Research progress of Gastrodia elata Blume polysaccharides: a review of chemical structures and biological activities.

Gastrodia elata Blume (G. elata), listed as one of the 34 precious Chinese medicines, servers a dual purpose as both a medicinal herb and a food source. Polysaccharide is the main active ingredient in G. elata, which has pharmacological activities such as immune regulation, anti-oxidation, anti-cancer, anti-aging, neuroprotection and antibacterial activity and so on. The biological activities of G. elata polysaccharide (GPs) is closely related to its chemical structures. However, no a review has synthetically summarized the chemical structures and pharmacological activities of GPs. This study delves into the chemical structures, pharmacological action of GPs, offering insights for the future development an application of these compounds.

Dimeric-(-)-epigallocatechin-3-gallate inhibits the proliferation of lung cancer cells by inhibiting the EGFR signaling pathway.

Non-small cell lung cancer (NSCLC) is one of the most general malignant tumors. The overexpression of epidermal growth factor receptor (EGFR) is a common marker in NSCLC, and it plays an important role in the proliferation, invasion, and metastasis of cancer cells. At present, drugs developed with EGFR as a target suffer from drug resistance, so it is necessary to study new compounds for the treatment of NSCLC. The active substance in green tea is EGCG, which has anti-cancer effects. In this study, we synthesized dimeric-(-)-epigallocatechin-3-gallate (prodelphinidin B-4-3,3‴-di-O-gallate, PBOG), and explored the effect of PBOG on lung cancer cells. PBOG can inhibit the proliferation and migration of NCI-H1975 cells, promote cell apoptosis, and inhibit cell cycle progression. In addition, PBOG can bind to the EGFR ectodomain protein and change the secondary structure of the protein. At the same time, PBOG decreases the expression of EGFR and downstream protein phosphorylation. Animal experiments confirmed that PBOG can inhibit tumor growth by inhibiting EGFR phosphorylation. Collectively, our study results show that PBOG may induce a decrease in intracellular phosphorylated EGFR expression by binding to the EGFR ectodomain protein, thereby inducing apoptosis and inhibiting cell cycle progression, thus providing a new strategy to treat lung cancer.

Discovery of EGFR-Targeted Environment-Sensitive fluorescent probes for cell imaging and efficient tumor detection.

Overexpression of human epidermal growth factor receptor (EGFR) plays an important role in several signaling pathways inside and outside the cell, especially in the processes of cell proliferation, differentiation, and death in various cancers. Due to the complexity of the structure and function of EGFR, research on the fluorescence visualization of EGFR protein visualization has proved challenging. One possible strategy for designing a receptor-targeting fluorescent probe with a switching mechanism is to introduce an environment-sensitive fluorophore into the drug ligand. Based on this strategic molecular design, we introduced two environment-sensitive small molecular fluorophores, dansyl chloride (DNS) and nitrobenzoxadiazole (NBD), to replace the morpholine group of gefitinib, achieving a series of fluorescent molecular probes bearing a switching mechanism. The GN probes exhibited prominent environment sensitivity, suggesting good performance as turn-on EGFR-targeting fluorescent ligands. The representative probe GN3 specifically responded to tumor cells overexpressing EGFR, which was validated with live-cell fluorescence imaging and in vivo xenograft tumor imaging. Ligand-induced EGFR phosphorylation in A431 cells was considerably inhibited by probe GN3, demonstrating that this probe still functions as an EGFR inhibitor. Owing to the turn-on response of GN3 to EGFR in tumor cells, and the competitive replacement behavior to the EGFR inhibitor gefitinib, these probes have the potential to be used for fluorescence imaging of cells overexpressing EGFR.

Synthesis and in vitro biological evaluation of novel dendrocandin analogue as potential anti-tumor agent.

Dendrocandins are characteristic chemical structures of D. officinale and have strong physiological bioactivities. In this study, a dendrocandin analogue (1) has been prepared by total synthesis (9 steps, 12.6% overall yield) in which coupling reaction and Wittig reaction as the key steps. Compound 1 was also evaluated for its anticancer activity in vitro against six human cancer cells (MCF-7, A549, A431, SW480, HepG-2 and HL-60) using MTT assays. Compound 1 showed potent cytotoxicity, with the IC50 value 16.27 ± 0.26 µM. The expression levels of apoptotic proteins indicated that compound 1 can up-regulate the expression of apoptotic proteins, leading to apoptosis. This compound suggested that it's potential as anticancer agent for further development.

Novel Perbutyrylated Glucose Derivatives of (-)-Epigallocatechin-3-Gallate Inhibit Cancer Cells Proliferation by Decreasing Phosphorylation of the EGFR: Synthesis, Cytotoxicity, and Molecular Docking.

