Free radical scavenging activity and antiulcer activity of garcinol from Garcinia indica fruit rind.

Garcinol, a polyisoprenylated benzophenone derivative, was purified from Garcinia indica fruit rind, and its free radical scavenging activity was studied using electron spin resonance (ESR) spectrometry. In the hypoxanthine/xanthine oxidase system, emulsified garcinol suppressed superoxide anion to almost the same extent as DL-alpha-tocopherol by weight. In the Fenton reaction system, garcinol also suppressed hydroxyl radical more strongly than DL-alpha-tocopherol. In the H(2)O(2)/NaOH/DMSO system, garcinol suppressed superoxide anion, hydroxyl radical, and methyl radical. It was thus confirmed that this derivative is a potent free radical scavenger and able to scavenge both hydrophilic and hydrophobic ones including reactive oxygen species. Orally administered garcinol prevented acute ulceration in rats induced by indomethacin and water immersion stress caused by radical formation. These results suggested garcinol might have potential as a free radical scavenger and clinical application as an antiulcer drug.

Antioxidative and anti-glycation activity of garcinol from Garcinia indica fruit rind.

Garcinol, a polyisoprenylated benzophenone derivative, was purified from Garcinia indica fruit rind, and its antioxidative activity, chelating activity, free radical scavenging activity, and anti-glycation activity were studied. Garcinol exhibited moderate antioxidative activity in the micellar linoleic acid peroxidation system and also exhibited chelating activity at almost the same level as citrate. It also showed nearly 3 times greater DPPH (1, 1-diphenyl-2-picrylhydrazyl) free radical scavenging activity than DL-alpha-tocopherol by weight in aqueous ethanol solution. In a phenazine methosulfate/NADH-nitroblue tetrazolium system, garcinol exhibited superoxide anion scavenging activity and suppressed protein glycation in a bovine serum albumin/fructose system. Thus, garcinol might be beneficial as a potent antioxidant and a glycation inhibitor under specified conditions.

Free radical scavenging activity of grape seed extract and antioxidants by electron spin resonance spectrometry in an H(2)O(2)/NaOH/DMSO system.

The scavenging effects of grape seed extract (GSE) on free radicals formed in an H(2)O(2)/NaOH/DMSO system were examined using a spin-trapping electron spin resonance (ESR) method and compared with other natural antioxidants, ascorbic acid, dl-alpha-tocopherol, and beta-carotene. GSE reduced greatly the ESR signal intensity of superoxide radical-5,5-dimethyl-1-pyrroline-N-oxide (DMPO) adducts. GSE also exhibited weak scavenging activity on hydroxyl radical and a little scavenging activity on methyl radical. Ascorbic acid exhibited strong superoxide and hydroxyl radical scavenging activities, but it increased the amount of methyl radical at high concentration. dl-alpha-Tocopherol reduced the amount of superoxide anion, especially the amount of methyl radical. However, it slightly reduced the amount of hydroxyl radical. beta-Carotene reduced the amount of hydroxyl radical and methyl radical, but it also slightly reduced superoxide anion. In the case of combination use of beta-carotene and dl-alpha-tocopherol, all radical species were suppressed. Combination of GSE and dl-alpha-tocopherol also could reduce all radical species. beta-Carotene and dl-alpha-tocopherol could reduce the methyl radical formation induced by ascorbic acid.

Calbrain, a novel two EF-hand calcium-binding protein that suppresses Ca2+/calmodulin-dependent protein kinase II activity in the brain.

A cDNA clone that encodes a novel Ca2+-binding protein was isolated from a human brain cDNA library. The gene for this clone, termed calbrain, encodes a 70-amino acid polypeptide with a predicted molecular mass of 8.06 kDa. The analysis of deduced amino acid sequence revealed that calbrain contains two putative EF-hand motifs that show significantly high homology to those of the calmodulin (CaM) family rather than two EF-hand protein families. By Northern hybridization analysis, an approximate 1.5-kilobase pair transcript of calbrain was detected exclusively in the brain, and in situ hybridization study revealed its abundant expression in the hippocampus, habenular area in the epithalamus, and in the cerebellum. A recombinant calbrain protein showed a Ca2+ binding capacity, suggesting the functional potency as a regulator of Ca2+-mediated cellular processes. Ca2+/calmodulin-dependent kinase II, the most abundant protein kinase in the hippocampus and strongly implicated in the basic neuronal functions, was used to evaluate the physiological roles of calbrain. Studies in vitro revealed that calbrain competitively inhibited CaM binding to Ca2+/calmodulin-dependent kinase II (Ki = 129 nM) and reduced its kinase activity and autophosphorylation.

Relationship between molecular weights of pectin and hypocholesterolemic effects in rats.

Hypocholesterolemic activities and other properties of three different molecular weight pectin were examined. The low-molecular-weight pectin (M(r) not equal to 66,000) obtained by decomposition of original pectin (M(r) not equal to 750,000) had the properties of low viscosity and high solubility, but it lost hypocholesterolemic activities in rats. On the other hand, the medium-molecular-weight pectin (M(r) not equal to 185,000) had characteristics of both low viscosity and hypocholesterolemic activities.

Immunopotentiation by a new antitumor polysaccharide, DMG, a degraded D-manno-D-glucan from Microellobosporia grisea culture fluid.

The immunopharmacological behavior of DMG, an antitumor polysaccharide, was studied in mice. DMG administered ip or sc stimulated peritoneal macrophages to produce high levels of interleukin-1 activity, which can amplify successive immune responses. DMG dose-dependently and schedule-dependently increased the cellular immune response against allogeneic tumor cells and the humoral immune response to sheep erythrocytes. DMG also enhanced nonspecific antitumor effector functions, such as natural killer activity of spleen and peritoneal cells, and the cytostatic activity of peritoneal macrophages. Peritoneal macrophages activated by ip or sc injection of DMG exhibited high cytostatic activity, especially after exposure in vitro to lymphokine supernatants containing macrophage activation factor. Moreover, granulocyte/macrophage colony-stimulating activity in the serum increased 2-10 hr after DMG administration. Thus, DMG potentiated antigen-specific immunological functions and nonspecific functions of host defense systems against cancer both qualitatively and quantitatively.