Effects of buckwheat in a renal ischemia-reperfusion model.

Experiments were done to find whether buckwheat extract ameliorates the renal injury induced by ischemia-reperfusion. In ischemic-reperfused control rats, the activities of antioxidative enzymes in renal tissue and blood and renal parameters deviated from the normal range, indicating dysfunction of the kidneys. In contrast, when buckwheat extract was given orally for 20 consecutive days before ischemia and reperfusion, the activities of the antioxidation enzymes superoxide dismutase, catalase, and glutathione peroxidase were higher, while thiobarbituric acid-reactive substance levels in serum and renal tissue were lower in the treated rats than in the controls. Decreased levels of urea nitrogen and creatinine in serum demonstrated a protective effect against the renal dysfunction caused by ischemia and recirculation. On the other hand, it was demonstrated that buckwheat extract had a protective effect on cultured proximal tubule cells subjected to hypoxia-reoxygenation, probably by preventing oxygen free radicals from attacking the cell membranes.

Antiproliferative constituents in the plant 8. Seeds of Rhynchosia volubilis.

The MeOH extract of the seeds of Rhynchosia volubilis (Leguminosae) showed antiproliferative activity against human gastric adenocarcinoma [MK-1, 50% growth inhibition (GI50): 25 microg/ml], human uterus carcinoma (HeLa, GI50: 30 microg/ml), and murine melanoma (B16F10, GI50: 8 microg/ml) cells. Bioactivity-guided fractionation resulted in the isolation of gallic acid methylester (1), gallic acid (2), 7-O-galloylcatechin (3), 1,6-di-O-galloylglucose (4), 1-O-galloylglucose (5), and trigalloylgallic acid (6), and their antiproliferative activity was estimated. All showed much stronger inhibition against B16F10 cell growth than against HeLa and MK-1 cell growth. Compound 2 and its tetramer (6) with a free carboxyl group showed higher activity than those which did not have a free carboxyl group. In relation to the gallic acid tetramer (6), two gallic acid dimers (ellagic acid and dehydrodigallic acid) and trimers (tergallic acid dilactone and flavogallonic acid dilactone) were tested for their activity, and compared with those of the isolates.

Study on the inhibitory effect of tannins and flavonoids against the 1,1-diphenyl-2 picrylhydrazyl radical.

Fifty-one tannins and forty-one flavonoids isolated from Oriental medicinal herbs were evaluated for their antioxidant ability with a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-generating system. The results showed that tannins and certain flavonoids are potential free-radical scavengers, and that their activity against the DPPH radical is closely associated with their chemical structure. A comparison of the two classes of compounds showed that tannins have more potential than flavonoids because almost all the tannins demonstrated significant scavenging action within a low concentration range, whereas the activity of flavonoids varied distinctively among the different compounds. An increase of galloyl groups, molecular weight, and ortho-hydroxyl structure enhanced the activity of tannins, whereas the number and position of hydroxyl groups were important features for the scavenging of free radicals by flavonoids. Moreover, it appeared that when the free hydroxyl group was methoxylated or glycosylated, the inhibitory activity was obviously decreased or even abolished.

Magnesium lithospermate B suppresses the increase of active oxygen in rats after subtotal nephrectomy.

Subtotally nephrectomized rats were found to have decreased activities of superoxide dismutase (SOD) and catalase, and spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) showed that the amount of hydroxyl radical in the residual kidney tissue was greater than that in normal rat kidney. This indicated both direct and indirect involvement of free radicals in renal failure. In contrast, rats given magnesium lithospermate B (10 mg/kg body weight) orally for 30 days after subtotal nephrectomy showed restoration of SOD and catalase activities to almost normal levels. Hydroxyl radical, which is highly reactive and for which there is no scavenger system in the body, was decreased markedly in kidney homogenates obtained from rats given magnesium lithospermate B and in an experimental system for hydroxyl radical production to which magnesium lithospermate B was directly added. The increased levels of uremic toxins in the blood were also low in rats given magnesium lithospermate B. This indicates that magnesium lithospermate B helps to inhibit the progression of renal failure by scavenging radicals.

