51 resultados para stigmasterol


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Sediments collected from three continental slope sites of Leg 67 have been examined for total organic carbon content and amount of the sterols beta-sitosterol and stigmasterol. The amount of beta-sitosterol relative to stigmasterol is found to increase landward in the sediment, despite differing ages of the samples studied. The ratio of beta-sitosterol to stigmasterol in near-shore sediments is proposed as a source proximity indicator.

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Increased interest in the cholesterol-lowering effect of plant sterols has led to development of plant sterol-enriched foods. When products are enriched, the safety of the added components must be evaluated. In the case of plant sterols, oxidation is the reaction of main concern. In vitro studies have indicated that cholesterol oxides may have harmful effects. Due their structural similarity, plant sterol oxidation products may have similar health implications. This study concentrated on developing high-performance liquid chromatography (HPLC) methods that enable the investigation of formation of both primary and secondary oxidation products and thus can be used for oxidation mechanism studies of plant sterols. The applicability of the methods for following the oxidation reactions of plant sterols was evaluated by using oxidized stigmasterol and sterol mixture as model samples. An HPLC method with ultraviolet and fluorescence detection (HPLC-UV-FL) was developed. It allowed the specific detection of hydroperoxides with FL detection after post-column reagent addition. The formation of primary and secondary oxidation products and amount of unoxidized sterol could be followed by using UV detection. With the HPLC-UV-FL method, separation between oxides was essential and oxides of only one plant sterol could be quantified in one run. Quantification with UV can lead to inaccuracy of the results since the number of double bonds had effect on the UV absorbance. In the case of liquid chromatography-mass spectrometry (LC-MS), separation of oxides with different functionalities was important because some oxides of the same sterol have similar molecular weight and moreover epimers have similar fragmentation behaviour. On the other hand, coelution of different plant sterol oxides with the same functional group was acceptable since they differ in molecular weights. Results revealed that all studied plant sterols and cholesterol seem to have similar fragmentation behaviour, with only relative ion abundances being slightly different. The major advantage of MS detection coupled with LC separation is the capability to analyse totally or partly coeluting analytes if these have different molecular weights. The HPLC-UV-FL and LC-MS methods were demonstrated to be suitable for studying the photo-oxidation and thermo-oxidation reactions of plant sterols. The HPLC-UV-FL method was able to show different formation rates of hydroperoxides during photo-oxidation. The method also confirmed that plant sterols have similar photo-oxidation behaviour to cholesterol. When thermo-oxidation of plant sterols was investigated by HPLC-UV-FL and LC-MS, the results revealed that the formation and decomposition of individual hydroperoxides and secondary oxidation products could be studied. The methods used revealed that all of the plant sterols had similar thermo-oxidation behaviour when compared with each other, and the predominant reactions and oxidation rates were temperature dependent. Overall, these findings showed that with these LC methods the oxidation mechanisms of plant sterols can be examined in detail, including the formation and degradation of individual hydroperoxides and secondary oxidation products, with less sample pretreatment and without derivatization.

