Anti-inflammatory activity and conformational behavior of a branched (1 leads to 3)-beta-D-glucan from an alkaline extract of Dictyophora indusiata Fisch

A (1 leads to 6)-branched (1 leads to 3)-beta-D-glucan (T-5-N), isolated from a M sodium hydroxide extract of the fruit bodies of Dictyophora indusita Fisch., markedly exhibited anti-inflammatory effects on both carrageenan-induced edema and scalded edematous hyperalgesia in rat's hindpaws. The activities of T-5-N (25 mg/kg i.p. X 2) were more potent than those of phenylbutazone (25-50 mg/kg i.p. X 2). The conformational behavior of T-5-N was studied. Its molecular weight in neutral solution was about three times that in 0.25M sodium hydroxide. This finding, in addition to the results of optical rotatory measurement and complex-formation with Congo Red, indicated that T-5-N has an ordered, triple-helical structure in neutral or slightly alkaline solution (less than 0.15M NaOH), and has single chains in highly alkaline solution (greater than 0.25M NaOH). The conformational transition occurs at concentrations of sodium hydroxide in the range of 0.15-0.25M.

Polysaccharides in fungi. XXXVI. Hypoglycemic activity of a polysaccharide (CS-F30) from the cultural mycelium of Cordyceps sinensis and its effect on glucose metabolism in mouse liver

A polysaccharide (CS-F30) obtained from the cultural mycelium of Cordyceps sinensis showed potent hypoglycemic activity in genetic diabetic mice after intraperitoneal administration, and the plasma glucose level was quickly reduced in normal and streptozotocin-induced diabetic mice after intravenous administration. Administration of CS-F-30 to normal mice significantly increased the activities of hepatic glucokinase, hexokinase and glucose-6-phosphate dehydrogenase, although the glycogen content in the liver was reduced. Furthermore, CS-F30 lowered the plasma triglyceride level and cholesterol level in mice.

Structural features and hypoglycemic activity of a polysaccharide (CS-F10) from the cultured mycelium of Cordyceps sinensis

A polysaccharide (CS-F10) purified from a hot water extract of the cultured mycelium of Cordyceps sinensis was composed of galactose, glucose and mannose in a molar ratio of 43:33:24; its molecular weight was estimated to be about 15000. The results of chemical and spectroscopic investigations suggest that CS-F10 has a comb-type structure, and has alpha-D-glucopyranosyl residues on the terminal of the side-chains and characteristic sugar residues of C. sinensis i.e., 1,5-linked beta-D-galactofuranosyl residues. CS-F10 significantly lowered the plasma glucose level in normal, streptozotocin (STZ)-induced diabetic and epinephrine-induced hyperglycemic mice after intraperitoneal administration (50 mg/kg). Administration of CS-F10 to STZ-induced diabetic mice significantly increased the activity of hepatic glucokinase. A significant reduction in the hepatic glucose output was observed following the infusion of CS-F10 using the perfused rat liver. CS-F10 also significantly decreased protein content of facilitative glucose transporter isoform 2 (GLUT2) from rat liver following i.p. administration. These effects presumably contribute to the hypoglycemic activity.

Polysaccharides in fungi. XXXII. Hypoglycemic activity and chemical properties of a polysaccharide from the cultural mycelium of Cordyceps sinensis

Crude polysaccharides were obtained from a hot-water extract and alkaline extracts of the cultural mycelium of Cordyceps sinensis. They showed significant activity in normal mice and streptozotocin-induced diabetic mice as a result of intraperitoneal (i.p.) injection. A crude polysaccharide (CS-OHEP) obtained from 5% sodium hydroxide extract slightly lowered the plasma glucose level in normal mice by oral (p.o.) administration. A neutral polysaccharide (CS-F30) exhibited higher hypoglycemic activity than its crude polysaccharide (CS-OHEP), exhibited by i.p. injection, and it significantly lowered the glucose level by p.o. administration (50 mg/kg). However, it hardly affected the plasma insulin level in normal mice. CS-F30 ([alpha]D + 21 degrees in water) is composed of galactose, glucose and mannose (molar percent, 62:28:10), and its molecular weight is about 45000.

