Inhibition of lysophospholipase D activity by unsaturated lysophosphatidic acids or seed extracts containing 1-linoleoyl and 1-oleoyl lysophosphatidic acid.
Lysophospholipase D (lysoPLD), generating lipid mediator lysophosphatidic acid (LPA) from lysophosphatidyclcholine (LPC), is known to be inhibited by lysophosphatidic acids. Meanwhile, some plant lipids are known to contain lysophospholipids as minor components. Therefore, it is interesting to test whether edible seed samples, rich in phospholipids, may contain lysophospholipids, which express a strong inhibition of lysoPLD activity. First, the structural importance of fatty acyl group in LPAs was examined by determining the inhibitory effect of various LPAs on bovine lysoPLD activity. The most potent in the inhibition of lysoPLD activity was linoleoyl-LPA ( K i, 0.21 microM), followed by arachidonoyl-LPA ( K i, 0.55 microM), oleoyl-LPA ( K i, 1.2 microM), and palmitoyl-LPA ( K i, 1.4 microM), based on the fluoresecent assay. The same order of inhibitory potency among LPA analogs with different acyl chains was also found in the spectrophotometric assay. Subsequently, the extracts of 12 edible seeds were screened for the inhibition of lysoPLD activity using both spectrophotometric and fluorescent assays. Among seed extracts tested, the extract from soybean seed, sesame seed, or sunflower seed (30 mg seed weight/mL) was found to exhibit a potent inhibition (>80%) of lysoPLD activity. In further study employing ESI-MS/MS analysis, major LPA components in seed extracts were identified to be 1-linoleoyl LPA, 1-oleoyl LPA, and 1-palmitoyl LPA with 1-linoleoyl LPA being more predominant. Thus, the potent inhibition of lysoPLD activity by seed extracts might be ascribed to the presence of LPA with linoleoyl group rather than other acyl chains.
Liu
Xi-Wen
XW
Department of Food and Nutrition and College of Pharmacy, Chungnam National University, Gung-Dong 220, Yuseong-Gu, Taejon 305-764, Korea. mrkim@cnu.ac.kr
Sok
Dai-Eun
DE
Yook
Hong-Sun
HS
Sohn
Cheon-Bae
CB
Chung
Young-Jin
YJ
Kim
Mee Ree
MR
D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006368:Helianthus / Q000737:chemistry; D008041:Linoleic Acids / Q000494:pharmacology; D008246:Lysophospholipids / Q000737:chemistry / Q000494:pharmacology*; D009829:Oleic Acids / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D012639:Seeds / Q000737:chemistry*; D031685:Sesamum / Q000737:chemistry; D013025:Glycine max / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D000099189:Lysophospholipase D
D004791:Enzyme Inhibitors; D008041:Linoleic Acids; D008246:Lysophospholipids; D009829:Oleic Acids; D010727:Phosphoric Diester Hydrolases; D010936:Plant Extracts; D000099189:Lysophospholipase D