Biosynthesis of the Phytosterol Side Chain

Goad, L. John; Hammam, A. S. A.; Dennis, Allen L.; Goodwin, T. W.

doi:10.1038/2101322a0

Cited by 49 publications

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“…116" @-sitosterol 137.5-138"; /3-sitosterol acetate 121 -122" [12]). The infrared spectrum was identical to that of /3-sitosterol and the mass spectrum (8)(9) ,lo) and 24-methylene cycloartanol (91 -92 ,lo) respectively (Table 1). Although cyclolaudenol and 24-methylenecycloartanol show some separation on QF-I the presence of very small amounts of cyclolaudenol in the larch preparations cannot be completely excluded.…”

Section: Identification Of Larch Xterolsmentioning

confidence: 80%

“…Although the route shown in the Scheme may ultimately prove to be the major pathway a consideration of the retention data of the minor 4a-methyl sterols in larch and also in grapefruit [lo] indicates that some of the enzymes involved may be relatively non-specific, for addition of the C-29 methyl group or reduction of the side chain double bond occurs irrespective of the structure of the sterol nucleus. For example, whilst there is good evidence that C-24 methylene or ethylidene groups are reduced to produce the C-24 methyl and ethyl groups of the typical phytosterols [8, it is not clear if this reduction occurs principally a t the 4a-methyl sterol level to give 24-methyl and 24-ethyl lophenol or a t the 4-desmethyl level, since fucosterol or 29-isofucosterol have been reported to occur together with @-sitosterol in a number of plants [7,34,11 b]. The absence of stigmasterol from larch leaves is in accord with a previous report on several pine barks where @-sitosterol was also shown to predominate [36].…”

Section: Discussionmentioning

confidence: 99%

“…During studies in our Department on the biosynthesis of the phytosterol side chain [8] a plant tissue was required which contained ,4-sitosterol as the major sterol component. Preliminary examination by gasliquid chromatography showed that a number of conifer species contained predominantly /3-sitosterol together with minor amounts of campesterol.…”

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Studies on Phytosterol Biosynthesis: the Sterols of Larix decidua Leaves

Goad

Goodwin

1967

European Journal of Biochemistry

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The sterols of Larix decidua leaves consist of B-sitosterol, campesterol, cycloartenol, 24-methylene cycloartanol, cycloeucalenol, 24-methylene lophenol, 24-ethylidene lophenol, together with a number of unidentified 4a-methyl sterols. The pattern of incorporation of [2-14C]mevalonic acid into these compounds has been examined.Recent reports have described the isolation from plants of sterols which may be biosynthetic intermediates between squalene and the typical phytosterols [I -71 and the incorporation of [2J4C] mevalonic acid, [I-'%] acetate and [methyl-14C] methiorline into such compounds has been described [6,7]. During studies in our Department on the biosynthesis of the phytosterol side chain [8] a plant tissue was required which contained ,4-sitosterol as the major sterol component. Preliminary examination by gasliquid chromatography showed that a number of conifer species contained predominantly /3-sitosterol together with minor amounts of campesterol. This paper reports the results of an analysis of the sterols of the newly opened leaves of the deciduous conifer larch ( L a r i x decidua). Some observations on the incorporation of [2-l4CC] mevalonic acid into sterols by the leaves of this tree are also included. EXPERIMENTAL PROCEDUREExperimental methods were generally those described previously [7]. Two batches of larch leaves were collected locally in the springtime of successive years when the leaves had been developing for about two to three weeks. Batch 1The non-saponifiable lipid (6.25 g) was extracted from the leaves (650g) by homogenisation in 1.31 of ethanol followed by addition of 200ml of water and 200 g of potassium hydroxide and refluxing for 2l/, h. The leaf debris was removed by filtration through a pad of glass wool and the non-saponifiable lipids obtained by extraction with diethyl ether in the usual manner. The total sterol (213 mg) was obtained by digitonin precipitation [7,9], the digitonides washed with diethyl ether only and then cleaved with pyridine in the usual way. The sterols were first separated by chromatography on 20 g of alumina (Brockmann grade 111) and eluting with 24'200ml portions of light petroleum containing increasing amounts of diethyl ether ["]. Three sterol fractions were obtained, the 4,4'-dimethyl sterols (24 mg), the 4a-methyl sterols (7.3 mg) and the 4-desmethyl sterols (142.6 mg). These were further purged by preparative thin layer chromatography on silica gel plates incorporating Rhodamine 6 G and with chloroform as developer [7]. Separation of the 4,4'-dimethyl and 4a-methyl fractions into their constituent components (see below) was achieved by acetylation followed by chromatography on thin layers of silica gel impregnated with loo/, silver nitrate with 40°/0 benzene in n-hexane as developer. Sterols were located by spraying with an acetone solution of Rhodamine 6 G followed by examination in ultraviolet light [lo].Batch 2 2.5 kg of larch leaves were extracted exhaustively with acetone followed by diethyl ether-light petroleum (1 : l, v/v) to yield 51 *...

