One chromatographic tool with Sephadex G-10 for green chemistry screening of extracts from Nicotiana glauca Graham

Introduction.

Sephadex G-10 resin is a polymeric network composed of dextran units cross-linked by epichlorohydrin. Its physicochemical properties make it an excellent stationary phase for size-exclusion chromatography. This material allows to use physiological solutions (Krebs’, Tyrode’s, Locke’s… For example, Krebs-HEPES) as mobile phases.

In organic chemistry and pharmacology, the real-time monitoring of natural products is very important in the chemical and biological characterization of active compounds of extracts from living organisms. One example is the direct coupling chromatographic separation of organic extracts to study living tissues or organs.

Methods.

Size-exclusion chromatographic separation with Sephadex G-10 was carried out: medium-pressure liquid chromatography separation (MPLC) coupled directly to biological detection using perfused organs was used for chemical study of hydro-ethanolic extracts from Nicotiana glauca Graham (Solanaceae). The elution medium was Krebs-HEPES (a physiological solution). Perfused rings or portions of organs from the rat were employed: aorta artery, trachea, deferent conduct and ileum.

The chemical characterization of the separated and isolated compounds was realized by mass spectrometry analysis and infrared spectroscopy.

Results.

This type of pore size in Sephadex G-10 allows the lowest fractionation range (substance with molecular weight is below 700 Da (or g/mol), normally around 100-1000 Da. For this reason, anabasine (162.23 Da of molecular weight, MW) and nornicotine (MW: 148.21 Da) were isolated and identified as compounds responsible for contractile actions in smooth muscle of rat ileum and trachea.

This application of Sephadex G-10 separation could be carried out by a single person, with non-contaminating mediums, reducing time and cost of research, and minimizing the number of animals slaughtered.

Conclusions.

The application of Sephadex G-10 chromatography simplifies and rationalizes the bio-guided isolation and identification of natural products, positioning this approach within the framework of green chemistry dereplication methodologies and paving the way for future automated or robotic platforms.