3-hydroxyl Group Research Articles

STUDY OF THE INTERACTION BETWEEN OXICAM DERIVATIVES AND COX1 USING FINGERPRINT DESCRIPTORS AND MOLECULAR DOCKING

Oxicam derivatives play an important role in the treatment of pain and inflammation. The mechanism of action of these compounds consists in the inhibition of cyclooxygenase (COX) and the blockade of isoform 1 of this enzyme (COX-1) is considered to generate adverse effects. The aim of this paper is to establish which of the atoms in the oxicams molecules are responsible for their inhibitory activities, using electronegativity as fingerprint descriptor. Using this descriptor and molecular docking programs, the atoms in the molecule that have a greater contribution to COX-1 inhibition have been identified. In the case of the studied molecules, the oxygen atoms and the nitrogen atoms are highlighted. The oxygen atoms participate in the interaction as electron acceptors through U-MO molecular levels (74.1%) and the nitrogen atoms participate in the interaction both as a nucleophilic center through the molecular state of HOMO (13.7%) and as an electrophilic center through the molecular state of LUMO (13.2%). In the case of three out of four of the studied compounds, the 4-hydroxyl group of the thiazine ring participates in the interaction with COX-1. The results are also supported by the 2D and 3Ddiagrams of the applied docking method.

Acankoreagenin and acankoreosides, a family of lupane triterpenoids with anti-inflammatory properties: an overview.

Acankoreagenin (ACK, also known as acankoreanogenin and HLEDA) and impressic acid are two lupane-type triterpenes that can be isolated from various Acanthopanax and Schefflera species. They efficiently block activation of the NF-κB signaling pathway and the release of proinflammatory cytokines and/or the action of inflammation mediators (HMGB1, iNOS, and NO). These effects are the basis for the antiviral and anticancer activities reported with these pentacyclic compounds or their various glycoside derivatives. More than 15 acankoreosides (Ack-A to -O, and -R) and a few other mono- and bidesmosidic saponins (acantrifoside A and acangraciliside S) derive from the ACK aglycone. Compounds like Ack-A and -B are remarkable anti-inflammatory agents, inhibiting cytokine release from activated macrophages. Despite their effectiveness, ACK and impressic acid are far much less known and studied than the structurally related compounds betulinic acid and 23-hydroxybetulinic acid (anemosapogenin). The structural differences (notably the R/S stereoisomerism of the 3-hydroxyl group) and functional similarities of these compounds are discussed. The complete series of acankoreosides is presented for the first time. These natural products deserve further attention as anti-inflammatory agents, and ACK is recommended as a template for the design of new anticancer and antiviral drugs.

Functional role of residues involved in substrate binding of human 4-hydroxyphenylpyruvate dioxygenase.

4-Hydroxylphenylpyruvate dioxygenase (HPPD) catalyzes the conversion of 4-hydroxylphenylpyruvate (HPP) to homogentisate, the important step for tyrosine catabolism. Comparison of the structure of human HPPD with the substrate-bound structure of A. thaliana HPPD revealed notably different orientations of the C-terminal helix. This helix performed as a closed conformation in human enzyme. Simulation revealed a different substrate-binding mode in which the carboxyl group of HPP interacted by a H-bond network formed by Gln334, Glu349 (the metal-binding ligand), and Asn363 (in the C-terminal helix). The 4-hydroxyl group of HPP interacted with Gln251 and Gln265. The relative activity and substrate-binding affinity were preserved for the Q334A mutant, implying the alternative role of Asn363 for HPP binding and catalysis. The reduction in kcat/Km of the Asn363 mutants confirmed the critical role in catalysis. Compared to the N363A mutant, the dramatic reduction in the Kd and thermal stability of the N363D mutant implies the side-chain effect in the hinge region rotation of the C-terminal helix. The activity and binding affinity were not recovered by double mutation; however, the 4-hydroxyphenylacetate intermediate formation by the uncoupled reaction of Q334N/N363Q and Q334A/N363D mutants indicated the importance of the H-bond network in the electrophilic reaction. These results highlight the functional role of the H-bond network in a closed conformation of the C-terminal helix to stabilize the bound substrate. The extremely low activity and reduction in Q251E's Kd suggest that interaction coupled with the H-bond network is crucial to locate the substrate for nucleophilic reaction.

