Protection of rat hepatocytes exposed to CCl4 in-vitro by cynandione A, a biacetophenone from Cynanchum wilfordii

Natural compounds against nonalcoholic fatty liver disease: A review on the involvement of the LKB1/AMPK signaling pathway

Although various therapeutic approaches are used to manage nonalcoholic fatty liver disease (NAFLD), the best approach to NAFLD management is unclear. NAFLD is a liver disorder associated with obesity, metabolic syndrome, and diabetes mellitus. NAFLD progression can lead to cirrhosis and end-stage liver disease. Hepatic kinase B1 (LKB1) is an upstream kinase of 5'-adenosine monophosphate-activated protein kinase (AMPK), a crucial regulator in hepatic lipid metabolism. Activation of LKB1/AMPK inhibits fatty acid synthesis, increases mitochondrial β-oxidation, decreases the expression of genes encoding lipogenic enzymes, improves nonalcoholic steatohepatitis, and suppresses NAFLD progression. One potential opening for new and safe chemicals that can tackle the NAFLD pathogenesis through the LKB1-AMPK pathway includes natural bioactive compounds. Accordingly, we summarized in vitro and in vivo studies regarding the effect of natural bioactive compounds such as a few members of the polyphenols, terpenoids, alkaloids, and some natural extracts on NAFLD through the LKB1/AMPK signaling pathway. This manuscript may shed light on the way to finding a new therapeutic agent for NAFLD management.

Short and scalable synthesis of cynandione A

A two-step gram-scale synthesis of cynandione A is described. The key to success is the one-pot tandem oxidation/regioselective arylation of 1,4-hydroquinone in the presence of an excess amount of oxidant. Natural bond orbital charge analysis was performed in order to understand the regioselectivity of the arylation step. The highly practical and scalable synthesis developed herein is expected to assist the in-depth biological evaluation of cynandione A in various animal models.

Proliferation and Metabolic Profiling of Cynanchum wilfordii Adventitious Roots Using Explants from Different Cultivation Methods

Cynanchum wilfordii root is used in traditional herbal medicine owing to its various pharmacological activities. However, C. wilfordii roots are misused owing to their morphological similarities with C. auriculatum. Adventitious root (AR) culture can prevent such misuse, and the selection of plant materials is an important procedure for producing high-quality ARs. This study aimed to compare the proliferation and metabolic profiles of C. wilfordii ARs in two types of explants from different cultivation methods (either cultivated in open field (ECF) or cultivated on a heap of C. wilfordii (ECH)). After 4 weeks of culture, the proliferation rate and number and length of secondary ARs were determined, and 3/4 Murashige and Skoog (MS) salt medium, 4.92 μM indole-3-butyric acid (IBA), and 5% sucrose were suggested as the best proliferation conditions for ARs originating from both ECF and ECH. Through metabolic profiling, ARs from ECH were found to show higher accumulation patterns for flavonoids, polysaccharides, hydroxyacetophenones, aromatic amino acids, and mono-unsaturated fatty acids, which were ascribed to the activation of flavonoid biosynthesis, the phenylpropanoid pathway, and fatty acid desaturase, stimulated by abiotic stresses. In contrast, ARs from ECF had higher levels of TCA cycle intermediates, amino acids in the aspartate-glutamate pathway, and saturated and polyunsaturated fatty acids, indicating energy metabolism and plant development. Overall, the current study provided information on the optimal conditions for inducing C. wilfordii ARs with higher amounts of bioactive compounds.

S-Acetyl-Glutathione Attenuates Carbon Tetrachloride-Induced Liver Injury by Modulating Oxidative Imbalance and Inflammation

