Sterols from some black sea ulvaceae

The free and esterified sterol composition of Ulva rigida and Enteromorpha linza (Ulvaceae) from the Black Sea was investigated. The main sterol component of Ulva rigida was identified as fucosterol. The influence of the season and water pollution on the sterol composition was investigated. The origin of the C₂₆,- and C₂₅-sterols and of saringasterol in these seaweeds is discussed.     

Free amino acids in some sponges

Most invertebrates, particularly those of marine origin, have relatively high concentrations of free amino acids which are considered an important constituent of their osmoregulatory mechanisms [1]. Very little information is available on the free amino acid distribution in Porifera [2,3]. Common amino acids in some sponges were recognised by paper chromatography by Inskip and Cassidy [4] and Ackermann et al. [5,6] included a few sponges in their survey of the occurence of nitrogen compounds in marine invertebrates. More recently Bergquist and Hartman [7] surveyed semiquantitatively the distribution of free amino acids in several sponges. In the present paper we report on the amino acid composition of 12 species of sponges belonging to the class Demospongiae as a part of a study on the metabolites of Porifera [8]. Fresh sponges were extracted with aqueous ethanol. The organic solvent was removed and the aqueous solution, after removal of the ether soluble compounds, was separated into cationic, anionic and neutral fractions by ion-exchange chromatography. The cation fraction was analysed for amino acids using an automatic amino acid analyser. The results, which are presented in Table 1, show that all species of sponges examined have a similar composition in common amino acids. Glycine almost always appears as the dominant protein amino acid, followed by high concentrations of alanine and glutamic acid, whereas relatively lower concentrations of basic amino acids are present. In Axinella cannabina, Chondrosia reniformis, Chondrilla nucula, Cliona viridis and Hymeniacidon sanguinea, glycine represents more than 77% of the total amino acids. The high percentage of free glycine (90.4%) in Chondrosia reniformis is noteworthy. The anionic and the neutral fractions were examined for sulfur-containing amino acids using PC. Taurine (Table 2) was detected in all the Porifera examined; this is in agreement with previous observations [5–7]. N-Methyltaurine was identified in some of the species examined, whereas neither N,N-dimethyltaurine nor N,N,N-trimethyltaurine were found.     

Sterols of some chilean algae

The distribution of sterols in 14 Chilean Rhodophyceae and in Lessonia sp. (Phaeophyceae) has been examined. Cholesterol is present in all the red algae examined. Golidium filicinum contains, in addition desmosterol and 24-methylene-cholesterol. Cholest-7-en-3-β-ol was found in Cryptonemia angustate and Neoagardhiella gaudichaudii. Fucosterol and 24-methylenecholesterol were found in Lessonia sp.     

Fatty acids of sponges from the Sea of Okhotsk

The fatty acid (FA) composition of Demospongiae species from the Sea of Okhotsk was studied. Fifteen sponge species were investigated for the first time, and the previously studied species Desmacella rosea and Myxilla incrustans were reexamined for their FA composition. Gas chromatography-mass spectrometry revealed 150 different fatty acids, of which 15 have not been identified in sponge lipids previously. The relative content of saturated FAs varied from 7.6 in Melonachora kobjakovae to 29.6% in Amphilectus digitata, with an average of 14.6% of total FAs. The relative content of monoenic FAs ranged from 12.8 in T. dirhaphis to 27.0% in Polymastia sp., with an average of 20.6% of total FAs. Non-methylen-interrupted, primarily unsaturated Δ5,9-FAs contributed a significantly to the amount of polyunsaturated fatty acids of sponges; this being a distinguishing feature of the FA composition of the investigated group of organisms.     