Discovery of Pyrrolidine-2,3-diones as Novel Inhibitors of P. aeruginosa PBP3.

The alarming threat of the spread of multidrug resistant bacteria currently leaves clinicians with very limited options to combat infections, especially those from Gram-negative bacteria. Hence, innovative strategies to deliver the next generation of antibacterials are urgently needed. Penicillin binding proteins (PBPs) are proven targets inhibited by β-lactam antibiotics. To discover novel, non-β-lactam inhibitors against PBP3 of Pseudomonas aeruginosa, we optimised a fluorescence assay based on a well-known thioester artificial substrate and performed a target screening using a focused protease-targeted library of 2455 compounds, which led to the identification of pyrrolidine-2,3-dione as a potential scaffold to inhibit the PBP3 target. Further chemical optimisation using a one-pot three-component reaction protocol delivered compounds with excellent target inhibition, initial antibacterial activities against P. aeruginosa and no apparent cytotoxicity. Our investigation revealed the key structural features; for instance, 3-hydroxyl group (R2) and a heteroaryl group (R1) appended to the N-pyrroldine-2,3-dione via methylene linker required for target inhibition. Overall, the discovery of the pyrrolidine-2,3-dione class of inhibitors of PBP3 brings opportunities to target multidrug-resistant bacterial strains and calls for further optimisation to improve antibacterial activity against P. aeruginosa.

Selective enzymatic α-1,6- monoglucosylation of mogroside IIIE for the bio-creation of α-siamenoside I, a potential high-intensity sweetener

A new compound, α-siamenoside I (α-SI), with a glucose unit selectively bound to the 6-hydroxyl group of the 24-O-β-glucosyl moiety of mogroside IIIE by α-1,6-glucosidic bond, was bio-created by two screened cyclodextrin glycosyltransferases with a maximum yield of 59.3%. Compared to mogroside IIIE, α-SI showed a significantly increased sweetness intensity (508 times sweeter than 5% sucrose), which is superior to siamenoside I (SI), the sweetest triterpenoid saponin isolated from Siraitia grosvenorii to date. Sensory evaluation showed that the taste quality of α-SI also was obviously better than mogroside IIIE. In addition to α-SI possessing a good stability similar to that of SI, it also did not cause a significant decrease in cell viability at a concentration of 200 μg/mL and had a negative influence on islets function at 1 μM. All of these preliminarily results pave the way for promoting α-SI as a potential low-calorie sweetener.

In silico analysis of the antidiabetic terpenoid acankoreagenin binding to PPARγ.

Acankoreagenin (ACK) is a lupane triterpene found in several Acanthopanax and Schefflera plant species. ACK, also known as acankoreanogenin or HLEDA, bears a major structural analogy with other lupane triterpenoids such as impressic acid (IA) and the largely used phytochemical betulinic acid (BA). These compounds display marked anti-inflammatory, anti-diabetes, and anti-cancer properties. BA can form stable complexes with the peroxisome proliferator-activated receptor gamma (PPARγ). The tridimensional structure of the BA-PPARγ complex was used to perform a molecular docking analysis of the binding of ACK and IA to the protein. The 3-hydroxyl epimers (R/S) of each natural product were also modeled to examine the role of the C3-OH stereochemistry that distinguishes BA [3(S)] from ACK and AI [3(R)]. Calculations indicate that ACK can form more stable complexes with PPARγ than BA, upon insertion of the drug into the same binding pocket. The inversion of the C3-OH stereochemistry is not an obstacle for binding and the additional carboxy group of ACK at C23 position seems to reinforce the protein interaction. The 3-hydroxyl group does not play a major role in the geometry of the protein-drug complex, which is preserved between BA and ACK. Additional structure-binding relationships are provided, through the evaluation of the PPARγ binding capacity of ACK derivatives. Binding of ACK to PPARγ would account for its marked antidiabetic effect, at least partially. ACK can be used as a platform to design new antidiabetic compounds.

