Anti-lipid peroxidative effect of an extract of the stems of Kadsura heteroclita and its major constituent, kadsurin, in mice

Dibenzocyclooctadiene lignans from the family Schisandraceae: A review of phytochemistry, structure-activity relationship, and hepatoprotective effects

Liver injury is a common pathological process characterized by massive degeneration and abnormal death of liver cells. With increase in dead cells and necrosis, liver injury eventually leads to nonalcoholic fatty liver disease (NAFLD), hepatic fibrosis, and even hepatocellular carcinoma (HCC). Consequently, it is necessary to treat liver injury and to prevent its progression. The drug Bicylol is widely employed in China to treat chronic hepatitis B virus (HBV) and has therapeutic potential for liver injury. It is the derivative of dibenzocyclooctadiene lignans extracted from Schisandra chinensis (SC). The Schisandraceae family is a rich source of dibenzocyclooctadiene lignans, which possesses potential liver protective activity. This study aimed to comprehensively summarize the phytochemistry, structure-activity relationship and molecular mechanisms underlying the liver protective activities of dibenzocyclooctadiene lignans from the Schisandraceae family. Here, we had discussed the analysis of absorption or permeation properties of 358 compounds based on Lipinski's rule of five. So far, 358 dibenzocyclooctadiene lignans have been reported, with 37 of them exhibited hepatoprotective effects. The molecular mechanism of the active compounds mainly involves antioxidative stress, anti-inflammation and autophagy through Kelch-like ECH-associating protein 1/nuclear factor erythroid 2 related factor 2/antioxidant response element (Keap1/Nrf2/ARE), nuclear factor kappa B (NF-кB), and transforming growth factor β (TGF-β)/Smad 2/3 signaling pathways. This review is expected to provide scientific ideas for future research related to developing and utilizing the dibenzocyclooctadiene lignans from Schisandraceae family.

A review of the phytochemistry and pharmacology of Kadsura heteroclita, an important plant in Tujia ethnomedicine

ETHNOPHARMACOLOGICAL RELEVANCE

Kadsura heteroclita (Roxb.) Craib (traditionally known as "Xue Tong") is an important member of the economically and medicinally important plant family Schisandraceae. "Xue Tong" is an imperative ingredient of the Tujia ethnomedicine, traditionally used for the treatment of rheumatoid arthritis (RA), hepatitis, and muscles and joint spasm. The plant is known to be a rich source of lignans and triterpenoids. These classes of natural products have been known to possess various pharmacological activities.

AIM OF REVIEW

This review was motivated by the importance of K. heteroclita in traditional Chinese medicine (TCM). It aims to compile the available information on its botanical distribution and description, traditional uses, phytochemistry, pharmacological activities, toxicity, and quality control to provide a solid base for further research and development.

MATERIALS AND METHODS

Relevant literature was collected by several scientific databases including PubMed, CNKI, Scifinder, The Plant List, Google Scholar, Baidu Scholar, Books (Tujia pharmaceutical records, Guangxi Chinese herbal medicine, Hunan pharmaceutical records and Field identification manual of Chinese herbal medicine) and other literature sources (Flora of China, Pharmacopoeia of the People's Republic of China) which helped in collecting maximum data about the studied species.

RESULTS

Traditional uses of K. heteroclita have proven its medicinal importance, providing a rationale for scientific research. Phytochemical studies on the stem of K. heteroclita resulted in the identification of 187 chemical constituents, among which lignans and triterpenoids are the predominant groups. The isolates and crude extracts have been found to exhibit a wide spectrum of in vivo and in vitro pharmacological activities such as anti-RA, anti-inflammatory and analgesic, hepatoprotection, anti-HIV, anti-cancer and anti-HBV. Schisanlactone E (xuetongsu), a triterpenoid, is one of the major components of K. heteroclita exhibiting anti-cancer, neuroprotective and anti-neuroinflammation activities. Interestingly and luckily, this plant has been found to be safe and non-toxic within the therapeutic dose range.

CONCLUSION

Pharmacological investigations have validated the use of K. heteroclita in traditional Chinese medicine (TCM). Literature review has demonstrated that lignans and triterpenoids are possibly responsible for most of the biological activities exhibited by this plant. To conclude, this plant shows immense potential for the discovery of more potent bioactive secondary metabolites and therefore further phytochemical and biological studies on other parts of K. heteroclita need to be conducted and more compounds need to be tested regarding their biological activities to completely explore its value as a tremendously important medicinal plant species.

Two New Dibenzylbutyrolactone Type Lignans from the Stems of Kadsura heteroclita

Two new lignans, named as 6-hydroxyhinokinin and 6-hydroxyhinokinin-6- O-β-D-glucopyranoside, together with five known compounds: elemol, oplodiol, catechin, β-sitosterol and daucosterol were isolated from Kadsura heteroclita. The structures of these compounds were characterized by extensive 1D and 2D NMR spectral experiments, chemical analysis and comparison with literature data. The absolute structures of the novel lignans were elucidated as 8 S, 8′ S, based on their optical rotations.

