In the
adipocere which is one of
postmortem changes, some specific
fatty acids possessing higher melting points together with
soap play an important role in the formation of
adipocere. These
fatty acids were clarified to be mainly 10-hydroxystearic and 10-hydroxypalmitic
acids. Moreover, slight amounts of 10-oxostearic and 10-oxopalmitic
acids, which have higher melting points than those of hydroxy
fatty acids, exist in the
adipocere as well. The substantial
adipocere is formed and stabilized by these specific
fatty acids together with the
soap. The hydroxy
fatty acid (OHFA) and oxo
fatty acid (OXOFA) are biosynthesized by some
enzymes from bacteria. Various aerobic and anaerobic bacteria are involved in the formation of
adipocere. For example, microbial conversion of various
unsaturated fatty acids to 10-OHFA by Micrococcus luteus was investigated. As a result, 10-OHFA was synthesized only from
fatty acids possessing cis-9-unsaturation. It was also clarified that 10-OHFAs were converted to the corresponding 10-OXOFAs but the 10-OXO compounds were inactive as substrates. Furthermore, the
enzyme preparations from Flavobacterium meningosepticum solubilized by sonication catalyzed not only hydration of
oleic acid to produce
10-hydroxystearic acid but also dehydrogenation of this product in the presence of
deuterium. On the other hand, we found out that there was
10-hydroxy-12-octadecenoic acid (10-OHLA) from
linoleic acid in some kinds of
adipocere. 10-OHFA existing in
adipocere has been thought not to exist in a living body. However, recently 10-epoxy-12-octadecenoic
acid (
leukotoxin, LTx) which is one of
lipid peroxides was found not only in rice plants but in polymorphonuclear leukocytes. It was also clarified that these polymorphonuclear leukocytes produced the same 10-OHLA as the compound found in
adipocere. Since LTx was found from leukocytes related to inflammatory response, it has been interested in involvement of not only the basic mechanism of
biological defense but also the mechanism of
shock as a vasoactive substance. A
postmortem change itself is little associated with a phenomenon on a living body. However, 10-OHLA found in
adipocere existed also in polymorphonuclear leukocytes, suggesting that this compound metabolized from LTx is closely related to a
biological reaction.