Polar auxin transport May Be responsive to specific features of flavonoid structure

Polar auxin transport (PAT) is essential to control root growth. Flavonoids are widely thought to be PAT inhibitors leading to short root developments. However, we found that the flavonoids scutellarin and scutellarein, which both have a 6-hydroxyl group unlike the structure of known flavonoid-PAT-inhibitors, promote PAT in roots. They increase root length; rescue the short roots induced by the PAT-specific inhibitor TIBA; enhance the expression of the PAT mediators PIN1, PIN2 and AUX1; increase the auxin concentration at the quiescent center; and change the distribution of the meristem organizer WOX5. In contrast, rutin and naringenin, which have no 6-hydroxyl group and have different structural features in B-ring, shows the opposite/no effects. Our evidence suggests that flavonoids with and without a 6-hydroxyl group might result in opposite effects on root growth and thus act as chemical switches in regulating PAT.

Protolytic Equilibria in Organized Solutions: Ionization and Tautomerism of Fluorescein Dyes and Related Indicators in Cetyltrimethylammonium Chloride Micellar Solutions at High Ionic Strength of the Bulk Phase

Ionic equilibrium of 22 hydroxyxanthenes, including halogen and nitro derivatives of fluorescein, and their thio- and aza analogues, were studied spectrophotometrically in micellar solutions of cetyltrimethylammonium chloride at ionic strength of the bulk phase 4.0 M KCl. This micellar pseudophase is characterized by the electrostatic surface potential of +(15–16) mV and the ETN value of 0.623. In the case of dyes bearing the COOH group, colorless lactone is the predominant tautomer of the molecular form H2R. A new classification of fluoresceins is developed. The dyes were divided into four groups based on the nature of tautomerism of the anions. In the case of the fluorescein type, the monoanions HR− exist predominantly as “carboxylate” tautomers, with ionized carboxylic and non–ionized hydroxylic group. For the dyes of the eosin type, the situation is opposite, while for the intervening type of compounds, the concentrations of the two tautomers are comparable. Dyes capable of forming lactone anions HR− were classified as the fourth type. For some of them, even the dianion R2− exists as a lactone. The relationship between the stepwise ionization constants, Ka1/Ka2, varies from 1.3 to 1.07 × 105 and is determined by the state of tautomeric equilibrium of molecules and ions.

Substrate Specificities of GH8, GH39, and GH52 β-xylosidases from Bacillus halodurans C-125 Toward Substituted Xylooligosaccharides.

Substrate specificities of glycoside hydrolase families 8 (Rex), 39 (BhXyl39), and 52 (BhXyl52) β-xylosidases from Bacillus halodurans C-125 were investigated. BhXyl39 hydrolyzed xylotriose most efficiently among the linear xylooligosaccharides. The activity decreased in the order of xylohexaose > xylopentaose > xylotetraose and it had little effect on xylobiose. In contrast, BhXyl52 hydrolyzed xylobiose and xylotriose most efficiently, and its activity decreased when the main chain became longer as follows: xylotetraose > xylopentaose > xylohexaose. Rex produced O-β-D-xylopyranosyl-(1 → 4)-[O-α-L-arabinofuranosyl-(1 → 3)]-O-β-D-xylopyranosyl-(1 → 4)-β-D-xylopyranose (Ara2Xyl3) and O-β-D-xylopyranosyl-(1 → 4)-[O-4-O-methyl-α-D-glucuronopyranosyl-(l → 2)]-β-D-xylopyranosyl-(1 → 4)-β-D-xylopyranose (MeGlcA2Xyl3), which lost a xylose residue from the reducing end of O-β-D-xylopyranosyl-(1 → 4)-[O-α-L-arabinofuranosyl-(1 → 3)]-O-β-D-xylopyranosyl-(1 → 4)-β-D-xylopyranosyl-(1 → 4)-β-D-xylopyranose (Ara3Xyl4) and O-β-D-xylopyranosyl-(1 → 4)-[O-4-O-methyl-α-D-glucuronopyranosyl-(1 → 2)]-β-D-xylopyranosyl-(1 → 4)-β-D-xylopyranosyl-(1 → 4)-β-D-xylopyranose (MeGlcA3Xyl4). It was considered that there is no space to accommodate side chains at subsite -1. BhXyl39 rapidly hydrolyzes the non-reducing-end xylose linkages of MeGlcA3Xyl4, while the arabinose branch does not significantly affect the enzyme activity because it degrades Ara3Xyl4 as rapidly as unmodified xylotetraose. The model structure suggested that BhXyl39 enhanced the activity for MeGlcA3Xyl4 by forming a hydrogen bond between glucuronic acid and Lys265. BhXyl52 did not hydrolyze Ara3Xyl4 and MeGlcA3Xyl4 because it has a narrow substrate binding pocket and 2- and 3-hydroxyl groups of xylose at subsite +1 hydrogen bond to the enzyme.

