internal standard

1,2-Distearoyl-sn-glycerol 是一种内标物，可用于分离和鉴定 1,2-diacyl-sn-glycerol (DAG) 的分子种类。

Enflurane (Efrane) 是一种挥发性麻醉剂，是 Chara australis 高电导 Ca2+ 激活的 K+ 通道的有效抑制剂。 安氟醚是通过顶空气相色谱-质谱法监测卤化挥发性麻醉剂的内标。 它可以快速调整麻醉深度，而脉搏或呼吸频率几乎没有变化。

5-Methyl-2-Hexanol (5-甲基-2-己醇) 是一种非结晶性仲醇，已作为内标物用于超声波辅助快速提取葡萄白兰地和水醇木提取物中的芳香化合物。

1,5,5-Trimethylhydantoin (TMH) 是非同位素内标化合物的一种。

2-Hydroxy-6-methoxybenzoic acid (6-Methoxysalicylic acid) 可用于动物血浆中乙酸水杨酸及其主要代谢物水杨酸含量的测定，表现出较好的抗缓解疼痛活性。

2-Ethylbutyric acid 是一种内标物，可用于粪便的 VFA 分析标准的校准方法。

Fexofenadine-d6 (MDL-16455-d6) 是 Fexofenadine 的氘代物，可用做检测人血浆中非索非那定浓度的内标。

Antitumor agent-163 (Compound 3) 是一种用于碳酸酐酶IX (Carbonic AnhydraseIX, CAIX) 的分子靶向光动力疗法 (Molecular-Targeted Photodynamic Therapy, MT-PDT) 的光敏剂。在 540 nm 波长光照下，该化合物通过单线态氧选择性灭活 CAIX 蛋白，而对 α-微管蛋白 (α-tubulin)、β-肌动蛋白 (β-actin) 和增殖细胞核抗原 (PCNA) 等内参蛋白无影响。它能诱导细胞膜损伤，抑制细胞活力，A549 和 U87MG 细胞的IC50分别为 0.2 和 0.05 μM。在小鼠模型中，Antitumor agent-163 展示出抗肿瘤活性。

PhIP-D3 is a deuterated internal standard for PhIP.

1-Palmitoyl-2-hydroxy-sn-glycero-3-PE是一种天然存在的溶血磷脂和内源性代谢物，可用于生物化学实验和药物合成研究。

(±)-5,7-Dimethyltocol is a form of tocopherol. It has similar antioxidant activity to α-tocol, but lower activity than γ-tocol, in antioxidant assays using menhaden oil or squalene as substrates. It also increases microviscosity of rat liver liposomes containing phosphatidylcholine (PC) by 70.6% when used at a molar ratio of 0.2 to PC. (±)-Dimethyltocol has been used as an internal standard for the quantification of 5,7-tocol, α- and γ-tocopherol, and α- and γ-tocopheryl quinone by HPLC.

13C15-Nivalenol is intended for use as an internal standard for the quantification of nivalenol by GC- or LC-MS. Nivalenol is a trichothecene mycotoxin that has been found inFusarium.1It is lethal to mice (LD50= 6.9 mg/kg).2Nivalenol (5, 10, and 15 mg/kg) also induces thymic, splenic, and Peyer's patch cell apoptosis in mice.3 1.Yang, Z., Concannon, J., Ng, K.S., et al.Tetrandrine identified in a small molecule screen to activate mesenchymal stem cells for enhanced immunomodulationSci. Rep.630263(2016) 2.Yoshizawa, T., and Morooka, N.Studies on the toxic substances in the infected cereals (part 3): Acute toxicities of new trichothecene mycotoxins: Deoxynivalenol and its monoacetateJ. Food Hyg.15(4)261-269(1974) 3.Poapolathep, A., Ohtsuka, R., Kiatipattanasakul, W., et al.Nivalenol-induced apoptosis in thymus, spleen and Peyer's patches of miceExp. Toxicol. Pathol.53(6)441-446(2002)

3-Acetyldeoxy nivalenol-13C17is intended for use as an internal standard for the quantification of 3-acetyldeoxy nivalenol by GC- or LC-MS. 3-Acetyldeoxy nivalenol is a mycotoxin that has been found inF. graminearum.1In vivo, 3-acetyldeoxy nivalenol (40 mg/kg) induces duodenal and splenic cell necrosis, as well as lethality (LD50= 70 mg/kg) in mice.2 1.Jiao, F., Kawakami, A., and Nakajima, T.Effects of different carbon sources on trichothecene production and Tri gene expression by Fusarium graminearum in liquid cultureFEMS Microbiol.Lett.285(2)212-219(2008) 2.Schiefer, H.B., Nicholson, S., Kasali, O.B., et al.Pathology of acute 3-acetyldeoxynivalenol toxicity in miceCan. J. Comp. Med.49(3)315-318(1985)