Liver fibrosis, depending on the stage of the disease, could lead to organ dysfunction and cirrhosis, and no effective treatment is actually available. Emergent proof supports a link between oxidative stress, liver fibrogenesis and mitochondrial dysfunction as molecular bases of the pathology. A valid approach to protect against the disease would be to replenish the endogenous antioxidants; thus, we investigated the protective mechanisms of the S-acetyl-glutathione (SAG), a glutathione (GSH) prodrug. Preliminary in vitro analyses were conducted on primary hepatic cells. SAG pre-treatment significantly protected against cytotoxicity induced by CCl4. Additionally, CCl4 induced a marked increase in AST and ALT levels, whereas SAG significantly reduced these levels, reaching values found in the control group. For the in vivo analyses, mice were administered twice a week with eight consecutive intraperitoneal injections of 1 mL/kg CCl4 (diluted at 1:10 in olive oil) to induce oxidative imbalance and liver inflammation. SAG (30 mg/kg) was administered orally for 8 weeks. SAG significantly restored SOD activity, GSH levels and GPx activity, while it strongly reduced GSSG levels, lipid peroxidation and H₂O₂ and ROS levels in the liver. Additionally, CCl4 induced a decrease in anti-oxidants, including Nrf2, HO-1 and NQO-1, which were restored by treatment with SAG. The increased oxidative stress characteristic on liver disfunction causes the impairment of mitophagy and accumulation of dysfunctional and damaged mitochondria. Our results showed the protective effect of SAG administration in restoring mitophagy, as shown by the increased PINK1 and Parkin expressions in livers exposed to CCl4 intoxication. Thus, the SAG administration showed anti-inflammatory effects decreasing pro-inflammatory cytokines TNF-α, IL-6, MCP-1 and IL-1β in both serum and liver, and suppressing the TLR4/NFkB pathway. SAG attenuated reduced fibrosis, collagen deposition, hepatocellular damage and organ dysfunction. In conclusion, our results suggest that SAG administration protects the liver from CCl4 intoxication by restoring the oxidative balance, ameliorating the impairment of mitophagy and leading to reduced inflammation.

Cynanchum auriculatum Royle ex Wight., Cynanchum bungei Decne. and Cynanchum wilfordii (Maxim.) Hemsl.: Current Research and Prospects

Cynanchum auriculatum Royle ex Wight. (CA), Cynanchum bungei Decne. (CB) and Cynanchum wilfordii (Maxim.) Hemsl. (CW) are three close species belonging to the Asclepiadaceous family, and their dry roots as the bioactive part have been revealed to exhibit anti-tumor, neuroprotection, organ protection, reducing liver lipid and blood lipid, immunomodulatory, anti-inflammatory, and other activities. Until 2021, phytochemistry investigations have uncovered 232 compounds isolated from three species, which could be classified into C21-steroids, acetophenones, terpenoids, and alkaloids. In this review, the morphology characteristics, species identification, and the relationship of botany, extraction, and the separation of chemical constituents, along with the molecular mechanism and pharmacokinetics of bioactive constituents of three species, are summarized for the first time, and their phytochemistry, pharmacology, and clinical safety are also updated. Moreover, the direction and limitation of current research on three species is also discussed.

Cynandione A and PHA-543613 inhibit inflammation and stimulate macrophageal IL-10 expression following α7 nAChR activation

Cynandione A, an acetophenone isolated from Cynanchum Wilfordii Radix, attenuates inflammation. The present study aimed to study the mechanisms underlying cynandione A-induced antiinflammation. Treatment with cynandione A and the specific α7 nicotinic acetylcholine receptor (α7 nAChR) agonist PHA-543613 remarkably reduced overexpression of proinflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β in lipopolysaccharide (LPS)-treated RAW264.7 cells and primary peritoneal macrophages, and endotoxemic mice. Both cynandione A and PHA-543613 also stimulated IL-10 expression in naïve and LPS-treated macrophages and endotoxemic mice. Cynandione A- and PHA-543613-inhibited proinflammatory cytokine expression was completely blocked by the α7 nAChR antagonist methyllycaconitine and the IL-10 antibody. The stimulatory effect of cynandione A and PHA-543613 on IL-10 expression were suppressed by methyllycaconitine and knockdown of α7 nAChRs using siRNA/α7 nAChR. Cynandione A significantly stimulated STAT3 phosphorylation, which was attenuated by methyllycaconitine and the IL-10 neutralizing antibody. The STAT3 activation inhibitor NSC74859 also blocked cynandione A-inhibited proinflammatory cytokine expression. Taken together, our results, for the first time, demonstrate that cynandione A and PHA-543613 inhibit inflammation through macrophageal α7 nAChR activation and subsequent IL-10 expression.

