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At least 253 records · Page 14Linked to original sources
PubMed1999

Antimicrobial components of some cruciferae plants (Diplotaxis harra Forsk. and Erucaria microcarpa Boiss.)

The total herb of Diplotaxis harra Forsk. on treatment with myrosinase produces isopropyl isothiocyanate and 3- butenyl isothiocyanate in addition to (the non-volatile) 2-hydroxy-3-butenyl isothiocyanate which could be obtained as 5-vinyl-2-oxazolidinethione (goitrin) and methyl 4-isothiocyanatobutyrate (Erypestrin). On treating Erucaria microcarpa Boiss, herb with myrosinase, it produces isopropyl isothiocyanate, butyl isothiocyanate and benzyl isothiocyanate in addition to the non-volatile 8-methylsulphinyloctyl isothiocyanate (hirsutin). The plant extracts contain high percentages of arachidonic and palmitic acids, nonadecane, cholesterol, stigmasterol and B-sitosterol. The volatile constituents of D. harra and E. microcarpa showed higher activity against yeasts than Gram +ve, Gram -ve bacteria and fungi. The nonmethylated fatty acids of the two herbs showed higher activity against Gram +ve and Gram -ve bacteria than yeasts and fungi.

Anti-Bacterial Agents↗
PubMed2002

New withanolides and other constituents from the fruit of Withania somnifera.

Two new steroidal lactones of the withanolide-type, 5beta, 6alpha, 14alpha, 17beta, 20beta-pentahydroxy-1-oxo-20 S, 22R-witha-2, 24-dienolide (1)and 6alpha, 7alpha-epoxy-5alpha, 14alpha, 17alpha, 23beta-tetrahydroxy-1-oxo-22R-witha-2, 24-dienolide (2), were isolated from the fruit of Withania somnifera (L.) Dunal (Solanaceae) growing in Southern Egypt, together with two known coumarins, scopoletin (3)and aesculetin (4), a known triterpene, viz. Beta-amyrin (5), and two known phytosterols, viz. stigmasterol (6) and sitosterol (7). The structures of the isolated compounds have been elucidated by spectroscopic methods including UV, IR, (1)H-, (13)C-NMR, DEPT experiments, HRFAB-, FAB-, and EI-mass spectrometry. The in vitro antimicrobial activity of the new withanolide (1) and the alcoholic fruit extract are discussed.

Anti-Bacterial Agents↗
PubMed1988

Identification by methane chemical ionization gas chromatography/mass spectrometry of the products obtained by steam distillation and aqueous acid extraction of commercial Piper methysticum.

Bornyl cinnamate has been identified as a constituent of kava resin and of the steam distillate of Piper methysticum. 5-Hydroxydihydrokawain was identified in commercial samples of P. methysticum originating from Vanuatu provided an initial aqueous extraction was employed. Commercial preparations, and fresh samples of the root of this plant from Fiji, lacked this compound. Two previously described N-cinnamoyl pyrrolidine alkaloids were also observed along with stigmasterol in kava resin from Fiji and Vanuatu. The products derived from aqueous 2 M hydrochloric acid extraction of P. methysticum were determined from methane chemical ionization gas chromatography/mass spectrometry analysis which identified a series of hydroxylated compounds (15a-d) derived from formal decarbonylation of the parent kava lactones. The products (13a-c) of dehydration of these compounds were also observed. The efficiency of kava resin extraction from plant material by water (the traditional method of preparation of the kava beverage) was typically 5-10% of that recovered by direct extraction with an organic solvent.

Fiji↗
PubMed2005

Chemical constituents and antioxidant activity of Mallotus roxburghianus leaves.

Mallotus roxburghianus is used in the traditional medicine in North-Eastern India, but previously no work has been done on the identification of bioactive compounds. Two new compounds, 3-(1-C-beta-D-glucopyranosyl)-2,6-dihydroxy-5-methoxybenzoic acid (6) and 2,4,8,9,10-pentahydroxy-3,7-dimethoxyanthracene-6-O-beta-D-rhamnopyranoside (7) together with beta-sitosterol (1), stigmasterol (2), betulinic acid (3), 4-hydroxybenzoic acid (4), beta-sitosterol-beta-D-glucoside (5), and bergenin (8) were isolated and identified from the leaves of M. roxburghianus. The chloroform soluble portion of the alcoholic extract of leaf, and compounds 3, 6, 7, and 8 exhibited encouraging antioxidant activities.