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本文对禄春安息香(Styrax macranthus)种子和攀援孔药花(Porandra scandens)全草的化学成分进行了研究,共获得30个化合物,其中2个为新化合物。 从禄春安息香种子95%乙醇提取物中分离并鉴定了12个化合物,其中2个新化合物鉴定为3-[7-methoxy-2-(3,4-methylenedioxy phenyl) benzofuran-5-yl] propyl 3-[7-methoxy-2-(3,4-methylenedioxyphenyl)benzofuran-5-yl] propanoate (1) 和去甲氧基-egonol-龙胆双糖甙 (2);已知化合物分别为2-(3,4-二氧亚甲基苯基)-5-甲酰基-7-甲氧基-苯并呋喃 (3)、egonol (4)、去甲氧基-egonol (5)、去甲基-egonol (6)、egonol-葡萄糖甙 (7)、egonol-龙胆双糖甙 (8)、egonol-龙胆三糖甙 (9)、豆甾醇 (10)、二十四烷酸 1-甘油酯 (11) 和胡萝卜甙 (12)。生物活性测试发现,化合物2具有促进雌激素E2合成的作用。 从攀援孔药花全草95%乙醇提取物中分离并鉴定了19个化合物:(2S,3S,4R)-2-[(2R)-2-羟基-二十一烷酰基氨基]-二十一烷-1,3,4-三醇 (13)、(2S,3S,4R)–2–二十四烷酰基氨基-十八烷-1,3,4-三醇 (14)、胡萝卜甙 (12)、β-谷甾醇 (15)、(20S,22E,24R)-5α,8α-表二氧-麦角甾-6,22-二烯-3β-醇 (16)、6β-羟基-豆甾-4-烯-3-酮 (17)、十六烷酸 1-甘油酯 (18)、桦木酸 (19)、大黄素 (20)、二十二烷酸 1-甘油酯 (21)、对羟基苯甲醛 (22)、十七烷酸 1-甘油酯 (23)、金色酰胺醇乙酸酯(24)、十九烷酸 1-甘油酯 (25)、棕榈酸 (26)、(E)-p-香豆酸 (27)、(22E,24S)-24-麦角甾醇-7,22-二烯-3β,5α,6β-三醇 (28)、2-去氧-β-蜕皮激素 (29)和auranamide (30)。 综述了近十年来发现的2-芳基苯并呋喃类新木脂素的结构特征、来源、生物活性和化学全合成。 Phytochemical investigation on the seeds of Styrax macranthus and the whole plants of Porandra scandens led to the isolation of thirty compounds, two of which were new ones. Two new 2-aryl benzofuran derivatives, 3-[7-methoxy-2-(3,4-methylenedioxy phenyl) benzofuran-5-yl]propyl 3-[7-methoxy-2-(3,4-methylenedioxyphenyl)benzo furan-5-yl]propanoate (1) and demethoxy egonol gentiobioside (2), were isolated from the 95% aqueous ethanolic extract of the seeds of Styrax macranthus, together with 7-methoxy-2-(3,4-methylenedioxyphenyl) benzofuran-5-carbaldehyde (3), egonol (4), demethoxy egonol (5), demethyl egonol (6), egonol glucoside (7), egonol gentiobioside (8), egonol gentiotrioside (9), stigmasterol (10), 2,3-dihydroxypropyl tetracosoate (11), and daucosterol (12). In vitro test, compound 2 promote the synthesis of estrogen E2. Nineteen compounds were isolated from the 95% aqueous ethanolic extract of the whole plant of Porandra scandens for the first time. Their structures were identified as (2S,3S,4R)-2-[(2R)-2-hydroxy-heneicosanoylamino]-1,3,4- heneicosanetriol (13), (2S,3S,4R)-2-tetracosanoylamino-1,3,4-octadecanetriol (14), daucosterol (15), β-sitosterol (12), (20S,22E,24R)-5α,8α-epidioxy-ergosta-6,22-diene- 3β-ol (16), 6β-hydroxylstigmast-4-en-3-one (17), 1-glycerol-1-hexadecoate (18), betulinic acid (19), emodin (20), 1-glycerol-1-docosoate (21), p-hydroxybenzaldehyde (22), 1-glycerol-1-heptadecoate (23), aurantiamide acetate (24), 1-glycerol-1- nonadecoate (25), palmatic acid (26), (E)-p-coumaric acid (27), (22E,24S)- 24-metbylcbolesta-7,22-diene-3β,5α,6β-triol (28), 2-deoxycrustecdysone (29), and auranamide (30). The characteristic, natural resource, bioactivity, and the total synthesis of 2-aryl benzofurans were reviewed.

