Isolation and characterization of three new anti-proliferative Sesquiterpenes from Polygonum barbatum and their mechanism via apoptotic pathway

Access to CF3-benzofulvenes via palladium-catalyzed cascade arylation/Trost-Oppolzer cyclization/double-bond isomerization

Herein, we demonstrated a Pd-catalyzed cascade reaction that involves arylation, Trost-Oppolzer type Alder ene reaction, and double bond isomerization using the 4-(2-alkynylphenyl)-allylcarbonates and aryl boronic acids. This cascade process delivers a wide array of distinctive functionalized CF3-benzofulvenes in good yields with high stereoselectivity (E). A single palladium catalyst orchestrates the two individual reactions in a single operation. Trost-Oppolzer type Alder ene reaction is the key in this transformation, also called a rare acid-free iso-Nazarov type cyclization.

Polygonum barbatum extract reduces colorectal cancer cell proliferation, migration, invasion, and epithelial-mesenchymal transition via YAP and β-catenin pathway regulation

Colorectal cancer (CRC) is the third most common cancer worldwide with novel therapeutic developmental challenges. Polygonum barbatum has anticancer potential, but its mechanism(s) are unclear. This study investigates the inhibitory effect of P. barbatum on human CRC cells. Polygonum barbatum extract (PBE) and quercetin standard HPLC fingerprints were determined using analytical RP-HPLC and evaluations were completed using the human colon cancer cell line HCT-116 (KRASG13D mutation) and HT-29 (BRAF mutation) cells. Post-PBE treatment, cell viability, colony formation, migration, invasion, and apoptosis, as well as changes in the whole-transcriptome of cells were analyzed. PBE significantly reduced CRC cell growth, migration, and invasion, and the genes responsible for extracellular matrix (ECM) organization, cell motility, and cell growth were suppressed by PBE. The differentially expressed genes revealed that PBE treatment exerted a significant effect on the ECM interaction and focal adhesion pathways. Epithelial-to-mesenchymal transition markers, N-cadherin, vimentin, SLUG, and SNAIL, were shown to be regulated by PBE. These effects were associated with blockade of the Yes-associated protein and the GSK3β/β-catenin axis. PBE exerts a significant inhibitory effect on CRC cells and may be applicable in clinical trials.

Dual gold-catalyzed regioselective synthesis of benzofulvenes via 5-endo dig cyclization

An efficient dual gold-catalyzed regioselective synthesis of benzofulvenes has been developed from substituted allyloxy 1,5-diynes via 5-endo dig cyclization. In this intramolecular organic transformation a new C-C bond formation occurs and moderate to very good yields are obtained in one pot.

Naturally Isolated Sesquiterpene Lactone and Hydroxyanthraquinone Induce Apoptosis in Oral Squamous Cell Carcinoma Cell Line

Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers worldwide, especially in Asian countries. The emergence of its drug resistance and its side effects demands alternatives, to improve prognosis. Since the majority of cancer drugs are derived from natural sources, it provides a window to look for more biocompatible alternatives. In this study, two natural compounds, costunolide (CE) and aloe emodin (AE), were isolated from the stem of Lycium shawii. The compounds were examined for their anticancer and apoptotic potentials against OSCC (CAL 27) cells, using an in vitro analysis, such as a MTT assay, scratch assay, gene, and protein expressions. Both compounds, CE and AE, were found to be cytotoxic against the cancer cells with an IC₅₀ value of 32 and 38 µM, respectively. Moreover, the compounds were found to be non-toxic against normal NIH-3T3 cells and comparable with the standard drug i.e., 5-fluorouracil (IC₅₀ = 97.76 µM). These compounds were active against normal cells at higher concentrations. Nuclear staining displayed the presence of apoptosis-associated morphological changes, i.e., karyopyknosis and karyorrhexis in the treated cancer cells. Flow cytometry results further confirmed that these compounds induce apoptosis rather than necrosis, as the majority of the cells were found in the late apoptotic phase. Gene and protein expression analyses showed an increased expression of apoptotic genes, i.e., BAK, caspase 3, 6, and 9. Moreover, the compounds significantly downregulated the expression of the anti-apoptotic (BCL-2 L1), metastatic (MMP-2), and pro-inflammatory (COX-2) genes. Both compounds have shown promising anticancer, apoptotic, and anti-migratory activities against the OSCC cell line (i.e., CAL-27). However, further in vivo studies are required to explore these compounds as anticancer agents.

