-3-one, C -24S,25-epoxy-3-one) followed by derivatization with GP reagent.

It was also demonstrated (Mandeau et al., 2005) that the ethanolic extract of the sponge Euryspongia contained petrosterol and was shown to display anti-inflammatory activity. This petrosterol on partitioning and further chromatography yielded compounds 3-hydroxy-24-norchol-5- -23-oic acid and 3p-hydroxy-26-norcampest-5-m-25-oic acid. The sterols were evaluated for their action on the metabolism of... 

All of the sterols mentioned above have the configuration 3P hydroxy, as is also the case for most sterols isolated from sea stars (Table 26.8). A series of 3a-hydroxy-A5-stanols and 2,21- or 3,21-disulfated sterols, which have the same configuration at position 3 as that foimd in ophiurian sterols have been isolated from sea stars of the genus Pteraster, aU from polar seas. These observations, in at least two different species, suggest that the genus Pteraster is unusual in the order Spinulosida (Levina et al, 1996,1998 ... 

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