Antihypertensive and neuroprotective effects of astaxanthin in experimental animals.
Astaxanthin is a natural antioxidant carotenoid that occurs in a wide variety of living organisms. We investigated, for the first time, antihypertensive effects of astaxanthin (ASX-O) in spontaneously hypertensive rats (SHR). Oral administration of ASX-O for 14 d induced a significant reduction in the arterial blood pressure (BP) in SHR but not in normotensive Wistar Kyoto (WKY) strain. The long-term administration of ASX-O (50 mg/kg) for 5 weeks in stroke prone SHR (SHR-SP) induced a significant reduction in the BP. It also delayed the incidence of stroke in the SHR-SP. To investigate the action mechanism of ASX-O, the effects on PGF(2alpha)-induced contractions of rat aorta treated with NG-nitro-L-arginine methyl ester (L-NAME) were studied in vitro. ASX-O (1 to 10 microM) induced vasorelaxation mediated by nitric oxide (NO). The results suggest that the antihypertensive effect of ASX-O may be due to a NO-related mechanism. ASX-O also showed significant neuroprotective effects in ischemic mice, presumably due to its antioxidant potential. Pretreatment of the mice with ASX-O significantly shortened the latency of escaping onto the platform in the Morris water maze learning performance test. In conclusion, these results indicate that astaxanthin can exert beneficial effects in protection against hypertension and stroke and in improving memory in vascular dementia.
Hussein
Ghazi
G
International Research Center for Traditional Medicine, Toyama Prefecture, Japan. ghazihussein@hotmail.com
Nakamura
Masami
M
Zhao
Qi
Q
Iguchi
Tomomi
T
Goto
Hirozo
H
Sankawa
Ushio
U
Watanabe
Hiroshi
H
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001012:Aorta, Abdominal / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D066298:In Vitro Techniques; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017208:Rats, Wistar; D020521:Stroke / Q000503:physiopathology / Q000517:prevention & control*; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology; D024341:Xanthophylls; D019207:beta Carotene / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use*
D000959:Antihypertensive Agents; D018696:Neuroprotective Agents; D024341:Xanthophylls; D019207:beta Carotene; C005948:astaxanthine