Cynanchum bungei Decne and its two related species for "Baishouwu": A review on traditional uses, phytochemistry, and pharmacological activities

ETHNOPHARMACOLOGICAL RELEVANCE

Cynanchum bungei Decne. (CB) (Asclepiadaceae) and its two related species Cynanchum auriculatum Royle ex Wight. (CA) and Cynanchum wilfordii (Maxim.) Hemsl. (CW) are well known Chinese herbal medicines known by the name Baishouwu. Among them, CB has long been used for nourishing the kidney and liver, strengthening the bones and muscles, and regulating stomachache. However, to date, no comprehensive review on Baishouwu has been published.

AIM OF THE REVIEW

This review aims to provide a comprehensive summary on traditional uses, phytochemistry, pharmacology, and toxicology of the three herbal components of Baishouwu with the ultimate objective of providing a guide for future scientific and therapeutic potential use of Baishouwu.

MATERIAL AND METHODS

A literature search was undertaken on CB, CA and CW by analyzing the information from scientific databases (SciFinder, Pubmed, Elsevier, Google Scholar, Web of Science, and Baidu Scholar). Information was also gathered from local classic herbal literatures and conference papers on ethnopharmacology and the information provided in this review has been obtained from peer-reviewed papers.

RESULTS

Comparative analysis of literature search indicate that ethnopharmacological use of CB was recorded in China, however, CA and CW have been used in China, Korea and Japan. To date, 151 chemical compounds have been isolated from these species, and the major chemical constituents have been revealed to be acetophenones, C₂₁-steroids, terpenoids, and alkaloids. These compounds and extracts have been proven to exhibit significant pharmacological activities, including anti-tumor, anti-inflammatory, immunomodulatory, hypolipidemic, anti-obesity, hepatoprotective, antifungal, antiviral, anti-depressant, vasodilating and estrogenic activities.

CONCLUSIONS

CB, CA and CW collectively known as Baishouwu are valuable medicinal herbs with multiple pharmacological activities. The traditional use for nourishing liver is closely associated with the hepatoprotective activity. The available literature performs that various of the activity of Baishouwu can be attributed to acetophenones and C₂₁-steroids. It is high time that more efforts should be focused on the underlying mechanisms of their beneficial bioactivities and the structure activity relationship of the constituents, as well as their potential synergistic and antagonistic effects. The proper toxicology evaluation is crucial to guarantee the safety, efficacy, and eligibility for medical use. Further research on the comprehensive evaluation of medicinal quality and the understanding of multi-target network pharmacology of Baishouwu is in great request.

Ethnobotany, Phytochemistry and Pharmacological Effects of Plants in Genus Cynanchum Linn. (Asclepiadaceae)

Genus Cynanchum L. belongs to the family Asclepiadaceae, which comprise more than 200 species distributed worldwide. In Chinese medical practice, numerous drugs (such as tablets and powders) containing different parts of plants of this genus are used to treat snake bites, bruises, osteoblasts, rheumatoid arthritis and tumors. A search for original articles published on the cynanchum genus was performed by using several resources, including Flora of China Official Website and various scientific databases, such as PubMed, SciFinder, the Web of Science, Science Direct, and China Knowledge Resource Integrated (CNKI). Advances in the botanical, ethnomedicinal, phytochemical, and pharmacological studies of this genus are reviewed in this paper. Results showed that more than 440 compounds, including C21 steroids, steroidal saponins, alkaloids, flavonoids and terpene, have been isolated and identified from Cynanchum plants up to now. In vivo and in vitro studies have shown that plants possess an array of biological activities, including anti-tumor, neuroprotective and anti-fungal effects. Popular traditional prescription of Cynanchum sp. was also summed up in this paper. However, many Cynanchum species have received little or no attention. Moreover, few reports on the clinical use and toxic effects of Cynanchum sp. are available. Further attention should be focused on the study of these species to gather information on their respective toxicology data and relevant quality-control measures and clinical value of the crude extracts, active compounds, and bioactive metabolites from this genus. Further research on Cynanchum sp. should be conducted, and bioactivity-guided isolation strategies should be emphasized. In addition, systematic studies of the chemical composition of plants should be enhanced.