Tomato Paste Fraction Inhibiting the Formation of Advanced Glycation End-products

A water-soluble and low-molecular-weight fraction (SB) was obtained from tomato paste. The effects of SB on the formation of advanced glycation end-products (AGE) in protein glycation were studied by the methods of specific fluorescence, ELISA and a Western blot analysis, using the anti-AGE antibody after incubating protein with sugar. The results suggest that SB had strong inhibitory activity, in comparison with aminoguanidine as a positive control, and that the inhibitory mechanism of SB differed from that of aminoguanidine to involve trapping of reactive dicarbonyl intermediates in the early stage of glycation. SB contained an antioxidant, rutin, which showed potent inhibitory activity. The results also suggest that rutin chiefly contributed to inhibiting the formation of AGE, and that other compounds in SB may also have been related to the activity.

Structural features and hypoglycemic activities of two polysaccharides from a hot-water extract of Agrocybe cylindracea

A glucan (AG-HN1, [alpha]D +24 degrees) and a heteroglycan (AG-HN2, [alpha]D +26 degrees) were isolated from a hot-water extract of the fruiting bodies of Agrocybe cylindracea. The structures were investigated by a combination of chemical and spectroscopic methods. The results indicated that high molecular weight glucan AG-HN1 is primarily a beta-(1-->6)-branched (1-->3)-beta-D-glucan containing small amounts of (1-->4)-linked and (1-->6)-linked glucopyranosyl residues. Low molecular weight heteroglycan AG-HN2 gives galactose, glucose, fucose, and mannose on hydrolysis and appears to be chiefly composed of (1-->6)-linked gluco- and galacto-pyranosyl residues, many of them branched, and various nonreducing terminal residues. AG-HN1 showed a remarkable hypoglycemic activity in both normal and streptozotocin-induced diabetic mice by ip administration, and its activity was higher than that of AG-HN2.

Effect of buformin and metformin on formation of advanced glycation end products by methylglyoxal

BACKGROUND

The formation and accumulation of advanced glycation end products (AGE) in various tissues are known to be involved in the aging process and complications of long-term diabetes. Aminoguanidine as AGE inhibitors was first studied, and metformin as biguanide compounds have been reported to react with reactive dicarbonyl precursors such as methylglyoxal.

METHODS

We studied the effects of the biguanides of buformin and metformin on AGE formation by the methods of specific fluorescence, and enzyme-linked immunosorbent assay and a Western blot analysis using the anti-AGE antibody after incubating BSA or RNase with methylglyoxal.

RESULTS

Buformin is a more potent inhibitor of AGE formation than metformin, and suggests that the amino group of buformin trap the carbonyl group of methylglyoxal to suppress formation of AGE.

CONCLUSION

In addition to that of metformin, buformin may be clinically useful to prevent diabetic complications.

Growth suppressing activity for endothelial cells induced from macrophages by carboxymethylated curdlan

A carboxymethylated derivative of a linear (1-->3)-beta-D-glucan (CMCD) from Alcaligenes faecalis var. myxogenes acted directly on mouse peritoneal macrophages and mouse lymphoma P388D1 cells, and induced a growth suppressing activity for bovine artery endothelial cells (BAEs) from themselves at a concentration of 100 micrograms/ml. The suppressing activity was also detected in the mouse serum administered as an i.p. injection of CMCD at a dose of 100 mg/kg, suggesting that the growth suppressing activity was induced from macrophages potentiated by CMCD in vivo.

Polysaccharides in fungi. XXXV. Anti diabetic activity of an acidic polysaccharide from the fruiting bodies of Tremella aurantia

An acidic polysaccharide (TAP) was isolated from a hot-water extract of the fruiting bodies of Tremella aurantia. It showed remarkable hypoglycemic activity in normal mice and two diabetic mouse models, streptozotocin-induced diabetes and genetic diabetes, following intraperitoneal administration. Continuous oral administration of TAP solution (0.5g/l) for a long period was found to be also effective in hyperglycemia in glucose-loaded mice and no harmful physical effects were found. TAP had an [alpha]D -7 degrees in water, and its molecular weight was estimated to be about 1500000. TAP is composed of mannose, xylose, glucuronic acid and glucose (molar ratio, 4:2:1:0.3), and it contains 2.2% of O-acetyl groups.