Four New Lignans from Kadsura Interior and Their Bioactivity

A phytochemical investigation of the stems of Kadsura interior has led to an isolation of four new lignans, named kadsutherin E–H (1–4), together with two known lignans (5–6). The structures of the four new compounds were established on the basis of comprehensive spectroscopic analyses. Compounds 1–6 exhibited inhibition against adenosine diphosphate (ADP) induced platelet aggregation. Among the isolated compounds, kadsutherin F (2) showed the strongest anti-platelet aggregation activity with an inhibition of 49.47%.

Pharmacokinetics of Schizandrin and Its Pharmaceutical Products Assessed Using a Validated LC-MS/MS Method

Schisandra chinensis has been used as an important component in various prescriptions in traditional Chinese medicine and, more recently, in Western-based medicine for its anti-hepatotoxic effect. The aim of this study was to develop a selective, rapid, and sensitive ultra-performance liquid chromatography-tandem mass spectrometry method for pharmacokinetic studies of schizandrin in rats. Liquid-liquid extraction was used for plasma sample preparation. A UHPLC reverse-phase C18e column (100 mm × 2.1 mm, 2 μm) coupled with a mobile phase of methanol-0.1% formic acid (85:15, v/v) was used for sample separation. A triple quadrupole tandem mass spectrometer was used to detect the analytes in the selected reaction monitoring mode. The linear range of schizandrin in rat plasma was 5.0–1000 ng/mL (r² > 0.999), with a lower limit of quantification of 5 ng/mL. The method was validated with regard to accuracy, intra-day and inter-day precision, linearity, stability, recovery, and matrix effects in rat plasma, which were acceptable according to the biological method validation guidelines developed by the FDA. This method was successfully applied to a pharmacokinetic study after oral administration of 3 g/kg and 10 g/kg of Schisandra chinensis products, which yielded a maximum concentration of schizandrin of 0.08 ± 0.07 and 0.15 ± 0.09 μg/mL, respectively. A parallel study design was used to investigate the oral bioavailability of single compound of schizandrin and the herbal extract, the single compound of pure schizandrin (10 mg/kg, i.v.), pure schizandrin (10 mg/kg, p.o.), and the herbal extract of Schisandra chinensis (3 g/kg and 10 g/kg, p.o.) were given individually. The dose of Schisandra chinensis (3 g/kg) equivalent to schizandrin (5.2 mg/kg); the dose of Schisandra chinensis (10 g/kg) equivalent to schizandrin (17.3 mg/kg). The result demonstrated that the oral bioavailability of schizandrin was approximately 15.56 ± 10.47% in rats, however the oral bioavailability of herbal extract was higher than single compound. The method was successfully applied to the pharmacokinetic study of pure schizandrin after oral administration of its pharmaceutical industry products in rats.

Effect of ginseng extract on the TGF-β1 signaling pathway in CCl4-induced liver fibrosis in rats

Background

Liver diseases are major global health problems. Ginseng extract has antioxidant, immune-modulatory and anti-inflammatory activities. This study investigated the effect of ginseng extract on carbon tetrachloride (CCl4)-induced liver fibrosis in rats.

Methods

Male Wistar rats were divided into four groups: control group, ginseng group, CCl₄ group and CCl₄ + ginseng group. Liver injury was induced by the intraperitoneal (I.P) injection of 3 ml/kg CCl₄ (30% in olive oil) weekly for 8 weeks. The control group was I.P injected with olive oil. The expression of genes encoding transforming growth factor beta (TGF-β), type I TGF-β receptor (TβR-1), type II TGF-β receptor (TβR-II), mothers against decapentaplegic homolog 2 (Smad2), Smad3, Smad4, matrix metalloproteinase 2 (MMP2), MMP9, tissue inhibitor matrix metalloproteinase-1 (TIMP-1), Collagen 1a2 (Col1a2), Collagen 3a1 (Col3a1), interleukin-8 (IL-8) and interleukin -10 (IL-10) were measured by real-time PCR.

Results

Treatment with ginseng extract decreased hepatic fat deposition and lowered hepatic reticular fiber accumulation compared with the CCl₄ group. The CCl₄ group showed a significant increase in hepatotoxicity biomarkers and up-regulation of the expression of genes encoding TGF-β, TβR-I, TβR-II, MMP2, MMP9, Smad-2,-3, -4, and IL-8 compared with the control group. However, CCl₄ administration resulted in the significant down-regulation of IL-10 mRNA expression compared with the control group. Interestingly, ginseng extract supplementation completely reversed the biochemical markers of hepatotoxicity and the gene expression alterations induced by CCl₄.

