Influence of side chain structure changes on antioxidant potency of the [6]-gingerol related compounds.

[6]-Gingerol and [6]-shogaol are the major pungent components in ginger with a variety of biological activities including antioxidant activity. To explore their structure determinants for antioxidant activity, we synthesized eight compounds differentiated by their side chains which are characteristic of the C1-C2 double bond, the C4-C5 double bond or the 5-OH, and the six- or twelve-carbon unbranched alkyl chain. Our results show that their antioxidant activity depends significantly on the side chain structure, the reaction mediums and substrates. Noticeably, existence of the 5-OH decreases their formal hydrogen-transfer and electron-donating abilities, but increases their DNA damage- and lipid peroxidation-protecting abilities. Additionally, despite significantly reducing their DNA strand breakage-inhibiting activity, extension of the chain length from six to twelve carbons enhances their anti-haemolysis activity.

Danhong injection attenuates ischemia/reperfusion-induced brain damage which is associating with Nrf2 levels in vivo and in vitro.

Danhong injection, a Chinese Materia Medica standardized product extracted from Radix Salviae miltiorrhizae and Flos Carthami tinctorii, is used extensively for the treatment of cerebrovascular diseases such as acutely cerebral infarction in clinic. In this study, we further investigated the mechanisms of Danhong injection on cerebral ischemia/reperfusion (I/R) damage relating to Nrf2/ARE signalling pathway in vivo and in vitro. For in vivo experiment, cerebral I/R injury was induced through middle cerebral artery occlusion. Rats were randomly divided into five groups: sham-operated group, I/R injury group, 6 mg/kg edaravone injection (positive control drug) group, 0.9 ml/kg Danhong injection (DHI-L) group, 1.8 ml/kg Danhong injection (DHI-H) group. The neurological score, cerebral infarction and brain edema were assessed while levels of superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA) in brain tissue were also evaluated. Transcription levels of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), NAD(P)H: quinone oxidoreductase 1 (NQO1) were analysed by real-time polymerase chain reaction. For in vitro experiment, mouse Neuro-2A cells were wounded with H2O2 then cell viability and mRNA transcriptions levels of Nrf2, HO-1, NQO1 were detected. Protein expression level of Nrf2 was assayed by western blotting. The results showed that Danhong injection could ameliorate neurological score, cerebral infarction and brain edema. Also it can increase levels of SOD, GSH and decrease of MDA and upregulate expressions of Nrf2, HO-1, NQO1 in ischemic brain tissue in vivo. What's more, it increased the mRNA transcription of Nrf2 and HO-1 and upregulated protein expression of Nrf2 in vitro. These findings suggested that Danhong injection could prevent I/R-induced brain damage through activating Nrf2/ARE signaling pathway.