Sterols from sponges of Anavilhanas

Sponges present a wide variety of metabolites, and are considered one of the hotspots in research on the chemistry of natural products. Sterols from sponges have received attention because they present patterns of branches that distinguish them from all other living organisms. Freshwater sponges, native to rivers and lakes, have been studied chemically throughout the world, but there have been no studies on sponges from the Amazon region. The present work describes the sterols present in freshwater sponges collected in Anavilhanas, the world's second largest river archipelago, in the Negro river (Amazonas-Brazil), focussing on species whose family has not been studied previously in regard to their chemistry of natural products. Using a set of derivatization reactions for identification by chromatographic and spectrometric techniques, it was observed that the steroid extracts of sponges of the species Metania reticulata, Drulia browni and Drulia uruguayensis (Metaniidae) present 24-ethyl-cholest-5,22-dien-3β-ol as the principal sterol. Cholesterol, the main sterol in Spongillidae and Lubomirskiidae, was already detected but as a minor component along with three other sterols.     

Sterols and steryl esters in some Brassica and Sinapis seeds

The qualitative and quantitative composition of sterols in the free form and esterified to fatty acids was studied in seed oils from Brassica napus, B. campestris, B..iuncea, B. nigra, Sinapis alba and S. aruefisis (Brassica kaber). Sitosterol, followed by campesterol, predominated in both the free and the esterified sterols. The free sterols were richer in brassicasterol (ca 10–20%) than the steryl esters (3–10%). Small amounts of δ⁵-avenasterol and δ⁷-stigmastenol were also found in the Brassica oils, often more in the esterified than in the free form. The quantity of sterols was studied only in Brassica campestris, which had ca 0.3 % in the free as well as in the esterified form. In Sinapis alba, ca 10% of the sterols in the free form and 20 % in the esterified sterols were δ⁵-avenasterol. This compared to only a few per cent in both the free and esterified sterols in the Brassica oils. Similarly, ca 2 % of cholesterol was found among the sterols of Sinapis alba but only traces in the Brassica oils. The similarity of sterol compositions among the cultivated brassicas and wild mustard (Sinapis arvensis), and the specific characteristics of the sterols in white mustard (Sinapis alba) adds further weight to the suggestion that wild mustard should be treated as Brassica kaber and strengthens the generic separation of Sinapis alba.     

Sterols and fatty acids of some non-photosynthetic angiosperms

Sterols and fatty acids were extracted and identified from three parasitic angiosperms, Cuscuta campestris, Monotropa uniflora and M. hypopitys. Each plant contained the typical 16 and 18-carbon fatty acids of angiosperms, but the partially-photosynthetic Cuscuta contained much larger quantities of linolenic acid than the non-green Monotropa species which had smaller amounts of linolenic acid characteristic of non-photosynthetic tissue. Sterol quantity was three times higher in Cuscuta than in the Monotropa species. Sitosterol was the major sterol in all species with smaller amounts of campesterol and cholesterol.     

Sterols of some red algae

The sterol composition of 17 red algae has been determined. Only C-27 sterols have been found in substantial amounts; details of the structural elucidation of liagosterol (cholesta-5,23-diene-3β,25-diol) are given. The possible taxonomic significance of the sterol distribution is briefly discussed.     

Sterols from Candida lipolytica yeast grown on n-alkanes

The sterols of Candida lipolytica grown on n-alkanes were isolated by reverse phase HPLC and found to be mainly ergosterol, with small quantities of ergost-7-en-3β-ol, ergosta-7,22-dien-3β-ol, ergosta-7,24(28)-dien-3β-ol and ergosta-5,7,9(11),22-tetraen-3β-ol.     

Sterols of roots and nitrogen-fixing root nodules of some non-leguminous species

Sterols of both roots and nodules of three species of Alnus were found to consist only of sitosterol, whereas Casuarina cunninghamiana contained substantial amounts of campesterol, stigmasterol and sitosterol. In all four cases more sterol was extracted from nodules than from roots.     

Sterols,steryl esters and fatty acids in some Vicia faba seeds

Free and esterified sterol levels in seeds of five cultivars of Vicia faba were determined. Sitosterol was the most abundant free sterol, followed by stigmasterol and campesterol. Cholesterol could not be detected. Esters were generally present in greater quantities than the free form of the sterols. The fatty acid content of the plants is also reported.     

