<p style="text-indent:0px; line-height:12px;"><span style="font-weight:bold;line-height:130%"> Wako, Japan</span><hr class="legacyRuler"><hr class="legacyRuler"><hr class="invisible minimal-padding">By ANUK Staff<hr class="legacyRuler"><hr class="legacyRuler"><hr class="invisible minimal-padding">5.6.13</p><hr class="legacyRuler"><hr class="invisible minimal-padding"><p>Researchers from the RIKEN Plant Science Center have profiled the sulfur-containing compounds in onion extracts in an attempt to identify beneficial plant compounds. Kazuki Saito, Ryo Nakabayashi and colleagues developed a technique to rapidly catalog subsets of compounds in plant extracts based on mass spectrometry data as a first step toward a fully automated system for cataloging novel plant compounds.<hr class="legacyRuler"><hr class="legacyRuler"><hr class="invisible minimal-padding"><img src="https://cdn.andnowuknow.com/legacyWriterImages/riken050613body.jpg" alt="IMAGES 050313" /><hr class="legacyRuler"><hr class="legacyRuler"><hr class="invisible minimal-padding">Saito and his team profiled sulfur-containing compounds in onion extracts. The compounds produce a pair of peaks in the mass spectrum — one 20 times stronger than the other — associated with the ratio of the two most common naturally occurring isotopes of the sulfur atom. Saito and his colleagues were able to identify 67 sulfur-containing ions in the onion extract. Then, using isotope chemistry, they were able to establish the number of carbon atoms in each structure.<hr class="legacyRuler"><hr class="legacyRuler"><hr class="invisible minimal-padding">The researchers analyzed extracts from two sets of onions: one grown under a normal atmosphere, and another grown under an atmosphere in which the carbon in CO2 was replaced with the heavier carbon isotope, carbon-13.<hr class="legacyRuler"><hr class="legacyRuler"><hr class="invisible minimal-padding">Mass spectrometry is a powerful tool for identifying unknown compounds, as those which contain certain heteroatoms such as oxygen, nitrogen and sulfur produce a spectral fingerprint. Saito and his team hypothesized that this characteristic could be exploited to quickly catalog compounds in plant extracts.<hr class="legacyRuler"><hr class="legacyRuler"><hr class="invisible minimal-padding">By measuring how much heavier a plant compound was when formed from carbon-13, the researchers could calculate its carbon count and so determine its complete atomic make-up. In a final step, the team established the full chemical structure of some of the sulfur-containing compounds by comparing their data with that of known compounds.<hr class="legacyRuler"><hr class="legacyRuler"><hr class="invisible minimal-padding">“We are now planning to develop an automated structural assignment system,” says Nakabayashi. The researchers hope to automate this time-consuming process by incorporating an additional analysis technique called nuclear magnetic resonance (NMR), developing a database of high-quality mass spectrometry and NMR reference data, and establishing a computational algorithm for checking each compound against this database to establish its chemical structure.<hr class="legacyRuler"><hr class="legacyRuler"><hr class="invisible minimal-padding"><a class="btn btn-sm btn-primary col-lg-12" style="white-space: normal;" href=" http://www.rikenresearch.riken.jp/eng/research/7270.html" target="_new">Onion Report</a></p><hr class="legacyRuler"><hr class="invisible minimal-padding">
