Novel sesquiterpenes from Schisandra grandiflora: isolation, cytotoxic activity and synthesis of their triazole derivatives using "click" reaction

Down-regulation of human papillomavirus E6 oncogene and antiproliferative effect of Schisandra chinensis and Pueraria lobata natural extracts on Hela cell line

ETHNOPHARMACOLOGICAL RELEVANCE

Cervical cancer is one of the most common malignancies in women that continues to be a public health problem worldwide. Human papillomavirus (HPV) infection is closely related as the causative agent of almost all cases of cervical cancer. Currently, there is no effective treatment for the persistence of HPV. Although vaccines have shown promising results in recent years, they are still a costly strategy for developing countries and have no therapeutic effect on existing infections, which is why the need arises to search for new strategies that can be used in treatment, suppressing oncogenic HPV and disease progression. Extracts of Schisandra Chinensis and Pueraria lobata have been used in traditional medicine, and it has been shown in recent years that some of their bioactive compounds have pharmacological, antioxidant, antitumor, apoptotic, and proliferation effects in HPV-positive cells. However, its mechanism of action has yet to be fully explored.

AIM OF THE STUDY

The following study aimed to determine the chemical composition, antioxidant activity, and potential antiproliferative and viral oncogene effects of natural extracts of S. chinensis and P. lobata on HPV-18 positive cervical cancer cells.

MATERIALS AND METHODS

The HPV-18-positive HeLa cells were treated for 24 and 48 h with the ethanolic extracts of S chinensis and P. lobata. Subsequently, cell viability was evaluated using the resazurin method, the effect on the cell cycle of the extracts (1.0, 10, and 100 μg/mL) was measured by flow cytometry, the gene of expression of the E6/E7, P53, BCL-2, and E2F-1 were determined by RT-PCR and the protein expression of p53, Ki-67, x|and Bcl-2 by immunohistochemistry. Additionally, the chemical characterization of the two extracts was carried out using LC-MS, and the total phenolics content (TPC), Total flavonoid content (TFC), and DPPH radical scavenging capacity were determined. Data were analyzed using the Mann-Whitney and Kruskal Wallis U test with GraphPad Prism 6 software.

RESULTS

The natural extracts of Schisandra chinensis and Pueraria lobata induced down-regulation of E6 HPV oncogene (p<0.05) and a strong up-regulation of P53 (p<0.05), E2F-1 (p<0.05), and Bcl-2 (p<0.05) gene expression. Simultaneously, the natural extracts tend to increase the p53 protein levels and arrest the cell cycle of HeLa in the G1/S phase (p<0.05). Investigated extracts were characterized by the occurrence of bioactive lignans and isoflavones in S. chinensis and P. lobata, respectively.

CONCLUSION

The extracts of S. chinensis and P. lobata within their chemical characterization mainly present lignan and isoflavone-type compounds, which are probably responsible for inhibiting the expression of the HPV E6 oncogene and inducing an increase in the expression of p53, Bcl -2 and E2F-1 producing cell cycle detection in S phase in HeLa cells. Therefore, these extracts are good candidates to continue studying their antiviral and antiproliferative potential in cells transformed by HPV.

Comprehensive review of dibenzocyclooctadiene lignans from the Schisandra genus: anticancer potential, mechanistic insights and future prospects in oncology

