| Reference | [1]. J Ethnopharmacol. 2020 Apr 24;252:112558. doi: 10.1016/j.jep.2020.112558. Epub 2020 Jan 9.<br />
Lophenol and lathosterol from resin of Commiphora kua possess hepatoprotective effects in vivo.<br />
Ullah H(1), Khan A(2), Rehman NU(2), Halim SA(2), Khan H(3), Khan I(4), Csuk R(5), Al-Rawahi A(2), Al-Hatmi S(6), Al-Harrasi A(7).<br />
Author information: (1)Department of Pharmacy, Abdul Wali Khan University, Mardan, 23200, Pakistan. (2)Natural and Medical Sciences Research Center, University of Nizwa, PO Box 33, 616 Birkat Al Mauz, Nizwa, Oman. (3)Department of Pharmacy, Abdul Wali Khan University, Mardan, 23200, Pakistan. Electronic address: [email protected]. (4)Department of Pharmacy, University of Swabi, Swabi, 23430, Pakistan. (5)Organic Chemistry, Martin-Luther University Halle-Wittenberg, Kurt-Mothes-Str. 2, D-06120, Halle (Saale), Germany. (6)Oman Botanic Garden, Diwan of Royal Court, P.O. Box 808, PC 122, Muscat, Oman. (7)Natural and Medical Sciences Research Center, University of Nizwa, PO Box 33, 616 Birkat Al Mauz, Nizwa, Oman. Electronic address: [email protected].<br />
ETHNOPHARMACOLOGICAL RELEVANCE: Drug induced liver damage remains a prevalent concern in healthcare and may reduce the effectiveness of therapy by compromising therapeutic regimens. Many Commiphora species are known for their medicinal properties, and some of them are used traditionally for hepatoprotective effect. In the course of our drugs discovery from natural sources, phytosterols (lophenol (Lop) and lathosterol (Lat)), isolated from Commiphora kua were studied to evaluate their hepatoprotective effects in acetaminophen (APAP) induced hepatotoxicity in mice. AIMS AND OBJECTIVE: To evaluate the hepatoprotective effects of phytosterols isolated from C. kua using in vivo experimental model. MATERIALS AND METHODS: Mice of either sex were divided into 7 groups: Vehicle, silymarin (SLY), acetaminophen (APAP), Lop 25, Lop 50, Lat 25, Lat 50 (n = 5). Vehicle group received only vehicle (0.1% DMSO solution) for 7 days, APAP group received single dose of acetaminophen on day 7 and SLY group received silymarin for 7 days. Lop 25 and Lop 50 received low and high doses of Lop (25 μg/kg BW and 50 μg/kg BW), respectively, for 7 days, while Lat 25 and Lat 50 received low and high doses of Lat (25 μg/kg BW and 50 μg/kg BW) for 7 days. On day 7, all animals except Vehicle group kept fasted for 18 h and received APAP i. p. 400 mg/kg BW. After 20 h of APAP administration, the animals anesthetized with light chloroform and scarified by cervical decapitation. The blood serum and liver tissue samples were collected for biochemical and histopathological analysis. Liver function tests (LFTs) including lactate deydrogenase (LDH), alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST) and direct bilirubin) were used as biochemical parameters. While catalase (CAT), superoxide dismutase (SOD) and reduced glutathione (GSH) were taken as anti-oxidant enzymes. RESULTS: Significant increase in levels of ALT, AST, ALP, LDH and direct bilirubin, and significant decrease in concentration of anti-oxidant enzymes (SOD, CAT and GSH) was observed in APAP-treated group. Similarly, histological slides showed obvious signs of damage to liver cells, reflecting acetaminophen induced hepatotoxicity. Treatment of test animals with phytosterols resulted in significant recovery of LFTs profile and concentration of anti-oxidant enzymes. Similarly, significant improvement of liver tissues was noted in histological analysis. CONCLUSIONS: Both phytosterols possessed hepatoprotective potential and should be further evaluated for acute toxicity studies and pharmacokinetics/pharmacodynamics profile.<br />
DOI: 10.1016/j.jep.2020.112558 PMID: 31926985 [Indexed for MEDLINE]<br />
<br />
[2]. J Lipid Res. 2020 Feb;61(2):192-204. doi: 10.1194/jlr.RA119000317. Epub 2019 Sep 23.<br />
