Synthesis and characteristics of polyhydroxy triglycerides from milkweed oil

Synthesis and Characterization of the Intrinsic Properties of Milkweed Polyhydroxy Fatty Acids

“…This represents the C11 methylene protons of the linoleoyl species that are sandwiched between the methine protons of C10 and C12 of the acid. The main features of the 13 1 H-and 13 C-spectra also revealed that the polyhydroxy triglyceride starting material retained a trace amount of unsaturation, a condition that the DSC experiment also hinted. The 13 C similarly confirmed the trace olefin with resonance lines barely above the spectral baseline at 135 and 124 ppm, respectively, and the DEPT experiment also indicated the presence of a trace amount of glycerol (64, 62 ppm for the -OCH-and -CH 2 O-) in the sample.…”

“…MWPHFA were synthesized from the polyhydroxy triglyceride derivatives of milkweed oil [1] by saponification of the polyhydroxy triglyceride with KOH. Analysis of the FTIR spectrum of the isolated product indicated a material with different spectral characteristics from its triglyceride precursor, namely, the absence of the strong 1743 cm -1 ester carbonyl stretch of the parent now replaced by a 1714 cm -1 and a smaller 1558 cm -1 band corresponding to the -COOH and -COO -, respectively, at pH 5.5.…”

“…Milkweed polyhydroxy triglycerides (MWPHTG) were from our in-house stock that had previously been synthesized from our supply of milkweed oil [1]. KOH pellets, HCl, ethyl acetate, 2-propanol, and sodium bicarbonate were purchased from Fisher Scientific (Chicago, IL, USA), acetic anhydride was purchased from ACRŌ S Organics (Chicago, IL, USA) whereas pre-coated TLC plates (5 9 20 cm) were from EM Science (Darmstadt, Germany).…”

“…MWPHTG (21.0 g, 0.03188 mol), as previously reported above [1], was placed in a 250-mL jacketed reactor containing 2-propanol (35.0 mL). KOH pellets (87.7%, 5.0 g, 78.16 mmol) were added to the mixture which was then stirred and heated to 70°C, allowing for gentle reflux.…”

“…The common milkweed (Asclepias syriaca L.) is native in the Americas and its seed oil is very unsaturated (92%). Hydroxylation of the oil by functionalization of the olefinic groups introduces polar characteristics to an otherwise non-polar substrate and so broadens the utility and stability of this renewable resource [1]. The behavior of the induced polar environment within the triglyceride molecules can be further accentuated by removal of the esterifying glycerol moieties to generate polyhydroxy fatty acids.…”