Cancer remains one of the leading causes of mortality worldwide. The search for novel and effective anticancer agents has been a significant area of research. Dibenzocyclooctadiene lignans (DBCLS), derived from the Schisandra genus plants like: S. chinensis, S. sphenanthera, S. henryi, S. rubriflora, S. grandiflora, S. propinqua, and S. glabra, have been traditionally used in various medicinal systems and are known for their myriad health benefits, including anticancer properties. This comprehensive review aimed to collate and critically analyse the recent literature on the anticancer properties of DBCLS, focusing on their mechanistic approaches against different cancer types. An exhaustive literature search was performed using databases like PubMed/MedLine, Scopus, Web of Science, Embase, TRIP database and Google Scholar from 1980 to 2023. Peer-reviewed articles that elucidated the mechanistic approach of these lignans on cancer cell lines, in vivo models and preliminary clinical studies were included. Studies were assessed for their experimental designs, cancer types studied, and the mechanistic insights provided. The studies demonstrate that the anticancer effects of DBCLS compounds are primarily driven by their ability to trigger apoptosis, arrest the cell cycle, induce oxidative stress, modulate autophagy, and disrupt essential signaling pathways, notably MAPK, PI3K/Akt, and NF-κB. Additionally, these lignans have been shown to amplify the impact of traditional chemotherapy treatments, suggesting their potential role as supportive adjuncts in cancer therapy. Notably, several studies also emphasise their capacity to target cancer stem cells and mitigate multi-drug resistance specifically. DBCLS from the Schisandra genus have showcased significant potential as anticancer agents. Their multi-targeted mechanistic approach makes them promising candidates for further research, potentially leading to developing of new therapeutic strategies in cancer management.

The efficacy of natural bioactive compounds against prostate cancer: Molecular targets and synergistic activities

Globally, prostate cancer (PCa) is regarded as a challenging health issue, and the number of PCa patients continues to rise despite the availability of effective treatments in recent decades. The current therapy with chemotherapeutic drugs has been largely ineffective due to multidrug resistance and the conventional treatment has restricted drug accessibility to malignant tissues, necessitating a higher dosage resulting in increased cytotoxicity. Plant-derived bioactive compounds have recently attracted a great deal of attention in the field of PCa treatment due to their potent effects on several molecular targets and synergistic effects with anti-PCa drugs. This review emphasizes the molecular mechanism of phytochemicals on PCa cells, the synergistic effects of compound-drug interactions, and stem cell targeting for PCa treatment. Some potential compounds, such as curcumin, phenethyl-isothiocyanate, fisetin, baicalein, berberine, lutein, and many others, exert an anti-PCa effect via inhibiting proliferation, metastasis, cell cycle progression, and normal apoptosis pathways. In addition, multiple studies have demonstrated that the isolated natural compounds: d-limonene, paeonol, lanreotide, artesunate, and bicalutamide have potential synergistic effects. Further, a significant number of natural compounds effectively target PCa stem cells. However, further high-quality studies are needed to firmly establish the clinical efficacy of these phytochemicals against PCa.

Schisandra henryi-A Rare Species with High Medicinal Potential

Schisandra henryi (Schisandraceae) is a plant species endemic to Yunnan Province in China and is little known in Europe and America. To date, few studies, mainly performed by Chinese researchers, have been conducted on S. henryi. The chemical composition of this plant is dominated by lignans (dibenzocyclooctadiene, aryltetralin, dibenzylbutane), polyphenols (phenolic acids, flavonoids), triterpenoids, and nortriterpenoids. The research on the chemical profile of S. henryi showed a similar chemical composition to S. chinensis-a globally known pharmacopoeial species with valuable medicinal properties whichis the best-known species of the genus Schisandra. The whole genus is characterized by the presence of the aforementioned specific dibenzocyclooctadiene lignans, known as "Schisandra lignans". This paper was intended to provide a comprehensive review of the scientific literature published on the research conducted on S. henryi, with particular emphasis on the chemical composition and biological properties. Recently, a phytochemical, biological, and biotechnological study conducted by our team highlighted the great potential of S. henryi in in vitro cultures. The biotechnological research revealed the possibilities of the use of biomass from S. henryi as an alternative to raw material that cannot be easily obtained from natural sites. Moreover, the characterization of dibenzocyclooctadiene lignans specific to the Schisandraceae family was provided. Except for several scientific studies which have confirmed the most valuable pharmacological properties of these lignans, hepatoprotective and hepatoregenerative, this article also reviews studies that have confirmed the anti-inflammatory, neuroprotective, anticancer, antiviral, antioxidant, cardioprotective, and anti-osteoporotic effects and their application for treating intestinal dysfunction.