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海洋是一个巨大的天然产物宝库,约占地球表面积70%的海洋蕴藏着80%的生物资源。由于海洋生态环境的特殊性,导致海洋生物能够产生大量结构独特多变和活性特殊多样的代谢产物。我国海域辽阔,海洋资源丰富,为寻找结构新颖、生理活性独特的先导化合物,加强对海洋资源的开发利用,本论文对中国沿海的三种海洋红藻和两株放线菌次生代谢产物以及生物活性进行研究,为新药研究与开发提供模式结构和药物前体。 对红藻似瘤凹顶藻Laurencia similis乙酸乙酯萃取物进行分离纯化,从中得到单体化合物35个,通过波谱学方法(IR、MS、NMR等)鉴定了他们的结构。分别为:2, 2, 5, 5, 6, 6-sixibromo-3, 3-bi-1H-indole (1),3,5-dibromo- 1-methyl-indole (2),3',5',6,6'-tetrabromo-2,4-dimmethyldiphenyl ether (3),1,2,5- tribromo-3-bromoamino-7-bromomethylnaphthalene (4),2,5,8-tribromo-3-bromo- amino-7-bromomethylnaphthalene (5),2,5,6-tribromo-3-bromoamino-7-bromo- methylnaphthalene (6), 2,5,6,5',6'-pentabromo-3,4,3',4'-tetramethoxybenzophenone (7), (4E)-1-bromo-5-[(1'S*,3'R*)-3'-bromo-2',2'-dimethyl-6'-methylenecyclohexyl] -3-methylpent-4-ene-2,3-diol (8),4-hydroxy-Palisadin C (9),Isopalisol (10),Luzonensol (11),Palisadin B (12),Aplysistatin (13),Palisadin A (14),5-Acetoxypalisadin B (15),Aristolan-1(10)- en-9-ol (16),Aristol-8-en-1-one (17),Aristolan-9-en-1-one (18),Aristolan-1(10)-en- 9-one (19),Aristofone (20),Aristolan-1(10)-8-diene (21),Aristolan-1,9-diene (22),10-Hydroxyaristolan-9-one (23),7,11,15-trimethyl-3-methylene-hexadecan-1,2-diol (24),3β-Hydroxyergosta- 5,24(28)-dien-7-one (25),Isofucosterol (26),β-sitosterol (27),豆甾-4-烯-3α,6β-二醇 (28),Cholesta-5-en-3β-ol (29),Stigmasterol (30),2,3,5,6-四溴-吲哚 (31),2,3,6-tribromo-1H-indole (32),3,5,6-tribromo-1-methylindole (33),3,5,6-tribromo -1H-indole (34),2,3,5-tribromo-1-methylindole (35),其中化合物1-9为新化合物,化合物10-15、20和化合物24-30均为首次从该种海藻中得到。对新化合物1-9进行PTP1B酶抑制剂活性筛选,新化合物1、3、7显示强的PTP1B酶抑制活性。 对红藻齐藤凹顶藻Laurencia saitoi乙酸乙酯萃取物进行分离纯化,从中得到单体化合物11个,通过波谱学方法(IR、MS、NMR等)鉴定了他们的结构,分别为:2-hydroxyl-Luzofuranone (1),2-hydroxyl-Luzofuranone B (2),4-hydroxyl-Palisudin C (3),2-bromo-γ-ionone (4),Aplysistatin (5),5-Acetoxypalisadin B (6),Palisadin B (7),Palisadin A (8),Pacifigorgiol (9),豆甾-4-烯-3α,6β-二醇 (10),2, 3, 5, 6-四溴-吲哚 (11),其中化合物1-4为新化合物,所有化合物均为首次从该种海藻中得到。通过MTT法对分离得到的新化合物1-4进行肿瘤细胞毒活性筛选,结果显示4个新化合物对所测肿瘤细胞株均无明显的活性。 对红藻瘤状软骨凹顶藻Chondrophycus papillous乙酸乙酯萃取物进行分离纯化,从中得到单体化合物5个,通过波谱学方法(MS、NMR等)鉴定了他们的结构,分别为邻苯二甲酸二丁酯 (1),邻苯二甲酸二异辛酯 (2),胆甾醇 (3),3,7,11,15-tetramethyl-hexadec-2-en-1-ol (4),4-羟基苯甲醛 (5),所有化合物均为首次从该种海藻中得到。 对海洋放线菌M159乙酸乙酯萃取物进行分离纯化,从中得到单体化合物13个,通过波谱学方法(MS、NMR等)鉴定了他们的结构,分别为:5-(4',6'-dihydroxy-6-methyloctyl)furan-2(5H)-one (A),phenethyl alcohol (1),4-羟基苯甲醛(2),anthranilic acid (3),4-Hydroxy-3-methoxy- phenyl-propionic acid (4),5-(6,7-dihydroxy-6-methyloctyl)furan-2(5H)-one (5),p-Hydroxyphenylethyl alcohol (6),3-Indoleacrylic acid (7),Indol-3-carboxylic acid (8),Adenine cordyceposide (9),腺嘌呤核苷(10),尿嘧啶核苷(11),Thymidine (12),其中化合物A为新化合物。所有化合物均为首次从该株放线菌中得到。 对海洋放线菌L211乙酸乙酯萃取物进行分离纯化,从中得到单体化合物15个,通过波谱学方法(MS、NMR等)鉴定了7个结构,分别为:spatozoate (1),anthranilic acid (2),3-Indolylethanol (3),1-Acetyl-β-carbolin (4),p-Hydroxyphen- ylethyl alcohol (5),Indole-3-acetic acid (6),Indol-3-carboxylic acid (7),所有化合物均为首次从该株放线菌中得到。

