An evidence suggests that even low-dose irradiation can lead to progressive cognitive decline as well as memory deficits in both humans and experimental animals in part due to hippocampal dysfunction. To determine whether or not green tea (GT) and epigallocatechin gallate (EGCG) could attenuate memory impairment as well as suppress hippocampal neurogenesis, passive avoidance and object recognition memory test as well as TUNEL assay and immunohistochemical detection with markers of neurogenesis (Ki-67 and doublecortin (DCX)) were performed using adult mice treated with relatively low-dose gamma irradiation (2.0 Gy). GT was administered intraperitonially at a dosage of 50 mg/kg of body weight at 36 and 12 hr pre-irradiation and at 30 minutes post-irradiation, or orally at a dosage of 250 mg/kg of body weight/day for 7 days before autopsy. EGCG (25 mg/kg of body weight) was administered intraperitonially at 36 and 12 hr pre-irradiation and at 30 minutes post-irradiation. In the passive avoidance and object recognition memory test, mice trained for 1 day after acute irradiation (2 Gy) showed significant memory deficits compared with sham controls. The number of TUNEL-positive apoptotic nuclei in the dentate gyrus increased by 12 h after irradiation. In addition, the numbers of Ki-67- and DCX-positive cells significantly decreased. GT treatment prior to irradiation attenuated memory defects, blocked apoptotic death, as well as reduced the number of DCX-positive cells. Therefore, GT may attenuate memory defects in adult mice exposed to a relatively low dose of radiation possibly by inhibiting the detrimental effects of irradiation on hippocampal neurogenesis.

Panax ginseng, also known as Korean ginseng, has long been used as a broad tonic in Oriental medicine to augment vitality, health, and longevity, particularly in older people. This study investigated the effects of Korean red ginseng (RG) on bone loss in ovariectomized (OVX) mice. C3H/HeN mice (10-weeks-old) were divided into sham and OVX groups. OVX mice were treated with vehicle, 17β-estradiol (E2), RG (oral administration, 250 mg/kg/day), or RG (intraperitoneal administration, 50 mg/kg/every other day) for 6 weeks. Serum E2 concentration and alkaline phosphatase (ALP) activity were measured. Tibiae were analyzed using microcomputed tomography. Biomechanical properties and osteoclast surface level were measured. There was no significant difference in the degree of grip strength, body weight, uterine weight, mechanical property, tibiae length, or tibiae weight between the OVX and RG-treated groups. Compared with the OVX group, the serum ALP level was significantly lower in the RG-treated groups. Serum E2 levels and osteoclast surface levels did not change between the OVX and RG-treated groups. RG could not preserve trabecular bone volume, trabecular bone number, trabecular separation, trabecular thickness, structure model index, or bone mineral density of the proximal tibiae metaphysic. In conclusion, there was no definite effect of RG on OVX-induced bone loss in C3H/HeN mice.

These experiments were performed to investigate the safety of the three medicinal herbs-Curcuma longa Linne, Paeonia japonica Miyabe, Scutellaria baikalensis George-irradiated with gamma rays in respect of genotoxicity. The methanol-soluble and water-soluble fractions of the methanol-water extracts of the 10 kGy gamma-irradiated herbs were examined in two short-term in vitro tests : (1) Salmonella typhimurium reversion assay (Ames test) in strain TA 98, TA 100 and TA 102 (2) Micronucleus test in cultured Chinese hamster ovary (CHO) cells. No mutagenicity was detected in the two assays with or without metabolic activation. From these results, the safety of the herbs irradiated with gamma rays at practical doses could be revealed in further tests of genotoxicity in vivo, chronic and reproductive toxicity.

The yields of solvent fractions of irradiated red ginseng powder were increased in the order of petroleum ether(PE)$lt;diethyl ether(DE)$lt;ethyl acetate(EA)$lt;n-butanol (BU)$lt;aqueous fraction(AQ), and did not show any changes in fraction yields by irradiation dose levels. Inhibition activities of lipid peroxide formation were increased in the order of AQ$lt;BU $lt;PE$lt;EA$lt;DE. Inhibition activities of malonaldehyde formation were increased in the order of AQ≤BU$lt;EA$lt;PE$lt;DE. AQ fraction showed little effects on the antioxidative activity and all the activities of the samples did not changed by gamma irradiation. The reverse mutation assay using Salmonella typhunurium (TA98, TA100 and TA102) demonstrated that the nonirradiated and irradiated red ginseng powder extract did not have mutagenic activity (presence of S9 mix or not). The chromosomal aberration test in mammalian animal cell (Chinese hamster lung fibroblast, CHL) showed no significant increase in incidence of structural and numerical aberrations, comparing gamma-irradiated red ginseng powder extracts to nonirradiated red ginseng powder extract in the concentration of the sample producing cytotoxicity(presence of S9 mix or not). Therefore, gamma-irradiatied red ginseng powder (upto 10 kGy) could be safe on the genotoxic point of view.