Rutin, a Flavonoid That Is a Main Component of Saussurea involucrata, Attenuates the Senescence Effect in D-Galactose Aging Mouse Model

Abstract

Saussurea involucrata (Kar. et Kir.), known as the snow lotus, grows in the Tian Shan and A'er Tai areas of China. It has recently been reported that the ethyl acetate extract of S. involucrata (SI-2) can inhibit proliferation and induce apoptosis in PC-3 human prostate cancer cells. This study investigated the protective effect of ethyl acetate extract of S. involucrata (SI-2) or rutin, a flavonoid extracted from ethyl acetate extract of S. involucrata (SI-2), on D-galactose- (D-gal-) induced brain injury in mice. Administering SI-2 or rutin (30 mg/kg/d and 30 mg/kg/d) for 6 weeks, concomitant with D-gal injection, significantly increased superoxide dismutase and glutathione peroxidase activities and decreased the MDA level in plasma. Furthermore, the result showed that the percentages of cleaved caspase-3 and PARP in the D-gal-treated mice were much higher than those in the control. Pretreatment using SI-2 or rutin decreased the expression of cyclooxygenase-2 via downregulation of NF-kappaB, resulting in a decrease in lipid peroxidation. Furthermore, our results also showed that oral administration of rutin to these mice significantly improved behavioral performance in a step-through passive avoidance task and these results suggest that SI-2 or rutin exerts potent antiaging effects on D-gal in mice via antioxidative mechanisms.

Figure 1

Chemical structure of rutin.

Figure 2

Effect of ethyl acetate extract of Saussurea involucrata (SI-2) or rutin on neuronal damage analysis in D-galactose-treated (aged) mice. Immunocytochemistry staining shows that cleaved caspase-3 (a) and cleaved PARP (b) in galactose-treated group were significantly increased compared with vehicle-treated group (PBS) and decreased in galatose + SI-2 (SI + D-gal) or rutin (Rutin) treated group compared with galatose (D-Gal) alone group in the CA1 subfield of hippocampus after 6 weeks of administration. (c) H&E staining for morphologicl analysis.

Figure 3

Effect of ethyl acetate extract of Saussurea involucrata (SI-2) or rutin on plasma ROS level in D-galactose-treated (aged) mice. The control group received subcutaneous (s.c.) injections of phosphate-buffered saline. The aged group received D-galactose (300 mg/kg, s.c.). SI-2 + G-gal or rutin + G-gal groups received D-galactose (300 mg/kg/day, s.c.) plus SI-2 or rutin (30 mg/kg/day, p.o.). Treatments were administered for 6 weeks. SI-2 + G-gal or rutin + G-gal treatment groups attenuated the aging characteristics of increased ROS level. Data are presented as mean ± standard deviation (SD) (n = 3 mice). *P < 0.05 versus the aged group.

Figure 4

Modulation of the cyclooxygenase-2 (COX-2) isozyme and NF-kappa B subunits (RELA and P50) by Saussurea involucrata (SI-2) or rutin pretreatment in D-galactose-treated (aged) mice. SI-2 or rutin pretreatment decreased this protein expression (a). SI-2 or rutin pretreatment also decreased COX-2 protein expression induced by D-galactose (b).

Figure 5

Effect of ethyl acetate extract of Saussurea involucrata (SI-2) or rutin on plasma MDA level and SOD and GPx activities in D-galactose-treated (aged) mice. The control group received subcutaneous (s.c.) injections of phosphate-buffered saline. The aged group received D-galactose (300 mg/kg, s.c.). SI-2 + G-gal or rutin + G-gal groups received D-galactose (300 mg/kg/day, s.c.) plus SI-2 or rutin (30 mg/kg/day, p.o.). Treatments were administered for 6 weeks. (SI-2) and rutin treatment attenuated the aging characteristics of increased MDA level and downregulated SOD and GPx activities. Data are presented as mean ± standard deviation (SD) (n = 6 mice). *P < 0.05 versus the aged group.

Figure 6

Effects of rutin (30 mg/kg) on the step-through latencies in rats. The control group received subcutaneous (s.c.) injections of phosphate-buffered saline. The aged group received D-galactose (300 mg/kg, s.c.). SI-2 + G-gal or rutin + G-gal groups received D-galactose (300 mg/kg/day, s.c.) plus SI-2 or rutin (30 mg/kg/day, p.o.). Treatments were administered for 6 weeks. Retention tests were performed one, two, and seven days after training, *P < 0.05, **P < 0.01, and compared to the same day control, Tukey-Kramer's test. Values are expressed as means ± SEM.