Antioxidants↗
PubMed2003

Triterpene constituents from the leaves of Melicope indica.

Phytochemical investigation of a petroleum ether extract of Melicope indica afforded two unusual pentacyclic triterpenes viz. neohop-13(18)-en-3alpha-ol (1) and fern-8(9)-en-3beta-ol (2) and the ubiquitous steroids, stigmasterol and sitosterol. The structures of 1 and 2 were independently elucidated on the basis of 2D NMR data and confirmed by comparison with those of related compounds. While compound 1 is a new natural product, this is the first report of occurrence of fern-8(9)-en-3beta-ol (2) from the genus Melicope.

Magnetic Resonance Spectroscopy↗
PubMed1984

A requirement for cholesterol and its structural features for a human macrophage-like cell line.

The lipid requirements of a human macrophagelike cell line were studied. The cells grew only about one generation in a medium supplemented with delipidated serum; during the growth the cholesterol content of the cells was depleted. Growth was restored by including in the medium serum lipids subjected to alkaline hydrolysis or cholesterol. The extent of growth was dependent on cholesterol concentration. No growth was obtained with 5-cholestene, 5-cholesten-3-one, cholesteryl chloride, coprostanol, beta-sitosterol, or stigmasterol. Very limited growth occurred with cholesterol methylether, epicholesterol, or beta-cholestanol. Therefore, for optimal growth of these cells there is a stringent requirement for the structural features of cholesterol, which include a 3-beta OH group, a delta 5-double bond, a trans ring A/B configuration, and freedom of the side chain from bulky groups. This stringency far exceeds what was previously reported for other cells. Of the six sterols that failed to support growth at all, five were incorporated into cells moderately to extensively. This suggests that assembly of a functional membrane is impaired when these sterols are used as substrates for growth.

Blood↗
PubMed1978

Quantitative GLC analysis of sterols in biological samples.

A GLC method for the quantitative analysis of cholesterol, beta-sitosterol, stigmasterol, campesterol, 7-dehydrocholesterol, and dihydrocholesterol in biological samples was developed to screen serum and lipid extracts of heart and liver tissue for these sterols precisely. The addition of the internal standard, cholestane, at the beginning of the procedure led to a reduction in the required sample size and the elimination of several steps. The only critical measurements are those of the biological samples and internal standard.

Animals↗
PubMed1980

Antitumor agents XXXVIII: Isolation and structural elucidation of novel germacranolides and triterpenes from Elephantopus mollis.

The ethanolic extract of Elephantopus mollis yielded three novel cytotoxic antitumor germacranolides, molephantin, molephantinin, and phantomolin. The extract also yielded three inactive known triterpenes, beta-amyrin acetate, lupeol acetate, and epifriedelanol, as well as stigmasterol. The structure and stereochemistry of the cytotoxic antitumor agents molephantin, molephantinin, and phantomolin were determined on the basis of chemical transformations and spectral evidence. Preliminary in vivo tumor assays indicated that molephantinin and phantomolin were potent inhibitors of Ehrlich ascites carcinoma and Walker 256 carcinosarcoma. Molephantinin also showed significant antileukemic activity in the P-388 lymphocytic leukemia screen.

Animals↗
PubMed1982

Herbal remedies of the Maritime Indians: sterols and triterpenes of Achillea millefolium L. (Yarrow).

As part of ongoing studies of the medicinal aspects of Maritime flora, particularly the herbal remedies of the Micmac and Malecite Indians, the sterols and triterpenes of Achillea millefolium L. (Compositae), a widely used herbal remedy known commonly as yarrow, were determined. Using modern techniques, including nuclear magnetic resonance spectroscopy and combined GC-mass spectrometry, beta-sitosterol was identified as the major sterol and alpha-amyrin as the major triterpene of this plant. The sterols stigmasterol, campesterol, and cholesterol and the triterpenses beta-amyrin, taraxasterol, and pseudotaraxasterol were also identified. Successful therapeutic application of yarrow may be partly due to the presence of one or more of these compounds since many sterols and triterpenes exhibit a wide range of pharmacological activities. This is the first reported occurrence of cholesterol, campesterol, and the four triterpenes in yarrow.

Canada↗
PubMedDate not supplied

Biflavonoids and a glucopyranoside derivative from Ouratea semiserrata.