Discovery of degradable niclosamide derivatives able to specially inhibit small cell lung cancer (SCLC)

Small cell lung cancer (SCLC) is exceedingly tough to treat and easy to develop resistance upon long use of the first-line drug carboplatin or radiotherapy. Novel medicines effective and specific against SCLC are greatly needed. Herein, we focused on the discovery of such a medicine by exploring a drug niclosamide with repurposing strategy. Initial screening efforts revealed that niclosamide, an anthelmintic drug, possessed the in vitro anticancer activity and an obvious sensitivity towards SCLC. This observation inspired the evaluation for two different kinds of niclosamide derivatives. 2 with a degradable ester as a linker exhibited the comparable activity but slightly inferior selectivity to SCLC, by contrast, the cytotoxicities of 4 and 5 with non-degradable ether linkages completely disappeared, clearly validating the importance of 2-free hydroxyl group or 2-hydroxyl group released in the antitumor activity. Mechanism study unfolded that, similar to niclosamide, 2 inhibited growth of cancer cells via p 53 activation and subsequent underwent cytochrome c dependent apoptosis. Further structural modification to afford phosphate sodium 8 with significantly enhanced aqueous solubility (22.1 mg/mL) and a good selectivity towards SCLC demonstrated more promising druggability profiles. Accordingly, niclosamide as an attractive lead hold a huge potential for developing targeted anti-SCLC drugs.

Catalysis and specificity of the polycondensation of aminopropyltrimethoxysilane on nucleic acids

The polycondensation of a silane derivative such as aminopropyltrimethoxysilane (ATMS) in the presence of nucleic acids has never been investigated. Our group has previously demonstrated that in chloroform ATMS hydrolysis and polycondensation were faster when the reaction were carried out in the presence of double stranded DNA (146 bp). The results showed that the kinetics of ATMS hydrolysis was affected by the base type used, a fast hydrolysis reaction rate being observed with nucleotide molecules containing adenosine group, and that in the absence of water the amino group of deoxyadenosine units, and not the hydroxylic group of the sucrose residue, can react with ATMS methoxy groups. The present work was initiated aiming at providing a better understanding of this effect. It was observed that the polymerization degree of oligodeoxyadenylate has a clear impact on the kinetic of reaction this effect being as much important as the polymerization degree of the oligodeoxyadenylate was high. Structural investigation by molecular modeling showed that this enhanced reactivity can be explained by conformational effects. Altogether, these results are accounted for assuming that DNA can act as a specific template for ATMS polycondensation, in organic medium such as chloroform, opening the way to possible DNA encapsulation, and a new way for DNA chemical modification in organic solvent.

Deoxycholic acid as a molecular scaffold for tyrosyl-DNA phosphodiesterase 1 inhibition: A synthesis, structure–activity relationship and molecular modeling study