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Chemical investigation of the ethanol extract of the marine green alga Chaetomorpha basiretorsa Setchell led to the isolation of a new sterol stigmast-4,28-dien-3 alpha 6 beta-diol 1 in addition to the five known sterols of beta-lawsaritol 2, saringosterol 3, 24-hydroperoxy-24-vinyl - cholesterol 4, beta-stigmasterol 5, 29-hydroxystigmasta-5, 24(28) -dien-3 beta-ol 6. Compounds were isolated by normal phase silica gel and Sephadex LH - 20 gel colum chromatography, reverse phase HPLC and recrystalization. Their structures were elucidated by spectroscopic methods including MS, IR 1D/2D NMR and X-ray analysis. Cytotoxicity of compounds was screened by using the standard WIT method. All these compounds were isolated from the green alga Chaetomorpha basiretorsa Setchell for the first time and they were inactive (50% inhibitory concentration was greater than 10 mu g /cm(3)) against KB, Bel -7402, PC - 3M, Ketr 3 and MCF - 7 cell lines.

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Six steroids have been isolated from ethanolic extract of green alga Chaetomorpha basiretorsa Setchell by a combination of repeated normal phase silica gel and Sephadex LH-20 gel column chromatography as well as recrystallization. Using spectroscopic methods including MS and NMR, their structures were determined as beta-lawsaritol (1), saringosterol (2), 24-hydroperoxy-24-vinyl-cholesterol (3), beta-stigmasterol (4), stigmast-4-en-3 alpha, 6 beta-diol (5), 29-hydroxystigmasta-5, 24 (28)-dien-3 beta-ol (6). All these compounds were obtained from this genus for the first time and they were inactive (IC50 > 10 mu g /ml) against KB, Bel-7402, PC-3M, Ketr 3 and MCF-7 cell lines.

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The main objective of this thesis is to outline the synthetic chemistry involved in the preparation of a range of novel lanostane and cholestane derivatives, and subsequent investigation into their biological activity in cancer cells. The biological results obtained throughout the project have driven the strategic synthesis of new compounds, in an effort to optimise the anti cancer potential of lanostane and cholestane derivatives. The first chapter begins with an overview of steroidal compounds and details a literature review of the natural sources of these moieties, as well as their biosynthesis and reported synthetic derivatives. The biological activity of interesting natural and synthetic analogues is also discussed. In addition, an insight into some currently prescribed pharmaceutical compounds, with functional groups relevant to this project, is presented. The second chapter discusses the methods employed for the synthesis of these novel lanostane and cholestane derivatives, and comprises three main sections. Firstly, various oxidation products of lanosterol are synthesised, mainly via epoxidations of the C-8,9 and C- 24,25 alkenes, and also allylic oxidations at these positions. Secondly, amine derivatives of lanosterol are formed by cleaving the lanostane side chain, thereby yielding a new cholestane nucleus, and performing several reductive aminations on the resulting key aldehyde intermediates. Various amines such as piperidine, morpholine, diethylamine and aniline are employed in the reductive amination reactions to yield novel cholestane steroids with amine side chains. Finally, starting from stigmasterol and proceeding with the same methodology of cleaving the steroidal side chain and subsequently performing reductive aminations, novel cholestane derivatives of the biologically active amines are synthesised. The cytotoxicity of these compounds against CaCo-2 and U937 cell lines is presented in terms of percentage viability of cells, IC50 value and apoptosis. The MTT assay is used to determine the percentage viability of cells, and the IC50 data is generated from the MTT results. Apoptosis is measured in terms of fold increase relative to a carrier control. In summary, the compounds formed are discussed in terms of chemical synthesis, spectroscopic interpretation and biological activity. The main reaction pathways involved in the chemistry within this project are various oxidations and reductive amination. The final chapter is a detailed account of the full experimental procedures for the compounds synthesised during this work, including characterisation using spectroscopic and analytical data.

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Ethnopharmacological relevance
The two plants investigated here (Fagonia cretica L. and Hedera nepalensis K. Koch) have been previously reported as natural folk medicines for the treatment of diabetes but until now no scientific investigation of potential anti-diabetic effects has been reported. 


Materials and methods
In vitro inhibitory effect of the two tested plants and their five isolated compounds on the dipeptidyl peptidase 4 (DPP-4) was studied for the assessment of anti-diabetic activity. 

