Thiols play vital roles in cellular metabolism knowledge of which may be important in the design of future anticancer drugs. Previous work on the composition of the thiols present in human cancer cell lines has shown ...Thiols play vital roles in cellular metabolism knowledge of which may be important in the design of future anticancer drugs. Previous work on the composition of the thiols present in human cancer cell lines has shown the presence of an unknown low molecular weight species, deemed to be a “Conthiol”, which could be important in this respect. This was prepared and isolated from a human prostate cancer cell line (LNCaP) in the form of an adduct of 2-mercuri-4-nitrophenol;it accounts for 56.5% of the total cellular thiols present in this cell line. Initial LC-MS analysis of this adduct had indicated that the possible molecular weight of the thiol was in the region of 467 daltons. In further analytical studies to identify the thiol, attempts were made to release it from the adduct by passage through a Thiopropyl Sepharose6B column. LC-MS analysis of the column eluate revealed two components yielding negative ion fragments of 427 m/z and 449 m/z. Only the former component contained thiol, indicating that a breakdown and/or possible rearrangement of the Conthiol had occurred. Further investigations of the column thiol eluate using ICP-MS analysis showed that the sulfur content agreed with the spectrophotometric analysis result (Ellman assay) and that the molecule did not contain phosphate. Amino acid analyses of the eluate were negative. In an attempt to prevent the breakdown of the thiol released by the Thiopropyl Sepharose 6B column, the adduct was treated with 5% v/v bromine water prior to applying to the column. In this instance the thiol containing eluate obtained from the column was treated with an equimolar quantity of mercuric chloride forming a fresh adduct, RS-Hg-SR. LC-MS analysis of this mercurial adduct detected a negative ion fragment of 782 m/z which on further ionization gave a ladder like pattern showing loss of mass units of 58 in each rung. This would seem to suggest the presence of a repeat polymer like structure containing 5 monomers, which, plus the thiol atom, gives a possible formula weight o展开更多
This study aimed in the identification and quantification of phenolic compounds in different four varieties of rapeseeds (Brassica napus L.) using LC-MS and HPLC. LC-MS analysis guided to identify 12 phenolic compound...This study aimed in the identification and quantification of phenolic compounds in different four varieties of rapeseeds (Brassica napus L.) using LC-MS and HPLC. LC-MS analysis guided to identify 12 phenolic compounds including sinapine, sinapine(4-O-8')guaiacyl, feruloyl choline(4-O-8') guaiacyl, kaempferol-3-O-sinapoyl-sophoroside-7-O-glucoside, kaempferol-3-O-β-sophoroside, cyclic spermidine-alkaloid, feruloyl choline(5-8')guaiacyl, kaempferol-sinapoyl-trihexoside,1,2-di- O-sinapoyl-gentiobiose, 1,2-di-O-sinapoyl-glucose, feruloyl choline(4-O-8')guaiacyl-di-sinapoyl, and sinapine(4-O-8')guaiacyl-di-sinapoyl, respectively. Total phenolic compounds in rapeseed meals were ranged from 38.50 (2012 “Sunmang”) to 63.95 mg/g dry weight (DW) (2014 Jeju local cultivar). Main phenolic compositions were cyclic spermidine-alkaloid, kaempferol, feruloyl choline, and sinapine. Sinapine was predominant compound among all the samples ranged from 29.74 to 52.24 mg/g DW (mean 79% of total phenolic contents). This study provided the information for the variation of phenolic compounds between the varieties of rapeseeds and the cultivation periods. Furthermore, this information can be developed for bio-energy industry as a reducer of the cost of the bio-energy products.展开更多
文摘Thiols play vital roles in cellular metabolism knowledge of which may be important in the design of future anticancer drugs. Previous work on the composition of the thiols present in human cancer cell lines has shown the presence of an unknown low molecular weight species, deemed to be a “Conthiol”, which could be important in this respect. This was prepared and isolated from a human prostate cancer cell line (LNCaP) in the form of an adduct of 2-mercuri-4-nitrophenol;it accounts for 56.5% of the total cellular thiols present in this cell line. Initial LC-MS analysis of this adduct had indicated that the possible molecular weight of the thiol was in the region of 467 daltons. In further analytical studies to identify the thiol, attempts were made to release it from the adduct by passage through a Thiopropyl Sepharose6B column. LC-MS analysis of the column eluate revealed two components yielding negative ion fragments of 427 m/z and 449 m/z. Only the former component contained thiol, indicating that a breakdown and/or possible rearrangement of the Conthiol had occurred. Further investigations of the column thiol eluate using ICP-MS analysis showed that the sulfur content agreed with the spectrophotometric analysis result (Ellman assay) and that the molecule did not contain phosphate. Amino acid analyses of the eluate were negative. In an attempt to prevent the breakdown of the thiol released by the Thiopropyl Sepharose 6B column, the adduct was treated with 5% v/v bromine water prior to applying to the column. In this instance the thiol containing eluate obtained from the column was treated with an equimolar quantity of mercuric chloride forming a fresh adduct, RS-Hg-SR. LC-MS analysis of this mercurial adduct detected a negative ion fragment of 782 m/z which on further ionization gave a ladder like pattern showing loss of mass units of 58 in each rung. This would seem to suggest the presence of a repeat polymer like structure containing 5 monomers, which, plus the thiol atom, gives a possible formula weight o
文摘This study aimed in the identification and quantification of phenolic compounds in different four varieties of rapeseeds (Brassica napus L.) using LC-MS and HPLC. LC-MS analysis guided to identify 12 phenolic compounds including sinapine, sinapine(4-O-8')guaiacyl, feruloyl choline(4-O-8') guaiacyl, kaempferol-3-O-sinapoyl-sophoroside-7-O-glucoside, kaempferol-3-O-β-sophoroside, cyclic spermidine-alkaloid, feruloyl choline(5-8')guaiacyl, kaempferol-sinapoyl-trihexoside,1,2-di- O-sinapoyl-gentiobiose, 1,2-di-O-sinapoyl-glucose, feruloyl choline(4-O-8')guaiacyl-di-sinapoyl, and sinapine(4-O-8')guaiacyl-di-sinapoyl, respectively. Total phenolic compounds in rapeseed meals were ranged from 38.50 (2012 “Sunmang”) to 63.95 mg/g dry weight (DW) (2014 Jeju local cultivar). Main phenolic compositions were cyclic spermidine-alkaloid, kaempferol, feruloyl choline, and sinapine. Sinapine was predominant compound among all the samples ranged from 29.74 to 52.24 mg/g DW (mean 79% of total phenolic contents). This study provided the information for the variation of phenolic compounds between the varieties of rapeseeds and the cultivation periods. Furthermore, this information can be developed for bio-energy industry as a reducer of the cost of the bio-energy products.