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Section: Identification Of Larch Xterolsmentioning

confidence: 80%

Section: Discussionmentioning

confidence: 99%

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Studies on Phytosterol Biosynthesis: the Sterols of Larix decidua Leaves

Goad

Goodwin

1967

European Journal of Biochemistry

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“…The wide availability of fungi and their easy attainment make them more popular among the natural products community evaluation program (Berdy, 2005). The concentration towards L. suphureus was brought into attention due to the eburicoic acid biosynthesis in 1960's and there obtained 30% of L. sulphureus dry weight from this triterpenoid acid (Goad et al, 1966). Recent studies showed that natural products acquired biological activity and it contains enzymes which are specific to catalyze their biosynthesis (Li and Siehr, 1980;Alquini et al, 2004;Kobayashi and Kim, 2003).…”

Section: Introductionmentioning

confidence: 99%

Sulphureuine B, a drimane type sesquiterpenoid isolated from <i>Laetiporus sulphureus</i> induces apoptosis in glioma cells

Zhang¹,

Wen²,

Zhang³

et al. 2015

Bangladesh J Pharmacol

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Sulphureuine B, a drimane type sesquiterpenoid isolated from Laetiporus sulphureus induces apoptosis in glioma cells BJP IntroductionMalignant gliomas are the major life-threatening primary brain tumor with the average survival of less than a year due to the ineffectiveness of radiation and other medical care (Legler et al., 1999). Glioblastomas existing as a spread over to wide area with invasion into typical brain but customarily repeated or developed after radiation as focal point (Garden et al., 1991), indicating that only a small proportion of tumor cells are accountable for regrowth. Even though there occurs the availability of treatment such as combination of surgery, radiation, chemotherapeutics for malicious glioblastomas, still these are considered as locally protruding tumors suffered with poor prediction. A survey from European Organization for Research and Treatment of Cancer (Stupp et al., 2005) displayed that the total viability was increased two more months with associated adjuvant radiation therapy with temozolomide chased by associated temozolomide when compared with the radiation treatment alone. Glioblastomas are very harmful neoplasms which can manifest clear angiogenesis with increased vascular endothelial growth factor expressions which further assist blood vessel production using precursors of endothelium (Plate et al., 1992, Plate et al., 1994. Also it is proved that in the glioblastoma medical care, either surgical treatment followed by radiation treatment or the surgery followed by chemotherapy yields a mean survival of less than 12 months (Fine et al., 1993). Earlier immunotherapy treatments for glioma tumor have concentrated on submissive and non-specific strategies and resulted uncertain benefits (Zeltzer et al., 1999).Sesquiterpenoids are compounds possessing 15-carbons and can be obtained biosynthetically from 5-carbon isoprene units or can be industrially synthesized using feed stocks of monoterpenoids. These compounds attracted industrial attention due to their beneficial to the characteristic flavors and smell of spices, flowers, AbstractA drimane type sesquiterpenoids, sulphureuine B was isolated from the edible mushroom Laetiporus sulphureus and its antiproliferative properties were investigated using U-87MG glioma cells. It was observed that sulphureuine B-induced apoptosis in U-87MG cells and the mechanisms involved are endoplasmic reticulum stress, mitochondrial and death receptor mediated pathways. Endoplasmic reticulum stress was identified from the results of enormous cytoplasmic vacuolation, CHOP elevation and caspase-12 cleavage. Further, we found that treatment of sulphureuine B-induced PERK, IRE1α, and ATF6α activations. In addition, sulphureuine B-induced Bcl-2 downregulation, cleavage of PARP, and caspase-8 activation were also affected. All these experimental results clearly revealed that sulphureuine B-induced apoptosis mediated through endoplasmic reticulum stress, mitochondrial, and death receptor signaling pathways. Article Info

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“…MVA, mevalonic acid; Tlc, thin ayer chromatography. liminary reports [7,8]. Evidence for the occurrence in Fucus spiralis of cycloartenol (11), the postulated phytosterol precursor 11,9,101, is also present,ed.…”

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Studies in Phytosterol Biosynthesis: Observations on the Biosynthesis of Fucosterol in the Marine Brown Alga Fucus spiralis

Goad¹,

Goodwin²

1969

European Journal of Biochemistry

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Fucosterol biosynthesised by Fucus spiralis from [2-14C,(4R)-4-3Hl] mevalonic acid has a 3H/14C atomic ratio of 315. Isomerisation of the labelled fucosteryl acetate gave 3/3-acetoxystigmasta-5,24-diene with a 3H/14C atomic ratio of 2/5. This demonstrated that the fucosterol had a 3H atom located a t C-25 and therefore proves that hydrogen (tritium) migration from C-24 to C-25 occurs during alkylation of the phytosterol side chain. Cycloartenol and 24-methylene cycloartanol also isolated from the Fucus spiralis were shown to be radioactively labelled, there was no evidence of radioactive lanosterol. Tritium was shown to be present a t C-3 of the biosynthesised cycloartenol but was absent from C-3 of the fucosterol.Sterol biosynthesis in plants is currently being intensively studied in several laboratories [i J but such work has concentrated mainly on higher plants. Continuing our own investigations on phytosterol biosynthesis we have now examined the marine brown alga Fucus spiralis. The major sterol [2,3] of the brown algae (Phaeophyceae) is fucosterol (I). With I Laminaria saceharina it has been shown previously that the C-24 ethylidene group of fucosterol arises by a double transmethylation reaction from methionine[4] as required by the proposed alkylation mechanism [5, Sj. The present paper provides further information concerning the mechanism of the transmethylation reaction and extends our earlier preUnusual Abbreviations. MVA, mevalonic acid; Tlc, thin ayer chromatography. liminary reports [7,8]. Evidence for the occurrence in Fucus spiralis of cycloartenol (11), the postulated phytosterol precursor 11,9,101, is also present,ed.

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Biosynthesis of the Phytosterol Side Chain

Cited by 49 publications

References 20 publications

Studies on Phytosterol Biosynthesis: the Sterols of Larix decidua Leaves

Studies on Phytosterol Biosynthesis: the Sterols of Larix decidua Leaves

Sulphureuine B, a drimane type sesquiterpenoid isolated from <i>Laetiporus sulphureus</i> induces apoptosis in glioma cells

Studies in Phytosterol Biosynthesis: Observations on the Biosynthesis of Fucosterol in the Marine Brown Alga Fucus spiralis

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