Sesquiterpene from Polygonum barbatum disrupts mitochondrial membrane potential to induce apoptosis and inhibits metastasis by downregulating matrix metalloproteinase and osteopontin in NCI-H460 cells

Globally, lung cancer accounts for 18% of cancer-associated mortalities. Among the subtypes, non-small cell lung cancer (NSCLC) is the most prevalent. The increased resistance and poor survival rates signify disease aggressiveness and thus require a search for an alternative anticancer molecule. Earlier, the sesquiterpene, i.e., compound 3 ((E)-methyl 6-acetoxy-7-methoxy-1-(2-methylpropylidene)-1H-indene-3-carboxylate) from Polygonum barbatum, was isolated, characterized by us, and reported for preliminary anticancer activity. Therefore, based on these results, this study was designed to explore the underlying molecular mechanism of apoptosis and metastasis against NCI-H460 cells. The molecular mechanism of compound 3 inducing apoptosis and inhibiting metastasis was elucidated by analyzing mitochondrial membrane potential, DNA fragmentation, clonogenic assay, invasion assay, and expression of apoptotic (caspases 3, 6, 8, 9, and BAK) and metastatic markers (MMP 2, MMP 9, and osteopontin). Compound 3 significantly inhibited cell proliferation and induced apoptosis via the intrinsic route, i.e., the mitochondrial pathway, by disrupting mitochondrial membrane potential. The enhanced expression of caspases 6, 9, BAK, and HRK with downregulation of Bcl-2L1 and Ki67 further confirmed the involvement of the intrinsic apoptotic pathway. Moreover, compound 3 restricted the invasive nature of NCI-H460 cells evinced by reduced cell invasion in Boyden chamber invasion assay and downregulating the expression of metastatic markers, i.e., matrix metalloproteinase 2/9 and VEGF. It was also found to block osteopontin by negatively regulating its expression, a marker protein in cancer management. Conclusively, this sesquiterpene exhibited potent anticancer and antimetastatic activity and can be explored further as possible pharmacophores.

Natural products based crown ethers: synthesis and their anticancer potential

Natural products based novel crown ethers have been prepared by employing biologically active natural structures including tetrahydroisoquinoline, chrysin and biochanin-A as the side arms. The resulting crown scaffolds were evaluated for their anticancer potential against two cancer cell lines i.e. NCI-H460 (non-small lung carcinoma), MCF-7 (breast adenocarcinoma). The comparative study showed that the addition of crown scaffold put marked effects on antiproliferative profile of parent natural precursors and is significant for lung carcinoma in particular. Biochanin-A derived crown ether showed three (03) folds higher antiproliferative activity (IC₅₀ = 6.08 ± 0.07 µM) against lung carcinoma as compared to standard drug cisplatin (IC₅₀ = 19.00 ± 1.24 µM). Cytotoxic trends for NIH-3T3 cell lines were also examined and found reduced as compared to parent natural structures. Hence, these findings could open a new pathway towards developing effective carcinostatic drugs.HIGHLIGHTSFour natural products based novel crown ethers have been developed.Comparative antiproliferative screening of crown ethers and natural precursors.Addition of crown showed marked effects on anticancer profile of natural products.Crown formation is significant for lung carcinoma potential in particular.Biochanin-A derived crown ether found three folds more active than standard drug.

β-Caryophyllene promotes oxidative stress and apoptosis in KB cells through activation of mitochondrial-mediated pathway - An in-vitro and in-silico study

Beta-caryophyllene (BCP), are natural bicyclic sesquiterpenes which are present in numerous plants worldwide. BCP has antioxidant, antimicrobial, and antifungal properties. Here, we studied its anticancer, anti-inflammatory, and cytotoxic effects. Cells treated with BCP, in a dose-dependent manner, exhibited morphological changes, showed lower cell growth, underwent apoptosis and lost the ability to metastasis through the suppression of NF-ҡ B via PI3K/AKT signalling pathway. These results elucidate that the inhibition of NF-ҡ B and PI3K/AKT is one of the most important mechanism by which BCP suppresses cancer cell proliferation and enhances apoptosis.

Review On Documented Medicinal Plants Used For The Treatment Of Cancer

Background:

Cancer is a frightful disease and it is the second leading cause of death worldwide. Naturally derived compounds are gaining interest of research workers as they have less toxic side effects as compared to currently used treatments such as chemotherapy. Plants are the pool of chemical compounds which provides a promising future for research on cancer.

Objective:

This review paper provides updated information gathered on medicinal plants and isolated phytoconstituents used as anticancer agents and summarises the plant extracts and their isolated chemical constituents exhibiting anticancer potential on clinical trials.