Sterols of bryophytes

Sterol compositions of six species of bryophytes were studied. The major sterols identified were campesterol, 22-dihydrobrassicasterol, sitosterol, clionasterol, stigmasterol, cholesterol, 24-methyl-5,22-cholestadienol and 24-methyl-5,7,22-cholestatrienol. The quantitative determinations of the α- and β-epimers of 24-methyl and 24-ethylcholesterols were made based on 220 MHz ¹H NMR spectroscopy and capillary gas chromatography. Sterol compositions of bryophytes from other studies are reviewed, and possible sterol biosynthetic pathways in bryophytes are discussed.     

Sterols from three Lactarius species

The sterol composition of three fungi was determined. Ergosterol is the major sterol, accompanied by other closely related sterols.     

微波法提取菱角中甾醇类化合物的研究

本文研究了微波法提取菱角中甾醇类化合物的新方法。通过正交实验确定了甾醇的最佳提取条件为：95％乙醇作提取剂,微波功率420W,料液比1：5,提取时间60s,提取2次。以紫外分光光度法测定了样品中植物总甾醇的含量,其中菱角皮中含总甾醇0．624mg,／g,菱角仁中含总甾醇0．640mg／g。该方法的平均回收率为91．6％。与超声波法及索氏回流法相比,微波法提取菱角中甾醇类化合物的提取时间极短,由3～6h减少为60s,而提取效率却提高了1／3左右。从节能、技术经济和资源综合利用的角度来看,微波法将有广阔的应用前景。     

Halysitid tabulates: sponges in corals' clothing

Abundant pyritic pseudomorphs of monaxonic siliceous spicules (ophirhabds and ?heloclones) have been found entrapped in the calcareous skeleton of the halysitid tabulate Quepora ?agglomeratiformis (Whitfield) from late Ordovician limestones of Frobisher Bay, Baffin Island, Canada. The finding indicates a poriferan (choristid or sublithistid) affinity of halysitids, early Palaeozoic marine fossils related so far to corals. They probably derived from a monaxonic group of early demosponges that adapted during the Ordovician to Ca²⁺ stress conditions in epicontinental seas by excreting the excessive Ca²⁺ influx to their tissues as variously designed chains of basally secreted calcareous tubes.     

Sterols and related metabolites from five species of sponges

Free sterol fractions were isolated from the marine sponges Phyllospongia madagascarensis, Scalarispongia sp., Oceanapia sp., Monanchora clathrata and studied by GLC, GLC–MS, and spectroscopy NMR. P. madagascarensis and Scalarispongia sp. contained common Δ⁵-sterols; cholesterol was shown to be a main sterol of both the sponges. Oceanapia sp. contained stanols and minor Δ⁵-sterols with 24R-24,25-methylene-5α-cholestan-3β-ol as a main constituent. Many free sterols from M. clathrata were Δ⁷-series compounds, and latosterol was a main sterol. Δ⁴-3-Ketosteroids and Δ⁵-sterol esters were found in the Antarctic sponge Haliclona sp., but free sterols were practically absent except for trace amount of cholesterol. A chemotaxonomic application of sterols in relation to the genera Phyllospongia, Oceanapia and the family Crambeidae is provided. The known cases of the absence of sterols in sponges and probable reasons of the phenomenon are discussed.     

Sterols of Mediterranean Florideophyceae

The distribution of sterols in 31 Mediterranean Florideophyceae has been investigated. Cholesterol is present in the greatest majority of the species examined, while the occurrence of other C-27 sterols (desmosterol, 22-dehydrocholesterol, liagosterol and cholest-7-en-3β-ol) is much more restricted. Two species (Rytiphloea tinctoria and Vidalia volubilis) contain, in addition to C-27 sterols, large amounts of C-28 and C-29 compounds.