Click Chemistry in Natural Product Modification

Click chemistry is perhaps the most powerful synthetic toolbox that can efficiently access the molecular diversity and unique functions of complex natural products up to now. It enables the ready synthesis of diverse sets of natural product derivatives either for the optimization of their drawbacks or for the construction of natural product-like drug screening libraries. This paper showcases the state-of-the-art development of click chemistry in natural product modification and summarizes the pharmacological activities of the active derivatives as well as the mechanism of action. The aim of this paper is to gain a deep understanding of the fruitful achievements and to provide perspectives, trends, and directions regarding further research in natural product medicinal chemistry.

1,2,3-Triazole-Containing Compounds as Anti-Lung Cancer Agents: Current Developments, Mechanisms of Action, and Structure-Activity Relationship

Lung cancer is the most common malignancy and leads to around one-quarter of all cancer deaths. Great advances have been achieved in the treatment of lung cancer with novel anticancer agents and improved technology. However, morbidity and mortality rates remain extremely high, calling for an urgent need to develop novel anti-lung cancer agents. 1,2,3-Triazole could be readily interact with diverse enzymes and receptors in organisms through weak interaction. 1,2,3-Triazole can not only be acted as a linker to tether different pharmacophores but also serve as a pharmacophore. This review aims to summarize the recent advances in 1,2,3-triazole-containing compounds with anti-lung cancer potential, and their structure-activity relationship (SAR) together with mechanisms of action is also discussed to pave the way for the further rational development of novel anti-lung cancer candidates.

Antiprotozoal and Antitumor Activity of Natural Polycyclic Endoperoxides: Origin, Structures and Biological Activity

Polycyclic endoperoxides are rare natural metabolites found and isolated in plants, fungi, and marine invertebrates. The purpose of this review is a comparative analysis of the pharmacological potential of these natural products. According to PASS (Prediction of Activity Spectra for Substances) estimates, they are more likely to exhibit antiprotozoal and antitumor properties. Some of them are now widely used in clinical medicine. All polycyclic endoperoxides presented in this article demonstrate antiprotozoal activity and can be divided into three groups. The third group includes endoperoxides, which show weak antiprotozoal activity with a reliability of up to 70%, and this group includes only 1.1% of metabolites. The second group includes the largest number of endoperoxides, which are 65% and show average antiprotozoal activity with a confidence level of 70 to 90%. Lastly, the third group includes endoperoxides, which are 33.9% and show strong antiprotozoal activity with a confidence level of 90 to 99.6%. Interestingly, artemisinin and its analogs show strong antiprotozoal activity with 79 to 99.6% confidence against obligate intracellular parasites which belong to the genera Plasmodium, Toxoplasma, Leishmania, and Coccidia. In addition to antiprotozoal activities, polycyclic endoperoxides show antitumor activity in the proportion: 4.6% show weak activity with a reliability of up to 70%, 65.6% show an average activity with a reliability of 70 to 90%, and 29.8% show strong activity with a reliability of 90 to 98.3%. It should also be noted that some polycyclic endoperoxides, in addition to antiprotozoal and antitumor properties, show other strong activities with a confidence level of 90 to 97%. These include antifungal activity against the genera Aspergillus, Candida, and Cryptococcus, as well as anti-inflammatory activity. This review provides insights on further utilization of polycyclic endoperoxides by medicinal chemists, pharmacologists, and the pharmaceutical industry.

Exploring the Chemistry and Therapeutic Potential of Triazoles: A Comprehensive Literature Review

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Triazole is a valuable platform in medicinal chemistry, possessing assorted pharmacological properties, which could play a major role in the common mechanisms associated with various disorders like cancer, infections, inflammation, convulsions, oxidative stress and neurodegeneration. Structural modification of this scaffold could be helpful in the generation of new therapeutically useful agents. Although research endeavors are moving towards the growth of synthetic analogs of triazole, there is still a lot of scope to achieve drug discovery break-through in this area. Upcoming therapeutic prospective of this moiety has captured the attention of medicinal chemists to synthesize novel triazole derivatives. The authors amalgamated the chemistry, synthetic strategies and detailed pharmacological activities of the triazole nucleus in the present review. Information regarding the marketed triazole derivatives has also been incorporated. The objective of the review is to provide insights to designing and synthesizing novel triazole derivatives with advanced and unexplored pharmacological implications.

