EFFECT OF THE ANTIRETROVIRAL AGENT HYPERICIN ON RAT-LIVER MITOCHONDRIA

被引：33

作者：

UTSUMI, T

OKUMA, M

KANNO, T

TAKEHARA, Y

YOSHIOKA, T

FUJITA, Y

HORTON, AA

UTSUMI, K

机构：

[1] INST MED SCI,CTR ADULT DIS,KURASHIKI,OKAYAMA 710,JAPAN

[2] KURASHIKI CENT HOSP,DEPT NEUROSURG,KURASHIKI,OKAYAMA 710,JAPAN

[3] UNIV BIRMINGHAM,SCH BIOCHEM,BIRMINGHAM B15 2TT,W MIDLANDS,ENGLAND

来源：

BIOCHEMICAL PHARMACOLOGY | 1995年 / 50卷 / 05期

关键词：

FREE RADICALS; HYPERICIN; LIPID PEROXIDATION; MITOCHONDRIAL FUNCTIONS; PHOTOSENSITIZATION; SPIN TRAPPING;

D O I：

10.1016/0006-2952(95)00143-N

中图分类号：

R9 [药学];

学科分类号：

1007 ;

摘要：

The photosensitizing effect of hypericin (HY), an antiretroviral agent, on the functions of isolated rat liver mitochondria has been investigated. The respiratory control ratio (RCR), ADP/O and membrane potential of mitochondria were decreased by HY in a light-dependent manner. Uncoupled respiration of mitochondria in the presence of succinate was also inhibited by HY in a light-dependent manner. The ID50 of hypericin for these inhibitions was approximately 0.5 mu M. These inhibitory effects of HY were not observed when photosensitization was conducted under anaerobic conditions and were not affected by desferrioxamine (DSF) or superoxide dismutase (SOD). Upon photosensitization of HY, mitochondria consumed oxygen in the absence of respiratory substrate with concomitant formation of thiobarbituric acid reactive substance (TEARS). The amount of oxygen consumed was 100-times greater than that of TEARS formed. The oxygen uptake was partially inhibited by NaN3, and formation of TEARS was inhibited by DSF. Upon photosensitization of HY in the presence of mitochondrial membranes, the electron spin resonance (ESR) signal of 2,2-dimethyl-5-hydroxy-1-pyrrolidinyloxyl (DMPO/. OH) was increased by a mechanism which was suppressed by DSF. An ESR signal for singlet oxygen bound to 2,5-dimethylfuran, 2,2,6,6-tetramethyl-4-piperidone (TEMP) was also detected under light in the presence of mitochondria. This signal of the TEMP-N-oxyl radical (TEMPO) was decreased by azide, which physically quenches singlet oxygen, but was increased by DSF. These results indicate that HY might inhibit mitochondrial functions by a type II photodynamic mechanism but that lipid peroxidation of biological membranes through an active oxygen-mediated photodynamic mechanism is not involved.

引用

页码：655 / 662

页数：8

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