Three New Dibenzocyclooctadiene Lignans from Kadsura longipedunculata

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.

Promising Therapeutic Candidate for Myocardial Ischemia/Reperfusion Injury: What Are the Possible Mechanisms and Roles of Phytochemicals?

Percutaneous coronary intervention (PCI) is one of the most effective reperfusion strategies for acute myocardial infarction (AMI) despite myocardial ischemia/reperfusion (I/R) injury, causing one of the causes of most cardiomyocyte injuries and deaths. The pathological processes of myocardial I/R injury include apoptosis, autophagy, and irreversible cell death caused by calcium overload, oxidative stress, and inflammation. Eventually, myocardial I/R injury causes a spike of further cardiomyocyte injury that contributes to final infarct size (IS) and bound with hospitalization of heart failure as well as all-cause mortality within the following 12 months. Therefore, the addition of adjuvant intervention to improve myocardial salvage and cardiac function calls for further investigation. Phytochemicals are non-nutritive bioactive secondary compounds abundantly found in Chinese herbal medicine. Great effort has been put into phytochemicals because they are often in line with the expectations to improve myocardial I/R injury without compromising the clinical efficacy or to even produce synergy. We summarized the previous efforts, briefly outlined the mechanism of myocardial I/R injury, and focused on exploring the cardioprotective effects and potential mechanisms of all phytochemical types that have been investigated under myocardial I/R injury. Phytochemicals deserve to be utilized as promising therapeutic candidates for further development and research on combating myocardial I/R injury. Nevertheless, more studies are needed to provide a better understanding of the mechanism of myocardial I/R injury treatment using phytochemicals and possible side effects associated with this approach.

Isovaleroylbinankadsurin A ameliorates cardiac ischemia/reperfusion injury through activating GR dependent RISK signaling

Ischemia/reperfusion (I/R) injury is a pathological process caused by reperfusion. The prevention of I/R injury is of great importance as it would enhance the efficacy of myocardial infarction treatment in patients. Isovaleroylbinankadsurin A (ISBA) has been demonstrated to possess multiple bioactivities for treating diseases. However, its protective effect on myocardial I/R injury remains unknown. In this study, the cardiomyocytes hypoxia/reoxygenation (H/R) in vitro model and coronary artery ligation in vivo model were used to examine the protective effect of ISBA. Apoptosis was determined by flow cytometry and Caspase 3 activity. Protein level was determined by Western blot. The mitochondrial viability was examined with mitochondrial viability stain assay. Mitochondrial membrane potential was detected by JC-1 staining and reactive oxygen species (ROS) was stained with 2',7'-dichlorodihydrofluorescein diacetate (DCF-DA). The binding interactions between ISBA and receptors was simulated by molecular docking. Results showed that ISBA effectively protected cardiomyocytes from I/R injury in in vitro and in vivo models. It remarkably blocked the apoptosis induced by H/R injury through the mitochondrial dependent pathway. Activation of the reperfusion injury salvage kinase (RISK) pathway was demonstrated to be essential for ISBA to exert its protective effect on cardiomyocytes. Moreover, molecular docking indicated that ISBA could directly bind to glucocorticoid receptor (GR) and thus induce its activation. Furthermore, the treatment of GR inhibitor RU486 partially counteracted the protective effect of ISBA on cardiomyocytes, consistent with the results of docking.Most attractively, by activating GR dependent RISK pathway, ISBA significantly elevated the cellular anti-oxidative capacity and hence alleviated oxidative damage induced by I/R injury. In conclusion, our study proved that ISBA protected the heart from myocardial I/R injury through activating GR dependent RISK pathway and consequently inhibiting the ROS generation. It provides a valuable reference for ISBA to be developed as a candidate drug for cardiovascular diseases.

Lignans from Tujia Ethnomedicine Heilaohu: Chemical Characterization and Evaluation of Their Cytotoxicity and Antioxidant Activities

Heilaohu, the roots of Kadsura coccinea, has a long history of use in Tujia ethnomedicine for the treatment of rheumatoid arthritis and gastroenteric disorders, and a lot of work has been done in order to know the material basis of its pharmacological activities. The chemical investigation led to the isolation and characterization of three new (1–3) and twenty known (4–23) lignans. Three new heilaohulignans A-C (1–3) and seventeen known (4–20) lignans possessed dibenzocyclooctadiene skeletons. Similarly, one was a diarylbutane (21) and two were spirobenzofuranoid dibenzocyclooctadiene (22–23) lignans. Among the known compounds, 4–5, 7, 13–15 and 17–22 were isolated from this species for the first time. The structures were established, using IR, UV, MS and NMR data. The absolute configurations of the new compounds were determined by circular dichroism (CD) spectra. The isolated lignans were further evaluated for their cytotoxicity and antioxidant activities. Compound 3 demonstrated strong cytotoxic activity with an IC₅₀ value of 9.92 µM, compounds 9 and 13 revealed weak cytotoxicity with IC₅₀ values of 21.72 µM and 18.72 µM, respectively in the HepG-2 human liver cancer cell line. Compound 3 also showed weak cytotoxicity against the BGC-823 human gastric cancer cell line and the HCT-116 human colon cancer cell line with IC₅₀ values of 16.75 µM and 16.59 µM, respectively. A chemiluminescence assay for antioxidant status of isolated compounds implied compounds 11 and 20, which showed weak activity with IC₅₀ values of 25.56 µM and 21.20 µM, respectively.

Dibenzocyclooctadiene lignans from Kadsura coccinea

In vitro anti-allergic screening of medicinal herbal extracts revealed that the EtOAc extract of the rhizoma of Kadsura coccinea inhibited nitric oxide (NO) production in a lipopolysaccharide and recombinant mouse interferon-γ activated murine macrophage-like cell line, RAW264.7. Further fractionation of the EtOAc extract led to the isolation of two new dibenzocyclooctadiene lignans kadsuralignan G (1) and kadsuralignan L (2), and three known analog compounds. The absolute stereostructures were established by circular dichroism spectra. Both 1 and 2 showed moderate NO production inhibitory activities.

Three new lignans, longipedunins A-C, from Kadsura longipedunculata and their inhibitory activity against HIV-1 protease

Three new lignans, longipedunins A (1), B (2) and C (3), together with three known compounds, benzoyl-binankadsurin A (4), acetyl-binankadsurin A (5) and schisanlactone A (6), were isolated from Kadsura longipedunculata. Their structures and stereochemistry were determined by spectral and single-crystal X-ray analyses. Compounds 1 and 6 showed appreciable inhibitory activity against HIV-1 protease with IC50 values of 50 and 20 microM, respectively.