(1----3)-alpha-D-glucan from an alkaline extract of Agrocybe cylindracea, and antitumor activity of its O-(carboxymethyl)ated derivatives

The structure of an alkali-soluble D-glucan (AG-AL) from the fruit body of Agrocybe cylindracea was investigated by a combination of chemical and spectroscopic methods indicating that it was a linear (1----3)-alpha-D-glucan (molecular weight, approximately 560,000), [alpha]20D +195 degrees (c 0.5, M sodium hydroxide). Both water-soluble and gelatinous products obtained by O-(carboxymethyl)ation of AG-AL showed potent antitumor activity against the solid form of Sarcoma 180 in mice, although the native D-glucan had little effect on the tumor.

Rational design of antitumor prostaglandins with high biological stability

microolecular design can overcome the metabolic instability of Delta7-PGA1, while maintaining its antitumor potency. Saturation of the C(13)-C(14) double bond enhances the biological stability but decreases the antiproliferative activity. Configurational inversion of the isomerase-sensitive C(12) stereocenter from the natural S to the unnatural R geometry not only enhances biological stability but also significantly suppresses the growth of the tumor cells. The 12R derivatives markedly increase the induction of p21, a Cdk inhibitor, leading to sharp cell cycle arrest at the G1 phase at a dose level so low that at this dose Delta7-PGA1 methyl ester scarcely exerts an effect. These conspicuous biological properties lead to long-term suppression of tumor cell growth. The structure-stability relationship demonstrates that the stability of prostaglandins (PGs) is crucially controlled by the C(12) configuration and is unaffected by the geometry of the hydroxy-bearing C(15). The successful design of antitumor PGs resistant to enzymatic metabolism provides a new strategy applicable to creating a useful PG for cancer chemotherapy.

[Polysaccharides in fungi. XXXIII. Hypoglycemic activity of an acidic polysaccharide (AC) from Tremella fuciformis]

Glucuronoxylomannan (AC) from the fruiting bodies of Tremella fuciformis exhibited a significant dose-dependent hypoglycemic activity in normal mice and also showed a significant activity in streptozotocin-induced diabetic mice, by intraperitoneal (i.p.) administration. The activities of AC-derivatives such as a product of AC which side chains had been removed were lower than that of native AC. AC raised the plasma insulin level in normal mice. Administration of AC to normal mice significantly increased the activities of hepatic hexokinase and glucose-6-phosphatase dehydrogenase, but it decreased that of hepatic glucose-6-phosphatase. Furthermore, AC reduced the glycogen content in the liver, increased the total lipid in epididymal adipose tissue, and lowered the plasma cholesterol level. The foregoing results indicated that the hypoglycemic activity of AC in normal mice was at least responsible for the increase of insulin secretion and for the acceleration of glucose metabolism. Single oral administration at a dose of 50-300 mg/kg of AC did not affect the plasma glucose level in normal mice, but continuous oral administrations of the AC solution (0.75 g/l) instead of water for a long time was found to be effective on the plasma glucose level in both experiments of the mice injected once i.p. with streptozotocin (170 mg/kg) at 0 d of AC administration and streptozotocin-induced diabetic mice.

Polysaccharides in fungi. XIV. Anti-inflammatory effect of the polysaccharides from the fruit bodies of several fungi

Anti-inflammatory assays on the carrageenin-induced edema and scald-induced hyperalgesia in the hindpaw of rats were studied on polysaccharides obtained from the fruit bodies of various fungi (polysaccharide AC, BC: Tremella fuciformis;MEA, MHA, MCW-A, MCW-N: Auricularia auricula-judae; T-2-HN: Dictophora indusiata;G-A: Ganoderma japonicum). The purified polysaccharides MHA, MCW-A, G-A and T-2-HN exhibited a significant inhibitory effect on carrageenin edema. Among these polysaccharides, T-2-HN (partially O-acetylated alpha-D-mannan) also showed the marked inhibitory effect on scald hyperalgesia. We have found that T-2-HN has more potent anti-inflammatory activity than phenylbutazone in the above two inflammatory models. Since the purified polysaccharide is free from protein and lipid, it is clear that anti-inflammatory effect arises from the polysaccharide itself. The polysaccharides (T-2-HN, locust bean gun, xanthan gum) had little effect on the metabolism of arachidonic acid in canine platelets. The mechanism of the anti-inflammatory activity of the polysaccharide remains obscure.