Conclusion

ginseng extract had an anti‐fibrosis effect via the regulation of the TGF‐β1/Smad signaling pathway in the CCl₄‐induced liver fibrosis model. The major target was the inhibition of the expression of TGF‐β1, Smad2, and Smad3.

Heteroclitins R-S: new dibenzocylooctadiene lignans from Kadsura heteroclita

AIM

To study the dibenzocylooctadiene lignans from the stems of Kadsura heteroclita.

METHOD

Chromatographic separations of silica gel and semi-preparative HPLC were used. All of the structures were elucidated on the basis of spectroscopic analysis, including 2D-NMR and HR-MS techniques.

RESULTS

Four dibenzocylooctadiene lignans were isolated from K. heteroclita. Their structures were identified as heteroclitin R (1), heteroclitin S (2), gonisin O (3), and schisanlignone A (4).

CONCLUSION

Heteroclitin R (1) and heteroclitin S (2) are new natural lignans.

Bioactive triterpenoids from Kadsura heteroclita

A phytochemical study of Kadsura heteroclita led to the isolation of eight triterpenoids, including two new compounds, named kadheterilactone A (1) and kadheterilactone B (2), as well as six known compounds, longipedlactone H (3), longipedlactone A (4), longipedlactone F (5), kadsuranic acid A (6), nigranoic acid (7), and schisandronic acid (8). Their structures were elucidated on the basis of spectroscopic methods, including 2D NMR techniques. The cytotoxic activities of 1-8 were tested against several tumor cell lines by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium hydrobromide (MTT) assay in vitro. As a result, 4 and 5 turned out to be significantly cytotoxic against Hep-G2 and Bel-7402 tumor cell lines. All compounds were also tested for inhibition on HIV-1 protease (PR) and reverse transcriptase (RT). Compounds 6 and 7 showed strong inhibition on HIV-1 PR, while 8 exhibited moderate activity, others were only weakly active. No compounds were active against HIV-1 RT.

Schisanwilsonenes A-C, anti-HBV Carotane sesquiterpenoids from the fruits of Schisandra wilsoniana

Three carotane-type sesquiterpenoids, schisanwilsonenes A (1), B (2), and C (3), were isolated from the fruits of Schisandra wilsoniana. Their structures and relative configurations were elucidated on the basis of spectroscopic methods including 2D-NMR techniques, and the structure of 1 was confirmed by a single-crystal X-ray diffraction experiment. Schisanwilsonene A, at 50 microg/mL, exhibited antiviral activity, inhibiting HBsAg and HBeAg secretion by 76.5% and 28.9%.

Dibenzocyclooctane Lignans from the Stems ofKadsura induta and Their Antiviral Effect on Hepatitis B Virus

Two new dibenzocyclooctane lignans, kadsurindutins A (1) and B (2), were isolated from the stems of Kadsura induta, together with the known, structurally related lignans schisantherin L (3), schisantherin P (4), kadsulignan L (5), and neokadsuranin (6). Their structures and configurations were elucidated by spectroscopic methods (UV, ORD, CD, IR, 1D- and 2D-NMR) in combination with mass-spectrometric (HR-MS) techniques. Compounds 1, 5, and 6 showed in vitro antiviral effects on hepatitis B virus.

Four new nonaoxygenated C18 dibenzocylcooctadiene lignans from Kadsura philippinensis

Four new nona-oxygenated C18 dibenzocyclooctadiene lignans, kadsuphilins C-F (1-4), were isolated from the EtOAc soluble portion of the alcoholic extract of the aerial parts of Kadsura philippinensis. The structures of 1-4 were elucidated on the basis of extensive spectroscopic analyses, including 2D NMR (HMQC, HMBC, and NOESY) experiments, comparison of the spectral data with those of the related metabolites. The stereochemistries of the biphenyl and octadiene moieties were deduced from circular dichorism (CD) and the NOESY spectra, respectively. The in vitro antiplatelet aggregation activity of metabolites 1-4 also have been evaluated.

Heteroclitin H, a new lignan from Kadsura heteroclita

A new dibenzocyclooctadiene lignan, heteroclitin H (1), was isolated together with seven known compounds, heteroclitin D (2), interiorin B (3), interiorin (4), neokasuranin (5), interiotherin C (6), gomisin J (7) and (+)-anwulignan (8), from the stems of Kadsura heteroclita. Their structures were elucidated by spectroscopic methods. This is the first report of the isolation of compounds 3, 5, 6, 7 and 8 from K. heteroclita.