Para-Bromoanilides of deoxycholic acid with various functional groups on the steroid scaffold were designed as promising tyrosyl-DNA phosphodiesterase 1 (Tdp1) inhibitors. Tdp1 is a DNA repair enzyme, involved in removing DNA damage caused by topoisomerase I poisons; an important class of anticancer drugs. Thus, reducing the activity of Tdp1 can increase the efficacy of anticancer drugs in current use. Inhibitory activity in the low micromolar and submicromolar concentrations was observed with 3,12-dimethoxy para-bromoanilide 17 being the most active with an IC50 value of 0.27 μM. The activity of N-methyl para-bromoanilides was 3–4.8 times lower than of the corresponding para-bromoanilides. Increased potency of the ligands was seen with higher molecular weight and log P values. The ligands were evaluated for their cytotoxic potential in a panel of tumor cell lines; all were nontoxic to the A549 pulmonary adenocarcinoma cell line. However, derivatives containing a hydroxyl group at the 12th position were more toxic than their 12-hydroxyl group counterparts (acetoxy-, oxo- and methoxy- group) against HCT-116 human colon and HepG2 hepatocellular carcinomas. In addition, an N-methyl substitution led to an increase in toxicity for the HCT-116 and HepG2 cell lines. The excellent activity as well as low cytotoxicity, derivative 17 can be considered as a lead compound for further development.

Synthesis of the C1 – C16 fragment of bryostatin for incorporation into 20,20-fluorinated analogues

Abstract The stereoselective synthesis of a carboxylic acid ester corresponding to the C1–C16 fragment of bryostatin, with 4-methoxybenzyl (PMB) protection for the 7-hydroxyl group, is reported. The key steps included a Horner-Wadsworth-Emmons reaction between (5R)-3-[(E)-2-tri-isopropylsilyloxyethylidene]-6-(4-methoxybenzyloxy)-5-triethylsilyloxyhexanal and dimethyl (4S,6R,8S)-10-hydroxy-6,8-di-O-isopropylidene-4-(4-methoxybenzyloxy)-3,3-dimethyl-2-oxodecan-1-yl phosphonate, that gave the corresponding (E)-alkene, followed by selective cleavage of the triethylsilyl ether and cyclisation to give the required 2,6-cis-disubstituted 4-[(Z)-tri-isopropylsilyloxyethylide]tetrahydropyran. Oxidation of the primary alcohol gave the corresponding carboxylic acid that was converted into the required allyl ester.

Interaction of Halogenated Tyrosine/Phenylalanine Derivatives with Organic Anion Transporter 1 in the Renal Handling of Tumor Imaging Probes

Halogenated tyrosine/phenylalanine derivatives have been developed for use in tumor imaging and targeted alpha therapy. 3-Fluoro-α-methyl-l-tyrosine (FAMT), targeting amino acid transporter LAT1 (SLC7A5), is a cancer-specific positron emission tomography probe that exhibits high renal accumulation, which is supposed to be mediated by organic anion transporter OAT1 (SLC22A6). In the present study, we investigated the structural requirements of FAMT essential for interaction with OAT1. OAT1 transported FAMT with a K m of 171.9 μM. In structure-activity relationship analyses, removal of either the 3-halogen or 4-hydroxyl group from FAMT or its structural analog 3-iodo-α-methyl-l-tyrosine greatly decreased the interaction with OAT1, reducing the [14C]p-aminohippurate uptake inhibition and the efflux induction. By contrast, the α-methyl group, which is essential for LAT1 specificity, contributed to a lesser degree. In fluorinated tyrosine derivatives, fluorine at any position was accepted by OAT1 when there was a hydroxyl group at the ortho-position, whereas ortho-fluorine was less interactive when a hydroxyl group was at meta- or para-positions. The replacement of the ortho-fluorine with a bulky iodine atom greatly increased the interaction. In in vivo studies, probenecid decreased the renal accumulation (P < 0.001) and urinary excretion (P = 0.0012) of FAMT, whereas the plasma concentration was increased, suggesting the involvement of OAT1-mediated transepithelial organic anion excretion. LAT1-specific 2-fluoro-α-methyltyrosine, which had lower affinity for OAT1, exhibited lower renal accumulation (P = 0.0142) and higher tumor uptake (P = 0.0192) compared with FAMT. These results would provide a basis to design tumor-specific compounds that can avoid renal accumulation for tumor imaging and targeted alpha therapy. SIGNIFICANCE STATEMENT: We revealed the structural characteristics of halogenated tyrosine derivatives essential for interaction with the organic anion transporter responsible for their renal accumulation. We have confirmed that such interactions are important for renal handling and tumor uptake. The critical contribution of hydroxyl and halogen groups and their positions as well as the role of α-methyl group found in the present study may facilitate the development of tumor-specific compounds while avoiding renal accumulation for use in tumor imaging and targeted alpha therapy.

