Report: structures and hepatocytotoxicity of co-occurring substances in oleanolic acid tablets

Tablets of oleanolic acid (OA) have been approved by SFDA in China as an adjuvant therapy for acute and chronic hepatitis. Co-occurring substances present in the tablets of OA and their hepatocytotoxicity have not yet been reported. In the current investigation, the crude OA drug was separated by repeated column chromatography. The structures of the isolated compounds were characterized by spectral analysis and the cytotoxicity of each compound was evaluated in vitro against the human normal liver cell L02 at concentrations from 0.125 to 1000 μmol/L using the MTT method. As a result, OA and its 11 co-occurring trace compounds including one new triterpenoid, 3-O- (4-oxo-pentanoyl)-olean-12- en-28-oic acid, were isolated and structurally characterized. Cytotoxicity tests indicated that these compounds were all non-toxic at concentrations up to 50μmol/L. Clear structure-activity relationship (SAR) was also observed. The results suggested that OA tablets of similar origin might not cause obvious cytotoxicity to the normal liver cell. The work may facilitate further SAR studies of OA-type triterpenoids.

Novel dammarane-type sapogenins from Panax ginseng berry and their biological activities

Three new dammarane-type sapogenins (1, 3, and 5) together with two known ones (2 and 4) were isolated from the total hydrolyzed saponins extracted from Panax ginseng berry. Their structures were elucidated using a combination of 1D and 2D (1)H and (13)C NMR spectra and mass spectroscopy as 20(R)-25-methoxyl-dammarane-3β,12β,20-triol (1), 20(R)-25-methoxyl-dammarane-3β,6α,12β,20-tetrol (2), 20(R)-20-methoxyl-dammarane-3β,12β,25-triol (3), 20(R)-20,25-dimethoxyl-dammarane-3β,12β-diol (4), and (12R,20S,24S)-20,24-; 12,24-diepoxy-dammarane-3β-ol (5). Their antitumor activities were evaluated in six human cancer cell lines. The novel compounds 1 and 3 showed significant cytotoxic activity against the six cell lines. The IC(50) values of 3 against HepG2, Colon205, and HL-60 were the lowest (8.78, 8.64, and 3.98 μM, respectively). Compounds 1 and 20(S)-25-OCH(3)-PPD, which are a pair of configuration isomers, showed a 10- to 100-fold greater growth inhibition than ginsenoside-Rg(3) (an anti-cancer clinical agent in China). The data presented here may be useful for the development of novel anti-cancer agents.

Sapogenin levels in Narthecium ossifragum plants and Ovis aries lamb faeces during two alveld outbreaks in Møre og Romsdal, Norway, 2001

The proposal that saponins produced by the lily bog asphodel (Narthecium ossifragum) may be the direct cause of the hepatogenous photosensitization disease alveld seen in Norwegian lambs was investigated by comparing sapogenin levels in two control and two toxic pastures, and in faeces from lambs grazing the four pastures in the Halsa and Surnadal municipalities, Møre og Romsdal county, Norway. Generally similar levels of sapogenins, determined after hydrolysis of parent plant saponins, were found in Narthecium leaves collected in June/July 2001 from the two alveld outbreak areas and two nearby control areas. Differences in the median sapogenin levels determined for leaf samples in outbreak and control areas were not statistically significant. The total level of free and conjugated sapogenins in faeces recovered from the rectums of lambs grazing the outbreak and control pastures areas varied greatly. The results obtained do not support the hypothesis that a dose-response relationship exists between Narthecium saponin levels and the occurrence of alveld outbreaks.

Mechanistic studies on protopanaxadiol, Rh2, and ginseng (Panax quinquefolius) extract induced cytotoxicity in intestinal Caco-2 cells

Certain ginsenosides, also known as triterpene glycosides, have been recently reported to have a characteristic effect on cultured intestinal and leukemia cell growth. Ginsenoside aglycones 20(S)-protopanaxadiol (PD), 20(S)-protopanaxatriol (PT), and ginsenoside Rh2 have been identified as having a strong effect on reducing cell viability. Furthermore, ginsenoside Rh2 is thought to be a rare ginsenoside not found in all ginseng products. Rather, Rh2 has been recently reported to be a breakdown product of thermal processing of North American ginseng. In this study, pure ginsenosides PD, PT, Rh2 standards and an enriched Rh2 fraction derived from ginseng leaf were tested in cultured Caco-2 cells for relative cytotoxic potency. PD and Rh2 LC50 were similar after 24 to 72 h, whereas a drop in PT LC50 occurred later at 48 and 72 h. Furthermore, PD and Rh2 affected membrane integrity as indicated by LDH secretion earlier than PT and the enriched Rh2 fraction (P < or = 0.05). Ginsenoside Rh2 showed the greatest (P < or = 0.05) build up of necrotic cells (18.3 +/- 0.1%) at the respective LC50 after 24 h and PD (21.3 +/- 0.3%) showed the largest effect after 44 h of exposure. The effect on apoptotic cells at 44 h of treatment were significantly different (P < or = 0.05) for Rh2 (21 +/- 0.4%), PD (14.6 +/- 0.1%), enriched Rh2 leaf fraction (9.9 +/- 0.6%), and PT (2.3 +/- 0.1%) treatments. Caco-2 caspase-3 activity was different between ginsenoside exposure; Rh2 (10.6 +/- 0.3 nM pNA) had the greatest (P < or = 0.05) activity followed by the enriched Rh2 leaf fraction (8.3 +/- 0.2 nM pNA), PT (7.3 +/- 0.3 nM pNA). The PD (4.8 +/- 0.04 nM pNA) treatment was similar to untreated cells (4.3 +/- 0.05 nM pNA) in caspase-3 activity. These results show variable bioactive response in cultured intestinal cell to specific ginsenosides and an enriched Rh2 North American ginseng extract which may be explained on basis of hydrophobic/hydrophilic balance.