1,2,3-Triazole-containing hybrids as potential anticancer agents: Current developments, action mechanisms and structure-activity relationships

Anticancer agents are critical for the cancer treatment, but side effects and the drug resistance associated with the currently used anticancer agents create an urgent need to explore novel drugs with low side effects and high efficacy. 1,2,3-Triazole is privileged building block in the discovery of new anticancer agents, and some of its derivatives have already been applied in clinics or under clinical trials for fighting against cancers. Hybrid molecules occupy an important position in cancer control, and hybridization of 1,2,3-triazole framework with other anticancer pharmacophores may provide valuable therapeutic intervention for the treatment of cancer, especially drug-resistant cancer. This review emphasizes the recent advances in 1,2,3-triazole-containing hybrids with anticancer potential, covering articles published between 2015 and 2019, and the structure-activity relationships, together with mechanisms of action are also discussed.

Synthesis and biological evaluation of bergenin-1,2,3-triazole hybrids as novel class of anti-mitotic agents

In continuation of our investigation of pharmacologically-motivated natural products, we have isolated bergenin (1) as a major compound from Mallotus philippensis, which is deployed in different Indian traditional systems of medicine. Here, a series of bergenin-1,2,3-triazole hybrids were synthesized and evaluated for their potentials against a panel of cancer cell lines. Several of the hybrid derivatives were found more potent in comparison to parent compound bergenin (1). Among them, 4j demonstrated potent activity against A-549 and HeLa cell lines with IC₅₀ values of 1.86 µM and 1.33 μM, respectively, and was equipotent to doxorubicin. Cell cycle analysis showed that 4j arrested HeLa cells at G2/M phase and lead to accumulation of Cyclin B1 protein. Cell based tubulin polymerization assays and docking studies demonstrated that 4j disrupts tubulin assembly by occupying colchicine binding pocket of tubulin.

Phytochemicals in Prostate Cancer: From Bioactive Molecules to Upcoming Therapeutic Agents

Prostate cancer is a heterogeneous disease, the second deadliest malignancy in men and the most commonly diagnosed cancer among men. Traditional plants have been applied to handle various diseases and to develop new drugs. Medicinal plants are potential sources of natural bioactive compounds that include alkaloids, phenolic compounds, terpenes, and steroids. Many of these naturally-occurring bioactive constituents possess promising chemopreventive properties. In this sense, the aim of the present review is to provide a detailed overview of the role of plant-derived phytochemicals in prostate cancers, including the contribution of plant extracts and its corresponding isolated compounds.

New Cadinane Sesquiterpenes from the Stems of Kadsura heteroclita

As part of our continual efforts to exploit ‘Tujia Ethnomedicine’ for their pharmacophoric functionalities, we herein investigated Kadsura heteroclita collected from a deep Wulin mountain area in northern Hunan province. The current study resulted in the isolation of three new sesquiterpenes: 6α,9α,15-trihydroxycadinan-4-en-3-one (1), (+)-3,11,12-trihydroxycalamenene (2), (–)-3,10,11,12-tetrahydroxy-calamenene (3), along with four known sesquiterpenes (4–7), and a cytochalasin H (8). Their chemical structures were elucidated by 1D-, and 2D-NMR spectroscopy, and HRESI-MS, CD spectrometry. The antioxidant, and cytotoxic activities of the compounds were evaluated. Compound 8 exhibited a strong antioxidant effect with an IC₅₀ value of 3.67 µM on isolated human polymorphonuclear cells or neutrophils.

Synthesis and biological evaluation of Schizandrin derivatives as potential anti-cancer agents

A new series of Schizandrin (1) derivatives were synthesized utilizing the C-9 position of the Schizandrin core and evaluated for their cytotoxic activities against HeLa (cervical cancer), A549 (lung cancer), MCF-7 (breast cancer) and DU-145 (prostate cancer) cell lines. Among the synthesized series, 4e, 4f, 4g and 5 showed potent activities against tested cell lines. More significantly, compound 5 exhibited most potent cytotoxic activity against DU-145 with an IC₅₀ value of 1.38 μM which is comparable to the standard agent, doxorubicin. Further, flow cytometry analysis indicated that 5 arrested cells in G2/M phase and consequently leading to apoptosis. Molecular docking analysis showed that 5 occupied the colchicine binding pocket of tubulin. Overall, the present study demonstrates that 5, as a mitotic-agent.

