24-methylene Cycloartanol Research Articles

Phytochemical constituents and potential applications of Thomson Navel orange (Citrus × aurantium var. sinensis L.) peel extracts: Antioxidant, antimicrobial and antiproliferative properties

Citrus peel extracts represent a valuable source of bioactive compounds with multifaceted applications. Further studies are needed to explore their full potential and optimize extraction methods for broader commercial utilization. In this study, the detailed phytochemical composition of the polar and non-polar extracts from Tunisian Thomson Navel orange peels (Citrus × aurantium var. sinensis L.) peels was investigated. Moreover, the antioxidant, antimicrobial and cytotoxic effects were assessed in vitro. Results indicate that polar components were particularly abundant in this raw material. Chemical profiling of the non-polar extract using gas chromatography-mass spectrometry revealed the presence of volatile terpenic compounds (limonene, valencene, nootkatones, etc.), long-chain alkanes (tricosane, nonacosane, and triacontane), triterpenes (squalene, 2,3-oxidosqualene and α-amyrine), phytosterols (γ-, β- sitosterols, fucosterol, cycolartenol, and 24-methylene cycloartanol), fatty acids (linoleic and palmitic acids), and polylmethoxylated flavones (nobiletin, 3-methoxynobiletin, tangeretin and tetramethyl-O-scutellarin). The Spectrophotometric determination showed that the methanol extract contained 30.7 mg GAE/g extract and 9.5 mg QE/extract of total phenol content and total flavonoid content, respectively. Complementary HPLC-DAD analysis indicated that the flavanone glycosides (hesperidin and narirutin) and the flavonol quercetin were the basic components. The hesperidin-rich polar extract had better ABTS+*-radical scavenging activity (IC50 = 2.06 mg/mL), while the non-polar extract had the highest ability to reduce ferric ions (IC50 = 126.4 mg/mL). Both extracts showed a broad spectrum of antibacterial activity with the hesperidin-rich polar extract being more effective against the gram-positive bacteria (MIC values: 1.2–1.8 mg/mL), while the non-polar extract was found to be more effective in inhibiting gram-negative bacteria (MIC values: 0.5–1.8 mg/mL). A potent cytotoxic activity against Hep-2 carcinoma cell line has been observed for both extracts (IC50 values of 7 mg/mL and 13 mg/mL for the non-polar and polar extracts, respectively) and hesperidin (IC50 = 32 mg/mL). Consequently, both polar and non-polar extracts of Thomson navel orange peels are prospective for the development of cheap and effective natural antioxidant, antibacterial and cytotoxic agents.

Identifying potent inhibitory phytocompounds from Lagerstroemia speciosa against SARS-Coronavirus-2: structure-based virtual screening

The ongoing spillover of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) calls for expedited countermeasure through developing therapeutics from natural reservoirs and/or the use of less time-consuming drug discovery methodologies. This study aims to apply these approaches to identify potential blockers of the virus from the longstanding medicinal herb, Lagerstroemia speciosa, through comprehensive computational-based screening. Nineteen out of 22 L. speciosa phytochemicals were selected on the basis of their pharmacokinetic properties. SARS-CoV-2 Main protease (Mpro), RNA-directed RNA polymerase (RdRp), Envelope viroporin protein (Evp) and receptor-binding domain of Spike glycoprotein (S-RBD), as well as the human receptor Angiotensin-converting enzyme-2 (hACE2) were chosen as targets. The screening was performed by molecular docking, followed by 100-ns molecular dynamic simulations and free energy calculations. 24-Methylene cycloartanol acetate (24MCA) was found as the best inhibitor for both Evp and RdRp, and sitosterol acetate (SA) as the best hit for Mpro, S-RBD and hACE2. Dynamic simulations, binding mode analyses, free energy terms and share of key amino acids in protein–drug interactions confirmed the stable binding of these phytocompounds to the hotspot sites on the target proteins. With their possible multi-targeting capability, the introduced phytoligands might offer promising lead compounds for persistent fight with the rapidly evolving coronavirus. Therefore, experimental verification of their safety and efficacy is recommended.

Cycloartanes and pentacyclic triterpenes from Awka and ijebuode propolis and evaluation of their antimicrobial activity

Chemical investigation of propolis samples from southern Nigeria led to the isolation of cycloartanetype triterpenes namely: 24-methylene cycloartanol and ambonic acid along with pentacyclic triterpenes: Lupeol and α, β-amyrins. All compounds were identified and structures elucidated using proton nuclear magnetic resonance (1HNMR) spectroscopic data and comparison with literature.