Methods:

An extensive bibliographic investigation was carried out by analysing worldwide established scientific databases like SCOPUS, PUBMED, SCIELO, ScienceDirect, Springerlink, Web of Science, Wiley, SciFinder and Google Scholar etc. In next few decades, herbal medicine may become a new epoch of medical system.

Results:

Many researches are going on medicinal plants for the treatment of cancer but it is a time to increase further experimental studies on plant extracts and their chemical constituents to find out their mechanism of action at molecular level.

Conclusion:

The article may help many researchers to start off further experimentation that might lead to the drugs for the cancer treatment.

Novel ursane-type triterpene from the fresh leaves of Carissa carandas and evaluation of cytotoxicity

One novel ursolic acid derivative sabiracin 1 (11,25-epoxy-3β-hydroxy-urs-12-en-28-oic acid) was isolated from the leaves of Carissa carandas, together with five known compounds para hydroxy benzaldehyde (2), ursolic acid (3), carissin (4), 22α-hydroxyursolic acid (5) and β-sitosterol-3-O-β-D-glucopyranoside (6). Compounds 2 and 5 were isolated for the first time from this genus. Structure elucidation was done by the help of spectroscopic techniques. Compounds 1-3, 5 and 6 were examined against oral cancer (CAL-27) and lung cancer (NCI-H460) cell lines. 6 showed good activity against oral cancer (IC₅₀ 18.69 µM), moderate activity against lung cancer (IC₅₀ 63.34 µM) and no cytotoxicity against normal cell lines.

Evaluation of cytotoxicity of areca nut and its commercial products on normal human gingival fibroblast and oral squamous cell carcinoma cell lines

Consumption of areca nut products is the most common cause of oral cancers, particularly in South Asian countries. This study evaluates the cytotoxic and necrotizing effects of areca nut and its formulations on normal human gingival fibroblasts (HGF-1) and oral squamous cell carcinoma (OSCC, CAL-27) cell lines. Identification of various carcinogens and adulterants using LC-HR-ESI-MS/MS analysis was performed in the extracts of areca nut and its products. Apart from alkaloids and flavonoids, a major adulterant, saccharin was found in all the samples of chalia (one of the most common chewing products of areca nut) in the ranges between 1.697-7.170 mg/g of the sample. Cytotoxic studies showed that most of the areca nut products were found cytotoxic to HGF-1 cells while being relatively non-cytotoxic against CAL-27 cells, rather they promote the growth of cancer cells. Our findings revealed that the components of areca nut and its products were injurious to HGF-1 cells and caused necrosis, which may attenuate HGF-1 protection toward oral epithelial cells. Moreover, the non-cytotoxic effect of these products on cancer cell lines suggests further predisposal of the habitual chewers for developing oral carcinomas. This study will give a better understanding of the hazardous effects of areca nut products.

Inhibitory mechanism of BAC-IB17 against β-lactamase mediated resistance in methicillin-resistant Staphylococcus aureus and application as an oncolytic agent

Cancer remains a foremost cause of deaths worldwide, despite several advances in the medical science. The conventional chemotherapeutic methods are not only harmful for normal body cells but also become inactive due to the development of resistance by cancer cells. Therefore, the demand of safe anticancer agents is increasing and enforced the bottomless research on the bacteriocins. Several studies have reported the selective anticancer property of bacteriocins. Current research is the contribution to explore the exact mechanism of action and in vitro application of bacteriocin (BAC-IB17) as an oncolytic agent. In this study, β-lactamase mediated resistance of methicillin resistant Staphylococcus aureus (MRSA) was studied and inhibitory mechanism of MRSA by BAC-IB17 was investigated. Cytotoxic studies were conducted to analyze the anticancerous potential of BAC-IB17. Results revealed that BAC-IB17 inhibited the β-lactamase and produced profound effect on the membrane integrity of MRSA confirmed by scanning electron microscope (SEM). FTIR spectroscopic analysis revealed the changes in the functional groups of bacterial cells before and after treatment with BAC-IB17. BAC-IB17 also found anticancer in nature as it kills HeLa cell lines with the IC₅₀ value of 12.5 μg mL^-1 with no cytotoxic effect on normal cells at this concentration. This specific anticancer property of BAC-IB17 will make it a promising candidate for the treatment of cancer after further clinical trials. Moreover, BAC-IB17 may control MDR bacteria responsible for the secondary complications in cancer patients.