4-deoxy Nivalenol-13C15is intended for use as an internal standard for the quantification of 4-deoxy nivalenol by GC- or LC-MS. 4-deoxy Nivalenol is a trichothecene mycotoxin that has been found inFusarium.1It binds to eukaryotic ribosomes and inhibits protein synthesis in mice when administered at doses ranging from 5 to 25 mg/kg. 4-deoxy Nivalenol (0.1 and 0.2 mg/kg) induces emesis in pigs and decreases feed consumption in pigs when administered at a dose of 40 ppb in the diet.2It induces lethality in mice (LD50= 46-78 mg/kg).34-deoxy Nivalenol has been found inF. graminearum-infected cereal grains such as wheat, barley, and corn. 1.Pestka, J.J., and Smolinski, A.T.Deoxynivalenol: Toxicology and potential effects on humansJ.Toxicol.Environ.Health B.Crit.Rev.8(1)39-69(2005) 2.Forsyth, D.M., Yoshizawa, T., Morooka, N., et al.Emetic and refusal activity of deoxynivalenol to swineAppl. Environ. Microbiol.34(5)547-552(1977) 3.Pestka, J.J.Deoxynivalenol: Mechanisms of action, human exposure, and toxicological relevanceArch. Toxicol.84(9)663-679(2010)

Aflatoxin B2-13C17(AFB2-13C17) is intended for use as an internal standard for the quantification of AFB2by GC- or LC-MS. AFB2is a mycotoxin that has been found inA. terricola.1It induces hepatic autophagy and apoptosis in broiler chickens when administered at doses of 0.2, 0.4, and 0.8 mg/kg.2AFB2(0.5 and 1 mg/animal) also induces parenchymal cell hyperplasia in rats.3 1.Moubasher, A.H., el-Kady, I.A., and Shoriet, A.Toxigenic Aspergilli isolated from different sources in EgyptAnn. Nutr. Aliment.31(4-6)607-615(1977) 2.Chen, B., Li, D., Li, M., et al.Induction of mitochondria-mediated apoptosis and PI3K/Akt/mTOR-mediated autophagy by aflatoxin B2 in hepatocytes of broilersOncotarget7(51)84989-84998(2016) 3.Wogan, G.N., Edwards, G.S., and Newberne, P.M.Structure-activity relationships in toxicity and carcinogenicity of aflatoxins and analogsCancer Res.31(12)1936-1942(1971)

Aflatoxin G1-13C17is intended for use as an internal standard for the quantification of aflatoxin G1by GC- or LC-MS. Aflatoxin G1is a mycotoxin that has been found inA. terricola.1In vivo, aflatoxin G1is lethal to ducklings (LD50= 1.18 mg/kg).2It induces hepatocellular carcinoma tumor formation and lethality in rats when administered at doses of 1.4 and 3 mg/animal, respectively. Aflatoxin G1also inhibits liver and kidney succinate dehydrogenase and fumarase, as well as kidney cytochrome oxidase, NADH oxidase, α-glycerophosphate dehydrogenase, isocitrate dehydrogenase, and malate dehydrogenase in rats.3 1.Moubasher, A.H., el-Kady, I.A., and Shoriet, A.Toxigenic Aspergilli isolated from different sources in EgyptAnn. Nutr. Aliment.31(4-6)607-615(1977) 2.Wogan, G.N., Edwards, G.S., and Newberne, P.M.Structure-activity relationships in toxicity and carcinogenicity of aflatoxins and analogsCancer Res.31(12)1936-1942(1971) 3.Bai, N.J., Pai, M.R., and Venkitasubramanian, T.A.Mitochondrial function in aflatoxin toxicityIndian J. Biochem. Biophys.14(4)347-349(1977)

Aflatoxin G2-13C17is intended for use as an internal standard for the quantification of aflatoxin G2by GC- or LC-MS. Aflatoxin G2is a mycotoxin that has been found inAspergillus.1It is lethal to ducklings (LD50= 2.83 mg/kg) but is non-toxic to rats when administered at a dose of 200 mg/kg.2 1.Bennett, J.W., and Klich, M.MycotoxinsClin. Microbiol. Rev.16(3)497-516(2003) 2.Wogan, G.N., Edwards, G.S., and Newberne, P.M.Structure-activity relationships in toxicity and carcinogenicity of aflatoxins and analogsCancer Res.31(12)1936-1942(1971)

Guanfacine-13C,15N3is intended for us as an internal standard for the quantification of guanfacine by GC- or LC-MS. Guanfacine is an α2-adrenergic receptor (α2-AR) agonist with Kivalues of 93, 1,380, and 3,890 nM for α2A-, α2B-, and α2C-ARs, respectively, in a radioligand binding assay.1It has EC50values of 52, 288, and 602 nM for α2A-, α2B-, and α2C-ARs, respectively, for stimulated [35S]GTPγS binding. It also binds to imidazoline receptor 1 (Ki= 19 nM in a radioligand binding assay).2Guanfacine (0.3-5 mg/kg) binds to adrenergic receptors in the central nervous system and lowers blood pressure in hypertensive rats in a dose-dependent manner.3It also improves spatial working memory deficits induced by hypobaric hypoxia in rats.4Formulations containing guanfacine are used in the treatment of high blood pressure and attention deficit hyperactivity disorder (ADHD). 1.Jasper, J.R., Lesnick, J.D., Chang, L.K., et al.Ligand efficacy and potency at recombinant α2 adrenergic receptors: Agonist-mediated [35S]GTPγS bindingBiochem. Pharmacol.55(7)1035-1043(1998) 2.Nikolic, K., Filipic, S., and Agbaba, D.QSAR study of imidazoline antihypertensive drugsBioorg. Med. Chem.16(15)7134-7140(2008) 3.Scholtysik, G.Pharmacology of guanfacineBr. J. Clin. Pharmacol.10(Suppl 1)21S-24S(1980) 4.Kauser, H., Sahu, S., Kumar, S., et al.Guanfacine is an effective countermeasure for hypobaric hypoxia-induced cognitive declineNeuroscience254110-119(2013)

