Dehydroabietic Acid Derivatives Research Articles

Contents of an Early Byzantine Amphora from Kruglaya Bay, the Black Sea

A fragment of an amphora found in the Kruglaya Bay near Sevastopol was filled with an unknown brown substance with a strong smell of tar. On the vessel’s neck, there is a round stamp ~30 mm in diameter, depicting the bust of an emperor encircled by an inscription. It resembles stamps on amphorae made in Alexandria and the Geronisos Island. The inscription reads, “επί Πτολεμαίου επάρχου”. The gas chromatography–mass spectrometry analysis revealed dehydroabietic acid, methyl dehydroabietate, norabietatrienes, retene, and other phenanthrene derivatives, suggesting that the substance resulted from dry distillation of wood of the Pinaceae family. The headspace analysis yielded components of turpentine oil such as α-pinene, camphene, limonene, cymenes, and others terpenes. To establish the sample’s origin, the amphora’s content was compared with modern pinewood tar obtained by the traditional method. Given nearly identical chromatogram profiles of the amphora’s contents and of tar in areas relating to resin acids, similar values of peak areas of biomarker components, and the presence of turpentine oil components in the sample, it is highly probable that the amphora indeed contained tar.

Design, synthesis and an anti-proliferative activity study of C-14 amide substituted derivatives of dehydroabietic acid

Design, synthesis and an anti-proliferative activity study of C-14 amide substituted derivatives of dehydroabietic acid

Anti-Virulence Strategy of Novel Dehydroabietic Acid Derivatives: Design, Synthesis, and Antibacterial Evaluation.

Anti-virulence strategies are attractive and interesting strategies for controlling bacterial diseases because virulence factors are fundamental to the infection process of numerous serious phytopathogenics. To extend the novel anti-virulence agents, a series of dehydroabietic acid (DAA) derivatives decorated with amino alcohol unit were semi-synthesized based on structural modification of the renewable natural DAA and evaluated for their antibacterial activity against Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas axonopodis pv. citri (Xac), and Pseudomonas syringae pv. actinidiae (Psa). Compound 2b showed the most promising antibacterial activity against Xoo with an EC50 of 2.7 μg mL-1. Furthermore, compound 2b demonstrated remarkable control effectiveness against bacterial leaf blight (BLB) in rice, with values of 48.6% and 61.4% for curative and protective activities. In addition, antibacterial behavior suggested that compound 2b could suppress various virulence factors, including EPS, biofilm, swimming motility, and flagella. Therefore, the current study provided promising lead compounds for novel bactericides discovery by inhibiting bacterial virulence factors.

Synthesis and Anti-Cancer Applications of Benzimidazole Derivatives - Recent Studies.

Cancer is a life-threatening disease. Anti-cancer drugs are the focus of research. The heterocyclic molecules like benzimidazole occupy a central position in searching for novel and effective anti-cancer drugs. The medicinal chemists designed and synthesized several benzimidazole derivatives and conjugates to evaluate them as potential anti-cancer agents. The purpose of this compilation of literature is to cover the progress of benzimidazole-based anti-cancer agents, their synthesis, and their evaluation for cancer disease treatment. The recent literatures have been collected from various search engines and peer-reviewed journals. The compounds like benzimidazole derivatives of dehydroabietic acid, piperidyl benzimidazole carboxamide, benzimidazole-quinazolinone hybrids, benzimidazole-thiazole conjugate, and benzimidazole pendant cyanopyrimidine derivatives have been discussed in detail. This review article will help the medicinal chemists to design and synthesize benzimidazole-based molecules and evaluate them as anti-cancer agents.

Semisynthetic Abietic and Dehydroabietic Acid Derivatives and Triptoquinone Epimers Interfere with LPS-Triggered Activation of Dendritic Cells.