The anti-HBsAg (human type B hepatitis, surface antigen) and anti-HBeAg (human type B hepatitis, e antigen) C18 dibenzocyclooctadiene lignans from Kadsura matsudai and Schizandra arisanensis

The C(18) dibenzocyclooctadiene lignans including three novel schizanrin F (1), G (2), H (3), along with the known kadsurarin (4), were isolated from Kadsura matsudai. A new C(19) homolignan named schiarisanrin E (5), together with the known C(18) lignans, gomisin B (6), G (7) and (+)-gomisin K(3) (8) were obtained from Schizandra arisanensis. Gomisin B, G and (+)-gomisin K(3) showed moderate to strong activity for antihepatitis in anti-HBsAg (human type B hepatitis, surface antigen) and/or anti-HBeAg (human type B hepatitis, e antigen) tests. The structural elucidations of new compounds 1-3 and 5 were based on two-dimensional (2D) NMR techniques including COSY, HMQC, HMBC, NOESY and CD spectra. Preliminary structure-activity relationship studies for these isolated lignans are also discussed.

The protective effects of PMC against chronic carbon tetrachloride-induced hepatotoxicity in vivo

In this study, PMC (2,2,5,7,8-pentamethyl-6-hydroxychromane), a derivative of alpha-tocopherol, dose-dependently (1-10 mg/kg) ameliorated the increase in plasma aspartate aminotransferase (GOT) and alanine aminotransferase (GPT) levels caused by chronic repeated carbon tetrachloride (CCl4) intoxication in mice. Moreover, PMC significantly improved the CCl4-induced increase of hepatic glutathione peroxidase, reductase, and superoxide dismutase activities. PMC also restored the decrement in the glutathione content of hepatic tissues in CCl4-intoxicated mice. Furthermore, it also dose-dependently inhibited the formation of lipid peroxidative products during carbon tetrachloride treatment. Histopathological changes of hepatic lesions induced by carbon tetrachloride were significantly improved by treatment with PMC in a dose-dependent manner. These results suggest that PMC exerts effective protection in chronic chemical-induced hepatic injury in vivo.

Preventive effect of gamma-glutamylcysteinylethyl ester on carbon tetrachloride-induced hepatic triglyceride accumulation in mice

The effect of gamma-glutamylcysteinylethyl ester (gamma-GCE), which is a precursor of reduced glutathione (GSH), on carbon tetrachloride (CCl4)-induced hepatic triglyceride (TG) accumulation in mice was investigated in comparison with that of GSH. Administration of gamma-GCE (160 micromol/kg), but not GSH (160 micromol/kg), to mice at 3 h after CCl4 injection (1 ml/kg, i.p.) significantly attenuated an increase in hepatic TG concentration at 6, 12, and 24 h after the CCl4 injection. A decrease in hepatic GSH concentration after the CCl4 injection was significantly diminished by the gamma-GCE administration, but not by the GSH administration. The correlation coefficient between hepatic TG concentration and hepatic GSH concentration was -0.627 (P < 0.001) when the results of all mice were grouped together. These results indicate that gamma-GCE can attenuate CCl4-induced hepatic TG accumulation in mice through the maintenance of hepatic GSH level.

Chromatography of medicinal plants and Chinese traditional medicines

Applications of chromatographic techniques to medicinal plants and Chinese traditional medicines are outlined in this review. Areas involved are quantitation of active principles or index or principal components; quality evaluation of crude drugs; identification, characterization and preparative isolation of new compounds for medical use from plants; analysis of pharmaceutical preparations of plant origin and pharmacokinetic and pharmacological studies of herbal drugs and their preparations.

Gamma-glutamylcysteinylethyl ester attenuates progression of carbon tetrachloride-induced acute liver injury in mice

We examined the effect of gamma-glutamylcysteinylethyl ester (gamma-GCE), which is readily transported into hepatocytes and increases hepatocellular reduced glutathione (GSH) levels, on the progression of carbon tetrachloride (CCl4)-induced liver injury in mice in comparison with that of GSH. Administration of more than 160 micromol/kg of gamma-GCE, but not GSH, to mice at 3 h after intraperitoneal injection of CCl4 (1 ml/kg) significantly attenuated increases in serum aspartate aminotransferase and alanine aminotransferase activities at 24 h after the CCl4 injection. Increases in hepatic lipid peroxide (LPO) concentrations and decreases in hepatic GSH concentrations after the CCl4 injection were significantly diminished by the gamma-GCE (160 micromol/kg) administration, but not by the same dose of GSH. Gamma-GCE, gamma-glutamylcysteine, and cysteine acted as substrates for glutathione peroxidases much less efficiently than GSH in the post-mitochondrial fraction of normal mouse liver cells. These results indicate that gamma-GCE attenuates the progression of CCl4-induced acute liver injury in mice through the maintenance of hepatic GSH levels, leading to inhibition of hepatic LPO formation, which could be due to an efficient utilization of GSH converted from gamma-GCE in the liver cells.