Polysaccharides in fungi. XXXVII. Immunomodulating activities of carboxymethylated derivatives of linear (1-->3)-alpha-D-glucans extracted from the fruiting bodies of Agrocybe cylindracea and Amanita muscaria

Immunomodulating activities of three carboxymethylated derivatives (AG-AL-CMS, AG-AL-CMI, and AM-APP-CM) of linear (1-->3)-alpha-D-glucans from Agrocybe cylindracea and Amanita muscaria were evaluated with murine peritoneal macrophages playing an important role in tumor immunity. The ratio of macrophages in peritoneal exudate cells increased more than 50% after the administration of three carboxymethylated (1-->3)-alpha-D-glucans. These carboxymethylated (1-->3)-alpha-D-glucans exhibited higher potentiating activities for macrophages than carboxymethylated linear (1-->3)-beta-D-glucan (CMPS) in the potency of reduction of nitro blue tetrazolium, products of nitric oxide and the soluble cytotoxic factor, the amount of glucose consumption, and the activation of acid phosphatase. AG-AL-CMS, AG-AL-CMI, and AM-APP-CM were found to induce the tumor regressing factor in mouse serum, although the ability of the induction of this factor was weaker than that of CMPS. The reticuloendothelial system-potentiating activation of three carboxymethylated alpha-D-glucans was similar to that of the carboxymethylated beta-D-glucan. AG-AL-CMS and AG-AL-CMI, but not AM-APP-CM, were suggested to possess a higher-order structure, resulting from the formation of a fluorescent complex with aniline blue.

Antidiabetic effect of an acidic polysaccharide (TAP) from Tremella aurantia and its degradation product (TAP-H)

Continuous oral administration of the acidic polysaccharide (TAP) solution (0.5 g/l) and the TAP-H (degradation products of TAP) solution (1.5 g/l) instead of water for 10 weeks were found to depress plasma glucose increases in diabetes using genetically non-insulin-dependent diabetic model (KK-Ay) mice. TAP and TAP-H significantly lowered levels of insulin, total-cholesterol and triglyceride in the blood of the mice. In excretion to feces, TAP and TAP-H significantly increased the total bile acid, while the cholesterol content of both groups was less than that of the control. Furthermore, TAP and TAP-H significantly decreased the plasma lipoperoxide level. The study shows that TAP and TAP-H have an antidiabetic effect on diabetes model mice.

Potent prostaglandin A1 analogs that suppress tumor cell growth through induction of p21 and reduction of cyclin E

Although the cyclopentenone prostaglandin A1 (PGA1) is known to arrest the cell cycle at the G1 phase in vitro and to suppress tumor growth in vivo, its relatively weak activity limits its usefulness in cancer chemotherapy. In an attempt to develop antitumor drugs of greater potency and conspicuous biological specificity, we synthesized novel analogs based on the structure of PGA1. Of the newly synthesized analogs, 15-epi-delta7-PGA1 methyl ester (NAG-0092), 12-iso-delta7-PGA1 methyl ester (NAG-0093), and ent-delta7-PGA1 methyl ester (NAG-0022) possess a cross-conjugated dienone structure around the five-member ring with unnatural configurations at C(12) and/or C(15) and were found to be far more potent than native PGA1 in inhibiting cell growth and causing G1 arrest in A172 human glioma cells. These three analogs induced the expression of p21 at both RNA and protein levels in a time- and dose-dependent fashion. Kinase assays with A172 cells treated with these analogs revealed that both cyclin A- and E-dependent kinase activities were markedly reduced, although cyclin D1-dependent kinase activity was unaffected. Immunoprecipitation-Western blot analysis showed that the decrease in cyclin A-dependent kinase activity was due to an increased association of p21 with cyclin A-cyclin-dependent kinase 2 complexes, whereas the decrease in cyclin E-dependent activity was due to a combined mechanism involving reduction in cyclin E protein itself and increased association of p21. Thus, these newly synthesized PGA1 analogs may prove to be powerful tools in cancer chemotherapy as well as in investigations of the structural basis of the antiproliferative activity of A series prostaglandins.

