Dimethylthiophene Research Articles

Ethnomedicinal and traditional application of Allium wallichii Kunth (Himalayan Onion): An unexplored and underutilized nutraceutical plant foods from Himalayan regions.

Background: Allium wallichii Kunth (Family: Amaryllidaceae), commonly known as “Himalayan onion” is well recorded as popular ethnomedicine for medicinal and nutritional uses by different people and communities native to Bhutan, India, Myanmar, Nepal and Southwestern China. Methods: Despite the wide ethnomedicinal and pharmacological studies on A. wallichii, there are no concise elaborated article comprising reviews of published literature. So, herein we designed this review article to discuss the potential health benefit in both traditional ethnopharmacology and modern pharmacology. To achieve this exhaustive literature searches using A. wallichii as keywords for screening of relevant information online databases such as Google Scholar, PubMed, Science Direct, SciELO, Scopus and SpringerLink were performed. Results: Only few published studies relevant to our objective was found and presented under different section of the current work. It was observed that different parts of A. wallichii was recorded in different regions of the Asia for health, economical and nutraceutical benefits such as dysentery, cholera, cold, cough, blood cholesterol levels, itching, to remove maggots from wounds, leech remover, antidote, cut, wounds (finger and toe infections), gastric problems, bile complaints, moth repellent, bodyache, sinusitis, carminative, dizziness, mumps, hypertension, intestinal pain, liver diseases, indigestion for children, high altitude sickness, condiment for curries, pickles, soup and vegetable source for cash income. Major bioactive phytochemicals such as 1,2 bis (methylthio) ethene, diosgenin, 2,4 dimethyl thiophene, tigogenin, dimethyl disulfide and trisulfide were reported. However, in modern pharmacology anti-microbial, antioxidant, and anti-cancer activities was established. Conclusion: It was concluded that A. wallichii need special attention for protected cultivation and conservation in near future for maximum output and utilization are required. Moreover, A. wallichii could be considered as an excellent source of safe and effective medicinal and nutritional herbal remedies for human and animal consumption after only careful investigation. Keywords: Allium wallichii, Himalayan onion, Nutraceuticals, Anti-cancer

Thermodynamic research on the effect of H2O on transformation of organic sulphur during coal pyrolysis under CO2 atmosphere

This study investigates the effect of H2O on transformation of organic sulphur in coal during CO2 atmospheres by thermodynamic equilibrium calculation by HSC Chemistry. The effect of water vapour on the release of sulphur containing compounds was studied. Detailed S distribution between 200-1400°C was explored. The results show that CO2 not only promotes the formation of inorganic compounds, but also moves the peak of released less complicated organic compounds such as Thiophene, Methylthiophene, Dimethylthiophene, etc. to a much lower temperature. The ranking of the sulphur release in CO2 atmosphere by HSC is: SO2 > Methyl thiophene > Dimethyl thiophene > Ethyl thiophene > dimethyl sulfone. Temperature affects the transformation of sulphur greatly during pyrolysis in CO2 atmosphere. Below 700 °C, COS and H2S are two major sulphur containing compounds formed during pyrolysis in CO2. Above 700 °C, SO2 plays the main role. H2O at different temperature range during heating also reacts with organic sulphur compounds, leading to a further decomposition. Since more organic S stays in inert gas, water promotes the decomposition of organic S compounds more intense than that in CO2 atmosphere. Besides, the effect of water vapour on S distribution depends on the amount of H2O in the reaction.

Effect of freeze dried, hot air dried and fresh onions on the composition of volatile sulfocompounds in onion oils

The bioactivity of onion, particularly its oil, has gained increasing research attention. Preparation of onion oil is challenging due to its low oil content and abundance of water. In this study, pilot-scale drying combined with laboratory extraction was conducted for sample preparation. GC/MS and solid phase microextraction (SPME) analyses were performed to evaluate the correlation between onion oil and drying. Results showed that drying significantly influenced the sulfocompounds composition of onion oils. Dipropyl disulfide and dispropyl trisulfide were the most abundant compounds in fresh onions (accounting for 68.41% to 93.13% of the total volatile sulfocompounds). The total contents of sulfocompounds in vacuum freeze dried and hot air dried onion powder were 4.96% and 39.79%, respectively, which account for 24.59% to 48.89% of the total content. Dimethyl sulfides and thiophenes were the main compounds in the onion oils. The highest content of sulfocompounds was obtained in the oil of hot air dried powder. Pilot-scale hot air drying was the optimal pretreatment method for onion oil extraction. It enjoys lower energy lost, shorter process time, and higher quality of the oil compared with freeze drying. The results may be helpful for onion oil production and bioactivity evaluation.

Selectivity of Adsorption of Thiophene and its Derivatives on Titania Anatase Surfaces: A Density Functional Theory Study

We used density functional theory calculations to examine the adsorption of thiophene and its derivatives (methyl and dimethyl thiophenes) on the (001), (101) and (100) surfaces of titania anatase, of relevance to adsorptive desulfurization of liquid fuels. The adsorption of isomers of methyl and dimethyl thiophenes allows evaluation of electronic, steric hindrance and dispersive attraction impacts on adsorption energies. Adsorption of all species is found to preferentially form a sulfone-like species, where the sulfur containing molecule is partially oxidized on the surface. Oxygen molecules trapped in O-vacancies may serve as the preferred adsorption site for sulfoxide formation. Comparison is made between DFT and DFT-D results, which include a semi-empirical dispersion correction. DFT-D gives a more accurate representation of the interactions between the adsorbate (thiophene) molecules and the adsorbent (anatase) surface. The selectivity of different surfaces towards sulfur-containing molecules is estimated by comparing the adsorption energies of the thiophenes and their corresponding hydrocarbons.

Etudes photochimiques—III : Photochimie du thiophene

Thiophene, methyl and dimethyl thiophenes on irradiation in a primary amine yield pyrroles. A mechanism in which the first step is the formation of a thioketone or of a thioaldehyde is postulated by analogy with furan photochemistry.