In Silico Prediction of Biomarkers from Amaranthus tricolor (L) Targeted against HIV-1 Protease

Acquired immunodeficiency syndrome is caused by a retrovirus human immunodeficiency virus (HIV). Resistance to antiviral drugs is alarming in antiretroviral therapy and medical management of HIV-infected patients. Thus, identifying novel antiviral drugs is critical and medicinal plants are an excellent source for such discoveries. The current study aimed to isolate and characterize the chemical constituents from leaves of Amaranthus tricolor (L) and to discover novel HIV-1 protease inhibitors. Amaranthus tricolor methanolic extract (ATME) was fractionated into chloroform and aqueous phases. The chloroform fraction was separated by column chromatography using mobile phase n-hexane: ethyl acetate (6:4 v/v). Among various fractions, SOWIS-III was purified and studied for structural interpretation. The compounds were docked with HIV-1 protease as a drug target. The structural interpretation of the SOWIS-III fraction was identified as flavanol glycoside 24-methylene cycloartanol and SOWIS-P as a gallic acid derivative methyl 3,4,5-trihydroxybenzoate. The docking studies of 24-Methylenecycloartanol and HIV-1 protease showed 10 amino acid interactions with the estimated free energy of binding of -10.14 kcal/mol and the antiviral activity depicted as 36.88 nM. Methyl 3,4,5-trihydroxybenzoate and HIV-1 protease show five amino acid interactions with the estimated free energy of binding of -5.03 kcal/mol with 205.24 μM estimated antiviral activity. Hence, 24-methylene cycloartanol and methyl 3,4,5-trihydroxybenzoate can serve as drug candidates for HIV.

Identification and Characterization of Sterol Acyltransferases Responsible for Steryl Ester Biosynthesis in Tomato.

Steryl esters (SEs) serve as a storage pool of sterols that helps to maintain proper levels of free sterols (FSs) in cell membranes throughout plant growth and development, and participates in the recycling of FSs and fatty acids released from cell membranes in aging tissues. SEs are synthesized by sterol acyltransferases, a family of enzymes that catalyze the transfer of fatty acil groups to the hydroxyl group at C-3 position of the sterol backbone. Sterol acyltransferases are categorized into acyl-CoA:sterol acyltransferases (ASAT) and phospholipid:sterol acyltransferases (PSAT) depending on whether the fatty acyl donor substrate is a long-chain acyl-CoA or a phospolipid. Until now, only Arabidopsis ASAT and PSAT enzymes (AtASAT1 and AtPSAT1) have been cloned and characterized in plants. Here we report the identification, cloning, and functional characterization of the tomato (Solanum lycopersicum cv. Micro-Tom) orthologs. SlPSAT1 and SlASAT1 were able to restore SE to wild type levels in the Arabidopsis psat1-2 and asat1-1 knock-out mutants, respectively. Expression of SlPSAT1 in the psat1-2 background also prevented the toxicity caused by an external supply of mevalonate and the early senescence phenotype observed in detached leaves of this mutant, whereas expression of SlASAT1 in the asat1-1 mutant revealed a clear substrate preference of the tomato enzyme for the sterol precursors cycloartenol and 24-methylene cycloartanol. Subcellular localization studies using fluorescently tagged SlPSAT1 and SlASAT1 proteins revealed that SlPSAT1 localize in cytoplasmic lipid droplets (LDs) while, in contrast to the endoplasmic reticulum (ER) localization of AtASAT1, SlASAT1 resides in the plasma membrane (PM). The possibility that PM-localized SlASAT1 may act catalytically in trans on their sterol substrates, which are presumably embedded in the ER membrane, is discussed. The widespread expression of SlPSAT1 and SlASAT1 genes in different tomato organs together with their moderate transcriptional response to several stresses suggests a dual role of SlPSAT1 and SlASAT1 in tomato plant and fruit development and the adaptive responses to stress. Overall, this study contributes to enlarge the current knowledge on plant sterol acyltransferases and set the basis for further studies aimed at understanding the role of SE metabolism in tomato plant growth and development.

Triterpene alcohols and sterols from rice bran reduce postprandial hyperglycemia in rodents and humans.

