3 hydroxy palmitic acid

3-hydroxy Palmitic acid is a form of the 16:0 lipid palmitic acid . The lipid A part of lipopolysaccharides contain various 3-hydroxy fatty acids, making oxylipins such as 3-hydroxy palmitic acid useful as chemical markers of endotoxins. In R. solanacearum, 3-hydroxy palmitic acid is converted by an S-adenosyl methionine-dependent methyltransferase to 3-hydroxy palmitic acid methyl ester, which acts as a quorum sensing signal molecule for post-transcriptional modulation of genes involved in virulence. Long-chain 3-hydroxy fatty acids, such as 3-hydroxy palmitic acid, are also known to accumulate during long-chain 3-hydroxy-acyl-CoA dehydrogenase and mitochondrial trifunctional protein deficiencies. Such accumulation induces oxidative stress, leading to mitochondrial bioenergetics deregulation and eventual multi-organ dysfunction.

3-hydroxy Palmitic acid methyl ester (3-hydroxy PAME) is an esterized long-chain fatty acid involved in quorum sensing in R. solanacearum, a bacteria that causes lethal wilting in plants. 3-hydroxy-PAME (175 nM) increases levels of PhcA-regulated virulence factors, greater than 20-, 30-, and 25-fold for EPS I, EGL, and PME, respectively, in the AW1-83 strain of R. solanacearum.

Branched fatty acid esters of hydroxy fatty acids (FAHFAs) are newly identified endogenous lipids regulated by fasting and high-fat feeding and associated with insulin sensitivity. Structurally, these esters are comprised of a C-16 or C-18 fatty acid (e.g., palmitoleic, palmitic, oleic, or stearic acid) linked to either a C-16 or C-18 hydroxy substituent. 12-PAHSA is a FAHFA in which palmitic acid is esterified at the 12th carbon of hydroxy stearic acid. Among the FAHFA family members, PAHSAs are the most abundant in the adipose tissue of glucose tolerant AG4OX mice, which overexpress the Glut4 glucose transporter specifically in adipose tissue. 12-PAHSA is present at 2- to 3-fold higher levels in adipose tissue of AG4OX mice compared to wild type mice. Levels of 12-PAHSA are also higher in fasted wild-type mice compared to fed mice and are reduced upon high-fat diet-induced obesity in insulin-resistant mice.

1-Palmitoyl-d9-2-hydroxy-sn-glycero-3-PA (1-palmitoyl-d9LPA) serves as an internal standard for the quantification of 1-palmitoyl LPA using GC- or LC-MS. This compound, an analog of LPA with palmitic acid at the sn-1 position, activates reporter gene expression in PC12 cells fitted with human lysophosphatidic acid receptor 4 (LPA4) at 0.01 to 10 µM concentrations. Additionally, 1-palmitoyl LPA prompts aggregation in isolated human platelets within the 12-300 µM range, a process reversible by prostaglandin E1 (PGE1), theophylline, or EDTA. It also interacts with calcium and magnesium to boost the efficacy of ampicillin, piperacillin, and ceftazidime against P. aeruginosa strains from cystic fibrosis patients.

1-Palmitoyl-2-12-PAHSA-3-oleoyl-sn-glycerol, an endogenous triacylglycerol, comprises palmitic acid (at the sn-1 position), the fatty acid ester of hydroxy fatty acids (FAHFA), 12-PAHSA (at the sn-2 position), and oleic acid (at the sn-3 position). Identified in the lipid extract of mouse adipose tissue, this triacylglycerol demonstrates that levels of FAHFA-containing triacylglycerols are over 100-fold higher than those of non-esterified FAHFAs, suggesting their role as intracellular storage reservoirs for FAHFAs.