Lung cancer is one of the most commonly occurring cancer mortality worldwide. The epidermal growth factor receptor (EGFR) plays an important role in cellular functions and has become the new promising target. Natural products and their derivatives with various structures, unique biological activities, and specific selectivity have served as lead compounds for EGFR. D-glucose and EGCG were used as starting materials. A series of glucoside derivatives of EGCG (7-12) were synthesized and evaluated for their in vitro anticancer activity against five human cancer cell lines, including HL-60, SMMC-7721, A-549, MCF-7, and SW480. In addition, we investigated the structure-activity relationship and physicochemical property-activity relationship of EGCG derivatives. Compounds 11 and 12 showed better growth inhibition than others in four cancer cell lines (HL-60, SMMC-7721, A-549, and MCF), with IC50 values in the range of 22.90-37.87 µM. Compounds 11 and 12 decreased phosphorylation of EGFR and downstream signaling protein, which also have more hydrophobic interactions than EGCG by docking study. The most active compounds 11 and 12, both having perbutyrylated glucose residue, we found that perbutyrylation of the glucose residue leads to increased cytotoxic activity and suggested that their potential as anticancer agents for further development.

Synthesis, antitumor activity, and molecular docking of (-)-epigallocatechin-3-gallate-4ß-triazolopodophyllotoxin conjugates.

Two new (-)-epigallocatechin-3-gallate-4ß-triazolopodophyllotoxin conjugates (7 and 8) were synthesized and evaluated for biological activity. Compound 8 showed highly potent anticancer activity against A-549 cell line with IC50 of 2.16 ± 1.02 µM, which displayed the highest selectivity index value (SI = 14.5) in A-549 cells. Molecular docking indicated that compound 8 could bind with the active site of Top-II. Therefore, compound 8 might be a promising candidate for further development.

Cationic Pillar[6]arene Induces Cell Apoptosis by Inhibiting Protein Tyrosine Phosphorylation Via Host-Guest Recognition.

We reported for the first time that cationic pillar[6]arene (cPA6) could tightly bind to peptide polymer (MW~20-50 kDa), an artificial substrate for tyrosine (Tyr) phosphorylation, and efficiently inhibit Tyr protein phosphorylation through host-guest recognition. We synthesized a nanocomposite of black phosphorus nanosheets loaded with cPA6 (BPNS@cPA6) to explore the effect of cPA6 on cells. BPNS@cPA6 was able to enter HepG2 cells, induced apoptosis, and inhibited cell proliferation by reducing the level of Tyr phosphorylation. Furthermore, BPNS@cPA6 showed a stronger ability of inhibiting cell proliferation in tumor cells than in normal cells. Our results revealed the supramolecular modulation of enzymatic Tyr phosphorylation by the host-guest recognition of cPA6.

Two unusual dendrobine-type alkaloids from Dendrobium findlayanum.

Two unusual dendrobine-type alkaloids, findlayines E and F (1, 2), along with five known dendrobine-type alkaloids (3-7), were isolated from the stems of Dendrobium findlayanum Par. et Rchb. f. Compound 1 is the first example of dendrobine-type alkaloids with a 2-ethoxy-2-oxoethyl group attaching to the C-2, and compound 2 is a nor-dendrobine-type alkaloid, featuring a 5-decarboxylated structure. The structures of compounds 1 and 2 were elucidated by means of extensive spectroscopic analyses, and their absolute configuration were confirmed by electronic circular dichroism (ECD) calculations. All isolates were evaluated for their cytotoxicity against HL-60, SMMC-7721, A-549 and MCF-7 human cancer cells.

The oxidation of (-)-epigallocatechin-3-gallate inhibits T-cell acute lymphoblastic leukemia cell line HPB-ALL via the regulation of Notch1 expression.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy, and commonly associated with activating mutations in the Notch1 pathway. (-)-Epigallocatechin-3-gallate (EGCG) is the most abundant and active catechin and has been shown to regulate Notch signaling. Taking into account the highly oxidizable and unstable of EGCG, we proposed that EGCG oxides may have greater potential to regulate Notch signaling than EGCG. In this study, we isolated and identified EGCG oxides (compound 2-4), using a chemical oxidation strategy, and evaluated for cytotoxicity against T-cell acute lymphoblastic leukemia cell line (HPB-ALL) by using the MTS assay. We found compound 3 significantly induced cell proliferation inhibition (38.3858 ± 1.67106 µM), cell apoptosis and cell cycle arrest in a dose-dependent manner. Remarkably, compound 3 inhibited expression of Notch1 compared with EGCG in HPB-ALL cells. Meanwhile, we found that compound 3 significantly inhibited c-Myc and Hes1, which are downstream target genes of Notch1. The findings demonstrate for the first time that an oxidation product of EGCG (compound 3) inhibits T-cell acute lymphoblastic leukemia cell line (HPB-ALL) and is a promising agent for cancer therapy deserving further research.