Cynandione A inhibits lipopolysaccharide-induced cell adhesion via suppression of the protein expression of VCAM‑1 in human endothelial cells

Cynandione A (CA) is one of the most active compounds in the roots of Cynanchum wilfordii, the extracts of which have been used extensively in East Asia to treat various diseases including anti‑ischemic stroke. In the present study, the anti‑adherent activity of CA in lipopolysaccharide (LPS)‑stimulated human umbilical vascular endothelial cells (HUVECs) was investigated. CA markedly reduced the expression of vascular adhesion molecule‑1 (VCAM‑1) by LPS in HUVECs. The results also demonstrated that CA significantly reduced the expression of pro‑inflammatory and chemoattractant cytokines, including interleukin (IL)‑1β, IL‑6, IL‑8, monocyte chemoattractant protein‑1 and tumor necrosis factor‑α, in LPS‑activated human endothelial cells. CA inhibited the phosphorylation of mitogen‑activated protein kinases, including the extracellular signal‑regulated kinase 1/2 and p38 kinases. It was found that CA decreased the IKK/IκB‑α phosphorylation of inhibitor of nuclear factor (NF)‑κB kinase/inhibitor of NF‑κB‑α, suppressed translocation of the NF‑κB p65 subunit into the nucleus and inhibited the transcriptional activity of NF‑κB. CA also decreased human monocyte cell adhesion to endothelial cells in LPS‑stimulated conditions. These results demonstrated that CA inhibited the protein expression of VCAM‑1 and pro‑inflammatory cytokines by suppressing the transcriptional activity of NF‑κB. The results also suggested that CA may be important in the development of anti‑inflammatory drugs by inhibiting the expression of cell adhesion molecules.

Immune-Enhancing Effects of a High Molecular Weight Fraction of Cynanchum wilfordii Hemsley in Macrophages and Immunosuppressed Mice

The objective of this study was to investigate the immune-enhancing activity of a high molecular weight fraction (HMF) of Cynanchum wilfordii in RAW 264.7 macrophages and the cyclophosphamide (CYC)-induced mouse model of immunosuppression. To identify the bioactive substances of HMF, a crude polysaccharide (HMFO) was obtained and treated with sodium periodate (an oxidation agent) or digested with protease. In macrophages, HMF treatment enhanced the production of nitric oxide (NO) and cytokines (tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and interleukin 1β (IL-1β)), as well as phagocytic ability. In CYC-immunosuppressed mice, HMF improved relative spleen and thymus weights, natural killer (NK) cell activity, and splenic lymphocyte proliferation. These increases in NO and cytokines were mediated by up-regulation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Periodate treatment, but not protease treatment, decreased the immune-enhancing activity of HMFO, suggesting that polysaccharides are the active ingredients in C. wilfordii extract.

Analysis of Cynandione A's Anti-Ischemic Stroke Effects from Pathways and Protein-Protein Interactome

Ischemic stroke is the third leading cause of death in the world. Our previous study found that cynandione A (CYNA), the main component from the root of Cynanchum bungei, exhibits anti-ischemic stroke activity. In this work, we investigated the therapeutic mechanisms of CYNA to ischemic stroke at protein network level. First, PC12 cells and cerebellar granule neurons were prepared to validate the effects of CYNA against glutamate injury. Our experiments suggested that CYNA could dose-dependently mitigate glutamate-induced neurons neurotoxicity and inhibit glutamate-induced upregulation of KHSRP and HMGB1, further confirming the neuroprotective effects of CYNA in vivo. Then, on the pathway sub-networks, which present biological processes that can be impacted directly or in periphery nodes by drugs via their targets, we found that CYNA regulates 11 pathways associated with the biological process of thrombotic or embolic occlusion of a cerebral artery. Meanwhile, by defining a network-based anti-ischemic stroke effect score, we showed that CYNA has a significantly higher effect score than random counterparts, which suggests a synergistic effect of CYNA to ischemic stroke. This study may shed new lights on the study of network based pharmacology.