Two new biflavonoids, 5-hydroxy-7-methoxyflavone-(4' --> O --> 8")-4"',5",7"-trihydroxyflavone and 5-hydroxy-7-methoxyflavone-(4' --> O --> 8")-5",7"-dihydroxy-4"'-methoxyflavone, and the glucopyranoside derivative, 1-O-(4-hydroxyphenyl)-6-O-(4-hydroxybenzoyl)-beta-D-glucopyranoside, as well as the known biflavones lanaraflavone, amentoflavone and podocarpusflavone, the triterpenes lupeol and friedelin, the lignans eudesmin and epieudesmin, the flavonol glycoside rutin, the steroids beta-sitosterol, stigmasterol, 3beta-O-beta-D-glucopyranosylsitosterol, 7-oxostigmast-5-en-3beta-ol and 7-oxostigmasta-5,22-dien-3beta-ol, the carbohydrates alpha- and beta-glucopyranose and 1-O-(4-hydroxybenzoyl)-beta-D-glucopyranoside, and the norsesquiterpene 6,9-dihydroxymegastigma-4,7-dien-3-one, have been isolated from leaves and branches of Ouratea semiserrata. The structures of these compounds were established from spectral data, including two-dimensional NMR experiments and mass spectra.

Flavonoids↗
PubMedDate not supplied

Steroids and triterpenes from Eleocharis acutangula and E. sellowiana (Cyperaceae).

From the hexane extract of the underground parts of Eleocharis acutangula (Roxb.) Schult., lup-20(29)-ene-3beta,16beta-diol and a mixture of campesterol, stigmasterol and sitosterol were isolated. The hexane extracts of aerial and underground parts of E. sellowiana Kunth furnished two new substances, namely neohop-13(18)-en-3alpha-ol and stigmast-22-en-3beta,6beta,9alpha-triol, together with a mixture of steroids, betulinic acid, stigmast-4-en-6beta-ol-3-one and fern-9(11)-en-3alpha-ol. The molecular structures were determined by spectral analysis (1D- and 2D-NMR experiments and MS) and comparison with literature data.

Cyperaceae↗
PubMed2002

Antitubercular constituents from the hexane fraction of Morinda citrifolia Linn. (Rubiaceae).

A crude ethanol extract and hexane fraction from Morinda citrifolia Linn. (Rubiaceae) show antitubercular activity. The major constituents of the hexane fraction are E-phytol, cycloartenol, stigmasterol, beta-sitosterol, campesta-5,7,22-trien-3beta-ol and the ketosteroids stigmasta-4-en-3-one and stigmasta-4-22-dien-3-one. E-Phytol, a mixture of the two ketosteroids, and the epidioxysterol derived from campesta-5,7,22-trien-3beta-ol all show pronounced antitubercular activity.

Antitubercular Agents↗
PubMed2001

Estimation of triterpenoids from Heliotropium marifolium Koen. ex Retz. in vivo and in vitro. I. Antimicrobial screening.

The hexane extract of Heliotropium marifolium yielded a mixture of triterpenoids: beta-sitosterol, stigmasterol, beta-amyrin, friedelan-3beta-ol (epifriedelenol), cycloartenone, beta-amyrin acetate, friedelin and epifriedenyl acetate. Isolated triterpenoid and reference antibiotics (gentamycin/mycostatin) were tested against selected pathogenic bacteria and fungi, e.g. Escherichia coli, Staphylococcus aureus, Aspergillus niger and Penicillium chrysogenum. The inhibition zone (IZ) and the activity index (AI) of isolated compounds were recorded and it was found that epifriedenyl acetate (IZ = 17; AI = 1.06) was the most active. The present study deals with the quantification and assessment of their growth inhibitory potency. It has been reported that cycloartenone was the major triterpenoid in both in vivo (0.54%) and in vitro (0.11%) cell cultures.

Bacteria↗
PubMed2001

Lipid composition and fluidity of plasma membranes isolated from corn (Zea mays L.) roots.