Polysaccharides in fungi. XXVI. Two branched (1----3)-beta-D-glucans from hot water extract of Yu ĕr

Two water-insoluble glucans, U-3-N ([alpha]D +1.0 degree, 0.5 M sodium hydroxide) and U-3-AP1 ([alpha]D +2.5 degrees, 1 M sodium hydroxide) were isolated from hot-water extract of the fruiting bodies of Yũ ĕr (Chinese name) (Auricularia sp.). U-3-N and U-3-AP1 were investigated by a combination of chemical and spectroscopic methods. The results indicated that U-3-N (molecular weight, 6.1 x 10(5)) was similar to beta-(1----6)-branched (1----3)-beta-D-glucan (N-5P: molecular weight, 5.6 x 10(5)) isolated from the alkaline extract of the fruiting bodies, and U-3-AP1 (molecular weight, 6.3 x 10(4)) was beta-(1----6)-branched (1----3)-beta-D-glucan containing beta-(1----6)-linked D-glucopyranosyl residues. U-3-N showed potent anti-tumor activity against the solid form of sarcoma 180, although U-3-AP1 had little effect on the tumor.

Polysaccharides in fungi. XXX. Antitumor and immunomodulating activities of two polysaccharides from the fruiting bodies of Armillariella tabescens

The effects of two polysaccharides, AT-HW and AT-AL obtained from the fruiting bodies of Armillariella tabescens on murine sarcoma 180 tumor and peritoneal macrophages were examined at intraperitoneal administration. AT-HW from the hot-water extract and AT-AL from the alkaline extract significantly inhibited the tumor, and the results of different administration schedule and phagocytic system blockade suggested that the mechanism of AT-AL differed from that of AT-HW and branched (1----3)-beta-D-glucans. AT-HW and AT-AL showed reticuloendothelial system-potentiating activity, increased the number of peritoneal exudate cells, activated on macrophages (acid phosphatase activity, glucose consumption, superoxide anion production), and enhanced mitogenic reaction, although AT-HW did not produce superoxide anion in vitro.

Structure and antitumor activity of a branched (1----3)-beta-D-glucan from the alkaline extract of Amanita muscaria

A beta-(1----6)-branched (1----3)-beta-D-glucan(AM-ASN) was isolated from the alkaline extract of the fruiting bodies of Amanita muscaria. AM-ASN had [alpha]D - 11 degrees in 0.5 M sodium hydroxide. Its estimated molecular weight was 95,000 in this alkaline solution and 260,000 in a neutral solution. The branches in the glucan were primarily single, (1----6)-linked D-glucopyranosyl groups, two for every seven residues in the (1----3)-linked main chain. AM-ASN exhibited significant antitumor activity against Sarcoma 180 in mice, and a mixture of AM-ASN with mitomycin C was more effective against the tumor than mitomycin C only.

Effect of a polysaccharide (TAP) from the fruiting bodies of Tremella aurantia on glucose metabolism in mouse liver

An acidic polysaccharide (TAP) obtained from the fruiting bodies of Tremella aurantia significantly increased the activities of glucokinase, hexokinase, and glucose-6-phosphate dehydrogenase, and decreased the activity of glucose-6-phosphatase in normal and diabetic mouse liver after intraperitoneal administration, while the glycogen content in the liver was reduced. Furthermore, TAP lowered the plasma cholesterol level in normal and diabetic mice.

Structural features of an anti-diabetic polysaccharide (TAP) from Tremella aurantia

The structure of an anti-diabetic polysaccharide (TAP) obtained from the fruiting bodies of Tremella aurantia was investigated by methylation analysis, Smith degradation, partial acid hydrolysis, 13C-NMR spectrometry, and enzymatic digestion. The results suggested that TAP was composed of (1-->3)-linked alpha-D-mannopyranosyl residues as a backbone, some of which were substituted at position 2 with (1-->3)-linked beta-D-xylopyranose side chains and with beta-D-glucopyransyluronic acid at position 4 linked to terminal alpha-D-mannopyranose.