Cynandione A attenuates lipopolysaccharide-induced production of inflammatory mediators via MAPK inhibition and NF-κB inactivation in RAW264.7 macrophages and protects mice against endotoxin shock

Cynanchum wilfordii has been traditionally used in eastern Asia for the treatment of various diseases such as gastrointestinal diseases and arteriosclerosis. Cynandione A (CA), an acetophenone, is one of major constituents from roots of C. wilfordii. In the present study, the anti-inflammatory activities of CA were investigated in lipopolysaccharide (LPS)-treated RAW264.7 macrophages and LPS-administered C57BL/6 N mice. CA significantly decreased LPS-induced production of nitric oxide and prostaglandin E2 in a dose-dependent manner, while CA up to 200 μM did not exhibit cytotoxic activity. Our data also showed that CA significantly attenuated expression of iNOS and COX-2 in LPS-stimulated macrophages. CA inhibited phosphorylation of IκB-α and MAP kinases such as ERK and p38. Furthermore, we demonstrated that CA inhibited translocation of NF-κB to the nucleus, transcription of the NF-κB minimal promoter and NF-κB DNA binding activity. Administration of CA significantly decreased the plasma levels of pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1β in LPS-injected mice and improved survival of septic mice with lethal endotoxemia. These results demonstrate that CA has effective inhibitory effects on production of inflammatory mediators via suppressing activation of NF-κB and MAPK signaling pathways, suggesting that CA may be used as a potential anti-inflammatory agent for the prevention and treatment of inflammatory diseases.

A C 21 -Steroidal Glycoside Isolated from the Roots of Cynanchum auriculatum Induces Cell Cycle Arrest and Apoptosis in Human Gastric Cancer SGC-7901 Cells

Caudatin 3-O-β-D-cymaropyranosyl-(1 → 4)-β-D-oleandropyranosyl-(1 → 4)-β-D-cymaropyranosyl-(1 → 4)-β-D-cymaropyranoside (CGII) is one of the C₂₁-steroidal glycosides isolated from the roots of Cynanchum auriculatum ROYLE ex WIGHT. This study aimed to determine the cell growth, cell proliferation, and apoptotic cell death of human gastric cancer cells after CGII treatment. MTT assay was used to determine cell growth; fluorescence-activated cell sorting analysis was used to evaluate cell cycle distribution and apoptotic cell death. Immunoblotting was applied for measuring the expression of proteins involved in the cell cycle progression. The activities of caspase-3, -8, and -9 were detected by colorimetric caspase activity assays. CGII inhibited cell growth of human gastric cancer SGC-7901 cells in a concentration- and time-dependent manner. Treatment of SGC-7901 cells with CGII resulted in G1 phase cell cycle arrest, accompanied with decreased expression of cyclin D1 and cyclin-dependent kinases 4 and 6. CGII induced cell apoptosis and activated caspase-3, caspase-8, and caspase-9. In contrast, pan-caspase inhibitor z-VAD-fmk partially abolished the CGII-induced growth inhibition of SGC-7901 cells. In conclusion, CGII inhibits cell growth of human gastric cancer cells by inducing G1 phase cell cycle arrest and caspase-dependent apoptosis cascades.

Caudatin inhibits human hepatoma cell growth and metastasis through modulation of the Wnt/β-catenin pathway

In the present study, we investigated the antitumor activity of caudatin in the human hepatoma cell line SMMC‑7721 by analysis of cell viability, cell cycle distribution, apoptosis and metastasis. The results showed that caudatin impaired the cell viability and inhibited the growth of SMMC-7721 cells in a time- and dose-dependent manner and resulted in cell cycle arrest in the G2 phase. In addition, SMMC-7721 cells, treated with caudatin exhibited typical characteristics of apoptosis. Furthermore, caudatin treatment resulted in a decrease in β-catenin and GSK3β in SMMC-7721 cells, with a concomitant reduction in metastatic capability and expression of Wnt signaling pathway targeted genes including cox-2, mmp-2 and mmp-9. Our findings revealed that caudatin inhibits human hepatoma cell growth and metastasis by targeting the GSK3β/β-catenin pathway and suppressing VEGF production.