Synthesis and antitumor activity of camptothecin- 4ß-triazolopodophyllotoxin conjugates.

Two new compounds (9 and 10) having a camptothecin (CPT) analog conjugated to the 4ß-azido-4-deoxypodophyllotixin analog by untilizing the copper-catalyzed azide-alkyne cycloadditon (CuAAC) reaction, and were evaluated for their cytotoxicity against a panel of five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7 and SW480) using the MTT (3-(4,5-dimethyl-thiahiazo-2-yl)-2,5-diphenyltetrazolium bromide) assay. Two novel conjugates shown weak cytotoxicity, compound 10 showed highly potent against HL-60 cell line tested, with IC50 value 17.69 ± 0.19 µM. This compound suggested its potential as anticancer agents for further development. [Formula: see text].

Design, synthesis and cholinesterase inhibitory activity of α-mangostin derivatives.

α-mangostin, a polyphenol xanthone derivative, was mainly isolated from pericarps of the mangosteen fruit (Garcinia mangostana L.). In present investigation, a series of derivatives were designed, synthesised and evaluated in vitro for their inhibitory activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Among the synthesised xanthones, compounds 1, 9, 13 and 16 showed AChE selective inhibitory activity, 15 was a BuChE selective inhibitor while 2, 3, 5, 6, 7, 12 and 14 were dual inhibitors. The most potent inhibitor of AChE was 16 while 5 was the most potent inhibitor of BuChE with IC50 values of 5.26 µM and 7.55 µM respectively.

Glucoside Derivatives Of Podophyllotoxin: Synthesis, Physicochemical Properties, And Cytotoxicity.

BACKGROUND: Widespread concern of the side effects and the broad-spectrum anticancer property of podophyllotoxin as an antitumor agent highlight the need for the development of new podophyllotoxin derivatives. Although some per-butyrylated glucosides of podophyllotoxin and 4ß-triazolyl-podophyllotoxin glycosides show good anticancer activity, the per-acetylated/free of podophyllotoxin glucosides and their per-acetylated are not well studied. METHODS: A few glucoside derivatives of PPT were synthesized and evaluated for their in vitro cytotoxic activities against five human cancer cell lines, HL-60 (leukemia), SMMC-7721 (hepatoma), A-549 (lung cancer), MCF-7 (breast cancer), and SW480 (colon cancer), as well as the normal human pulmonary epithelial cell line (BEAS-2B). In addition, we investigated the structure-activity relationship and the physicochemical property-anticancer activity relationship of these compounds. RESULTS: Compound 6b shows the highest cytotoxic potency against all five cancer cell lines tested, with IC50 values ranging from 3.27±0.21 to 11.37±0.52 µM. We have also found that 6b displays higher selectivity than the etoposide except in the case of HL-60 cell line. The active compounds possess similar physicochemical properties: MSA > 900, %PSA < 20, ClogP > 2, MW > 700 Da, and RB > 10. CONCLUSION: We synthesized several glucoside derivatives of PPT and tested their cytotoxicity. Among them, compound 6b showed the highest cytotoxicity. Further studies including selectivity of active compounds have shown that the selectivity indexes of 6b are much greater than the etoposide except in the case of HL-60 cell line. The active compounds possessed similar physicochemical properties. This study indicates that active glucoside analogs of podophyllotoxin have potential as lead compounds for developing novel anticancer agents.

Design, Synthesis, and Biological Evaluation of Novel Biotinylated Podophyllotoxin Derivatives as Potential Antitumor Agents.

Podophyllotoxin has long been used as an active substance for cytotoxic activity. Fourteen novel biotinylated podophyllotoxin derivatives were designed, synthesized, and evaluated for cytotoxic activity for this study. The synthesized compounds were evaluated for cytotoxic activity in the following human cancer cell lines, SW480, MCF-7, A-549, SMMC-7721, and HL-60 by MTT assay. Most of them exhibited potent cytotoxic effects and compound 15 showed the highest cytotoxic activity among the five cancer cell lines tested, having its IC50 values in the range of 0.13 to 0.84 µM. Apoptosis analysis revealed that compound 15 caused obvious induction of cell apoptosis. Compound 15 significantly down-regulated the expression level of the marker proteins (caspase-3 and PARP) in H1299 and H1975 cells, activated the transcription of IRE1α, increased the expression of GRP78 and XBP-1s, and finally induced apoptosis of H1299 cells. In vivo studies showed that 15 at a dose of 20 mg/kg suppressed tumor growth of S180 cell xenografts in icr mice significantly. Further molecular docking studies suggested that compound 15 could bind well with the ATPase domain of Topoisomerase-II. These data suggest that compound 15 is a promising agent for cancer therapy deserving further research.