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.

Novel Gomisin B analogues as potential cytotoxic agents: Design, synthesis, biological evaluation and docking studies

As part of pharmacological-phytochemical integrated studies on medicinal flora, Gomisin B (1) was isolated as major phytochemical lead from schisandra grandiflora, a plant traditionally used in different Asian systems of medicine. A series of 1,2,3-triazoles derivatives were synthesized at the C-7' position of the gomisin B core through diastereoselective Michael addition followed by regioselective Huisgen 1,3-dipolar cycloaddition reactions. All these triazolyl derivatives (5a-5q) were well characterized using modern spectroscopic techniques and evaluated for their anti-cancer activity against a panel of five human cancerous cell-lines. Among them, compound 5b exhibited the best cytotoxicity against SIHA cell (IC₅₀ 0.24 μM) which was more than the standard drug doxorubicin, while the other derivatives were exhibited moderate to low activities in tested cell lines. The cell cycle analysis indicated that compound 5b stalled HeLa cells at G2/M phase. 5b promoted tubulin polymerization and this was supported by the docking studies, wherein 5b showed significant binding affinity at the colchicine binding pocket of tubulin. Overall, we identified a novel small molecule that demonstrated anticancer activity by promoting in vitro tubulin assembly.

Renchangianins F and G: two new sesquiterpenoids from Kadsura renchangiana

Phytochemical investigation on the stems of Kadsura renchangiana led to the isolation of two new sesquiterpenoids, renchangianins F and G (1 and 2). Their structures were elucidated by spectroscopic methods, including 2D NMR techniques. The in vitro cytotoxic activities of the isolates were studied against HepG2, A549, and LN229 cancer cell lines.

New seco-limonoids from Cipadessa baccifera: Isolation, structure determination, synthesis and their antiproliferative activities

A comprehensive reinvestigation of chemical constituents from CHCl₃-soluble extract of Cipadessa baccifera led to the isolation of two new limonoids 1, 2 together with six known compounds 3-8. Their structures were established on the basis of extensive analysis of spectroscopic (IR, MS, 2D NMR) data. Further, a series of cipaferen G (3) derivatives were efficiently synthesized utilizing Yamaguchi esterification (2, 4, 6-trichlorobenzoyl chloride, Et₃N, THF, DMAP, toluene) at the C-3 position of the limonoids core, which is being reported for the first time. The anti-proliferative activity of the isolates and the synthetic analogues were studied against HeLa, PANC 1, HepG2, SKNSH, MDA-MB-231 and IMR32 cancer cells using the sulphorodamine B assay. Among the tested compounds, 13d and 13h manifested potent activity against IMR32, HepG2 cell lines with GI₅₀ 0.013 and 0.01μM, respectively.

Triterpenoids from the stems of Schisandra grandiflora and their biological activity

One new ursane-type triterpenoid (1), named granditriol, along with 14 known compounds (2-15), was isolated from the organic extracts of Schisandra grandiflora stems. The structure of the new compound was elucidated by extensive spectroscopic methods as 28-norursa-12,17,19,21-tetraen-2α,3α,23-triol. These isolates were evaluated for anti-phytopathogenic fungi activity and cytotoxicity against human cancer cell line (HepG2). Asiatic acid (8) and 2α,3α,19α-trihydroxyurs-12-en-28-oic acid (9) inhibited the growth of two plant pathogens, Alternaria alternata and Alternaria solani. In addition, compounds 12, 15, and 11 displayed notable anti-proliferative activity against HepG2 cells. Compound 1 is the first report of 28-nortriterpenoid from the Schisandraceae family. All these were obtained from this plant for the first time.