Magnesium lithospermate B ameliorates cisplatin-induced injury in cultured renal epithelial cells.

A study was conducted to clarify whether magnesium lithospermate B ameliorates cisplatin-induced renal injury in terms of lactate dehydrogenase and malondialdehyde leakage from LLC-PK1 cells in culture. Magnesium lithospermate B was shown to suppress the cytotoxicity of cisplatin, the suppressive effect increasing with the dose of magnesium lithospermate B.

Anti-AIDS agents, 18. Sodium and potassium salts of caffeic acid tetramers from Arnebia euchroma as anti-HIV agents.

Monosodium and monopotassium salts [2-4] of isomeric caffeic acid tetramers were isolated from Arnebia euchroma as anti-HIV agents. Mixtures of dipotassium and disodium salts [1] of a caffeic acid tetramer and dipotassium and potassium-sodium salts [5] of a caffeic acid tetramer glucoside were also isolated from the active fraction. The structures of 1-5 were characterized by chemical and spectral evidence. Compounds 2-4 demonstrated potent anti-HIV activity with EC50 values of 2.8, 4.0, and 1.5 micrograms/ml, respectively. Treatment of 1-4 with dilute HCl yielded known caffeic acid tetramers [8 and 9], which were found to be less active, indicating the importance of the sodium and potassium salts to the enhanced anti-HIV activity.

Effects of a Dan Shen component, magnesium lithospermate B, in nephrectomized rats.

Magnesium lithospermate B, a compound newly isolated from Dan Shen, was given orally to rats for 70 days after excision of five-sixths of their kidney volume. As a result, mesangial proliferation, tubulo-interstitial lesions and glomerular sclerotic lesions, which were conspicuous in rats that were not given magnesium lithospermate B after nephrectomy, were inhibited. Furthermore, a decrease in blood urea nitrogen, improvement of hypoproteinemia, hypoalbuminemia and hypercholesteremia, and inhibition of urinary protein excretion were observed. The levels of creatinine, methylguanidine and guanidino-succinic acid, which accumulate in the blood with the progress of renal failure, were decreased significantly in rats given magnesium lithospermate B. These results indicate that magnesium lithospermate B, a component of an Oriental medicine has potential as a new therapeutic agent for inhibiting the progression of renal dysfunction.

Identification of an active principle in essential oils and hexane-soluble fractions of Curcuma xanthorrhiza Roxb. showing triglyceride-lowering action in rats.

Curcuma xanthorrhiza Roxb. (C. xanthorrhiza), known as temu lawak or Javanese turmeric, has been traditionally used in Indonesia for food and medicinal purposes. As little attention has been focused on the role of C. xanthorrhiza in lipid metabolism, the hypotriglyceridaemic activity and the active principles of the essential oil and hexane-soluble fractions prepared from C. xanthorrhiza were investigated in rats. The major component (approx. 65%) of the essential oil was identified as alpha-curcumene by capillary gas chromatography/mass spectrometry. Addition of essential oils (0.02%), prepared by steam distillation, to a purified diet resulted in a lower hepatic triglyceride concentration without influencing the serum triglyceride, whereas addition of the hexane-soluble fraction (0.5%) resulted in a lower concentration of serum as well as liver triglycerides. Rats fed the essential oil and hexane-soluble fraction had lower hepatic fatty acid synthase activity. The fraction containing alpha-curcumene, prepared from the hexane-soluble fraction by silica gel column chromatography, suppressed the synthesis of fatty acids from [14C]acetate in primary cultured rat hepatocytes. Thus, alpha-curcumene is one of the active principles exerting triglyceride-lowering activity in C. xanthorrhiza.

Tannins and related compounds. CXXII. New dimeric, trimeric and tetrameric ellagitannins, lambertianins A-D, from Rubus lambertianus Seringe.

