Bioactive constituents of Corni Fructus: The therapeutic use of morroniside, loganin, and 7-O-galloyl-D-sedoheptulose as renoprotective agents in type 2 diabetes.

Corni Fructus, the fruit of Cornus officinalis Sieb. et Zucc. (Cornaceae), is an important crude herb used in Chinese medicine to exhibit several biological activities, including hypoglycemic, antineoplastic, and antimicrobial effects, and to improve liver and kidney functions. We have been investigating the mechanism and bioactive constituents of Corni Fructus using diabetic animal models. Morroniside, loganin, and 7-O-galloyl-D-sedoheptulose, the main active compounds of Corni Fructus, exhibit the same lowering effects of elevated triglyceride, oxidative stress and advanced glycation endproduct (AGE) formation in the kidney of db/db mice. The effects of morroniside and 7-O-galloyl-D-sedoheptulose were mediated through modulation by renal sterol regulatory element binding proteins and nuclear factor-kappa B expression, but the effect of loganin was presumably mediated by hypoglycemic and antioxidant effects in the kidney, and also indirectly by the amelioration of metabolic disorders in other organs such as the liver. These findings led us to conclude that morroniside, loganin, and 7-O-galloyl-D-sedoheptulose would synergistically contribute to the inhibition of metabolic disorders (hyperglycemia and dyslipidemia), oxidative stress, inflammation, as well as AGE formation in the diabetic kidney.

Effect of sun ginseng methanol extract on lipopolysaccharide-induced liver injury in rats.

Sun ginseng (SG) is heat-processed Panax ginseng C.A. Meyer steamed at 120 degrees C, which has ginsenoside-Rg(3), -Rk(1), and -Rg(5) as its main ginsenoside components. The effect of SG on lipopolysaccharide (LPS)-induced liver injury in rats was investigated in this study. Intravenous injection of LPS induced excessive nitric oxide (*NO) generation in serum and increased the hepatic mitochondrial thiobarbituric acid-reactive substance (TBA-RS) level. However, the elevated TBA-RS level was significantly lowered by 15 consecutive days of SG administrations. In addition, up-regulated hepatic inducible nitric oxide synthase and heme oxygenase 1 levels in LPS-treated control rats were significantly lowered and increased, respectively, by 100 mg/kg body weight/day of SG administration. These antioxidant effects were thought to be partially related to the deactivation of nuclear factor-kappaB by SG administration.

Therapeutic potential of heat-processed Panax ginseng with respect to oxidative tissue damage.

Panax ginseng has been reported to exhibit a wide range of pharmacological and physiological actions. A method of heat-processing to enhance the efficacy of ginseng is well established in South Korea based on a long history of ethnopharmacological evidence. We investigated the increase in free radical-scavenging activity of Panax ginseng as a result of heat-processing and its active compounds related to fortified antioxidant activity. In addition, the therapeutic potential of heat-processed ginseng (HPG) with respect to oxidative tissue damage was examined using rat models. Based upon chemical and biological activity tests, the free radical-scavenging active components such as less-polar ginsenosides and maltol in Panax ginseng significantly increased depending on the temperature of heat-processing. According to animal experiments related to oxidative tissue damage, HPG displayed hepatoprotective action by reducing the elevated thiobarbituric acid reactive substance (TBA-RS) level, as well as nuclear factor-kappa B (NF-kappaB) and inducible nitric oxide synthase (iNOS) protein expressions, while increasing heme oxygenase-1 in the lipopolysaccharide-treated rat liver, and HPG also displayed renal protective action by ameliorating physiological abnormalities and reducing elevated TBA-RS, advanced glycation endproduct (AGE) levels, NF-kappaB, cyclooxygenase-2, iNOS, 3-nitrotyrosine, N?-(carboxymethyl)lysine, and receptors for AGE protein expression in the diabetic rat kidney. Therefore, HPG clearly has a therapeutic potential with respect to oxidative tissue damage by inhibiting protein expression related to oxidative stress and AGEs, and further investigations of active compounds are underway. This investigation of specified bioactive constituents is important for the development of scientific ginseng-derived drugs as part of ethnomedicine.