Synthesis and antitumor activity of biotinylated camptothecin derivatives as potent cytotoxic agents.

A series of biotinylated camptothecin derivatives were designed and synthesized. The key to the synthesis was achieved by employing an esterification reaction and click chemistry. All of the new derivatives were tested for cytotoxicity against five human tumor cell lines, including HL-60, SMMC-7721, A-549, MCF-7, and SW480 with IC50 values ranging from 0.13 to 21.53 µM. Most of the derivatives exhibited potent cytotoxicity, especially compound 17 (IC50 = 0.13-3.31 µM) and compound 18 (IC50 = 0.23-1.48 µM), which exhibited the highest potencies. The structure-activity relationships (SARs) of the biotinylated camptothecin derivatives were discussed for exploring novel anticancer agents.

Synthesis and anticancer activity of dimeric podophyllotoxin derivatives.

BACKGROUND: Podophyllotoxin is a potent cytotoxic agent and serves as a useful lead compound for the development of antitumor drugs. Several podophyllotoxin-derived antitumor agents, including etoposide, are currently in clinical use; however, their therapeutic efficacy is often limited due to side effects and the development of resistance by cancer cells. Previous studies have shown that 4ß-1,2,3-triazole derivatives of podophyllotoxin exhibit more potent anticancer activity and better binding to topoisomerase-II than etoposide. The effect of dimerization of such derivatives on the anticancer activity has not been studied. METHODS: Two moieties of podophyllotoxin were linked at the C-4 position via 1,2,3-triazole rings to give a series of novel dimeric podophyllotoxin derivatives. 4ß-Azido-substituted podophyllotoxin derivatives (23 and 24) were coupled with various dipropargyl functionalized linkers by utilizing the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction to provide dimeric products in very good yield. The in vitro anticancer activity of the synthesized compounds was evaluated by MTT assay against a panel of five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW480). The normal BEAS-2B (lung) cell line was also included for study in order to evaluate the cancer selectivity of the most active compound as compared with normal cells. RESULTS: A group of 16 dimeric podophyllotoxin derivatives with different linkers were synthesized and structurally characterized. Most compounds do not show significant cytotoxicity (IC50 > 40 mM) against all five cancer cell lines. However, one compound (29) which bears a perbutyrylated glucose residue on the glycerol linker is highly potent against all five cancer cell lines tested, with IC50 values ranging from 0.43 to 3.50 µM. This compound (29) also shows good selectivity towards cancer cell lines as compared with the normal BEAS-2B (lung) cell line, showing selectivity indexes from 4.4 to 35.7. CONCLUSION: The anticancer activity of dimeric podophyllotoxin derivatives is generally speaking not improved as compared to their monomeric counterparts, and the potency of these dimeric derivatives can be largely affected by the nature of the linker between the two moieties. Among the synthesized derivatives, compound 29 is significantly more cytotoxic and selective towards cancer cells than etoposide and cisplatin, which are currently in clinical use. Compound 29 is a promising anticancer drug and needs further studies.

Seco-Dendrobine-Type Alkaloids and Bioactive Phenolics from Dendrobium findlayanum.

Investigation of the 95% EtOH extract of stems of Dendrobium findlayanum afforded four new seco-dendrobines, findlayines A-D (1-4); two known dendrobines, dendrobine (5) and 2-hydroxydendrobine (6); and four new phenolic compounds, dendrofindlaphenols A-C (7, 9, and 10) and 6″-de-O-methyldendrofindlaphenol A (8). Compounds 1 and 2 are the first seco-dendrobines possessing a seven-membered lactam moiety, with 3 and 4 derived from the oxidative cleavage of the C-2-C-3 bond of dendrobine. The structures were established using spectroscopic methods and by comparison with literature data. The absolute configurations of 1-4 were confirmed via single-crystal X-ray diffraction data. Cytotoxic activity assays against HL-60, SMMC-7721, A-549, MCF-7, and SW480 human cancer cell lines revealed IC50 values ranging from 2.3 to 5.3 µM for compound 7, from 19.4 to 34.4 µM for 8, and from 49.4 to 96.8 µg/mL for the EtOAc extract. An assay of the inhibition of NO production with RAW 264.7 cells indicated that 8 had an IC50 value of 21.4 µM, and the EtOAc extract, 10.5 µg/mL. The EtOAc extract possessed DPPH radical scavenging activity of 69.93% at 100 µg/mL.