Chemical examination of the leaves of Rubus lambertianus Seringe (Rosaceae) has led to the isolation of four new ellagitannins, which were characterized on the basis of chemical and spectroscopic evidence to be dimers [lambertianins A (6) and B (7)], a trimer [lambertianin C (8)] and a tetramer [lambertianin D (10)], all having sanguisorbic acid ester group(s) as linking unit(s) between glucopyranose moieties. Furthermore, HPLC analyses of fifteen Rubus species collected in Japan and Taiwan revealed that the trimer (8) and the tetramer (10), together with sanguiin H-6 (1), occur widely in these species.

Inhibition of DNA topoisomerases by sanguiin H-6, a cytotoxic dimeric ellagitannin from Sanguisorba officinalis.

Many tannins were previously identified as candidate topoisomerase poisons. Here we report further studies on sanguiin H-6, a dimeric ellagitannin isolated from Sanguisorba officinalis as an inhibitor of DNA topoisomerases. Catalytic strand-passing activities of topoisomerases I and II were inhibited in vitro with IC50 values of 1 microM and 0.01 microM, respectively. This inhibition was not associated with stabilization of covalent enzyme-DNA complexes but rather by a mechanism preventing formation of such covalent intermediates, as measured by interference with drug-induced cleavage in vitro. The IC50 values for topoisomerase I-DNA complexes induced by camptothecin and with topoisomerase II-DNA complexes induced by VP-16 were 0.02 microM and 0.16 microM, respectively. Pre-incubation studies followed by drug-dilution revealed that the in vitro inhibitory effects of sanguiin H-6 were irreversible, and for topoisomerase I, the test compound prevented enzyme-DNA interaction as seen by shifts in mobility on agarose gels. By measuring interference with drug-induced protein-linked DNA breaks in isolated HeLa nuclei, inhibition of topoisomerases I and II on a natural chromatin template was demonstrated with IC50 values of 5 microM and > 10 microM, respectively. Sanguiin H-6 inhibited HeLa cell growth with an ED50 of 12 microM and also interfered in a dose-dependent fashion with intracellular topoisomerase activities but with lower potencies than those observed using subcellular assay systems. Based on these studies, sanguiin H-6 could be broadly classified as a type of poison which does not stimulate the formation of cleavable-complexes, with intracellular activity but without any marked selectivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of magnesium lithospermate B on the renal and urinary kallikrein activities in rats with adenine-induced renal failure.

A study was conducted to examine the effect of magnesium lithospermate B on both the urinary and renal total and active kallikrein and prokallikrein in rats with adenine-induced renal failure. In rats given magnesium lithospermate B at a dose of 10 mg/kg body weight/day for 12 days, significant increases of urinary total and active kallikrein were associated with significant increases of urine volume and urinary total and active kallikrein were associated with significant increases of urine volume and urinary creatinine excretion. The renal total and active kallikrein levels were also significantly elevated by the treatment with magnesium lithospermate B. On day 24, the urinary excretion of total and active kallikrein and prokallikrein was significantly increased. Concomitantly, a significant increase in renal kallikrein (total, active and pro-) was found in the rats given magnesium lithospermate B. A significant relationship existed between the urinary creatinine and active kallikrein excretion. These results suggest that magnesium lithospermate B may stimulate the synthesis of kallikrein and/or conversion to active kallikrein, thus improving renal function.

Effects of rhubarb tannins on renal function in rats with renal failure.

The effects of tannins purified from Rhei Rhizoma on various parameters of renal function were investigated in rats with adenine-induced renal failure. The glomerular filtration rate, renal plasma flow and renal blood flow were significantly increased in rats given (-)-epicatechin 3-O-gallate at a dose of 5 or 10 mg/kg body weight/day for 24 days. Administration of 5 mg of procyanidin B-2 3,3'-di-O-gallate also led to a significant increase in renal functional parameters. However, unlike the former two components, procyanidin C-1 3,3',3''-tri-O-gallate caused aggravation of renal function.