Results
A crude extract of Fagonia cretica possessed good inhibitory activity (IC50value: 38.1 μg/ml) which was also present in its n-hexane (FCN), ethyl acetate (FCE) or aqueous (FCA) fractions. A crude extract of Hedera nepalensis (HNC) possessed even higher inhibitory activity (IC50value: 17.2 μg/ml) and this activity was largely retained when further fractionated in either ethyl acetate (HNE; IC50: 34.4 μg/ml) or n-hexane (HNN; 34.2 μg/ml). Bioactivity guided isolation led to the identification of four known compounds (isolated for the first time) from Fagonia cretica: quinovic acid (1), quinovic acid-3β-O-β-d-glycopyranoside (2), quinovic acid-3β-O-β-d-glucopyranosyl-(28→1)-β-d-glucopyranosyl ester (3), and stigmasterol (4) all of which inhibited DPP-4 activity (IC50: 30.7, 57.9, 23.5 and >100 μM, respectively). The fifth DPP-4 inhibitor, the triterpenoid lupeol (5) was identified in Hedera nepalensis (IC50: 31.6 μM). 

Conclusion
The experimental study revealed that Fagonia cretica and Hedera nepalensis contain compounds with significant DPP-4 inhibitory activity which should be further investigated for their anti-diabetic potential.

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Dietary intake of fats and sterols has long been known to play a critical role in human health. High proportions of saturated fat, which increase blood cholesterol levels, are mainly found in animal fat and some plant oil (e.g. cocoa butter, palm oil etc.). The predominant polyunsaturated fatty acid (PUFA) in the Western diet is linoleic acid (LA; 18:2n-6), an essential fatty acid, which is commonly found in vegetable seed oils. This is the parent fatty acid of n-6 series PUFA, which can be converted in vivo to C20 and C22 n-6 long chain (LC) PUFA. α‐linolenic acid (ALA; 18:3n-3) is less abundant than LA and is another essential fatty acid; ALA is also present in some vegetable oils such as perilla, flaxseed, canola, soybean and walnut oils, and is the precursor of C20 and C22 n-3 LC PUFA. Sterols are widely distributed in animal tissue and plants, with cholesterol being the major sterol in animal tissue and β-sitosterol, campesterol and stigmasterol being the main sterols in plants. It has long been recognized that an increased dietary intake of saturated fat and (to a lesser extent) cholesterol, raises plasma/serum total and low-density lipoprotein (LDL)-cholesterol, and PUFA decreases these levels. Results from recent studies have shown that plasma/serum levels of lipids and lipoprotein lipids can also be decreased by plant sterols (phytosterols) and diacylglycerol (DAG). Conjugated linoleic acid (CLA, cis-9,trans-11−18:2) has been reported to have anticancer and antidiabetic activities. Fat as the DAG form has also been reported to have anti-obesity effects. Omega-3 PUFA have a beneficial effect on increased heart rate variability, decreased risk of stroke, reduction of both systolic and diastolic blood pressure and may be effective in managing depression in adults. Gamma-linolenic acid (GLA) and phytosterols have an anti-inflammatory activity. The GLA, when combined with docosahexaenoic acid (DHA), have been reported to have a beneficial effect in hyperactive children. These data show that various lipids are powerful bioactive compounds.

