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Alpha Lipoic Acid. The Ultimate Antioxidant. Identity & Structure. “ Thioctic acid” “ Lipolate ” ( F or you IUPAC nerdies ): (R/S)-5-(1,2-dithiolan-3-yl) pentanoic acid . R-Alpha. S-Alpha. Dihydro -. Lipoic Acid. Lipoic Acid. Lipoic Acid.
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Alpha Lipoic Acid The Ultimate Antioxidant
Identity & Structure • “Thioctic acid” • “Lipolate” • (For you IUPAC nerdies): (R/S)-5-(1,2-dithiolan-3-yl)pentanoic acid R-Alpha S-Alpha Dihydro- Lipoic Acid Lipoic Acid Lipoic Acid Alpha Lipoic Acid. University of Maryland Medical Center. https://umm.edu/health/ medical/altmed/supplement/alphalipoic-acid. Maldonado-Rojas, W.; Olivero-Verbel, J.; Ortega-Zuniga, C.; J. Braz. Chem. Soc. 2011, 22(12), 2250-2259.
Function: Antioxidant • “The Ultimate Antioxidant” • Both water- and fat- soluble • Multiple radical-fighting powers Antioxidant ROS Metal Antioxidant Scavenger Recycler Chelate Directly Removes Free Radicals Inhibits Free Rad. Generation Re-enables Used Antioxidants Rochette, L.; Ghibu, S.; Richard, C.; Zeller, M.; Cottin, Y.; Vergely, C. Molecular Nutrition and Food Research. 2013, 57(1), 114-125. Lipoic Acid. Linus Pauling Institute. Oregon State University. http://lpi.oregonstate.edu/ infocenter/othernuts/la/index.html#safety(accessed March 2, 2014).
Function: Enzyme Cofactor • Biologically active R- enantiomer binds to a specific lysine residue. • Example: Stimulation of glucose metabolism via insulin-signaling pathway. • Effective treatment for type 2 Diabetes. Lysine Residue R-Alpha Lipoic Acid Lipoic Acid. Linus Pauling Institute. Oregon State University. http://lpi.oregonstate.edu/ infocenter/othernuts/la/index.html#safety. Ziegler D. Treatments in Endocrinology. 2004, 3(3), 173-189.
Recommended Amounts • No established dosage recommendations or upper limit. • No adverse side effects. • Generally, 20-50 mg daily for antioxidant support. Eat all the vitamins! Alpha Lipoic Acid. University of Maryland Medical Center. https://umm.edu/health/ medical/altmed/supplement/alphalipoic-acid.
Characterization: IR • Broad 3000 cm-1 peak: Carboxylic Acid • Strong 1700 cm-1 peak: Ring Moiety • Higher than typical aromatic. SBDS-1H NMR 399.65 MHz. AIST:RIO-DB Spectral Database. http://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_disp.cgi?sdbsno=52043.
Characterization: H-NMR • 10 Peaks • Splitting indicates hydrocarbon chain. • Group of peaks above 3 consistent with sulfur. SBDS-1H NMR 399.65 MHz. AIST:RIO-DB Spectral Database. http://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_disp.cgi?sdbsno=52043.
Characterization: C-NMR • Shifting Downfield • Carbon 1 with carboxylic acid • Carbons 2, 3, and 4 adjacent to sulfur atoms SBDS-1H NMR 399.65 MHz. AIST:RIO-DB Spectral Database. http://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_disp.cgi?sdbsno=52043.
Characterization: UV/Vis • Absorbance due to Carboxylic Acid • UV range • 203 nm, 302 nm Goti, P.; Savsani, J.; Patel, P. International Journal of Pharmacy and Pharmaceutical Sciences, 2012, 4, 519-522.
Synthesis Methods • Fairly simple compound, Variety of sources. • Easier to synthesize than to extract. • Method 1: • Octanoic Acid • Reflux with Potassium Permanganate • Ethanol solvent • 8 Hours Subhash P.; Kale, Ramesh R.; Pasupathy, K.; Synlett, 2005, 1129-1132. Kim, Hyeon Jin; Kwon, Seung-Ryong; Kim, Kyuwon; Electrochemistry Communications, 2012, v20, 52-55.
Synthesis Methods • Method 2: • Tosylhydrazone Degenerations • Reflux with NaOH • Highly complex • Many byproducts Subhash P.; Kale, Ramesh R.; Pasupathy, K.; Synlett, 2005, 1129-1132. Kim, Hyeon Jin; Kwon, Seung-Ryong; Kim, Kyuwon; Electrochemistry Communications, 2012, v20, 52-55.
Synthesis Methods • Method 3: (BEST!) • Substitute octanoic acid using Na2S to form thiols • Bu4N+Br- catalyst in methanol to form sulfur ring • Hydrolyze to carboxylic acid
Alpha Lipoic Acid Thank You!