My name is Joey Li, and I am volunteering in the John L. Holmes Mass Spectrometry Facility in summer of 2024. I just finished my first year of Biomedical Science at the University of Ottawa, and I am going into my second year in September 2024. I volunteered in this lab with the goal of gaining more experience in the field of chemistry and getting an insight into research. My ultimate goal is to get admitted to medical school, where I wish to specialize in rheumatology so I can help improve the lives of those unfortunate enough to be diagnosed with autoimmune conditions. Volunteering in this lab not only allowed me to apply the skills I have learned in my first-year chemistry classes, but also allowed me to explore the diverse world of mass spectrometry and its vast range of applications in science research. Throughout the course of the summer, I learned how to prepare and analyze samples, identify and quantify different compounds in the samples using both the GC-MS and LC-MS, and the fascinating ways in which mass spectrometry instrumentation works
 

The name “turmeric” has multiple pronunciations. According to the Merriam-Webster dictionary, the original pronunciation emphasizes the first “R,” resulting in the pronunciation ‘tər-mə-rik. Nevertheless, due to many people omitting this “R,” a newly accepted pronunciation is ‘tü-mə-rik. The British pronunciation puts additional emphasis on the “U,” resulting in the pronunciation ‘tyü-mə-rik.

https://dictionary.cambridge.org/us/pronunciation/english/turmeric

The original objective of this study was to examine the abundance of the molecule curcumin in different extraction solvents. Curcumin is reported to be the most abundant molecule in turmeric and is responsible for its bright orange colour. Many studies show the anti-inflammatory effects of curcumin. Due to the extensive research on curcumin, the study was redirected to focus on a different set of molecules. The new objective still involved the comparison of molecule abundance; however, this time the focus was on different sources of turmeric and a different series of molecules known as turmerones

Each source of turmeric was extracted in acetonitrile, ethanol, hexanes, and ethyl acetate. The extracted samples were analyzed using the GC-MS, with two trials run on each sample. Initially, the starting temperature was set to 40°C, and the final temperature was set to 320°C, with increments of 20°C per minute. This produced chromatograms that were very condensed, so the initial and final temperatures were then set to 100°C and 250°C respectively, along with increments of 10°C per minute for the second trial. Fresh ginger, being a close relative of turmeric, was also analyzed using the same method. However, the results were irrelevant to the pattern found between the turmeric samples.

Fresh Turmeric Results Each of the four solvents used yielded roughly the same results. However, it is noteworthy that the hexane extraction is missing quite a few more peaks overall compared to the other solvents. The ethyl acetate extraction brings out all the peaks found in other solvents, while also showing an extra peak with a retention index of 1243. The ethyl acetate extraction contains everything from the other extractions as well as a few more molecules, so the focus of this section will be on that extraction. The table here lists all the identified compounds, along with their retention times and percent abundances. Since the mass of the turmeric sample was not measured for the extractions, the concentration cannot be quantified. The GC identified the presence of R-carvone with high confidence. However, carvone is not typically found in turmeric and was not found in any other samples. Cross-contamination was not possible, as the acetonitrile, ethanol, and hexane extractions were run before the ethyl acetate extraction. If carvone was present, it would have been identified in all fresh turmeric extracts. Vanillin is found in turmeric in very small amounts in all extracts of fresh turmeric. 

Three molecules stood out in all fresh turmeric extracts. These molecules are ar-turmerone, α-turmerone, and β-turmerone. α-turmerone can simply be referred to as turmerone, while a more common name for βturmerone is curlone. In the ethyl acetate extract for fresh turmeric, the percent abundances for arturmerone, α-turmerone, and β-turmerone were 21.26%, 20.56%, and 15.00%, respectively.

The image here shows the structure of each form of turmerone, as well as their mass spectra identified by the GC and their retention indices found in the NIST Chemistry Webbook. Since α-turmerone and βturmerone have one fewer double bond than ar-turmerone, they have a molecular weight of 218 as opposed to 216. According to the National Institutes of Health, ar-turmerone has neuroprotective effects, is an antioxidant, and decreases inflammation. α-turmerone is antimicrobial and also works as an anti-inflammatory but works through a different pathway and is less potent due to its lower stability than ar-turmerone. β

This graph shows the effect of aromatic-turmerone on the inflammatory response in microglial cells in mice. Aβ 1-42 induces the release of pro-inflammatory cytokines, thereby reducing cell viability. Treatment with ar-turmerone helped to offset the damage done by inflammatory cytokines and increase the cell’s viability. One criticism of the study that I may add is related to the experimental setup. Two groups were set in this study, one treated with only ar-turmerone and the other treated with both ar-turmerone and Aβ 1-42. This setup was intended to demonstrate the effect of ar-turmerone on cell viability. However, a more effective setup for this study would be to include a control group treated with only Aβ 1-42 and an experiment group treated with both ar-turmerone and Aβ 1-42. This would help demonstrate that ar-tumerone increases cell viability relative to the group treated with only Aβ 1-42.

Other notable differences were in the presence of molecules that were found in the fresh turmeric. This time, no carvone was observed, which was expected. The store-bought turmeric powder also lacks vanillin and linoleic acid. In place of linoleic acid, hexadecanoic acid is present in the turmeric powder. Both molecules have 32 hydrogens and 2 oxygens, but hexadecanoic acid has 2 fewer carbons than linoleic acid.

While both fresh turmeric and turmeric powder contain significant amount of α-turmerone, no trace of α-turmerone was found in the turmeric capsules. Instead, nearly half of the capsule is composed of ar-turmerone, which accounts for 46.68%. β-turmerone is still present in the turmeric capsules, with the lowest percent abundance of all three turmeric sources at 10.76%. Other notable differences in the turmeric capsules include the absence of zingiberene and the presence of octadecanoic acid

Why Do We See This Trend? An explanation for the higher abundance of ar-turmerone in processed sources of turmeric is the extraction process. In the extraction process, chemical stability is a crucial factor that affects the amount of a chemical in the extract. Ar-turmerone’s complete benzene ring provides it with much greater stability than α-turmerone, allowing it to remain intact and retain its bioactivity throughout the extraction process while also being less affected by storage conditions. Another explanation for the higher abundance of ar-turmerone is that it is a major part of turmeric essential oil and is generally present in higher concentrations than α-turmerone. Because of this, it is not surprising that an extraction would yield a higher proportion of ar-turmerone. A third explanation for the higher relative abundance of ar-turmerone relates to its superior health benefits over α-turmerone. In other words, the company may be purposely seeking to attain higher concentrations of ar-turmerone so that people can benefit from its effects. Refer to the graph shown earlier on the effects of Aβ 1-42 on cell viability in the presence of ar-turmerone. According to the same study, ar-turmerone’s superior stability allows it to bind to and inhibit more pro-inflammatory cytokines at a given moment in time compared to alpha-turmerone, making it a more effective anti-inflammatory molecule.