Hepatoprotective evaluation of the total flavonoids extracted from flowers of Abelmoschus manihot (L.) Medic: In vitro and in vivo studies

ETHNOPHARMACOLOGICAL RELEVANCE

The decoction of the flowers of Abelmoschus manihot (L.) Medic is traditionally used for the treatment of jaundice and various types of chronic and acute hepatitis in Anhui and Jiangsu Provinces of China. Phytochemical studies have indicated that total flavonoids extracted from flowers of Abelmoschus manihot (L.) Medic (TFA) were the major constituents of the flowers. The present study was designed to investigate the hepatoprotective effect of the plant extracts against carbon tetrachloride (CCl4) induced hepatocyte damage in vitro and liver injury in vivo.

MATERIAL AND METHODS

In the in vitro studies, freshly isolated rat hepatocytes were exposed to CCl4 (1%) along with/without various concentrations of TFA (4.5-72mg/L). Cell damage was assessed by the trypan blue exclusion method and alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in the medium were analyzed. In the in vivo studies, the hepatoprotective activity of TFA (125, 250 and 500mg/kg) were investigated on CCl4-induced liver damages in mice. The levels of ALT, AST and ALP, gamma glutamyltransferase (γ-GT), tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and nitric oxide (NO) were determined in serum. Hepatic malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and glutathione transferase (GST) were measured in the liver homogenates. Cytokine transcript levels of TNF-α, IL-1β and inducible nitric oxide synthase (iNOS) in the liver tissues of mice were measured using reverse transcription-polymerase chain reaction (RT-PCR). Livers were dissected out and evaluated for histomorphological changes.

RESULTS

A concentration-dependent increase in the percentage viability was observed when CCl4-exposed hepatocytes were treated with different concentrations of TFA. Levels of ALT, AST and ALP in the medium were significantly decreased. In the animal studies, TFA showed significant protection with the depletion of ALT, AST, ALP and γ-GT in serum as was raised by the induction of CCl4. Moreover, TFA decreased the MDA level and elevated the content of GSH in the liver as compared to those in the CCl4 group. Furthermore, activities of antioxidative enzymes, including SOD, GPx, CAT and GST, were enhanced dose dependently with TFA. Meanwhile, the inflammatory mediators (e.g., TNF-α, IL-1β and NO) were inhibited by TFA treatment both at the serum and mRNA levels. Additionally, histological analyses also showed that TFA reduced the extent of liver lesions induced by CCl4.

CONCLUSION

These results suggested that TFA protected mice against CCl4-induced liver injury through antioxidant stress and antiinflammatory effects. This finding justified the use of this plant in traditional medicine for the treatment of liver disease.

Cytotoxic and apoptosis-inducing properties of a C21-steroidal glycoside isolated from the roots of Cynanchum auriculatum

The present study aimed to investigate the anti-cancer effect of a C₂₁-steroidal glycoside (CG) isolated from the roots of Cynanchum auriculatum. CG was able to inhibit the growth of human cancer cells (SGC-7901 cells) in a concentration and time-dependent manner in vitro. SGC-7901 cells exposed to CG (10.8 and 21.6 μM) exhibited typical morphological apoptosis characteristics, such as nuclear-chromatin condensation and apoptotic body formation. Flow cytometric analysis showed that after treatment with CG at 10.8 and 21.6 μM for 24 h, the percentage of apoptotic cells increased to 30.4 and 43.2%, respectively, while the number of cells in the G₀/G₁, S and G₂/M phases of the cell cycle decreased (P<0.05). Furthermore, treatment with CG at a concentration of 21.6 μM for 24 h significantly increased the expression of caspase-3 and the activity of caspase-3 was increased ∼3-fold in SGC-7901 cells. These results suggest that CG is the active anticancer component of the total C₂₁-glycosides of the roots of Cynanchum auriculatum which is able to inhibit the growth of cancer cells and induce cancer cell apoptosis through caspase-3-dependent pathways.

Synthesis and X-Ray Crystal Structure of Cynandione B Analogues

The synthesis of analogues of cynandione B, a phenolic acetophenone from Cynanchum taiwanianum, is described. The one-step conversion of benzochromenones to the heptacyclic spiroacetal core of cynandione B using methylmagnesium bromide is investigated and structural requirements for this novel transformation established. X-ray crystal structure analysis has established the relative configuration in these unusual heterocycles.