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The main aim of this study was to compare the procedure for dehydration of Gracilaria birdiae prepared handmade and laboratory, collected in the northern coast of Rio Grande do Norte. The sample was collected in the Rio do Fogo beach in march 2009. The sample collected followed by two processing, the first the material prepared in laboratory was air-dried at 50°C for 24 hours in air-flow oven. The second the handmade sample was air-dried on the sun during three days. The extract was prepared in three different solvents: ethanol, hydroethanol and water, resulting in ethanol, hidroethanol and aqueous extracts from handmade and laboratory sample. In according with results only the ethanol extract was fractionated yielding the fractions hexane, dichloromethane and ethyl acetate fractions. The different process to obtain Gracilaria birdiae resulted in the samples with different shades. The soluble solids content was higher in the laboratory sample. The chemical composition the both samples were characterized by presenting a considerable amounts of carbohydrates, with amior percentage protein and ash, respectively, in the handmade and laboratory sample. In two samples showed a low content of lipids and the lipid profile showed a higher proportion of monounsaturated fatty acids, with the absence polyunsaturated handmade sample. The phytochemical screening by chemical reactions showed the presence of flavonoids, tannins, alkaloids and saponins the laboratory sample, presenting a greater diversity of bioactive compounds. Through of the analysis by thin layer chromatography was possible to identify the phytosterols β-sitosterol and stigmasterol the both samples, also suggest the presence of β-carotene and chlorophyll α the laboratory sample. The levels of total phenolics and flavonoids were more significant in the ethanol extract of the laboratory sample. The in vitro lethality showed that extracts of the laboratory sample and handmade from 125 to 500 μg/ mL, respectively, were highly lethal. In the evaluation of antioxidant capacity by the system β-carotene/ácido linoleic method and by DPPH radical scavernging assay, the ethanol extract from the laboratory process showed significantly greater activity than the other extracts, being and the first and second methods, respectively, lower and equivalent to the synthetic antioxidant BHT. The handmade ethanol extract has not demonstrated skill in deactivating free radicals, but showed activity in inhibiting lipid peroxidation, although the values were significantly lower than the laboratory sample. We conclude that the dehydration process in the laboratory is the most efficient technique to maintenance of the chemical composition present in the seaweed, providing beneficial properties such as antioxidant capacity. We emphasize that this property can be explored with the objective of adding commercial value to the final product, which will promote the expansion of production of this seaweed in the community of Rio do Fogo

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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From the stem bark of Xylopia aromatica (Annonaceae), have been isolated two new labdane dimers as their methyl esters, together with the known compounds ent-labda-8(17),13(16),14-trien-18-oic acid, sitosterol and stigmasterol. The structures of the dimers were elucidated on the basis of detailed spectroscopic analyses. (C) 1999 Elsevier B.V. Ltd. All rights reserved.

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Recently, marine organisms have attracted attention because of the complexity and potent biological activity from your secondary metabolites. Our planet has 80% it surface covered by oceans and seas, therefore, housing a wide number of different forms of life, among them, the sponges. These sessile and filtrating animals, according to numerous researches, come showing like true chemistry factories. The substances from these animals, sometimes show as news targets to therapeutics agents, and some countries has already use them for treatment of some diseases. Further of the secondary metabolites, the polysaccharides of marine origin also have been target of studies, because the presence of the sulfates groups in its molecules. Polysaccharides with differents biological activities have been related in a large number of researches. Actually, many studies show the sponges as source of promising medicine. These studies inspire new researches, because the few number of sponges species studied until now. Because of that, the present work shows the chemistry prospection of the sponge Callyspongia vaginalis. Chromatographic methods in silica gel allowed the isolations of two secondary metabolites: the known β- sitosterol and a ceramide, no reported in the genus Callyspongia, previously. The analysis of the their lipid extracts show different kinds of fatty acids with a variety of chain length (saponifiable fraction), and others metabolites like Lupenone and stigmasterol, also unprecedented in the genus. The Polysaccharide characterization and the elucidation of the secondary metabolites acquired through of chromatography analysis (CC, molecular exclusion) and spectrometric (NMR 1H and 13C, mass, IR), respectively and comparison with literature data

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Chemical investigation of Hyptidendron canum stems resulted in the isolation of betulinic, ursolic and euscaphic acids. From the leaves were isolated 3β-O-β-galactopiranosilsitosterol, ursolic aldehyde, and mixtures of maslinic acid and 2α-hydroxyursolic acid, α and β-amyrin, uvaol and erythrodiol, sitosterol and stigmasterol, spathulenol and globulol. Hexane and chloroform leave fractions as well as ursolic and betulinic acids showed antifungal activities against the yeast form of Paracoccidioides brasiliensis.

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As part of a continuing interest in exploring the chemistry of Brazilian medicinal plants, three new labdane diterpenoids, 6 alpha-acetoxymanoyl oxide (1), 6 alpha-malonyloxymanoyl oxide (2), and 6 alpha-malonyloxy-n-butyl ester manoyl oxide (3), together with the known betulinic acid, lupeol, sitosterol, and stigmasterol, were isolated from the aerial parts of Stemodia foliosa. The structures of 1-3 were established on the basis of interpretation of spectroscopic data, including HRESIMS, and 1D and 2D NMR techniques. All compounds were tested against a bacteria panel consisting of Staphylococcus aureus, Bacillus cereus, B. subtilis, B. anthracis, Micrococcus luteus, Mycobacterium smegmatis, and M. phlei. Compound 2 showed, moderate activity against these strains, with MIC values in the range 7-20 mu g/mL.