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Fructus Hippophaës recens
diation of 1.786 Gy/sec. A dose-dependent inhibition of degradation of
2-deoxyribose was observed with a half maximal inhibitory concentration
(IC 50
) of 500 µg/ml. At concentrations of 100 and 120 µg/ml the extract
inhibited radiation and DNA strand-breaks in a dose-dependent
manner. At a concentration of 120 µg/ml, the extract induced chromatin
compaction. A dose-dependent inhibition of degradation of 2-deoxyribose
was observed with an IC 50
of 500 µg/ml. At a concentration of
1000 µg/ml, 67% scavenging of hydroxyl radicals was observed. In ex
vivo experiments, the extract prevented strand-breaks in a dose-dependent
manner with a maximum effective concentration of 100 µg/ml. Postirradiation
treatment with high concentrations of the extract (150 µg/ml
or more) resulted in dense compaction of chromatin (58, 59). In another
study, an extract of the fresh fruits was investigated for radioprotective
effects in mitochondria isolated from mouse liver. Superoxide anions, reduced
and oxidized succinate-cytochrome C oxidoreductase, lipid peroxidation
and protein oxidation were used to measure extract-mediated
radioprotection. Pretreatment of mice with the extract (30 mg/kg body
weight (bw) administered intraperitoneally) before irradiation significantly
inhibited radiation-induced increases in superoxide anions, glutathione
levels, thiobarbituric acid reactive substances, NADH-ubiquinone
oxidoreductase, NADH-cytochrome C oxidoreductase activity and mitochondrial
membrane potential (p < 0.05). This study suggests that preirradiation
treatment of mice with the extract protects the functional integrity
of the mitochondria from radiation-induced oxidative stress (60).
The protective effect of an ethanol extract (30 mg/kg bw) of the fruits
against cobalt 60 gamma-irradiation (10 Gy) was evaluated in mice either
alone or 30 minutes before irradiation. After 24 hours of irradiation, a
significant reduction in splenocyte proliferation was observed (159 ±
45 counts/min/10 6 cells; in comparison with controls 607 ± 142 counts/
min). Treatment with the extract before irradiation reduced the steep decrease
and maintained the count at 444 ± 153 counts/min (as measured by
the 3H-thymidine uptake method). At 24 hours after irradiation, the
CD4/CDB lymphocyte ratio was reduced to 1.5 in comparison with the
non-irradiated control (1.9), but treatment with the extract before irradiation
resulted in a ratio of 2.1. These findings indicated that the immunostimulatory
activity of the extract might play an important role in the
manifestation of its radioprotective efficacy (61).
Neuroprotective action
An in vivo study examined the effect of juice from Hippophaë fruits on
lead-induced memory impairment and neuronal damage in the brains of
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