Asiatic Acid Derivatives Protect Primary Cultures of Rat Hepatocytes against Carbon Tetrachloride-Induced Injury via the Cellular Antioxidant System

We attempted to elucidate the hepatoprotective mechanism of two asiatic acid (AS) derivatives, 3β,23-dihydroxyurs-2-oxo-12-ene-28-oic acid (AS-10) and 3β,23-dihydroxyurs-12-ene-28-oic acid (AS-14), which exhibited significant protective activity against carbon tetrachloride (CCl4)-induced hepatotoxicity in primary cultures of rat hepatocytes. Our findings showed that AS-10 and AS-14 preserved the level of glutathione and the activities of antioxidant enzymes such as glutathione reductase, glutathione peroxidase, superoxide dismutase and catalase. In addition, these compounds ameliorated lipid peroxidation, as demonstrated by a reduction in the production of malondialdehyde. Furthermore, AS-10 and AS-14 did not restore the reduced total GSH level by BSO, indicating that the hepatoprotective activities of these compounds may be involved, in part, by regulating GSH synthesis. From these results, we suggest that both AS-10 and AS-14 exerted their hepatoprotective activities against CCl4-induced injury by preserving the cellular antioxidative defense system.

Hepatoprotective activity of Sapindus mukorossi and Rheum emodi extracts: In vitro and in vivo studies

AIM: To study the hepatoprotective capacity of Sapindus mukorossi (S. mukorossi) and Rheum emodi (R. emodi) extracts in CCl₄ treated male rats.

METHODS: The dried powder of S. mukorossi and R. emodi was extracted successively with petroleum ether, benzene, chloroform, and ethanol and concentrated in vacuum. Primary rat hepatocyte monolayer cultures were used for in vitro studies. In vivo, the hepatoprotective capacity of the extract of the fruit pericarp of S. mukorossi and the rhizomes of R. emodi was analyzed in liver injured CCl₄-treated male rats.

RESULTS: In vitro: primary hepatocytes monolayer cultures were treated with CCl₄ and extracts of S. mukorossi & R. emodi. A protective activity could be demonstrated in the CCl₄ damaged primary monolayer culture. In vivo: extracts of the fruit pericarp of S. mukorossi (2.5 mg/mL) and rhizomes of R. emodi (3.0 mg/mL) were found to have protective properties in rats with CCl₄ induced liver damage as judged from serum marker enzyme activities.

CONCLUSION: The extracts of S. mukorossi and R. emodi do have a protective capacity both in vitro on primary hepatocytes cultures and in in vivo in a rat model of CCl₄ mediated liver injury.

New Acylated Flavonol Diglycosides of Cynanchum Acutum

Three new acylated flavonol diglycosides that were characterized as quercetin 3- O-(6′”- O-E-isoferuloyl)-sophoroside (1), quercetin 3- O-(6′”- O-Z-isoferuloyl)-sophoroside (2) and quercetin 3- O-[2″- O-( E-6″′- O-isoferuloyl)-β-D-glucopyranosyl]-β-D-galactopyranoside (3), along with twelve known metabolites, have been isolated from the leaves of Cynanchum acutum L. The latter were identified as quercetin 3- O-β-D-neohesperidoside (4), rutin (5), quercetin 3- O-sophoroside (6), kaempferol 3- O-β-D-rutinoside (7), quercitrin (8), isoquercitrin (9), hyperin (10), guaijaverin (11), quercetin 7- O-β-D-glucopyranoside (12), quercetin (13), scopoletin (14) and ( E)-3-(3,4-dihydroxyphenyl)-propenoic acid (15). All metabolites have been isolated for the first time from the genus Cynanchum, except for 9 and 14. The structures were determined on the basis of chromatographic behavior, acid hydrolysis, chemical and physicochemical evidence (UV, HRESI-MS/MSn, 1H, 13C NMR, 1H-1H COSY, HSQC and HMBC). The chloroform extract and compounds 8 and 10 exhibited lethal effects towards brine shrimp, Artemia salina.