Abietic acid (AA), dehydroabietic acid (DHA) and triptoquinones (TQs) are bioactive abietane-type diterpenoids, which are present in many edible vegetables and medicinal herbs with health-promoting properties. Evidence suggests that beneficial effects of diterpenes operate, at least in part, through effects on cells in the immune system. Dendritic cells (DCs) are a key type of leukocyte involved in the initiation and regulation of the immune/inflammatory response and natural or synthetic compounds that modulate DC functions could be potential anti-inflammatory/immunomodulatory agents. Herein, we report the screening of 23 known semisynthetic AA and DHA derivatives, and TQs, synthesized previously by us, in a multi-analyte DC-based assay that detects inhibition of pro-inflammatory cytokine production. Based on the magnitude of the inhibitory effect observed and the number of cytokines inhibited, a variety of activities among compounds were observed, ranging from inactive/weak to very potent inhibitors. Structurally, either alcohol or methyl ester substituents on ring A along with the introduction of aromaticity and oxidation in ring C in the abietane skeleton were found in compounds with higher inhibitory properties. Two DHA derivatives and two TQs exhibited a significant inhibition in all pro-inflammatory cytokines tested and were further investigated. The results confirmed their ability to inhibit, dose dependently, LPS-stimulated expression of the co-stimulatory molecules CD40 and/or CD86 and the production of the pro-inflammatory cytokines IL-1β, IL-6, IL-12 and TNFα. Our results demonstrate that DC maturation process can be targeted by semisynthetic DHA derivatives and TQ epimers and indicate the potential of these compounds as optimizable anti-inflammatory/immunomodulatory agents.

Design, synthesis and biological evaluation of dehydroabietic acid derivative as potent vasodilatory agents

Using dehydroabietic acid as the lead compound for structural modification, 25 dehydroabietic acid derivatives were synthesized. Among them, compound D1 not only showed the strongest relaxation effect on the aortic vascular ring in vitro (Emax = 99.5 ± 2.1%, EC50 = 3.03 ± 0.96 µM), but also significantly reduced systolic and diastolic blood pressure in rats at a dose of 2.0 mg/kg in vivo. Next, the vascular protective effect of the best active D1 and its molecular mechanism were further investigated by HUVECs. The results showed that D1 induced endothelium-dependent diastole in the rat thoracic aorta in a concentration-dependent manner. Endothelium removal or aortic ring pretreatment with NG-nitro-l-arginine methylester (l-NAME), 1H-[1,2,4]-oxadiazolo-[4,3-a]-quinoxalin-1-one (ODQ), and tetraethylammonium (TEA) significantly inhibited D1-induced relaxation. In addition, wortmannin, KT5823, triciribine, diltiazem, BaCl2, 4-aminopyridine, indomethacin, propranolol, and atropine attenuated D1-induced vasorelaxation. D1 increased the phosphorylation of eNOS in HUVECs Furthermore, D1 attenuated the expression of TNF-α-induced cell adhesion molecules such as ICAM-1 and VCAM-1. However, this effect was attenuated by the eNOS inhibitors l-NAME and asymmetric dimethylarginine (ADMA). The findings suggest that D1-induced vasorelaxation through the PI3K/Akt/eNOS/NO/cGMP/PKG pathway by activating the KCa, Kir and KV channels or muscarinic and β-adrenergic receptors, and inhibiting the l-type Ca2+ channels, which is closely related to the hypotensive action of the agent. Furthermore, D1 exhibits an inhibitory effect on vascular inflammation, which is associated with the observed vascular protective effects.

Synthesis and Antiproliferative Activity of Novel Dehydroabietic Acid-Chalcone Hybrids.

Dehydroabietic Acid (DHA, 1) derivatives are known for their antiproliferative properties, among others. In the context of this work, DHA was initially modified to two key intermediates bearing a C18 methyl ester, a phenol moiety at C12, and an acetyl or formyl group at C13 position. These derivatives allowed us to synthesize a series of DHA-chalcone hybrids, suitable for structure–activity relationship studies (SARS), following their condensation with a variety of aryl-aldehydes and methyl ketones. The antiproliferative evaluation of the synthesized DHA-chalcone hybrids against three breast cancer cell lines (the estrogen-dependent MCF-7 and the estrogen-independent MDA-MB-231 and Hs578T) showed that eight derivatives (33, 35, 37, 38, 39, 41, 43, 44) exhibit low micromolar activity levels (IC50 2.21–11.5 μΜ/MCF-7). For instance, some of them showed better activity compared to the commercial anticancer drug 5-FU against MCF-7 cells (33, 41, 43, 44) and against MDA-MB231 (33 and 41). Hybrid 38 is a promising lead compound for the treatment of MCF-7 breast cancer, exhibiting comparable activity to 5-FU and being 12.9 times less toxic (SI = 22.7). Thus, our findings suggest that DHA-chalcone hybrids are drug candidates worth pursuing for further development in the search for novel breast cancer therapies.