Although the results of lipid analyses from several plant species have been available for many years a complete characterization of the corn root plasma membrane is still lacking. The present study provides a detailed analysis of individual lipids and a characterization of the membrane fluidity of corn (Zea mays L.) root plasma membranes isolated by phase-partitioning. Phospholipids (43.9 mol%), sterols (40.8 mol%), and sphingolipids in the form of glucocerebroside (6.8 mol%) constitute the major lipid classes. Stigmasterol (19.8 mol%), campesterol (13.0 mol%), phosphatidylcholine 15.8 mol%), and phosphatidylethanolamine (14.2 mol%) represent the most ubiquitous individual lipids. Hydroxy fatty acids make up 80.9 mol% and very long chain fatty acids are almost 78% of fatty acids in glucocerebroside. Hydroxy arachidic acid (20:0 h) and hydroxy lignoceric acid (24:0 h) are most prominent and glucocerebroside from corn root plasma membranes contains virtually no unsaturated fatty acids. Among the phospholipids only phosphatidylserine displayed a high proportion of very long chain fatty acids (e.g., behenic and lignoceric acid). Membrane fluidity was estimated by fluorescence anisotropy. Due to the high sterol content the plasma membrane of corn roots is relatively rigid.

Cell Fractionation↗
PubMed1995

The influence of sterols on the sensitivity of lipid bilayers to melittin.

The sensitivity of planar lipid bilayers to the permeabalizing effect of melittin was evaluated when sterols of varying structure were incorporated into the membrane. The addition of increasing amount of cholesterol (0-50 mole %) decreased the sensitivity of membranes formed from negatively charged phospholipids to melittin but did not (in amount of up to 66 mole %) change the sensitivity of membranes formed from zwitterionic lipids. 7-Dehydrocholesterol, stigmasterol and ergosterol had the same ability as that of cholesterol to decrease the membrane sensitivity to melittin, while lanosterol had no effect on the sensitivity of membranes to melittin. The results suggest that the effect of sterols is complex and cannot be explained only by a direct interaction of melittin with cholesterol, by a decrease of membrane fluidity, or by changes in distribution of surface charge.

Cholesterol↗
PubMed1978

Plasma-membrane lipid composition and ethanol tolerance in Saccharomyces cerevisiae.

Populations of cells suspended anaerobically in buffered (pH 4.5) M ethanol remained viable to a greater extent when their plasma membranes were enriched in linoleyl rather than oleyl residues irrespective of the nature of the sterol enrichment. However, populations with membranes enriched in ergosterol or stigmasterol and linoleyl residues were more resistant to ethanol than populations enriched in campesterol or cholesterol and linoleyl residues. Populations enriched in ergosterol and cetoleic acid lost viability at about the same rate as those enriched in oleyl residues, while populations grown in the presence of this sterol and palmitoleic acid were more resistant to ethanol. Suspending cells in buffered ethanol for up to 24 h did not lower the ethanol concentration.

Anaerobiosis↗
PubMed1981

Unsaponifiable matter and fatty acid composition of pea oil.

14 compounds were detected in the unsaponifiable matter of pea oil by gas liquid chromatography (GLC) and 8 of them were identified as hydrocarbons C30, C32, squalene, alpha-tocopherol, cholesterol, campesterol, stigmasterol and beta-sitosterol. The predominant unsaponifiable fraction was beta-sitosterol whereas the others were found in variable amounts. Two sterols were isolated by column chromatography. One of them was characterised as beta-sitosterol by measuring the melting point, [a]D, and infrared spectra and those of its acetate. However, the other sterol was unidentified. The fatty acid contents in pea oil were determined quantitatively by GLC. They were present in variable amounts, whereas linoleic acid was the major one.

Chromatography, Gas↗
PubMed1976

Identification of plant sterols in plasma and red blood cells of man and experimental animals.

Direct gas liquid chromatography (GLC) of total plasma lipids showed small peaks (0.5-1.5% of total free sterol area) corresponding to free C28 and C29 sterols in ca. 50% of some 3,000 normal subjects and patients with hyperlipemia. Comparable proportions of similar peaks were present in the sterol fraction isolated from the red blood cells of many of these subjects. The maximum levels of these components in the plasma and red blood cells of domestic and laboratory animals were up to 10 times higher than those seen in man. Detailed gas chromatography/mass spectrometry analyses of the plasma lipids from a much more limited number of subjects and animals showed that the GLC peaks corresponding to the free C28 and C29 sterols were largely due to the plant sterols campesterol, stigmasterol, and beta-sitosterol. In all instances, variable amounts (0.05-0.2% of the total free sterol area) of 7-dehydrocholesterol, desmosterol, lanosterol, and cholesterol alpha-oxide were also detected. While the total content and composition of the plasma plant sterols appeared to vary greatly among the subjects, it never exceeded 2% of total sterol in the normal subjects and patients examined. There was no evidence for a significant increase in the plant sterol content of the plasma of patients with hypercholesterolemia or hypertriglyceridemia.

Animals↗