Flavonoid scutellarin positively regulates root length through NUTCRACKER

Exploring approaches to regulate meristem is of special importance and broad interest. In this study, we found that the flavonoid scutellarin, which has a 6-hydroxyl and a 7-glucoside, increased root length through the transcription factor NUTCRACKER (NUC). This root lengthening disappeared in NUC-knockout and reappeared in NUC-rescue plants. Scutellarin induced NUC expression and promoted the division of cortex/endodermal initials. In contrast, naringenin, which has same chemical backbone but without 6-hydroxyl and with 7-hydroxyl group, showed the opposite or no effects. Our results demonstrate that scutellarin promotes root length through NUC-mediated regulatory pathways and reveal that flavonoids with and without the 6-hydroxyl and 7-glucoside have positive and negative effects on meristem size, respectively.

Enzymatic Monoglucosylation of Rubusoside and the Structure-Sweetness/Taste Relationship of Monoglucosyl Derivatives.

Monoglucosylation of rubusoside not only could increase its structural diversity but may also improve its taste. To biosynthesize the monoglucosyl rubusosides, a series of glycosyltransferases and glycosynthases were screened to identify the enzymes capable of specifically glycosylating the hydroxyl groups of the 13-O-β-d-glucosyl and 19-COO-β-d-glucosyl moieties. After structural characterization, the effect of structure on sweetness and taste was established based on these rubusoside-derived analogues, including two first characterized compounds. β-Monoglucosylation of two 2-hydroxyl groups, as well as α-monoglucosylations of the 4- and 6-hydroxyl groups of the 13-glucosyl moiety, could significantly increase the relative sweetness of rubusoside to 140 while maintaining or improving the taste quality. In contrast, monoglucosylations of other hydroxyl groups in our study usually decreased the taste quality of the rubusoside. Additionally, the possibility of a negative influence of these monoglucosylated derivatives on the function of islets was preliminarily excluded, which should facilitate the development of rubusoside-derived sweeteners.

Acid-catalyzed reaction of ethanol and oxazepam and its pharmacological consequence

Oxazepam (OX), an anxiolytic drug in clinical use, reacts with ethanol in aqueous and anhydrous ethanol solutions and simulated gastric fluid to form 3-O-ethyloxazepam (EtOX). In simulated gastric fluid containing 30% (by volume) ethanol, approximately 9.5% of OX is converted to EtOX in 2 hr at 37°C. Studies of this report indicate that the 3-hydroxyl group of OX is substituted by ethanol to form EtOX in acidic media. Pharmacokinetic studies in rats indicate that orally administered OX and EtOX at doses of 35 and 17.5 nmole/kg are absorbed to similar extents. EtOX is eliminated at a slower rate than OX. EtOX is less active than OX in two pharmacological activity tests in mice. It is known that ethanol and OX have additive effects in the central nervous system. The results of this study suggest that ingestion of ethanol shortly before, shortly after, or simultaneously with the intake of OX may result in the formation of EtOX in the strongly acidic medium of the stomach, reducing the pharmacological effects of OX.

Crystal structure of Oryza sativa TDC reveals the substrate specificity for TDC-mediated melatonin biosynthesis

Plant tryptophan decarboxylase (TDC) is a type II Pyridoxal-5′-phosphate-dependent decarboxylase (PLP_DC) that could be used as a target to genetically improve crops. However, lack of accurate structural information on plant TDC hampers the understanding of its decarboxylation mechanisms. In the present study, the crystal structures of Oryza sativa TDC (OsTDC) in its complexes with pyridoxal-5′-phosphate, tryptamine and serotonin were determined. The structures provide detailed interaction information between TDC and its substrates. The Y359 residue from the loop gate is a proton donor and forms a Lewis acid-base pair with serotonin/tryptamine, which is associated with product release. The H214 residue is responsible for PLP binding and proton transfer, and its proper interaction with Y359 is essential for OsTDC enzyme activity. The extra hydrogen bonds formed between the 5-hydroxyl group of serotonin and the backbone carboxyl groups of F104 and P105 explain the discrepancy between the catalytic activity of TDC in tryptophan and in 5-hydroxytryptophan. In addition, an evolutionary analysis revealed that type II PLP_DC originated from glutamic acid decarboxylase, potentially as an adaptive evolution of mechanism in organisms in extreme environments. This study is, to our knowledge, the first to present a detailed analysis of the crystal structure of OsTDC in these complexes. The information regarding the catalytic mechanism described here could facilitate the development of protocols to regulate melatonin levels and thereby contribute to crop improvement efforts to improve food security worldwide.