Antitumor agents, 129. Tannins and related compounds as selective cytotoxic agents.

Fifty-seven tannins and related compounds, including gallotannins, ellagitannins, and condensed and complex tannins, were evaluated for their cytotoxicities against human tumor cell lines, including malignant melanoma, lung carcinoma, ileocecal adenocarcinoma, epidermoid carcinoma, malignant melanoma, and medulloblastoma cell lines. Among them, chebulagic acid [1], geraniin [2], sanguiin H-11 [3], 4,5-di-O-galloylquinic acid [12], 1,3,4,5-tetra-O-galloylquinic acid [15], 1(beta)-O-galloylpedunculagin [24], furosin [29], castalagin [38], sanguiin H-2 [34], vescalagin [39], grandinin [40], phyllyraeoidin A [42], (-)-epicatechin 3-O-gallate [50], cinnamtannin B2 [55], and acutissimin A [56] exhibited moderate selective cytotoxicity against PRMI-7951 melanoma cells with ED50 values in the range of 0.1-0.8 microgram/ml. Selective cytotoxicities against the melanoma cells were also observed for strictinin [22], pedunculagin [23], eugeniin [25], elaeocarpusin [28], punicacortein C [37], casuarinin [41], sanguiin H-6 [43], procyanidin B-2 3,3'-di-O-gallate [51], procyanidin C-1 3,3',3"-tri-O-gallate [52], and cinnamtannin B1 [54] with ED50 values of 1-4 micrograms/ml. All of the tannins were found to be inactive (greater than 10 micrograms/ml) against lung carcinoma (A-549), ileocecal adenocarcinoma (HCT-8), epidermoid carcinoma of nasopharnyx (KB), and medulloblastoma (TE-671) tumor cells.

Effect of magnesium lithospermate B in rats with sodium-induced hypertension and renal failure.

To evaluate the antihypertensive effect of magnesium lithospermate B isolated from Salviae miltiorrhizae radix, determinations of blood pressure and urinary excretions of sodium, potassium, prostaglandin E2 (PGE2) and kallikrein, which have been proposed to play an important role in the regulation of blood pressure, were made in rats with sodium-induced hypertension and renal failure. In rats given magnesium lithospermate B, blood pressure was significantly decreased, whereas urinary excretion of electrolytes was significantly increased. Urinary PGE2 excretion following administration of magnesium lithospermate B increased as the dose of the compound was stepped up. The activity of kallikrein in urine was also increased by the treatment. From these results, the blood pressure-lowering action of magnesium lithospermate B may be due in part to enhancement of the kallikrein-prostaglandin system.

Potentiating effect of converting enzyme inhibitor captopril to the renal responses of magnesium lithospermate B in rats with adenine-induced renal failure.

The renal responses of magnesium lithospermate B were investigated in the presence or absence of pretreatment with the converting enzyme (kininase II) inhibitor, captopril, in rats with adenine-induced renal failure. Magnesium lithospermate B (10 mg/kg body weight) caused a marked increase in the levels of the renal functional parameters (glomerular filtration rate, renal plasma flow and renal blood flow), accompanied by significant increases in urinary excretions of prostaglandin E2 (PGE2), kallikrein, sodium and creatinine. The administration of magnesium lithospermate B in combination with captopril (2 mg/kg body weight, 2 times) caused a further increase in renal functional parameters, urinary sodium and creatinine excretions. However, the kallikrein activity was similar to the control level. There were no significant changes between urinary PGE2 following magnesium lithospermate B alone, or in combination with captopril. In addition, angiotensin converting enzyme activity did not change following the administration of magnesium lithospermate B alone, but was significantly decreased in rats given captopril, both alone and in combination with magnesium lithospermate B. The captopril administration group (captopril alone or in combination with magnesium lithospermate B) showed a significant decrease in blood pressure. From these results, it seems that the combination of magnesium lithospermate B and captopril induces a further increase in renal function by improving the renal circulatory state.

Effects of rhubarb tannins on uremic toxins.

