Holothurins

Actinia cari toxins, 308 Actiniaria, carotenoids, 320 Actinodendron plumosuniy polypeptide neurotoxins, 194 Actinopyga aglycones, 320 holothurins, 320 Activators... 

Vig PJS, Mehrotra BD, Desaiah D. 1990b. Holothurin An activator of bovine brain 3 -5 phosphodiesterase. Res Commun Chem Pathol Pharmacol 67(3) 419-42. 

Compounds 3a, 3g-31 and 7c are the only A9,1 glycosides isolated from sea cucumbers belonging to the order Dendrochirotida. In general, 3(3-hydroxyholost-9(ll)-ene based aglycones were characterized in holothurins isolated from animals of the order Aspidochirota. 

Four glycosides isolated from the sea cucumber Cucumaria lefevrei [50] are the only examples of holothurins with a 16a-acetoxy group in their aglycones, Fig. (14). Lefevreiosides A2 (14b), B (14c) and C (14d) show the same monosuliated tetrasaccharide chain and differ in the degree of unsaturation or the position of the double bond in their side chains. Lefevreioside Ai (14a) is the desulfated analog of glycoside 14b. 

Recently, we have isolated an antifungal holothurin from the sea cucumber Psolus patagonicus [53]. Patagonicoside A (Id), Fig. (16) is the first example of a 3 J)-hydroxyholost-7-ene aglycone substituted with 12a- and 17a-hydroxy groups. 

Recently, some examples of holothurins having uncommon non-holostane aglycones have appeared in the literature. These glycosides have been isolated from seven species of sea cucumbers belonging to the order Dendrochirota. All are sulfated compounds, the majority monosulfated at the glucose or xylose units. 

Avilov et al. [56,57] reported three holothurins that are devoid of a lactone function and have a shortened side chain. Kurilosides A (19a) and... 

Table 3., SC-NMR data for the sugar moieties of holothurins with pentaglycosidle ehains...

The crude holothurins from Philippine sea cucumbers belonging to Holothuriidae family have indirect mutagenic and clastogenic activity. Although no activity was noted in vitro (Rec- assay and Ames test) after metabolic activation, these holothurins produced aberration scores in Swiss albino mice (micronuclear test) when administered intraperitoneally [29]. Nevertheless, at peroral injection, they exhibited a 35-fold reduction in activity, which indicates inactivation in the alimentary canal [29]. On the contrary, Polycarpova et al. showed the absence of mutagenic activity of cucumarioside - triterpene glycoside from the sea cucumber Cucumaria Japonica [27]. 

Holothurin" is active in vitro against Amoeba proteus [24], holotoxins from Apostichopus japonicus are active against Trichomonas vaginalis [52]. The data on antiprotozoal activity of glycosides of Cucumaria echinata [49] were discussed above. These data were correlated with antifungal activities of the glycosides. 

Rats, intraperitoneally inoculated with crude holothurin and previously or simultaneously infected by Tripanosoma lewisi had lower parasitemia than in the controls [53]. But, on the contrary, a higher level of parasitemia was observed in rats treated after infection. Sen Lin confirmed these results in mice inoculated with Trypanosoma duttony [54, 55]. 

The action of "holothurin" on the membrane potential and conductivity of giant squid axon membrane was studied by De Groof Narahashi [85]. The action of holothurin on the outside of the intact axon at a concentration of 2x10 M caused irreversible membrane depolarization, while the membrane potential approached zero. Elimination of Na from outer side of membrane or from both sides led to partial depolarization. A possible mechanism, based on the biomembrane depolarization by glycosides, was proposed to be connected with the increasing membrane permeability for Na ions. 

Holothurin" (2x10" M) irreversibly blocks a neural and direct response of stimulated monocellular electroplax preparation of Electrophorus electricus [86]. It also produced irreversible depolarization in a monocellular electroplax preparation of Electrophorus electricus [86]. These effects on the resting potential have been attributed to an initial efflux which then decreased steadily. 

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