Directed Study of Abietic Acid Reaction in Pine Rosin under Non-Precious-Metal Catalyst

Pine rosin of Pinus merkusii Jung at de Vriese is produced industrially from a distillation process of pine sap. The high total Indonesian production leads the primary derivatization strategy into several derivates to fulfill the market demand. Abietic acid (AA) is a major compound in pine rosin, used as the object of observation in this study. The general methodology for transformation reported involves using palladium (Pd) and platinum (Pt)-based catalysts. Both are precious metal catalysts to proceed with oxidative dehydrogenative-aromatization of the rosin. The synthesized product provides dehydroabietic acid (DHA) derivatives in high yield. This paper reports that non-precious metal-based catalysts such as iron (Fe), zinc (Zn), or copper (Cu) with iodine (I2) were applied to deliver the reaction by steam cracking without nitrogen (N2) and oxygen (O2) for economical, efficient, and greenway’s catalyst. It was found that a similar product was isolated, including several by-products. Under high temperatures with a various metal transitions and halogen by FeCl3-I2 and Cu(NO3)2.3H2O and ZnCl2 catalyst, four compounds were identified employing spectroscopic methods in the reaction product: 7-hydroxy-dehydroabietic acid (5), 1,7-dihydroxy-dehydroabietic acid (6), 7-isopropyl-1-methylphenanthren-9-ol (7) and polymer (8). This modified pine rosin was mainly used as an emulsifier for the synthetic rubber industry, varnish, ink, paper sizing, etc. The products are determined based on LC-MS/MS, UV-Vis, and ATR-FTIR spectroscopy.

Fungal Degradation of Extractives Plays an Important Role in the Brown Rot Decay of Scots Pine Heartwood.

Scots pine heartwood is known to have resistance to wood decay due to the presence of extractives, namely stilbenes and resin acids. However, previous studies have indicated that these extractives are degradable by wood decaying fungi. This study aimed to investigate the relationship between extractive degradation and heartwood decay in detail and to gain insight into the mechanisms of extractive degradation. Mass losses recorded after a stacked-sample decay test with brown rot fungi showed that the heartwood had substantial decay resistance against Coniophora puteana but little resistance against Rhodonia placenta. Extracts obtained from the decayed heartwood samples revealed extensive degradation of stilbenes by R. placenta in the early stages of decay and a noticeable but statistically insignificant loss of resin acids. The extracts from R. placenta-degraded samples contained new compounds derived from the degraded extractives: hydroxylated stilbene derivatives appeared in the early decay stages and then disappeared, while compounds tentatively identified as hydroxylated derivatives of dehydroabietic acid accumulated in the later stages. The degradation of extractives was further analysed using simple degradation assays where an extract obtained from intact heartwood was incubated with fungal mycelium or extracellular culture fluid from liquid fungal cultures or with neat Fenton reagent. The assays showed that extractives can be eliminated by several fungal degradative systems and revealed differences between the degradative abilities of the two fungi. The results of the study indicate that extractive degradation plays an important role in heartwood decay and highlight the complexity of the fungal degradative systems.

Discovery of novel dehydroabietic acid derivatives as DNA/BSA binding and anticancer agents

To explore the biological properties of rosin derivatives, two dehydroabietic acid derivatives N-(5-dehydroabietyl-1,3,4-thiadiazole)-yl-pyridine-2-carboxamide (DTPC) and di-N-(5-dehydroabietyl-1,3,4-thiadiazole)-yl-pyridine-2,6-carboxamide (DDTPC) with 1,3,4-thiadiazole, pyridine and amide moieties were designed and synthesized according to superposition principle of activity group. They interact with calf thymus DNA (CT DNA) via intercalation based on the results of circular dichroism (CD) and fluorescence spectroscopy, DNA denaturation and viscosity studies. Fluorescence and CD spectral experiments indicate that they might be transported and stored by protein like bovine serum albumin (BSA). MTT assay was further carried out to examine their cytotoxicity, they both showed selective cytotoxicity and DTPC exhibited better cytotoxicity. The antiproliferative effect of DTPC toward A431 cell line was stronger than that of clinically used cisplatin and oxaliplatin. In addition, the cytotoxicity of DTPC and DDTPC was closely related with their DNA binding ability.

Synthesis, cytotoxicity and apoptosis‐inducing activity of novel 1H‐benzo[d]imidazole derivatives of dehydroabietic acid

AbstractWith the expectation of finding new and effective antitumor drugs, a series of novel N‐(1H‐benzo[d]imidazole‐2‐yl)‐benzamide/benzenesulfonamide derivatives of dehydroabietic acid were synthesized and evaluated for cytotoxic activity against three human cancer cell lines (MCF‐7, HeLa, and HepG2 cells) and one human normal hepatocyte cell line (LO2). As a result, a number of derivatives showed moderate to good antitumor activities. Among them, compound 8h exhibited the most potent activities against three cancer cell lines with IC50 values of 0.87 ± 0.18, 9.39 ± 0.72, and 8.31 ± 0.64 μM, respectively, and was less active to normal hepatocyte LO2 cells. Further mechanism studies revealed that compound 8h could arrest the cell cycle of MCF‐7 cells at S phase and induce the apoptosis of MCF‐7 cells in ROS‐mediated mitochondrial pathway.