Altered immunomodulating and toxicological properties of degraded Quillaja saponaria Molina saponins

Quillaja saponins are readily hydrolyzed under physiological conditions, yielding deacylated forms that are significantly less toxic than their precursors. Yet, deacylated saponins are unable to stimulate a strong primary immune response. Although deacylated saponins elicit a strong total IgG response, their capacity to stimulate a Thl type IgG isotype profile (i.e. high levels of IgG2a and IgG2b) has been significantly diminished. Instead, an IgG profile closer to that of a Th2 immune response is stimulated (i.e. high IgG1 levels). Deacylated saponins have also lost their capacity to elicit an effective T cell immunity, as shown by their stimulation of a marginal lymphoproliferative response and their inability to elicit the production of cytotoxic lymphocytes (CTL). Modification of the immune-modulating properties brought by the degradation of quillaja saponins during vaccine storage may change the intended immune response from a Th1 to a Th2 type. This alteration would have negligible effects on vaccines depending on Th2 immunity mediated by neutralizing antibodies. However, the performance of vaccines directed against intracellular pathogens as well as therapeutic cancer vaccines may be seriously affected by the loss of their capacity to stimulate both a Th1 immune response and the production of CTL.

Isolation of steroidal sapogenins implicated in experimentally induced cholangiopathy of sheep grazing Brachiaria decumbens in Brazil

As part of an experimental study, crystal-associated cholangiopathy was induced in 9 sheep by grazing pure pastures of Brachiaria decumbens in Brazil. One of these sheep showed characteristic lesions of photosensitization. The analysis of the B decumbens samples by acidic hydrolysis followed by TLC and infrared spectrum revealed diosgenin as the principal sapogenin present in the plant. In the rumen contents samples from the B decumbens-grazing group were identified by TLC, 1H and 13C NMR and EIMS as epismilagenin, episarsasapogenin, and a mixture of smilagenin and sarsasapogenin. In the bile samples from the B decumbens-grazing group, TLC analysis demonstrated 2 compounds similar to epismilagenin and episarsasapogenin. However, by this same method, those compounds were not observed in the rumen contents and bile from 2 sheep which served as control animals. The P chartarum spore counts remained very low during the experimental period.

Anti-inflammatory activity of aqueous extracts and steroidal sapogenins of Agave americana

Lyophilized aqueous extracts obtained from Agave americana L (Agavaceae) collected in the north of Sardinia were characterized with regard to their steroidal sapogenin content. Extracts of A. americana and genins isolated from them were evaluated for anti-inflammatory properties by testing their effects on carrageenin-induced edema. The effect of orally administered genins on gastric mucous membranes was also assessed. Lyophilized extracts administered by the intraperitoneal route at doses equivalent to 200 and 300 mg/kg of fresh plant starting material, showed good anti-inflammatory activity. Doses of genins (total steroidal sapogenins, hecogenin and tigogenin) equivalent to the amount in the lyophilized extracts produced an antiedentatous effect which was much stronger and more efficacious than that obtained with an i.p. administration of 5 mg/kg of indomethacin or dexamethasone 21-phosphate at a dose equivalent to the molar content of hecogenin administered. At the doses used to evaluate the anti-inflammatory activity, the genins did not have any harmful effect on the gastric mucous membranes. Lesions occurred when significantly higher doses of hecogenin were given, but gastric damage was still less than that caused by the drugs used for comparative purposes.

Saikosaponin A-induced cell death of a human hepatoma cell line (HuH-7): the significance of the 'sub-G1 peak' in a DNA histogram

Saikosaponin A (SSA) induced cell death in the human hepatoma cell line (HuH-7) was investigated. Shortly after exposure to SSA, a DNA histogram showed a 'sub-G1 peak', which was recently reported as suggestive of apoptosis by other researchers. However, the electrophoresis of DNA indicated that such was not the case in the present experiment. The decreased intake of rhodamine 123 and the swelling of mitochondria were remarkable shortly after SSA exposure. These data seem to support the idea that the sub-G1 peak represents necrosis rather than apoptosis. Interestingly, the DNA electrophoresis revealed the smear pattern of small DNA fragments shortly after SSA-exposure, although it did not show the apoptotic ladder pattern. This finding and the appearance of the 'sub-G1 peak' is thought to have been a result of the degradation of the nuclear DNA in the early stages of cell death. Because these findings are different not only from apoptosis, but also from typical necrosis, a distinct mechanism of cell death caused by SSA is suggested.