Hyperglycemia is a major public health problem worldwide and there is increasing demand for prevention of postprandial hyperglycemia in diabetic, prediabetic, and healthy humans. We investigated whether rice bran and triterpene alcohol and sterol preparation (TASP) lowered hyperglycemia in mice and humans. Brown rice and white rice supplemented with TASP lowered the postprandial hyperglycemia in humans. TASP and its components (cycloartenol [CA], 24-methylene cycloartanol, β-sitosterol, and campesterol) decreased postprandial hyperglycemia in C57BL/6J mice. Glucose transport into everted rat intestinal sacs and human HuTu80 cells transfected with sodium-glucose cotransporter-1 (SGLT1) was significantly reduced by the addition of CA. Intracellular localization analysis suggested that SGLT1 translocation to the apical plasma membrane was inhibited when the cells were treated with CA. We demonstrated for the first time that TASP from rice bran lowered postprandial hyperglycemia in mice and humans. The smaller increase in blood glucose following TASP consumption may be due to the CA-induced decrease in glucose absorption from the intestine, which may be related to decreased membrane translocation of SGLT1.

Chemical Constituents of Euphorbia sororia

Euphorbia sororia Schrenk, an annual herbaceous plant of the genus Euphorbia L. (Euphorbiaceae), is distributed mainly in Central Asia and the Hetian region of Xinjiang in China. Having diuretic, antihypertensive, antiasthmatic, and purgative properties, it is a commonly used medicinal material of Uighur doctors and has been recorded in the pharmacography of Uighur [1]. In this work, we report on the chemical constituents of the aerial parts of E. sororia. The 95% EtOH extracts of the plant were partitioned with EtOAc and n-BuOH, and the corresponding residues, submitted to different chromatographic techniques, such as silica gel, Sephadex LH-20, and MCI-gel columns, led to the isolation and identification of nine chemical compounds. Their structures were identified as astragalin (1), kaempferol-3-O-D-galactoside (2), rutin (3), 24-methylene cycloartanol (4), heptacosanol (5), octacosanol (6), adenosine (7), -sitosterol (8), and daucosterol (9), respectively. Compounds 1, 4–6 are reported from the plant for the first time [2, 3]. All the purified compounds were identified by spectral analysis (1H and 13C NMR, EI-MS) and by comparison with the literature data [2–8]. Plant Material. The plant materials were collected in the Tacheng region of Xinjiang (June 2004) and authenticated by Prof. Zhang Yan Fu (Xinjiang Institute of Materia Medica, China) for E. sororia. Extraction and Isolation. The air-dried aerial parts of E. sororia (10 kg) were extracted three times with 95% aqueous ethanol (v/v) (50 L 3 h) at reflux to give a crude extract (1.8 kg) after concentration at reduced pressure. The extract was suspended in water and extracted with petroleum ether, EtOAc, and n-BuOH successively. The petroleum ether fraction (45 g) was subjected to repeated silica gel column chromatography and eluted with petroleum ether–EtOAc gradient to give compounds 4–7. The EtOAc fraction (45 g) was subjected to repeated silica gel column chromatography and eluted with petroleum ether–EtOAc–MeOH gradient to give compounds 8 and 9. The n-BuOH fraction (30 g) was chromatographed over an AB-8 macroporous absorbent resin column with gradient elution by water, 10% EtOH, and 30% EtOH successively. The 30% EtOH fraction (10 g) was chromatographed over Sephadex LH-20 and MCI gel columns and eluted with H2O–CH3OH in a gradient manner to afford compounds 1–3. Astragalin (1). C21H20O11, light yellow needles (MeOH), mp 163–165 C. HCl-Mg reducion reaction is positive. 1H NMR (600 MHz, CD3OD, , ppm, J/Hz): 8.05 (2H, d, J = 8.4, H-2 , 6 ), 6.88 (2H, d, J = 8.4, H-3 , 5 ), 6.20 (1H, d, J = 1.2, H-6), 6.40 (1H, d, J = 1.2, H-8), 5.35 (1H, d, J = 6.8, H-1 ). 13C NMR (150 MHz, CD3OD, , ppm): 156.6 (C-2), 133.4 (C-3), 177.0 (C-4), 160.1 (C-5), 98.2 (C-6), 164.2 (C-7), 93.7 (C-8), 156.6 (C-9), 104.2 (C-10), 120.9 (C-1 ), 131.0 (C-2 , 6 ), 115.1 (C-3 , 5 ), 160.1 (C-4 ), 101.1 (C-1 ), 74.5 (C-2 ), 76.4 (C-3 ), 71.9 (C-4 ), 76.6 (C-5 ), 60.9 (C-6 ). Kaempferol-3-O-D-galactoside (2). C21H20O11, yellow powder (MeOH), mp 231–232 C. IR (KBr, , cm–1): 3455, 3173, 1656, 1590, 1558, 149, 1302, 1264, 1081, 798. 1H NMR (600MHz, CD3OD, , ppm, J/Hz): 12.50 (H, s, 5-OH), 8.08 (2H, d, J = 9.0, H-6 ), 6.84 (2H, d, J = 9.0, H-3 , 5 ), 6.40 (1H, d, J = 1.2, H-8), 6.20 (1H, d, J = 1.2, H-6), 5.35 (1H, d, J = 7.2, H-1 ). 13C NMR (150 MHz, CD3OD, , ppm, J/Hz): 176.6 (C-4), 164.2 (C-7), 160.1 (C-5), 159.1 (C-4 ), 156.3 (C-9), 156.3 (C-2), 133.2 (C-3), 131.4 (C-2 , 6 ), 120.2 (C-1 ), 114.6 (C-3 , 5 ), 104.4 (C-10), 102.0 (C-1 ), 98.2 (C-6), 93.7 (C-8), 75.7 (C-5 ), 73.9 (C-3 ), 71.7 (C-2 ), 68.0 (C-4 ), 60.1 (C-6 ). 24-Methylene Cycloartanol (4). C41H52O, white amorphous powder (CHCl3), mp 122–123 C. EI-MS m/z 441 [M + H]+. 1H NMR (600 MHz, CDCl3, , ppm, J/Hz): 0.33, 0.55 (each 1H, d, J = 4.2, H2-19), 0.81 (3H, s, H3-30), 0.90 (3H, s, H3-28), 0.90, (3H, d, J = 6.5, H3-21), 0.97 (6H, s, H3-18, 29), 1.02 (3H, d, J = 6.9, H3-27), 1.03 (3H, J = 6.9, H3-26), 4.62, 4.67 (each 1H, br.s, H2-31). 13C NMR (150 MHz, CDCl3, , ppm, J/Hz): 32.0 (C-1), 30.40 (C-2), 78.9 (C-3), 40.5 (C-4), 47.1