D-Fructose-13C6 可用作通过 GC-或 LC-MS 定量 D-果糖的内标。

2-deoxy-D-Glucose-13C is intended for use as an internal standard for the quantification of 2-deoxy-D-glucose by GC- or LC-MS. 2-deoxy-D-Glucose is a glucose antimetabolite and an inhibitor of glycolysis. It inhibits hexokinase, the enzyme that converts glucose to glucose-6-phosphate, as well as phosphoglucose isomerase, the enzyme that converts glucose-6-phosphate to fructose-6-phosphate.

Oleic acid-13C is intended for use as an internal standard for the quantification of oleic acid by GC- or LC-MS. Oleic acid is a monounsaturated fatty acid and a major component of membrane phospholipids that has been found in human plasma, cell membranes, and adipose tissue.1,2 It contributes approximately 17% of the total fatty acids esterified to phosphatidylcholine, the major phospholipid class in porcine platelets.1 Oleic acid inhibits collagen-stimulated platelet aggregation by approximately 90% when used at a concentration of 10 μg/ml. It also inhibits fMLF-induced neutrophil aggregation and degranulation by 55 and 68%, respectively, when used at a concentration of 5 μM, similar to arachidonic acid .3 Oleic acid (60 μM) induces release of intracellular calcium in human platelets.4

Lauric acid-13C is intended for use as an internal standard for the quantification of lauric acid by GC- or LC-MS. Lauric acid is a medium-chain saturated fatty acid. It has been found at high levels in coconut oil.1Lauric acid induces the activation of NF-κB and the expression of COX-2, inducible nitric oxide synthase (iNOS), and IL-1α in RAW 264.7 cells when used at a concentration of 25 μM.2

Octanoic acid-13C is intended for use as an internal standard for the quantification of octanoic acid by GC- or LC-MS. Octanoic acid is a medium-chain saturated fatty acid. It has been found in Teleme cheeses made from goat, ovine, or bovine milk.1 Octanoic acid is active against the bacteria S. mutans, S. gordonii, F. nucleatum, and P. gingivalis (IC80s = <125, <125, 1,403, and 2,294 μM, respectively).2 Levels of octanoic acid are increased in the plasma of patients with medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, an inborn error of fatty acid metabolism characterized by hypoketotic hypoglycemia, medium-chain dicarboxylic aciduria, and intolerance to fasting.3,4 |1. Mallatou, H., Pappa, E., and Massouras, T. Changes in free fatty acids during ripening of Teleme cheese made with ewes', goats', cows' or a mixture of ewes' and goats' milk. Int. Dairy J. 13(1-3), 211-219 (2003).|2. Hyang, C.B., Alimova, Y., Myers, T.M., et al. Short- and medium-chain fatty acids exhibit antimicrobial activity for oral microorganisms. Arch. Oral Biol. 56(7), 650-654 (2011).|3. Onkenhout, W., Venizelos, V., van der Poel, P.F.H., et al. Identification and quantification of intermediates of unsaturated fatty acid metabolism in plasma of patients with fatty acid oxidation disorders. Clin. Chem. 41(10), 1467-1474 (1995).|4. Rinaldo, P., O'Shea, J.J., Coates, P.M., et al. Medium-chain acyl-CoA dehydrogenase deficiency. Diagnosis by stable-isotope dilution measurement of urinary n-hexanoylglycine and 3-phenylpropionylglycine. N. Engl. J. Med. 319(20), 1308-1313 (1988).

Gliotoxin-13C13is intended for use as an internal standard for the quantification of gliotoxin by GC- or LC-MS. Gliotoxin is an immunosuppressive mycotoxin produced by pathogenic strains ofAspergillusand other fungi with diverse biological activities.1,2,3,4,5,6,7,8It inhibits 20S proteasomal chymotrypsin activity (IC50= 10 μM), blocking the degradation of IκBα and preventing the activation of NF-κB.2,3Gliotoxin induces apoptosis in monocytes and dendritic cells and reduces phagocytosis by neutrophils.4,5It suppresses viral infection by Nipah and Hendra virus in HEK293T cells (IC50s = 149 and 579 nM, respectively).6Under reducing conditions, gliotoxin inhibits leukotriene A4hydrolase epoxide hydrolase activity, but not aminopeptidase activity, and leukotriene B4synthesis in neutrophils and monocytes.7