Toxicity of isolated Lantana (Lantana camara L) constituents to male and female guinea pigs

A toxin fraction was obtained from Lantana camara L (red variety) leaves by batch extraction and column chromatography on silica gel (60-120 mesh). The main constituents of the toxin preparation were lantadene A and lantadene B and it was devoid of reduced lantadene A. Oral administration (125 mg/kg bwt) of the toxin to male and female guinea pigs caused icterus and photosensitization within 48 hr. All the affected animals had hepatomegaly and significant increases in conjugated and unconjugated bilirubin in blood plasma. The intoxicated animals of either sex had marked increases in acid phosphatase activity which was inhibited 45.77% and 49.35% by 1 mM tartrate in male and female animals respectively. The corresponding inhibition of acid phosphatase activity in control male and female guinea pigs was 15.91% and 20.33% respectively.

Effects of saikosaponin-d on enhanced CCl4-hepatotoxicity by phenobarbitone

The effects of saikosaponin-d extracted from the roots of Buplerum falcatum L. on increased toxicity of CCl4 and increased activities of microsomal enzymes induced by phenobarbitone have been examined. Saikosaponin-d showed protection against the CCl4-hepatotoxicity enhanced by phenobarbitone. It also inhibited increases in the content of cytochrome P450 and NADPH-cytochrome c reductase activity, which are induced by the phenobarbitone treatment, but the spectral characteristics of P450 were not altered. The rate of microsomal lipid peroxidation by NADPH and CCl4 was significantly lowered in-vitro in rats pretreated with phenobarbitone and saikosaponin-d compared with those pretreated with phenobarbitone alone.

Effects of saikosaponin-d on enhanced CCl4-hepatotoxicity by phenobarbitone

The effects of saikosaponin-d extracted from the roots of Buplerum falcatum L. on increased toxicity of CCl4 and increased activities of microsomal enzymes induced by phenobarbitone have been examined. Saikosaponin-d showed protection against the CCl4-hepatotoxicity enhanced by phenobarbitone. It also inhibited increases in the content of cytochrome P450 and NADPH-cytochrome c reductase activity, which are induced by the phenobarbitone treatment, but the spectral characteristics of P450 were not altered. The rate of microsomal lipid peroxidation by NADPH and CCl4 was significantly lowered in-vitro in rats pretreated with phenobarbitone and saikosaponin-d compared with those pretreated with phenobarbitone alone.

Preliminary pharmacobiological study of new steroidal sapogenins

The chemotherapeutic study of a limited series of steroidal sapogenins from several endemic species of the flora of the Canary Islands is presented here. On the whole, they possess a very weak antibacterial activity, a slight antifungal effect and one of them, vespertilin, displays interesting cytostatic activity (ID50 = 5 micrograms/ml). A pharmacodynamic screening carried out on this product mainly revealed very slight toxicity, antihistaminic activity and a light tranquilizing effect. The data obtained justify further research.

Fragility of erythrocytes in animals affected by lantana poisoning

Clinical observations on four male cow calves and three other lantana poisoned animals under field conditions have been made along with hematological studies, including observations on plasma bilirubin content and osmotic fragility of erythrocytes. Four healthy male cow calves served as control. Five clinically advanced cases succumbed within 1 to 10 days of observation. Hematocrit values in four of the seven affected animals were abnormally high. The total plasma bilirubin content in the fatal cases was of the order of 5 to 50 times the normal value while, in calves that recovered, it was not more than 3 times. The osmotic fragility of erythrocytes was measured by the rate of hemolysis in decreasing concentrations of saline. The erythrocytes of normal animals resisted hemolysis till the saline concentration was lowered to 0.60%, and it was complete at the low saline concentration of 0.30%. However, in lantana poisoned animals, hemolysis started even in 0.72% saline and was complete at a saline concentration of 0.44%. The hemolysis curves of animals that died were far removed from the normal, but those of the calves that recovered and the one that died but had the lowest bilirubin content closely approached the normal curve.

Effect of food toxicants on voluntary wheel running in rats

Voluntary wheel running in rats in reaction to a dietary deficiency of iron or food toxicants of natural (dioscin) and environmental (cadmium) origins was used to develop a behavioral model by which rapid detection of food contaminants was accomplished following induction of spontaneous activity by techniques of feed restriction. High levels of voluntary wheel running in reference controls were followed by significant depressions in running activity in animals fed the dietary toxicants. Analyses of blood and liver tissues and depressions of testes size confirmed the presence of the insults to metabolism.