The effects of each of several tannins purified from Rhei Rhizoma on serum constituents were investigated in rats with adenine-induced renal failure. Blood levels of urea nitrogen, methylguanidine (MG), and guanidinosuccinic acid (GSA) were significantly decreased in rats given (-)-epicatechin 3-O-gallate at a dose of 2.5, 5 or 10 mg/kg body weight/day for 24 days. The creatinine (Cr) level was also significantly decreased in rats given 5 and 10 mg of this compound. A significant decrease in urea nitrogen, MG, and GSA was found in rats given 6.25 mg of procyanidin B-2 3,3'-di-O-gallate. However, unlike the former two components the administration of 12.5 mg of procyanidin C-1 3,3',3''-tri-O-gallate produced a considerable or significant increase in bLood levels of urea nitrogen, Cr, MG, and GSA. RG-tannin had a weaker overall effect on serum constituents except for GSA in comparison with the corresponding effect of (-)-epicatechin 3-O-gallate and 6.25 mg of procyanidin B-2 3,3'-di-O-gallate. Rhatannin tended to increase the serum nitrogen constituents.

Augmentation of renal response by magnesium lithospermate B.

Magnesium lithospermate B and adenine were given simultaneously to rats p.o. in order to investigate their renal effects. In rats given magnesium lithospermate B at a dose of 5 mg/kg body weight/day for 12 or 24 days, glomerular filtration rate, renal plasma flow and renal blood flow were increased significantly. A significant increase in renal function parameters was also found in rats given 10 mg of magnesium lithospermate B. Urinary excretion of prostaglandin E2 was increased by administration of magnesium lithospermate B, while those of 6-keto-prostaglandin F1 alpha and thromboxane B2 were unaffected at a dose of 5 mg or 10 mg/kg body weight/day for 12 or 24 days. The activity of kallikrein in urine increased markedly and significantly in rats given 5 or 10 mg of magnesium lithospermate B for 12 or 24 days. From these results, it seems that magnesium lithospermate B increases renal function by improving the renal circulatory state through activation of kallikrein and promotion of prostaglandin E2 production.

Renal responses to magnesium lithospermate B.

Renal responses to magnesium lithospermate B isolated from Salviae miltiorrhizae radix were examined in normal rats. Urinary sodium, potassium, prostaglandin E2 and kallikrein excretion was significantly increased after magnesium lithospermate B administration, whereas excretion of urinary 6-keto-prostaglandin F1 alpha and thromboxane B2 was unchanged. Rats administered with the drug also revealed a slight elevation of plasma renin activity and the levels of angiotensins I and II. Plasma aldosterone was decreased slightly. No significant changes were observed in angiotensin-converting enzyme or blood pressure.

Magnesium lithospermate B improves renal function via the kallikrein-prostaglandin system in rats with renal failure.

The effect of magnesium lithospermate B on the renal responses of rats with renal failure was investigated in the presence and absence of pretreatment with the kallikrein inhibitor, aprotinin. Magnesium lithospermate B caused a marked increase in the levels of the renal functional parameters (glomerular filtration rate, renal plasma flow and renal blood flow), accompanied by significant increases in urinary prostaglandin excretion (increases of prostaglandin E2 and 6-keto-prostaglandin F1 alpha excretion by 82% and 36%, respectively). The urinary excretion of kallikrein was also increased following magnesium lithospermate B administration. However, pretreatment with aprotinin abolished the renal function-facilitating action of magnesium lithospermate B concomitantly with a markedly increased urinary excretion of prostaglandin E2, 6-keto-prostaglandin F1 alpha and kallikrein. These results suggest that the kallikrein-kinin-prostaglandin B.

Effect of magnesium lithospermate B on urinary prostaglandins in rats with renal failure.

Urinary excretion of prostaglandin E2 showed a significant increase following administration of magnesium lithospermate B [1] in rats with renal failure. In contrast, that of thromboxane B2 showed a significant decrease, indicating the improvement of renal failure.