Transcriptome-wide analysis of PIP reductase gene family identified a phenylpropene synthase crucial for the biosynthesis of dibenzocyclooctadiene lignans in Schisandra chinensis

Phenylpropenes, such as isoeugenol and eugenol, are produced as defend compounds, floral attractants, and flavor constituents by phenylpropene synthases belonging to the PIP reductase family. Moreover, isoeugenol is proposed to be involved in the biosynthesis of dibenzocyclooctadiene lignans, the main active compounds of Schisandra chinensis (Turcz.) Baill. fruits (SCF). S. chinensis, a woody vine plant, is widely used for its medicinal, horticultural, edible, and economic values. In this study, nine ScPIP genes were identified and characterized from the transcriptome datasets of SCF. The expression profiles revealed that ScPIP genes were differentially expressed during different developmental stages of SCF. Three ScPIPs were selected and cloned as candidate genes encoding phenylpropene synthases according to phylogenetic analysis. ScPIP1 was proved to function as isoeugenol synthase (IGS) and designated as ScIGS1 through in vivo functional characterization in Escherichia coli. Subcellular localization analysis demonstrated that ScIGS1 was localized in both the cytoplasm and nucleus. The three-dimensional (3D) model of ScIGS1 was obtained using homology modeling. Site-directed mutagenesis experiments revealed that the substitution of residues at positions 110 and 113 impacted the product specificity of ScIGS1 and the mutation of Lys157 to Ala abolishing catalytic function. Moreover, the kcat values of mutants were lower than that of ScIGS1 using a deep learning approach. In conclusion, this study provides a basis for further research on PIP reductases and the biosynthetic pathway of dibenzocyclooctadiene lignans.

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.

Dibenzocyclooctadiene lignans from Kadsura coccinea alleviate APAP-induced hepatotoxicity via oxidative stress inhibition and activating the Nrf2 pathway in vitro

Phytochemical investigation on the roots of Kadsura coccinea led to the isolation five previously unknown dibenzocyclooctadiene lignans, named heilaohusuins A-E (1-5). Their structures determined by NMR spectroscopy, HR-ESI-MS, and ECD spectra. Hepatoprotection effects of a series of dibenzocyclooctadiene derivatives (1-68) were investigated against acetaminophen (APAP) induced HepG2 cells. Compounds 2, 10, 13, 21, 32, 41, 46, and 49 showed remarkable protective effects, increasing the viabilities to > 52.2% (bicyclol, 52.1 ± 1.3%) at 10 μM. The structure-activity relationships (SAR) for hepatoprotective activity were summarized, according to the activity results of dibenzocyclooctadiene derivatives. Furthermore, we found that one new dibenzocyclooctadiene lignan heilaohusuin B attenuates hepatotoxicity, the mechanism might be closely correlated with oxidative stress inhibition via activating the Nrf2 pathway.

Dibenzocyclooctadiene lignans from Artemisia sieversiana and their anti-inflammatory activities

Two previously undescribed dibenzocyclooctadiene lignans, named sieverlignans D-E (1-2), as well as eight known ones (3-10), were isolated from the aerial parts of Artemisia sieversiana. Their structures were elucidated from extensive spectroscopic analysis, including HRMS, NMR and electronic circular dichroism (ECD) experiments. This study is the first to report dibenzocyclooctadiene lignans in the genus Artemisia and this plant. All the compounds were evaluated for their anti-neuroinflammatory activities on the lipopolysaccharides (LPS)-induced nitric oxide production in BV-2 murine microglial cells. Compounds 1 and 6 exhibited the moderate activities with their IC₅₀ values of 47.7 and 21.9 μM, compared to a positive control quercetin with the IC₅₀ value of 16.0 μM.

Characterization of lignans in Schisandra chinensis oil with a single analysis process by UPLC-Q/TOF-MS

Schisandra chinensis is a medicinal and edible plant that contains various bioactive compounds. Among these, lignans are the major functional compounds. Nevertheless, detailed information about lignans in Schisandra chinensis oil remains scarce. A powerful UPLC-Q/TOF-MS method was established for the rapid identification of the lignan constituents of Schisandra chinensis oils. The results showed that 21 lignans have been unambiguously identified, and four lignans have been tentatively identified in the Schisandra chinensis oils. In addition, semi-quantitative analysis indicated that the total lignan content in the Schisandra chinensis oils was distributed from 67.73 ± 0.06 to 87.61 ± 1.83 mg/g. Schisandrin and schisandrin B were the most abundant lignans in the Schisandra chinensis oils, their content ranging from 15.85 ± 0.09 to 20.57 ± 0.38 mg/g. Additionally, this study provided a systematic characterization of lignans in Schisandra chinensis oil and indicated that the oil might be used as lignan-related functional foods.