A nematode sterol C4α-methyltransferase catalyzes a new methylation reaction responsible for sterol diversity.<br />
Zhou W(1), Fisher PM(1), Vanderloop BH(1), Shen Y(1), Shi H(1), Maldonado AJ(2), Leaver DJ(1)(2), Nes WD(1).<br />
Author information: (1)Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX. (2)Department of Biology, Geology, and Physical Sciences, Sul Ross State University, Alpine, TX.<br />
Comment in J Lipid Res. 2020 Feb;61(2):129-132.<br />
Primitive sterol evolution plays an important role in fossil record interpretation and offers potential therapeutic avenues for human disease resulting from nematode infections. Recognizing that C4-methyl stenol products [8(14)-lophenol] can be synthesized in bacteria while C4-methyl stanol products (dinosterol) can be synthesized in dinoflagellates and preserved as sterane biomarkers in ancient sedimentary rock is key to eukaryotic sterol evolution. In this regard, nematodes have been proposed to convert dietary cholesterol to 8(14)-lophenol by a secondary metabolism pathway that could involve sterol C4 methylation analogous to the C2 methylation of hopanoids (radicle-type mechanism) or C24 methylation of sterols (carbocation-type mechanism). Here, we characterized dichotomous cholesterol metabolic pathways in Caenorhabditis elegans that generate 3-oxo sterol intermediates in separate paths to lophanol (4-methyl stanol) and 8(14)-lophenol (4-methyl stenol). We uncovered alternate C3-sterol oxidation and Δ7 desaturation steps that regulate sterol flux from which branching metabolite networks arise, while lophanol/8(14)-lophenol formation is shown to be dependent on a sterol C4α-methyltransferse (4-SMT) that requires 3-oxo sterol substrates and catalyzes a newly discovered 3-keto-enol tautomerism mechanism linked to S-adenosyl-l-methionine-dependent methylation. Alignment-specific substrate-binding domains similarly conserved in 4-SMT and 24-SMT enzymes, despite minimal amino acid sequence identity, suggests divergence from a common, primordial ancestor in the evolution of methyl sterols. The combination of these results provides evolutionary leads to sterol diversity and points to cryptic C4-methyl steroidogenic pathways of targeted convergence that mediate lineage-specific adaptations.-.<br />
DOI: 10.1194/jlr.RA119000317 PMCID: PMC6997595 PMID: 31548366 [Indexed for MEDLINE]<br />
<br />
[3]. J Lipid Res. 2007 May;48(5):1159-66. doi: 10.1194/jlr.M600552-JLR200. Epub 2007 Feb 4.<br />
Differential gene expression of Caenorhabditis elegans grown on unmethylated sterols or 4alpha-methylsterols.<br />
Merris M(1), Wang T, Soteropoulos P, Lenard J.<br />
Author information: (1)Department of Physiology and Biophysics, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.<br />
Transcriptional profiles of Caenorhabditis elegans grown on unmethylated sterols (desMSs) or on 4alpha-methylsterols (4MSs) were compared using microarrays. Thirty-four genes were upregulated and 2 were downregulated>2-fold by growth on 4MSs, including 13 cuticle collagen (col) genes, 1 cuticulin gene (cut-1), 2 groundhog-like (grl) genes, and 1 groundhog gene (grd-4); col-36 and grl-20 were increased 12- and 19-fold, respectively. Fifteen of these 17 genes have been assigned to metabolic mountain 17, suggesting coordinate 4MS-mediated regulation of expression. Quantitative RT-PCR was performed on 27-51 h old animals grown on cholesterol (a desMS) or lophenol (a 4MS). col-36 and grl-20 showed similar cyclic peaks of expression in cholesterol and similar alterations in lophenol, suggesting coregulation. Of six additional grl genes, only grl-3 was upregulated on lophenol; the rest were downregulated. Cyclicity of expression was lost or altered in all six. Nuclear receptor genes nhr-23, nhr-25, nhr-41, and daf-12 all showed cyclic expression in cholesterol and significant downregulation in lophenol by RT-PCR. Expression of the insulin-like receptor daf-2 was lower in lophenol, whereas that of its major downstream target daf-16 was higher. Thus, major changes in gene expression accompany growth on 4MSs, but with surprisingly little effect on normal growth and development.<br />
