The geminal coupling and paramagnetic shift of exomethylene protons in the α,β′-unsaturated γ-lactone group of sesquiterpene lactones containing C8-α-hydroxyl groups

Corn stalk contains 40-50% cellulose, 20-40% hemicellulose, 4-15% lignin which had potential as biosorbent in binding metal ions. In this study, demineralization and modification by adding citric acid (1.5 M and 2 M) of corn stalk were conducted to convert hydroxyl groups into carboxylic. Then, it was analyzed its functional groups using Boehm titration and FTIR. The modified corn stalk was applied directly to chemical laboratory liquid waste which contains multicomponent of heavy metal ions. By modifying the corn stalk, the number of hydroxyl and carboxylic groups increased, but the number of lactone group was constant. The success of the modification was characterized by the appearance of ester uptake at 1734 cm-1 and increased adsorption ability. The variations in the concentration of citric acid in modification corn stalk showed that biosorbent with addition 1.5 M citric acid had higher in the number of acid site than addition 2 M citric acid to absorb Ni and Cu. Keywords: Corn stalk, citric acid, biosorbent, functional group Batang jagung mengandung sekitar 40-50% selulosa, 20-40% hemiselulosa, 4-15% lignin yang berpotensi sebagai biosorben pengikat ion logam. Pada penelitian ini dilakukan demineralisasi dan modifikasi dengan penambahan asam sitrat (1,5 M dan 2 M) untuk mengubah gugus hidroksil pada selulosa membentuk karboksilat. Selanjutnya, dianalisis gugus fungsinya menggunakan titrasi Boehm dan FTIR. Hasil modifikasi diaplikasikan langsung pada limbah cair laboratorium kimia yang mengandung banyak jenis ion logam berat. Biosorben batang jagung setelah dimodifikasi mengalami peningkatan jumlah gugus fungsi hidroksil dan karboksilat, tetapi gugus lakton tetap. Keberhasilan modifikasi ditandai dengan munculnya serapan ester pada 1734 cm-1 dan peningkatan kemampuan adsorpsi. Dari hasil variasi konsentrasi asam sitrat diperoleh informasi bahwa biosorben dengan penambahan asam sitrat 1,5 M mempunyai situs asam lebih tinggi dan mempunyai kemampuan adsorpsi terhadap ion logam Ni dan Cu lebih besar dibanding penambahan asam sitrat 2 M. Kata kunci: Batang jagung, asam sitrat, biosorben, gugus fungsi

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Sesquiterpene Lactones fromArtemisiaGenus: Biological Activities and Methods of Analysis

Journal of Analytical Methods in Chemistry ◽

10.1155/2015/247685 ◽

2015 ◽

Vol 2015 ◽

pp. 1-21 ◽

Cited By ~ 43

Author(s):

Bianca Ivanescu ◽

Anca Miron ◽

Andreia Corciova

Keyword(s):

Michael Addition ◽

Biological Activities ◽

Sesquiterpene Lactones ◽

Optimal Conditions ◽

Amino Groups ◽

Extraction And Separation ◽

Wide Range ◽

Lactone Group ◽

Problematic Aspect ◽

Identification And Quantification

Sesquiterpene lactones are a large group of natural compounds, found primarily in plants ofAsteraceaefamily, with over 5000 structures reported to date. Within this family, genusArtemisiais very well represented, having approximately 500 species characterized by the presence of eudesmanolides and guaianolides, especially highly oxygenated ones, and rarely of germacranolides. Sesquiterpene lactones exhibit a wide range of biological activities, such as antitumor, anti-inflammatory, analgesic, antiulcer, antibacterial, antifungal, antiviral, antiparasitic, and insect deterrent. Many of the biological activities are attributed to theα-methylene-γ-lactone group in their molecule which reacts through a Michael-addition with free sulfhydryl or amino groups in proteins and alkylates them. Due to the fact that most sesquiterpene lactones are thermolabile, less volatile compounds, they present no specific chromophores in the molecule and are sensitive to acidic and basic mediums, and their identification and quantification represent a difficult task for the analyst. Another problematic aspect is represented by the complexity of vegetal samples, which may contain compounds that can interfere with the analysis. Therefore, this paper proposes an overview of the methods used for the identification and quantification of sesquiterpene lactones found inArtemisiagenus, as well as the optimal conditions for their extraction and separation.