Design, synthesis and structure-activity relationships of mangostin analogs as cytotoxic agents.

In order to better understand the structure-activity relationship of mangostin, a series of xanthone derivatives based on α-mangostin were designed and synthesized. All the compounds were evaluated for their cytotoxicity against a panel of five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7 and SW480) using MTT assays. Most of them showed cytotoxicity and most of all, compounds 1a and 2h showed the highest cytotoxic potency by HL-60 cancer cell lines with IC50 values of 5.96 µM and 6.90 µM respectively; compound 3e showed the highest cytotoxic potency against SMMC-7221 cancer cell line with IC50 values of 3.98 µM; compounds 2e and 2m showed lower cytotoxicity but higher selectivity than α-mangostin against HL-60 and SMMC-7221 cancer cell lines respectively. Structure-activity relationship analysis indicates that the maintenance of the isopentene group at C-8 is essential for the cytotoxic activity.

Protective effects of cycloartane triterpenoides from Passiflora edulis Sims against glutamate-induced neurotoxicity in PC12 cell.

Four new cycloartane triterpenoids, 1α,3ß-dihydroxy-16-keto-24(31)-en-cycloartane (1), 31-methoxyl-passifloic acid (2), cyclopassifloside XIV (3), and cyclopassifloside XV (4), together with six known compounds (5-10) were isolated from Passiflora edulis Sims. Their structures were elucidated on the basis of extensive spectroscopic analysis. All the compounds were evaluated for protective effects against damage of PC12 cell induced by glutamate according to traditional usage of the herbal medicine, and the results indicated that cycloartane triterpenoids maybe one of the active compositions of P. edulis Sims for the treatment of neurodegenerative disease.

Synthesis and Biological Testing of Novel Glucosylated Epigallocatechin Gallate (EGCG) Derivatives.

Epigallocatechin gallate (EGCG) is the most abundant component of green tea catechins and has strong physiological activities. In this study, two novel EGCG glycosides (EGCG-G1 and EGCG-G2) were chemoselectively synthesized by a chemical modification strategy. Each of these EGCG glycosides underwent structure identification, and the structures were assigned as follows: epigallocatechin gallate-4''-O-ß-d-glucopyranoside (EGCG-G1, 2) and epigallocatechin gallate-4',4''-O-ß-d-gluco-pyranoside (EGCG-G2, 3). The EGCG glycosides were evaluated for their anticancer activity in vitro against two human breast cell lines (MCF-7 and MDA-MB-231) using MTT assays. The inhibition rate of EGCG glycosides (EGCG-G1 and EGCG-G2) is not obvious. The EGCG glycosides are more stable than EGCG in aqueous solutions, but exhibited decreasing antioxidant activity in the DPPH radical-scavenging assay (EGCG > EGCG-G2 > EGCG-G1). Additionally, the EGCG glycosides exhibited increased water solubility: EGCG-G2 and EGCG-G1 were 15 and 31 times as soluble EGCG, respectively. The EGCG glycosides appear to be useful, and further studies regarding their biological activity are in progress.

Oleanane-type triterpene saponins from Hydrocotyle nepalensis.

Five new oleanane-type triterpene saponins including steganogenin 3-O-ß-D-glucopyranoside (1), steganogenin 3-O-α-L-rhamnopyranosyl-(1→2)-ß-D-glucopyranoside (2), steganogenin 3-O-ß-D-glucopyranosyl-(1→2)-ß-D-glucopyranoside (3), chichipegenin 3-O-α-L-rhamnopyranosyl-(1→2)-ß-D-glucopyranoside (4) and chichipegenin 3-O-ß-D-glucopyranosyl-(1→2)-ß-D-glucopyranoside (5), along with four known oleanane-type triterpenes and triterpene saponins (6-9) were isolated from EtOH extract of the whole plant of Hydrocotyle nepalensis. To the best of our knowledge, oleanane-type triterpenes possessing skeleton with 17, 22-seco-backbone (1-3) are not common in natural products. Compound 8 was isolated as a new natural product. The structures of new compounds were elucidated by extensive spectroscopic methods and chemical evidence. Moreover, the cytotoxic activity of all the isolates against five selected human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7 and SW480) was evaluated and the results indicated that compounds 6 and 7 show stronger cytotoxic activity.