- Synthesis, antimicrobial activity and in silico studies on thymol esters
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Derivatisation of parent structure in terpenoids often results in enhancement of biological activity of newly obtained compounds. Thymol, a naturally occurring phenol biosynthesized through the terpene pathway, is a well known biocide with strong antimicrobial attributes and diverse therapeutic activities. We have aimed our study on a single modification of phenolic functionality in thymol in order to obtain a small focused library of twenty thymyl esters, ten of which were new compounds. All compounds were involved in in vitro antimicrobial testing. Another important aspect of current study was implementation of in silico calculation of physico-chemical, pharmacokinetic and toxicological properties, which could be helpful by giving an additional guidance in further research.
- Lazarevi?, Jelena,Kolarevi?, Ana,Dordevi?, Aleksandra,Stojanovi?, Gordana,?melcerovi?, Andrija,Ciuffreda, Pierangela,Santaniello, Enzo
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p. 603 - 612
(2017/09/11)
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- Antinociceptive effect of extracts and compounds from Hofmeisteria schaffneri
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Ethnopharmacological relevance: Hofmeisteria schaffneri (Asteraceae) is a medicinal plant widely commercialized in the most important Markets of Mexico City for the treatment of gastro-intestinal complaints and skin afflictions. Aim of the study: The main goals of this study were to establish the potential acute toxicity and the antinociceptive activity in animal models of several preparations and compounds from Hofmeisteria schaffneri. Materials and methods: The aqueous and organic extracts as well as the essential oil of Hofmeisteria schaffneri were prepared by infusion, maceration and hydrodistillation, respectively. Investigation of the acute toxicity was accomplished by the Lorke method. The antinociceptive effect was assessed using the writhing and the hot plate tests. Natural compounds were isolated by standard phytochemical procedures. In addition, a few thymol esters were prepared by chemical synthesis. The stability of natural and synthetic esters was qualitatively analyzed by measuring their susceptibility to hydrolysis by pig liver estearase and mouse plasma at 37°C. Results: The LD50 for each preparation tested was higher than 5000mg/kg revealing that they were not toxic to mice after exposure for short space of time. On the other hand, the extracts showed significant antinociceptive effect when tested in the hot plate model. The most active natural product as antinociceptive agent was hofmeisterin III (1) which also was the most stable in the stability study. Its pharmacological effect seems to be partially mediated by an opioid mechanism since naloxone inhibits its action. Using compound 1 as a lead molecule, several synthetic thymol esters were prepared and only compounds 13, 15 and 17 were antinoceptive at the dose of 1mg/kg. Conclusions: The present investigation provided evidence of the efficacy of several preparations of Hofmeisteria schaffneri as antinociceptive agents. The most active preparation was the essential oil which contained large amount of hofmeisterin III (1) and other thymol derivatives. Some novel synthetic analogs of hofmeisterin III with antinociceptive properties were discovered. The nature of the ester chain of these analogs did not have a clear impact on the antinociceptive activity. The phyto-preparations analyzed in this study were not toxic to mice according to the Lorke's test; therefore considering their long term use of the plant they might be secure for human consumption.
- Angeles-Lopez, Guadalupe,Perez-Vasquez, Araceli,Hernandez-Luis, Francisco,Deciga-Campos, Myrna,Bye, Robert,Linares, Edelmira,Mata, Rachel
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p. 425 - 432
(2011/11/14)
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- Synthesis and in vitro antibacterial activity of thymol and carvacrol derivatives
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Fourteen esters of thymol and carvacrol were synthesized and characterized on the basis of spectral data. The NMR data for some of these are being given for the first time. The antibacterial activity screening of thymol, carvacrol and their esters were carried out against four Gram-positive (Streptococcus mutans MTCC 890, Staphylococcus aureus MTCC 96, Bacillus subtilis MTCC 121, Staphylococcus epidermidis MTCC 435) and one Gram-negative (Escherichia coli MTCC 723) bacteria. The enhancement in activity was noticed in the thymyl ester derivatives 4a-c (against S. mutans, B. subtilis and S. epidermidis) in comparison to thymol, whereas the carvacrol derivatives were found to be much less active than carvacrol.
- Mathela, Chandra S.,Singh, Krishna K.,Gupta, Vivek K.
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experimental part
p. 375 - 380
(2011/08/06)
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- Chemical composition of Inula cuspidata C.B. Clarke
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Thymyl isobutyrate, thymol, thymyl isovalerate, 8α-hydroxy presilphiperfolene and intermedeol have been isolated from steam volatile extract of Inula cuspidata and identified from their spectral data, synthesis and chemical modification of major constituents. Sharp qualitative and quantitative variations among the constituents of leaf, flower and roots of Inula cuspidata are noticed.
- Mathela,Tiwari,Padalia,Chanotiya
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p. 1249 - 1253
(2008/12/23)
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