Triterpene alcohols and sterols from rice bran lower postprandial glucose-dependent insulinotropic polypeptide release and prevent diet-induced obesity in mice

Obesity is now a worldwide health problem. Glucose-dependent insulinotropic polypeptide (GIP) is a gut hormone that is secreted following the ingestion of food and modulates energy metabolism. Previous studies reported that lowering diet-induced GIP secretion improved energy homeostasis in animals and humans, and attenuated diet-induced obesity in mice. Therefore, food-derived GIP regulators may be used in the development of foods that prevent obesity. Rice bran oil and its components are known to have beneficial effects on health. Therefore, the aim of the present study was to clarify the effects of the oil-soluble components of rice bran on postprandial GIP secretion and obesity in mice. Triterpene alcohols [cycloartenol (CA) and 24-methylene cycloartanol (24Me)], β-sitosterol, and campesterol decreased the diet-induced secretion of GIP in C57BL/6J mice. Mice fed a high-fat diet supplemented with a triterpene alcohol and sterol preparation (TASP) from rice bran for 23 wk gained less weight than control mice. Indirect calorimetry revealed that fat utilization was higher in TASP-fed mice than in control mice. Fatty acid oxidation-related gene expression in the muscles of mice fed a TASP-supplemented diet was enhanced, whereas fatty acid synthesis-related gene expression in the liver was suppressed. The treatment of HepG2 cells with CA and 24Me decreased the gene expression of sterol regulatory element-binding protein (SREBP)-1c. In conclusion, we clarified for the first time that triterpene alcohols and sterols from rice bran prevented diet-induced obesity by increasing fatty acid oxidation in muscles and decreasing fatty acid synthesis in the liver through GIP-dependent and GIP-independent mechanisms.

STUDIES ON HYPOCHOLESTEROLEMIC ACTIVITY OF STABILIZED RICE BRAN OIL.