Cytotoxic ethnic Yao medicine Baizuan, leaves of Schisandra viridis A. C. Smith

ETHNOPHARMACOLOGICAL RELEVANCE

The ethnic Chinese Yao medicine Baizuan, which are the leaves of Schisandra viridis A. C. Smith, is traditionally used, in combination with other herbs, to soften hard lumps and dispel nodes in the treatment of cancer, however, this property has not been well studied with a clear indication of the active principles.

AIM OF THE STUDY

The experiments were carried out to investigate the cytotoxic activity of the extracts and to identify the active principles from the extract, which could support the traditional application of treating cancer.

MATERIALS AND METHODS

Dried and ground plant material was extracted with water and ethanol and further purified by HPLC. The cytotoxicity of the extracts, fractions and pure compounds were evaluated for their abilities to inhibit the proliferation of breast cancer cells MCF7 and tongue cancer cells CAL27. The cytotoxicity of the pure compounds were also tested against Human Embryonic Kidney cell line HEK293.

RESULTS

Both aqueous and ethanol extracts showed activities against MCF7 and CAL27 cancer cells. Bioassay-guided fractionation and purification of the extracts resulted in six active principles, including five dibenzocyclooctene lignans namely gomisin H (1), schisandrin (2), angeloylgomisin H (3), (+)-gomisin M₂ (4) and (-)-rubschisandrin (5), and one triterpenoid, schisanol (6). Compounds 1-3 showed moderate cytotoxic activities with IC₅₀ values ranging from 100 to 200µg/mL against MCF7 and CAL27 cell lines. Dioxane containing lignans 4-5 and triterpenoid 6 were 10 times more active with IC₅₀ values of 14.5, 13.4, 10.6µg/mL against MCF7, and 21.2, 17.9, 11.7µg/mL against CAL27, respectively. Compounds 1-6 also showed cytotoxicity against HEK293 with IC₅₀ values ranging from 10 to 150µg/mL, respectively.

CONCLUSIONS

The traditional extraction protocol using boiled water afforded three moderately active lignans 1-3. Ethanol extraction, which is widely used in the preparation of herbal remedies in China, yielded three additional active compounds 4-5 with more potent activities. These results provided a rationale for the traditional application of the ethnic Yao medicine Baizuan in the treatment of cancer.

Current knowledge of Schisandra chinensis (Turcz.) Baill. (Chinese magnolia vine) as a medicinal plant species: a review on the bioactive components, pharmacological properties, analytical and biotechnological studies

Schisandra chinensis Turcz. (Baill.) is a plant species whose fruits have been well known in Far Eastern medicine for a long time. However, schisandra seems to be a plant still underestimated in contemporary therapy still in the countries of East Asia. The article presents latest available information on the chemical composition of this plant species. Special attention is given to dibenzo cyclooctadiene lignans. In addition, recent studies of the biological activity of dibenzocyclooctadiene lignans and schisandra fruit extracts are recapitulated. The paper gives a short resume of their beneficial effects in biological systems in vitro, in animals, and in humans, thus underlining their medicinal potential. The cosmetic properties are depicted, too. The analytical methods used for assaying schisandra lignans in the scientific studies and also in industry are also presented. Moreover, special attention is given to the information on the latest biotechnological studies of this plant species. The intention of this review is to contribute to a better understanding of the huge potential of the pharmacological relevance of S. chinensis.

Isolation and anti-hepatitis B virus activity of dibenzocyclooctadiene lignans from the fruits of Schisandra chinensis

Seven lignans with a dibenzocyclooctadiene skeleton, termed schinlignans A-G, and a 6,7-seco-homolignan, schischinone, together with seven known lignans, were isolated from the fruits of Schisandra chinensis (Turcz.) Baill. Their structures were elucidated by extensive spectroscopic methods, including HRESIMS, IR, UV, and 2D NMR (COSY, HMQC, COSY, and HMBC experiments). The stereochemistry at the chiral centers and the biphenyl moiety, were determined using ROESY, as well as via interpretation of their ECD spectra. Schinlignan G and methylgomisin O exhibited potent anti-hepatitis B virus activity against HBV DNA replication with IC50 values of 5.13 and 5.49μgmL(-1), respectively.

Dibenzocyclooctadiene lignans from Schisandra chinensis and their inhibitory activity on NO production in lipopolysaccharide-activated microglia cells

Four dibenzocyclooctadiene lignans, schisanchinins A-D, and 10 known compounds were isolated from the EtOAc extract of fruits of Schisandra chinensis (Turcz.) Baill. Structures of compounds 1-4 were elucidated using a combination of spectroscopic techniques, including MS, UV and IR, NMR ((1)H NMR, (13)C NMR, HMQC, HMBC). The stereochemistry of the chiral centers and the biphenyl configuration were determined using NOESY, as well as analysis of CD spectra. In vitro activity assays showed that 11 of the 14 compounds exhibited inhibitory activity on lipopolysaccharide (LPS)-induced NO release in primary murine BV2 microglia cells.