DOI: 10.1194/jlr.M600552-JLR200 PMID: 17277379 [Indexed for MEDLINE]<br />
<br />
[4]. Eur J Biochem. 1998 Aug 15;256(1):88-96. doi: 10.1046/j.1432-1327.1998.2560088.x.<br />
Two families of sterol methyltransferases are involved in the first and the second methylation steps of plant sterol biosynthesis.<br />
Bouvier-Navé P(1), Husselstein T, Benveniste P.<br />
Author information: (1)Institut de Biologie Moléculaire des Plantes, Département de Biologie Cellulaire et Moléculaire, Strasbourg, France. [email protected]<br />
Two methyl transfers are involved in the biosynthesis of 24-methyl and 24-ethyl sterols, which play major roles in plant growth and development. The first methyl transfer applies to cycloartenol, the second to 24-methylene lophenol. About ten cDNA clones encoding S-adenosyl-L-methionine (AdoMet) sterol methyltransferases (SMTs) have been isolated so far from various plants. According to their deduced amino acid sequences, they were classified in two families, smtl and smt2; in addition, smt2 cDNAs were shown to encode a 24-methylene lophenol C24 methyltransferase [Bouvier-Navé, P., Husselstein, T., Desprez, T. & Benveniste, P. (1997) Eur. J. Biochem. 246, 518-529]. We now report the comparison of two cDNAs isolated from Nicotiana tabacum, Ntsmt1-1 which belongs to the first SMT cDNA family and Ntsmt2-1 which belongs to the second. Both cDNAs were expressed in the yeast null mutant erg6, deficient in SMT. Whereas erg6 is devoid of 24-alkyl sterols, erg6 Ntsmt1-1 contained a majority of 24-methylene sterols and erg6 Ntsmt2-1, a majority of 24-ethylidene sterols, indicating distinct functions for the expression products of these cDNAs. In the presence of AdoMet, delipidated microsomes from erg6 Ntsm1-1 efficiently converted cycloartenol into 24-methylene cycloartanol, but did not produce any 24-ethylidene lophenol upon incubation with 24-methylene lophenol. This demonstrates that cDNA Ntsmt1-1 (and most probably the other plant SMT cDNAs of the first family) encode(s) a cycloartenol C24 methyltransferase. In contrast, delipidated microsomes of erg6 Ntsmt2-1 were shown to methylate preferentially 24-methylene lophenol, as expected from an SMT encoded by an smt2 cDNA. In summary, among various cDNAs isolated from N. tabacum, one (Ntsmt1-1) belongs to the first family of plant SMT cDNAs according to its deduced amino acid sequence and was shown to encode a cycloartenol C24 methyltransferase, whereas another (Ntsmt2-1) belongs to the second family and was shown to encode a 24-methylene lophenol C24 methyltransferase. Meanwhile, two cDNAs were isolated from Oriza sativa and shown to belong to smtl and to smt2 families, respectively. These data disclose the coexistence, in a given plant species, of two distinct SMTs, each catalyzing one step of methylation in the sterol biosynthesis pathway.<br />
DOI: 10.1046/j.1432-1327.1998.2560088.x PMID: 9746350 [Indexed for MEDLINE]<br />
<br />
[5]. Eur J Biochem. 1997 Jun 1;246(2):518-29. doi: 10.1111/j.1432-1033.1997.t01-1-00518.x.<br />
Identification of cDNAs encoding sterol methyl-transferases involved in the second methylation step of plant sterol biosynthesis.<br />
Bouvier-Navé P(1), Husselstein T, Desprez T, Benveniste P.<br />
Author information: (1)Institut de Biologie Moléculaire des Plantes, Département d'Enzymologie Cellulaire et Moléculaire, Institut de Botanique, Strasbourg, France.<br />
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.<br />
DOI: 10.1111/j.1432-1033.1997.t01-1-00518.x PMID: 9208946 [Indexed for MEDLINE]
|