Non-leaching, Highly Biocompatible Nanocellulose Surfaces That Efficiently Resist Fouling by Bacteria in an Artificial Dermis Model.

Bacterial biofilm infections incur massive costs on healthcare systems worldwide. Particularly worrisome are the infections associated with pressure ulcers and prosthetic, plastic, and reconstructive surgeries, where staphylococci are the major biofilm-forming pathogens. Non-leaching antimicrobial surfaces offer great promise for the design of bioactive coatings to be used in medical devices. However, the vast majority are cationic, which brings about undesirable toxicity. To circumvent this issue, we have developed antimicrobial nanocellulose films by direct functionalization of the surface with dehydroabietic acid derivatives. Our conceptually unique design generates non-leaching anionic surfaces that reduce the number of viable staphylococci in suspension, including drug-resistant Staphylococcus aureus, by an impressive 4-5 log units, upon contact. Moreover, the films clearly prevent bacterial colonization of the surface in a model mimicking the physiological environment in chronic wounds. Their activity is not hampered by high protein content, and they nurture fibroblast growth at the surface without causing significant hemolysis. In this work, we have generated nanocellulose films with indisputable antimicrobial activity demonstrated using state-of-the-art models that best depict an "in vivo scenario". Our approach is to use fully renewable polymers and find suitable alternatives to silver and cationic antimicrobials.

New dehydroabietic acid (DHA) derivatives with anticancer activity against HepG2 cancer cell lines as a potential drug targeting EGFR kinase domain. CoMFA study and virtual ligand-based screening

Liver cancer has become the third type of cancer that causes death; this is why the design of new chemotherapeutic drugs against this disease is a major need. With this idea, a series of Dehydroabietic Acid-Based Acylhydrazones have been used to generate a CoMFA model to design new anticancer agents. In this study, we employed a Comparative Molecular Field Analysis studies, we performed those methods on Dehydroabietic Acid-Based Acylhydrazones against HepG2 human cancer cell line. The statistical results are encouraging with Q2 equal to 0.527 and R2 equal to 0.962. The predictive ability of this model was determined using a test set of Dehydroabietic Acid-Based Acylhydrazones that gave an acceptable predictive correlation (R2test) value of 0.614. The developed model guides to design five new molecules with enhanced activity as potential drugs. On the other hand to determine a potential target to these ligands we have established a virtual screening using reverse docking with the most active molecule and 42 antiproliferative targets. Based on the affinity of complex ligand-Target, the intracellular domain of EGFR shows high stability. This suggests that our designed molecules can inhibit the target EGFR which is an important target on targeted therapy of many types of cancer. Communicated by Ramaswamy H. Sarma

Norway Spruce Balm: Phytochemical Composition and Ability to Enhance Re-epithelialization In Vitro.

The balm of the Norway spruce (Picea abies) is a well-known traditional herbal medicine used to cure wounds. Even though clinical trials have confirmed its empirical use, the active constituents, their mode of action, and the exact composition of this natural product are still unknown. In this study, the balm was subjected to fractionated extraction and further purified employing flash chromatography, HPLC-PDA-ELSD, preparative and analytical TLC. Hydroxycinnamic acids ( 1: - 3: ), the lignan pinoresinol ( 4: ), four hydroxylated derivatives of dehydroabietic acid (DHAA) ( 5: - 8: ), and dehydroabietic acid ( 9: ) were isolated. Their structures were elucidated by LC-MS, 1D- and 2D-NMR. Four extracts, two commercially available resin acids-pimaric acid ( 10: ) and isopimaric acid ( 11: )-and the isolated compounds were tested for increased re-epithelialization of cell-free areas in a human adult low calcium high temperature keratinocytes monolayer. Lysophosphatidic acid (10 µM) served as positive control and ranged between 100% and 150% rise in cell-covered area related to the vehicle control. Two extracts containing carboxylic acids and non-acidic apolar constituents, respectively, boosted wound closure by 47% and 36% at 10 and 3 µg/mL, respectively. Pinoresinol, DHAA, three of its hydroxylated derivatives, and pimaric and isopimaric acid as well as defined combinations of the hydroxylated DHAA derivatives led to a significantly enhanced wound closure by up to 90% at concentrations between 1 and 10 µM. Overall, lignans and diterpene resin acids, main constituents of Norway spruce balm, are able to increase migration or proliferation of keratinocytes in vitro. The presented data link the phytochemistry of this natural wound healing agent with boosted re-epithelialization.