The present investigation was carried out to study the effect of stabilized rice bran oil (SRBO) on hypocholesterolemic activity of experimental rats, and also the effect of feeding with stabilization rice bran oil (SRBO) and blend oil on the growth and lipid parameters of serum and liver of rats. Fatty acids composition and unsaponifiable matter of stabilization rice bran oil and blend oil were determined, Results showed that, stabilization rice bran oil had a higher content of saturated fatty acids (SFA), polyunsaturated fatty acids (PUFA) than that of blend oil. stabilization Rice bran oil contained relatively higher concentration of compesterol, stigmasterol, b-sitoisterol, cycloartanol, cycloartenol 24-Methylene cycloartanol and oryzanol compared to the blend oil. The serum total and LDL-cholesterol level of rats that maintained on stabilization rice bran oil diet was significantly lower than those fed on blend oil diet. HDL-cholesterol showed a tendency to be higher. Liver lipids of rats fed on stabilization rice bran oil were also markedly lower than their blend oil fed counterparts. Finally, it can be concluded that, using stabilization rice bran oil had the pronounced effects for lowering cholesterol levels of the blood in experimental rats. The cholesterol lowering ability stabilization of rice bran oil appears to be due to unsaponifiable matter and a higher content of polyunsaturated fatty acids.

High levels of cycloartenol derivatives from Euphorbia acanthothamnos

► cycloartenol derivatives were isolated from Euphorbia acanthothamnos . ► their structures are 24-methylene cycloartanol, cycloartenol and cycloartenol acetate. ► high levels indicate on their ecological significance for the plant.

Contribution à l’étude de la fraction insaponifiable de trois huiles d’olive issues des variétés Guasto, Rougette et Blanquette plantés dans l’est algérien

The sterol profile of three Algerian virgin olive oils produced from Guasto, Blanquette and Rougette cultivar’s, varieties grown in the East of the country, was established by gas chromatography using a flame ionization detector and coupled to mass spectrometry. Four sterol compounds were identified and characterized in the three oils which are, sitosterol always predominant (43-66%), delta 5-avenastérol (8-13%), stigmasterol (<i>≤<i/> 1,5%) and campesterol (1-2%); one methyl sterol (4-methylsterol) : citrostadienol (4-7%) and two triterpenic alcohols : 24-methylene cycloartanol (10-33%) and cycloartenol (3-13%). These results vary according to campany and variety. Our study shows that most of these compounds were affected by climatic conditions especially during the campanies 2004-2005 and 2005-2006. The amounts of the four identified sterols are in agreement with the European regulation (Reg. (EEC) n<i>°<i/>2568/91, appendix 1).

Phytosterols accumulation in the seeds of Linum usitatissimum L.

A comparative study was performed to determine the free sterols content and composition during the development of three varieties of linseed (H52, O116 and P129). Seed samples were collected at regular intervals from 7 to 60 days after flowering (DAF). Ten compounds were identified: cholesterol, campesterol, brassicasterol, stigmasterol, beta-sitosterol, Delta5-avenasterol, cycloartenol; 24-methylene cycloartanol, obtusifoliol, citrostadienol. The maximum level of 4-desmethylsterols (1,515 mg/100g oil) was reached at 7 DAF in P129 variety. H52 had the highest level of 4-4 dimethylsterols (355 mg/100g oil) at 28 DAF. The greatest amount of 4-monomethylsterols (35 mg/100g oil) was detected in H52 at 14 DAF. During linseed development, beta sitosterol (830 mg/100g oil) was the major 4-desmethylsterols, followed by campesterol (564 mg/100g oil) and stigmasterol (265 mg/100g oil). Some of these compounds followed nearly the same accumulation pattern during linseed maturation.

Preparative isolation and purification of chemical constituents from the root of Adenophora tetraphlla by high-speed counter-current chromatography with evaporative light scattering detection

Preparative high-speed counter-current chromatography (HSCCC), as a continuous liquid–liquid partition chromatography with no solid support matrix, combined with evaporative light scattering detection (ELSD) was employed for systematic separation and purification of non-chromophoric chemical components from Chinese medicinal herb Adenophora tetraphlla ( Thunb.), Fisch. Nine compounds, including α-spinasterol, β-sitosterol, nonacosan-10-ol, 24-methylene cycloartanol, lupenone, 3- O-palmitoyl-β-sitosterol, 3- O-β- d-glucose-β-sitosterol, eicosanoic acid and an unknown compound, were obtained. The compounds were all above 95% determined by high-performance liquid chromatography (HPLC)–ELSD, and their structures were identified by 1H NMR and chemical ionization mass spectroscopy (CI-MS). The results demonstrate that HSCCC coupled with ELSD is a feasible and efficient technique for systematic isolation of non-chromophoric components from traditional medicinal herbs.