Saikosaponin-d attenuates the development of liver fibrosis by preventing hepatocyte injury

Treatment of liver fibrosis and cirrhosis remains a challenging field. Hepatocyte injury and the activation of hepatic stellate cells are the 2 major events in the development of liver fibrosis and cirrhosis. It is known that several Chinese herbs have significant beneficial effects on the liver; therefore, the purpose of the present study was to investigate the therapeutic effect of saikosaponin-d (SSd) on liver fibrosis and cirrhosis. A rat model of liver fibrosis was established using the dimethylnitrosamine method. Liver tissue and serum were used to examine the effect of SSd on liver fibrosis. A hepatocyte culture was also used to investigate how SSd can protect hepatocytes from oxidative injury induced by carbon tetrachloride. The results showed that SSd significantly reduced collagen I deposition in the liver and alanine aminotransferase level in the serum. Moreover, SSd decreased the content of TGF-beta1 in the liver, which was significantly elevated after dimethylnitrosamine induced liver fibrosis. Furthermore, SSd was able to alleviate hepatocyte injury from oxidative stress. In conclusion, SSd could postpone the development of liver fibrosis by attenuating hepatocyte injury.

A Serendipitous Synthesis of the Novel Spiroacetal Core of Cynandione B

The novel spiroacetal core of cynandione B 2 is prepared from the isochromenone (S)-mellein 4 by treatment with methylmagnesium bromide. The expected lactol product undergoes spontaneous dimerization to form the spiroacetal system 8 as a single diastereoisomer, the stereochemistry of which is established from a single crystal X-ray structure analysis of a methanol solvate.

Mycelial culture of Phellinus linteus protects primary cultured rat hepatocytes against hepatotoxins

Hepatoprotective activity of Phellinus linteus was studied using H(2)O(2)- or galactosamine-injured primary cultures of rat hepatocytes as screening systems. The methanolic extract of the mycelial culture of Phellinus linteus significantly protected against hepatotoxins-induced toxicity in primary cultured rat hepatocytes as seen from the decreased level of glutamic pyruvic transaminase released from the injured hepatocytes. The methanolic extract of the mycelial culture of Phellinus linteus was subsequently fractionated with n-hexane, ethyl acetate, n-butanol and water. Among these fractions, 100 microg/mL of the ethyl acetate fraction was the most active one. The relative protections were 68.9 +/- 5.3% in H(2)O(2)-injured hepatocytes and 46.8 +/- 3.9% in galactosamine-injured hepatocytes, respectively. The ethyl acetate fraction appeared to maintain the glutathione level which was decreased by the treatment of H(2)O(2) or galactosamine and restored the level of RNA synthesis more than two times compared to galactosamine-injured hepatocytes. These results suggest that the ethyl acetate fraction of the mycelial culture of Phellinus linteus protects hepatocytes from H(2)O(2)- or galactosamine-induced injury by maintaining hepatic glutathione level and RNA synthesis as well.

Hepatoprotective dibenzylbutyrolactone lignans of Torreya nucifera against CCl4-induced toxicity in primary cultured rat hepatocytes

Three dibenzylbutyrolactone lignans, (-)-arctigenin, (-)-traxillagenin, and (-)-4'-demethyltraxillagenin, isolated from the bark of Torreya nucifera SIEB. et ZUCC. (Taxaceae) showed significant hepatoprotective activity in primary cultures of rat hepatocytes injured by carbon tetrachloride (CCl(4)). These lignans reduced the release of glutamic pyruvic transaminase into the culture medium from the CCl(4)-injured primary cultures of rat hepatocytes. Further investigation revealed that the three lignans significantly preserved the level of glutathione (GSH) and activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase in the CCl(4)-injured rat hepatocytes. The lignans also ameliorated lipid peroxidation as demonstrated by a reduction in malondialdehyde-related products. Moreover, these lignans significantly attenuated the GSH reduction caused by diethylmaleate which depletes GSH through the formation of stable conjugates. However, these lignans showed no effect on the GSH synthesis inhibited by buthionine sulfoximine. From these results, it can be concluded that arctigenin, traxillagenin, and 4'-demethyltraxillagenin may protect hepatocytes from CCl(4) injury by maintaining the GSH level.