Toosendanin relatives, trypanocidal principles from Meliae Cortex.

Africa Trypanosomiasis remains a serious health problem, but the approved drugs for this disease are so few that novel trypanocidal compounds are demanded. In search for trypanocidal principles from medicinal plants, we found MeOH extracts of Meliae Cortex with potent activity through the screening from about 300 kinds of methanolic extract. By bioassay-guided fractionation from this extract through the liquid-liquid partition and subsequent chromatographic technique using silica gel and ODS, finally we disclosed toosendanin (1) and its relatives as active principles. These active congeners showed not only potent trypanocidal activity but also little cytotoxicity to display the excellent selective index. Taking the isolated amount as well as trypanocidal activity into consideration, 1 was disclosed to be the responsible active principle in Meliae Cortex. Additionally, the derivatives of 1 were chemically prepared from 1 and bioactivity of them were also evaluated. Through the comparison with their trypanocidal activity among the isolated relatives and the synthesized derivatives of 1, the epoxide moiety was revealed to be essential for their potent trypanocidal activity. Furthermore, 3-O-acetyl group and 7-hydroxyl group were presumed to be important functional groups and introduction of methylpropionyl group into hemiacetal hydroxy moiety was clarified to enhance their typanocidal activity.

Live Fetal Stem Cells Therapy, Anti-Neu5Gc Responses and Impact on Human Heart, Brain and Immune System

Fetal stem cells used for clinical applications in humans can cause xenogenic immune reactions and impact vital organs by immune dysregulation. Animal stem/fetal cells express glycan antigens, such as Neu5Gc. Humans do not produce these antigens. Two major sialic acids are described in mammalian cells, Neu5Gc, the N-glycolylneuraminic acid, and Neu5Ac the N-acetylneuraminic acid. Neu5Gc synthesis starts from the N-acetylneuraminic acid (Neu5Ac) precursor modified by a hydroxylic group addition catalyzed by cytidinemonophospho-N-acetyl-neuraminic acid hydroxylase-Neu5Ac hydroxylase enzyme (CMAH). CMAH was inactivated by a 92 base pairs deletion over 2 million years ago and is non-functional in humans, Neu5Gc as well as the peptides derived from fetal cells is remarkably immunogenic for humans and promotes inflammation, arthritis, cancer. Accumulating evidence shows that xenotransplantation of animal stem cells results in inflammation autoimmune responses and immune-rejection and may cause death. Here we highlight the serious deleterious effects of the presence of Neu5Gc antigen in animal fetal cells and the effects of presence and absence of Neu5Gc antibodies in humans acquired through the consumption of animal products. There are many reports of immune reactions to animal stem cells and their derivatives. Insect biterelated anti-alpha-gal and anti-Neu5Gc antibodies, and those induced by animal cells, cause “immune enhancement” and serious allergic reactions and or immune-pathology leading to irreversible damage to vital organs in the human body. Therefore needless to say that the use of animal stem cells and their derivatives being marketed as nutritional supplements are harmful for human use and should not be used either as oral supplements or as peptide injections. There is no evidence of their safety or efficacy for treating disease conditions or for their anti-aging effects. Neu5Gc (xeno-antigen), are produced by Animal Stem/fetal Cells and the peptides derived from them. Remarkably, Neu5Gc is a xeno-antigen for humans, and promote inflammation, arthritis, cancer, and xeno-transplantation of animal stem cells can result in inflammation autoimmune responses and immune-rejection (GVHD) and death.