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New Drugs from Old Natural Compounds: Scarcely Investigated Sesquiterpenes as New Possible Therapeutic Agents

Current Medicinal Chemistry ◽

10.2174/0929867324666170404150351 ◽

2018 ◽

Vol 25 (10) ◽

pp. 1241-1258 ◽

Cited By ~ 18

Author(s):

Stefania Sut ◽

Filippo Maggi ◽

Marcello Nicoletti ◽

Valeria Baldan ◽

Stefano Dall`Acqua

Keyword(s):

Biological Effects ◽

Sesquiterpene Lactones ◽

Therapeutic Agents ◽

New Drugs ◽

In Vivo Studies ◽

Bicyclic Compounds ◽

Lactone Group ◽

Future Potential ◽

Cancer And Inflammation

Sesquiterpenes are natural products that have been extensively studied for their bioactivities, evidencing their potentiality as useful scaffolds for the development of drugs. Considering the different derivatives, the sesquiterpene lactones have been evaluated, especially on cancer cell and antineoplastic efficacy in in vivo studies. Their bioactivity is strictly related to the presence of the reactive α-methylene-γ-lactone group (αMγL). Nevertheless, several other sesquiterpenes lacking αMγL are known and have been studied for their biological effects and potential usefulness in the development of new drugs. In this review, we focused on several sesquiterpenes that are not presenting the αMγL moiety and may have future potential as scaffold for the development of new drugs, namely the bicyclic compounds belonging to the carotane type (daucanes) that present significant effects as antiproliferative and estrogenic agents. The monocyclic humulane derivatives correlated to zerumbone, and the bicyclic compound beta-caryophyllene and its derivatives that have been considered in the field of cancer and inflammation. It is noteworthy that published studies on sesquiterpenes, reported in this review, focus on pathologies of increasing importance, like estrogen, anti-proliferative, bone loss, immunity deficiency and anti-tumour activities. Some of the natural “old” sesquiterpenes can be considered for their possible role in drug discovery and in counteracting these “new” challenges.

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A new interpretation of the Acidic and Basic structures in Carbons. I. Lactone groups of the ordinary and fluorescein types in carbons

Australian Journal of Chemistry ◽

10.1071/ch9570295 ◽

1957 ◽

Vol 10 (3) ◽

pp. 295 ◽

Cited By ~ 87

Author(s):

VA Garten ◽

DE Weiss ◽

JB Willis

Keyword(s):

Carbon Black ◽

Hydroxyl Groups ◽

Dilute Acid ◽

Carboxylic Ester ◽

Titration Curves ◽

Infra Red ◽

Lactone Group ◽

Phenolic Hydroxyl Groups ◽

Effects Of Temperature ◽

New Interpretation

Methylation of a sugar carbon or carbon black with diazomethane produces a methoxyl group which is readily hydrolysed by dilute acid but which is not due to the presence of a simple carboxylic ester, since the titration curves of the carbons are those of much weaker acids. It most probably arises from the methylation of a lactone which is present in conjunction with a phenol, such as occurs in the fluorescein and phthalein dyestuffs. This, however, accounts for only part of the acidity of the carbons, some of which is due to a group which reacts with alkali but not with diazomethane and is probably a normal lactone group. The remainder of the acidity of the carbons is due to phenolic hydroxyl groups. Infra-red spectroscopic evidence is presented in support of these views. The effects of temperature and of oxidation on the concentration of these various groups have also been studied.

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