Evaluation of a sesquiterpene as possible drug lead against gelatinases via molecular dynamics simulations

Malignant tumors can be targeted by accounting for their metastatic capabilities. Matrix metalloproteinases (MMPs) are the key players in tumor metastasis facilitating through their proteolytic activities of angiogenesis and extracellular matrix components (ECM) degradation. MMP-2 and MMP-9 being the members of a distinguished class of MMPs more commonly known as gelatinases are the prominent enzymes which are involved in different cancer progression stages. Targeting these isoforms specifically has always been a challenging task due to highly similar structural and functional features among the other members of MMPs with well preserve active sites containing catalytic zinc atom that was the only reason that none of the MMP inhibitor has been successfully marketed for the tumor pathology up till now. Therefore, non-competitive inhibitors with different structural attributed are needed to be evaluated at the molecular level for further experiments. The present study deals with the application of molecular dynamics simulation for the investigation of an alternative pathway for the inhibition of MMP-2 and MMP-9 by a sesquiterpene isolated from Polygonum barbatum which demonstrates the characteristics binding to the S1' subsite of the enzymes followed by in vitro gene expression studies. The simulation results provide information on the possible binding profile producing inhibitory effects imposed by the inhibitor to these enzymes by acquiring different structural and dynamical features. Moreover, thermodynamic quantities based on the computationally intensive thermodynamic integration approach were also obtained in terms of inhibitor binding affinity computed for the inhibitor against MMP-2 and MMP-9 that completely augmented the experimental gene expression study.Communicated by Ramaswamy H. Sarma.

Total Synthesis of Anmindenol A and Its Application to the Design, Synthesis, and Biological Evaluation of Derivatives Thereof

The first total synthesis of anmindenol A is described in four steps. A notable feature of the synthetic route includes the efficient construction of the 3,10-dialkylsubstituted benzofulvene core via a stereoselective vinylogous Stork enamine aldol condensation. The strategy provided a blueprint for the practical preparation of derivatives with modifications in the C-10 alkyl substituents. The novel derivatives inhibited nitric oxide production in stimulated RAW 264.7 macrophage cells.

Composition, antioxidant capacity and cytotoxic activity of Eugenia uniflora L. chemotype-oils from the Amazon

ETHNOPHARMACOLOGICAL RELEVANCE

Oils and extracts of Eugenia uniflora have been reported as antimicrobial, antifungal, antinociceptive, antiprotozoal, antioxidant and cytotoxic.

AIM OF THE STUDY

The oils of five specimens (E1 to E5) that occur in the Brazilian Amazon were extracted, analyzed for their chemical composition, and submitted to antioxidant and cytotoxic assays.

MATERIAL AND METHODS

Oils were hydrodistilled, analyzed by GC and GC-MS, and submitted to PCA and HCA analyses. The antioxidant activity of the oils was evaluated by the DPPH radical scavenging and the β-carotene/linoleic acid assays. Antiproliferative effects of the oils and curzerene were tested against colon (HCT-116), gastric (AGP-01), and melanoma (SKMEL-19) human cancer cell lines and a normal human fibroblast cell line (MRC-5), using MTT assay.

RESULTS

Oxygenated sesquiterpenes and sesquiterpene hydrocarbons such as curzerene, selina-1,3,7(11)-trien-2-one, selina-1,3,7(11)-trien-2-one epoxide, germacrene B, caryophyllene oxide, and (E)-caryophyllene were predominant in the oils. PCA and HCA analyses classified the oils samples into four chemotypes. TEAC values of chemotype II (E3 oil, 228.3 ± 19.2 mg TE/mL) and chemotype III (E4 oil, 217.0 ± 23.3 mg TE/mL) displayed significant antioxidant activities. The oils E2 and E4 showed cytotoxic activity against all cell lines tested HCT-116 (IC₅₀ E2:16.26 μg/mL; IC₅₀ E4:9.28 μg/mL), AGP-01, (IC₅₀ E2:12.60 μg/mL; IC₅₀ E4:8.73 μg/mL), SKMEL-19 (IC₅₀ E2:12.20 μg/mL; IC₅₀ E4:15.42 μg/mL), and MRC-5 (IC₅₀ E2:10.27 μg/mL; IC₅₀ E4:14.95 μg/mL). Curzerene showed the more significant activity against melanoma cells (SKMEL-19, IC₅₀:5.17 μM), induced apoptosis at 5.0 μM and 10.0 μM compared to DMSO, exhibiting a decrease in the cell migration at 5.0 μM and 10.0 μM, after 30 h of treatment.

CONCLUSION

The curzerene chemotype oil and E. uniflora oils can be indicated as drug candidates for anticancer activity of the lung, colon, stomach, and melanoma, with a real prospect to their subsequent phytotherapeutic development.

