Location: Bio-oils ResearchTitle: Synthesis of Lesquerella-based bisphosphonates
|BOON, LAURALEE - Knox College
|BAMERT, SIERRA - Knox College
|FAYER, EFFRAT - Knox College
|COLEY, CHELSEA - Knox College
|HENRY, SHANNON - Knox College
|CERMAK, DIANA - Knox College
|Cermak, Steven - Steve
Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/3/2023
Publication Date: N/A
Interpretive Summary: Castor oil, which is obtained from castor seeds usually imported from India, serves as the main U.S. source of hydroxy fatty acids (HFA) or ricinoleic acid. HFA has been isolated and modified extensively for several applications ranging from industrial materials to pharmaceuticals. Unfortunately, castor seeds also contain several undesirable compounds which pose severe health risks, including ricin, an unusually stable, deadly protein; ricinine, a poisonous alkaloid; and several other allergens. The structural and chemical similarity of the primary HFA found in lesquerella, a U.S. crop, suggests that lesquerella oil and its derivatives may function as a competitive alternative to castor oil. Unfortunately, there is a significant difference in desired HFA abundance in lesquerella oil (50%) than castor oil (90%), requiring more extensive purification measures and careful identification of the correct components of lesquerella. In this research, we report the purification and synthesis, in high yields and high purity, of the desired HFA in lesquerella. This work is significant because it opens the potential for HFA from lesquerella to function effectively and replace the use of castor oil in a wide variety of biological activities, such as enzyme inhibitors, pesticides, antibiotics, and anti-cancer therapeutics.
Technical Abstract: Hydroxy fatty acids (HFAs) have found several uses in today’s market, with uses ranging from industrial materials to pharmaceuticals. Castor oil, which is obtained from castor seeds, has served as a primary source of the most common HFA, ricinoleic acid, the only HFA available in large enough quantity for commercial use. Unfortunately, castor seeds also contain several undesirable compounds which pose severe health risks, including ricin, an unusually stable, deadly protein; ricinine, a poisonous alkaloid; and several allergens. Lesquerella oil, obtained from seeds of the Lesquerella fendleri species, has been identified as the most promising alternative source of HFAs. Lesquerella oil is mainly comprised of lesquerolic acid, an HFA that is most homologous to ricinoleic acid; the only structural difference between the two is that lesquerolic acid possesses two additional methylene groups on the carboxyl end of the molecule. This structural and chemical similarity further suggests that lesquerella oil and its derivatives may function as a competitive alternative to castor oil. Unfortunately, the desired HFA, lesquerolic acid, constitutes approximately 55% of lesquerella oil whereas castor oil contains approximately 90% of the desired HFA. This difference in desired HFA abundance in lesquerella oil required more extensive purification measures and careful identification of the correct component. Additionally, the bisphosphonate moiety has been shown to display a wide variety of biological activities, primarily as osteoporosis drugs and anti-cancer therapeutics. We previously reported the synthesis of two families of alpha-hydroxy phosphonic acids based on ricinoleic acid and lesquerolic acid: a family that retains the cis alkene found in the HFA and one where the alkene has undergone hydrogenation to produce a saturated alpha-hydroxy phosphonic acid. We now report the synthesis of lesquerella-based bisphosphonates, both the unsaturated and saturated series. The lesquerolic acid-based compounds have been produced in high yields and high purity, and the synthesis of these compounds is reported in this manuscript.