Sesame lignans reduce LDL oxidative susceptibility by downregulating the platelet-activating factor acetylhydrolase

Y. Nakamura, H. Okumura, Y. Ono, Y. Kitagawa, T. Rogi, H. Shibata

Institute for Health Care Science, Suntory Wellness Limited, Kyoto, Japan. Yoshiko_Toyoda@suntory.co.jp

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• Pharmacology

OBJECTIVE: Low-density lipoprotein (LDL) oxidative susceptibility is recognized as a risk factor for atherosclerosis. We previously reported that the ingestion of a supplement containing sesame lignans (sesamin/episesamin) for 4 weeks reduced LDL oxidative susceptibility in humans.

MATERIALS AND METHODS: To elucidate the mechanisms underlying this observation, 12-week-old New Zealand White rabbits were fed a fat/cholesterol-enriched diet (100 g/day) for 6 weeks followed by oral administration of vehicle (control) or sesame lignans (50 mg/kg) for 4 weeks with the fat/cholesterol-enriched diet.

RESULTS: The results showed that the ingestion of sesame lignans prolonged LDL oxidation lag time, regardless of the existence of the anti-oxidative catechol metabolite of sesamin/episesamin in LDL. Plasma platelet-activating factor acetylhydrolase (PAF-AH) activity was significantly reduced by sesame lignans. The prolongation of LDL oxidation lag time was abolished by the addition of a PAF-AH inhibitor. The expression level of pro-inflammatory cytokines and macrophage infiltration observed in the liver following the feeding of the fat/cholesterol-enriched diet were also significantly reduced by sesame lignans.

CONCLUSIONS: These results indicate that sesame lignans reduce LDL oxidative susceptibility by downregulating plasma PAF-AH activity via the reduction of inflammation in the liver induced by fat/cholesterol-enriched diets.