Biological activity and safety profile of the essential oil from fruits of Heracleum mantegazzianum Sommier & Levier (Apiaceae).

A composition of essential oils obtained from Heracleum mantegazzianum (Apiaceae) was examined using a GC-MS method. n-Octyl acetate (19.92%), n-hexyl-2-methylbutanoate (10.84%), n-octanol (10.13%), n-octyl butanoate (8.88%), n-octyl-2-methylbutanoate (8.01%), n-hexyl acetate (7.11%), n-octyl isobutanoate (5.5%) and n-hexyl isobutanoate (5.43%) were the main compounds. The high-performance counter-current chromatography was applied for purification of aliphatic alcohols and esters. A mixture of n-hexane, acetonitrile and tetr-butyl methyl ether (1:1:0.1, v/v) allowed to obtain n-octanol, n-octyl acetate, n-hexyl-2- methylbutanoate, n-octyl isobutanoate and n-octyl-2-methylbutanoate, with the purity range of 94-99%, in one single 74 min run. The antimicrobial activity was also determined against plant and foodborne pathogens. While n-octanol shares responsibility for the antibacterial activity of the essential oil, n-octyl acetate determines its antifungal action. The cytotoxic activity assessed on two normal kidney fibroblast cell lines: Vero (animal) and HEK-293 (human embryonic), and two human cancer cell lines: FaDu (squamous cell carcinoma of the pharynx) and SCC25 (squamous cell carcinoma of the tongue), showed a moderate cytotoxicity with CC50 values ranging from 262.3 to 567.8 µg/mL. Results indicate that normal cell lines were more sensitive to the tested essential oil than cancer cell lines. The antioxidant activity of oil and pure compounds was not significant.

Performance of permethyl pillar[5]arene stationary phase for high-resolution gas chromatography.

This work presents the investigation of permethyl pillar[5]arene (MP5) as stationary phase for capillary gas chromatographic (GC) separations. The MP5 capillary column fabricated by the sol-gel coating method exhibited weak polarity and high column efficiency over 4200 plates/m for n-dodecane, n-octanol and naphthalene. Particularly, the MP5 stationary phase displays unique retention for dibromoalkanes, which was found to be closely related with the linker length, and shows high resolving capability for a wide range of positional and structural isomers, including alkylbenzenes, chlorobenzenes and chloronitrobenzenes, naphthalene derivatives, phenols and anilines. Moreover, the MP5 column showed good thermal stability and repeatability and reproducibility with the relative standard deviation in the range of 0.02-0.04% for intra-day, 0.32-0.46% for inter-day and 1.5-3.4% for between-column, respectively. This work demonstrates an promising future of pillar[n]arenes as a new type of stationary phase in chromatographic separations.

Evaluation of 1-octanol degradation by photocatalysis and ultrasound using SPME.

Solid-phase micro-extraction has been used for identifying, quantifying and following the evolution of intermediate products of octanol degradation by two advanced oxidation treatments (AOTs), photocatalytic and ultrasound processes, inducing mainly the same active species. Headspace extraction enabled direct extraction of the organic compounds in a heterogeneous process like photocatalysis. The presence of a solid does not affect the extraction percentage of alkanes, alkenes and aldehydes while alcohols and carboxylic acids are not completely extracted if the extraction time is too short. To extract C3-C8 alkanes, alkenes and aldehydes a Carboxen/PDMS fiber and an extraction time of 25 min are used. The presence of alcohol and carboxylic acids requires the use of the presence of salt under acidic conditions, a longer extraction time and a polyacrylate fiber (PA), having a polar fiber. The in situ derivatization--pyrenyldiazomethane on a PA fiber--increases the carboxylic acid extraction containing smaller hydrocarboned chain while diazomethane derivatization is not as efficient due to its volatility. Whatever be the treatment, photocatalysis or ultrasound processes, aldehydes are the main intermediate products, which is not surprising since the same oxidation species (HO2(o), O2(o-), OH(o)) are formed. Alkanes and alkenes are also detected in both processes; however, alkane formation is more important in photocatalysis while alkenes are formed in higher amounts by ultrasound. Moreover, the presence of carboxylic acids in more important amounts by ultrasound than by photocatalysis is attributed to the presence of holes (h+) in photocatalysis which induces photo-Kolbe degradation. The sonochemical formation of small-chained dienes and alkynes is probably due to pyrolysis of hydrophobic compounds in cavitation bubbles.

MRI study of non-aqueous phase liquid extraction from porous media.

Magnetic resonance imaging is used to investigate, at the pore scale, the dissolution and mobilisation of discrete non-aqueous phase liquid (octanol) ganglia trapped within porous media by capillary forces, by a mobile aqueous phase. Dissolution is observed to be described by a mass-transfer limited model. Mobilisation of entrapped ganglia commences at lower flowrates when a surfactant is introduced into the mobile aqueous phase.