Biosynthesis of avenacins and phytosterols in roots of Avena sativa cv. Image

In keeping with the proposal that avenacin biosynthesis is restricted to the tips of primary roots of oat seedlings, the incorporation of radioactivity from R-[2- 14 C ]mevalonic acid (MVA) into avenacins and β-amyrin by serial sections of primary roots was found to be more-or-less restricted to root tip sections. Squalene synthase (SQS) (EC 2.5.1.21) and 2,3-oxidosqualene:β-amyrin cyclase (OSβAC) (EC 5.4.99) were also most active in these sections. The incorporation of radiolabel from R-[2- 14 C ]MVA into cycloartenol and 24-methylene cycloartanol by, and the 2,3-oxidosqualene:cycloartenol cyclase (OSCC) (EC 5.4.99) activity in, the various serial sections were consistent with phytosterol biosynthesis occurring in all the sections of the root with some tailing-off in the rate of synthesis in the more distal sections.

INVESTIGATION OF PETROLEUM ETHER EXTRACT OF THE BULBS OF CRINUM AUGUSTUM ROX.

The bulbs of Crinum augustum Rox. Fam. Amaryllidaceae were extracted with ethanol (95%) by maceration and percolation. From the petroleum ether fraction four saturated straight chain hydrocarbons, 24-methylene cycloartanol and cycloeucalenol were isolated and identified. The identification of these compounds was based on GLC-Mass spectrometry. In addition, an alkaloid (ungeremine) was also isolated and characterized from the n-butanol extract.

Identification of cDNAs encoding sterol methyl-transferases involved in the second methylation step of plant sterol biosynthesis.

Two methyl transfers are involved in the course of plant sterol biosynthesis and responsible for the formation of 24-alkyl sterols (mainly 24-ethyl sterols) which play major roles in plant growth and development. The first methyl transfer applies to cycloartenol, the second one to 24-methylene lophenol. Five cDNA clones encoding two Arabidopsis thaliana, two Nicotiana tabacum and one Ricinus communis S-adenosyl-L-methionine (AdoMet) sterol methyltransferases (SMT) were isolated. The deduced amino acid sequences of A. thaliana and N. tabacum SMT are about 80% identical in all possible combinations. In contrast they are about 40% identical with the deduced amino acid sequence of R. communis SMT and the published Glycine max sequence. Both A. thaliana and one N. tabacum SMT cDNAs were expressed in a yeast null mutant erg6, deficient in AdoMet zymosterol C24-methyltransferase and containing C24-non-alkylated sterols. In all cases, several 24-ethylidene sterols were synthesized. A thorough study of the sterolic composition of erg6 expressing the A. thaliana cDNA 411 (erg6-4118-pYeDP60) showed 24-methylene and 24-ethylidene derivatives of 4-desmethyl, 4alpha-methyl and 4,4-dimethyl sterols as well as 24-methyl and 24-ethyl derivatives of 4-desmethyl sterols. The structure of 5alpha-stigmasta-8, Z-24(24(1))-dien-3beta-ol, the major sterol of transformed yeasts, was demonstrated by 400 MHz 1H NMR. Microsomes from erg6-4118-pYeDP60 were shown to possess AdoMet-dependent sterol-C-methyltransferase activity. Delipidated preparations of these microsomes converted cycloartenol into 24-methylene cycloartanol and 24-methylene lophenol into 24-ethylidene lophenol, thus allowing the first identification of a plant sterol-C-methyltransferase cDNA. The catalytic efficiency of the expressed SMT was 17-times higher with 24-methylene lophenol than with cycloartenol. This result provides evidence that the A. thaliana cDNA 411 (and most probably the 3 plant SMT cDNAs presenting 80% identity with it) encodes a 24-methylene lophenol-C-24(1) methyltransferase catalyzing the second methylation step of plant sterol biosynthesis.