Apoptotic and antimetastatic activities of betulin isolated from Quercus incana against non-small cell lung cancer cells

Background

Globally, the prevalence and mortality rates of lung cancer have been escalated with the increasing trend of tobacco smoking. The toxicity and irresponsive nature of the available drugs for lung cancer treatment demands an alternative approach.

Methods

In this study, four known compounds namely, cirsimaritin (4′,5, -dihydroxy-6,7-di-methoxyflavone) (1), eupatorin (5,3′-dihydroxy-6,7,4′-trimethoxyflavone) (2), betulin (Lup-20 (29)-ene-3, 28-diol) (3), and β-amyrin acetate (12-Oleanen-3yl acetate) (4) have been isolated from the leaves extract of Quercus incana. Preliminary screening of these natural compounds (1–4) was performed against non-small cell lung carcinoma (NCI-H460) and normal mouse fibroblast (NIH-3T3) cell lines.

Results

The compounds were found to be antiproliferative against cancer cells with wide therapeutic index in comparison to the normal cells. Effects of betulin (3) on cell migration, invasion, apoptosis, and expression of important apoptosis- and metastasis-related markers were observed at different concentrations. The results showed significant dose-dependent induction of apoptosis after the treatment with betulin (3) followed by increased expression of the caspases family (ie, caspase-3, -6, and -9), proapoptotic genes (BAX and BAK), and inhibiting anti-apoptotic genes (BCL-2L1 and p53). Furthermore, wound healing and transwell invasion assays suggested that betulin (3) could also regulate metastasis by inhibiting MMP-2/-9. Osteopontin, a central regulator of apoptosis and metastasis was also inhibited in a dose-dependent manner.

Conclusion

The present findings suggest that betulin (3) can be an attractive chemotherapeutic target for treating resistant lung cancers.

Isolation of dihydrobenzofuran derivatives from ethnomedicinal species Polygonum barbatum as anticancer compounds

Background

Ethnomedicinally, the family Polygonaceae is famous for the management of cancer. Various species of this family have been reported with anticancer potentials. This study was designed to isolate anticancer compounds from ethnomedicinally important species Polygonum barbatum.

Methods

The column chromatography was used for the isolation of compounds from the solvent fraction of P. barbatum. The characterization of isolated compounds was performed by various spectroscopic techniques like UV, IR, mass spectrometry and 1D-2D NMR spectroscopy. Keeping in view the ethnomedicinal importance of the family, genus and species of P. barbatum, the isolated compounds (1–3) were screened for anticancer potentials against oral cancer (CAL-27) and lungs cancer (NCI H460) cell lines using MTT assay. Active compound was further investigated for apoptosis by using morphological changes and flow cytometry analysis. In vivo anti-angiogenic study of the isolated compounds was also carried using chorioallantoic membrane assay. Docking studies were carried out to explore the mechanism of anticancer activity.

Results

Three dihydrobenzofuran derivatives (1–3) have been isolated from the ethyl acetate fraction of P. barbatum. The structures of isolated compounds were elucidated as methyl (2S,3S)-2-(3,4-dimethoxyphenyl)-4-((E)-3-ethoxy-3-oxoprop-1-en-1-yl)-7-methoxy-2,3-dihydrobenzo-furan-3-carboxylate (1), (E)-3-((2S,3S)-2-(3,4-dimethoxyphenyl)-7-methoxy-3-(methoxy carbonyl)-2,3-dihydrobenzofuran-4-yl)acrylic acid (2) and (2S,3S)-4-((E)-2-carboxyvinyl)-2-(3,4-dimethoxyphenyl)-7-hydroxy-2,3-dihydrobenzofuran-3-carboxylic acid (3). The compound 1 was found to be more potent with IC₅₀ of 48.52 ± 0.95 and 53.24 ± 1.49 against oral cancer cells as compared to standard drug (IC₅₀ = 97.76 ± 3.44 μM). Both compound also inhibited lung cancer cells but at higher concentrations. Morphological and flow cytometry analysis further confirms that compound 1 induces apoptosis after 24 to 48 h treatment. In antiangiogenesis assay, compounds 1, 2 and 3 exhibited IC₅₀ values of 8.2 ± 1.1, 13.4 ± 1.1 and 57.7 ± 0.3 μM respectively. The docking studies revealed that the compounds under study have the potential to target the DNA and thymidylate synthase (TS).

Conclusion

Based on its overwhelming potency against the tested cell lines and in angiogenesis assay, compound 1 can be further evaluated mechanistically and can be developed as anticancer drug candidate.

Electronic supplementary material

The online version of this article (10.1186/s40659-018-0209-0) contains supplementary material, which is available to authorized users.