Seed lipids of Sesamum indicum and related wild species in Sudan. The sterols

AbstractOil extracted from seeds of different varieties of the cultivated Sesamum indicum L and three related wild species, viz S alatum Thonn, S radiatum Schum &amp; Thonn, and S angustifolium (Oliv) Engl, were analysed for their total unsaponifiables and for the contents and composition of the three sterol fractions (desmethyl, monomethyl and dimethyl sterols). The sterols were analysed after saponification by preparative TLC, capillary GC and GC‐MS of their TMS ethers. Oils from the wild species contained more unsaponifiable material (2.3‐2.4%) compared with the cultivated species (1.1‐1.3%). Considerable differences were observed in the total sterol contents and the relative proportions of the three sterol fractions in the oils from the four species studied. Sitosterol, campesterol, stigmasterol and Δ5‐avenasterol were the major desmethyl sterols in all four species. The monomethyl sterol fraction consisted primarily of obtusifoliol, gramisterol, cycloeucalenol and citrostadienol. Cycloartenol and 24‐methylene cycloartanol were the predominant dimethyl sterols. Variations in the composition of the three sterol fractions were observed between S indicum oils traditionally pressed by the camel‐driven expellers and laboratory extracted oils from the same seeds.

Nutritional and biochemical aspects of the hypolipidemic action of rice bran oil: a review.

In this paper, we review the effects of rice bran oil (RBO), an unconventional oil recently introduced onto the Indian market for human use. RBO contains oleic acid (38.4%), linoleic acid (34.4%), and linolenic acid (2.2%) as unsaturated fatty acids, and palmitic (21.5%) and stearic (2.9%) acids as saturated fatty acids. The unsaponifiable fraction (4.2%) has total tocopherols (81.3 mg%), gamma-oryzanol (1.6%), and squalene (320 mg%). Oryzanol is a mixture of ferulic acid esters of triterpene alcohols such as cycloartenol (CA) (106 mg%) and 24-methylene cycloartanol (494 mg%). Studies on experimental rats demonstrated a hypolipidemic effect of RBO. The unsaponifiable fraction of RBO lowers cholesterol levels. Feeding phytosterols, CA, and 24-methylene cycloartanol in amounts present in RBO to hypercholesterolemic rats for 8 weeks indicates that CA alone reduces cholesterol and triglyceride levels significantly. Endogenous sterol excretion increases in animals given CA. The accumulation of CA in the liver inhibits cholesterol esterase activity, which in turn leads to reduction in circulating cholesterol levels. CA is structurally similar to cholesterol and may compete with the binding sites of cholesterol and sequestrate cholesterol, which is metabolized to its derivatives. RBO, which is rich in tocopherols and tocotrienols, may improve oxidative stability. Tocotrienols inhibit HMG CoA reductase, resulting in hypocholesterolemia. The hypolipidemic effect of RBO has also been established in human subjects. Thus, RBO could be a suitable edible oil for patients with hyperlipidemia.

Oxidative C4-demethylation of 24-methylene cycloartanol by a cyanide-sensitive enzymatic system from higher plant microsomes

Microsomes isolated from corn embryos (Zea mays) were shown to catalyse the C-4 monodemethylation of 28-[3H],24-methylene cycloartanol 1, leading to the corresponding 4 alpha-methyl sterol, cycloeucalenol 5. An enzymatic assay has been developed for the 4,4-dimethyl sterol 4-demethylase in higher plants. The demethylation process was shown to involve a 4-methyl, 4-hydroxymethyl derivative 2 which can be considered as the immediate metabolite of 1 by the 4-methyl oxidase. Compound 2 is further metabolized into 5 through a 4-methyl-4-carboxylic acid 3 and a 3-keto-4 alpha-methyl intermediate 4 which were identified. The conversion of 1 into 5 requires NADPH and molecular oxygen. The initial oxidative step was strictly dependent upon molecular oxygen, NADPH or NADH, and strongly inhibited by cyanide, whereas the overall process was completely insensitive to CO and to specific inhibitors of cytochrome P-450. It is concluded that in Zea mays microsomes, the C-4 demethylation of 1 results from a multistep process involving a terminal oxygenation system sensitive to cyanide which is distinct from cytochrome P-450 and in particular from that involved in the 14 alpha-demethylation of obtusifoliol.

Analysis of a thread used in the kshara sutra treatment in the ayurvedic medicinal system

From a Kshara Sutra thread which is used in the therapy of fistula in the Ayurvedic medicinal system, euphol, 3,12-di- O-acetyl-8- O-benzoylingol, 3,12-di- O-acetyl-8- O-tigloylingol, curcumin, p-coumaroylferuloylmethane and di- p-coumaroylmethane were isolated and characterized. In addition, GLC and GC/MS confirmed the presence of euphol, antiquol B, cycloeucalenol and 24-methylene cycloartanol in the thread.