Synthesis and anticancer evaluation of novel 1H-benzo[d]imidazole derivatives of dehydroabietic acid as PI3Kα inhibitors.

Phosphatidylinositol 3-kinase (PI3K) is one of the most attractive therapeutic targets for cancer treatment. In this study, a series of new 2-arylthio- and 2-arylamino-1H-benzo[d]imidazole derivatives of dehydroabietic acid were designed, synthesized and characterized by 1H NMR, 13C NMR, IR and MS spectra analyses. In the in vitro anticancer assay, some title compounds showed significant inhibitory activities against four cancer cell lines (HCT-116, MCF-7, HeLa and HepG2). Among them, compound 9g exhibited the most potent activity with IC50 values of 0.18±0.03, 0.43±0.05, 0.71±0.08 and 0.63±0.09μM against four cancer cell lines, and considerably lower cytotoxicity to human gastric mucosal cell line Ges-1 (IC50: 21.95±0.73μM). Besides, compound 9g displayed a certain selective activity to PI3Kα (IC50=0.012±0.002μM) over PI3Kβ, γ and δ, and meanwhile, it can remarkably decrease the expression level of p-Akt (Ser473). In addition, compound 9g could increase intracellular reactive oxygen species level, decrease mitochondrial membrane potential, upregulate Bax and cleaved caspase-3/9 levels, downregulate Bcl-2 level and thus induce the apoptosis of HCT-116 cells in a dose-dependent manner. The results suggested that compound 9g could be considered as a promising PI3Kα inhibitor.

Electrostatic Interactions of Negatively Charged DHAA Derivatives with the Voltage-Gated Potassium Channel Kv7.2/7.3

Many patients with epilepsy do not respond to existing pharmaceutical treatment, so there is a large need of new types of antiepileptic drugs. The voltage dependent M-type potassium current activates and deactivates slowly and is important to set the resting potential and to reduce repetitive firing of neurons. This current is generated by an ion channel composed of Kv7.2 and 7.3 subunits. Some inherited forms of epilepsy are caused by mutations in the genes coding for these subunits, and the Kv7.2/7.3 channel is a validated target for antiepileptic drugs. Today, there is no Kv7.2/7.3 channel-opening drug on the market. Our goal is to develop a Kv7.2/7.3-channel opening compound. Recently, our group designed a set of molecules, based on the structure of dehydroabietic acid (DHAA), that open the Shaker Kv channel from Drosophila melanogaster. We showed that he charge of the carboxyl group of the DHAA derivatives as well as potitively charged amino-acid residues of the channel's voltage sensor are required for the compounds to open the channel. In previous experiments we showed that DHAA-derivatives at concentrations as low as 0.3 μM open of the human hKv7.2/7.3 channel but it is not known if the mechanism is the same as for the Shaker Kv channel. Here we explored if the same mechanism is valid for the hKv7.2/7.3 channel expressed in Xenopus oocytes. To explore the role of the charge of the carboxyl group we tested the effect of the compounds at different pH. To explore the role of the charges of the voltage sensor S4 we systematically mutated the extracellular end of S4. Overall, the mechanism of DHAA derivatives on the hKv7.2/7.3 channel is the same as for the Shaker Kv channel, but there are quantitative differences.

Synthesis and biological evaluation of dehydroabietic acid-pyrimidine hybrids as antitumor agents

A series of novel dehydroabietic acid derivatives containing pyrimidine moieties were designed and synthesized to explore more efficacious and less toxic antitumor agents according to the principle of combination and hybridization. The cytotoxicity against human liver cancer (HepG2) cells, human breast cancer (MCF-7) cells, human colon cancer (HCT-116) cells, human lung cancer (A549) cells, and human normal liver cells (LO2) was estimated by MTT assay in vitro. Cytotoxic activity screening revealed that most of the compounds showed moderate to high levels of cytotoxicity against these four cancer cell lines and that some displayed more potent inhibitory activities compared with 5-FU. In particular, compound 3b exhibited promising cytotoxicity with IC50 values ranging from 7.00 to 11.93 μM against all the tested cell lines and displayed weak cytotoxicity towards normal cells. Besides, cell cycle analysis indicated that compound 3b mainly arrested MCF-7 cells at the S stage and induced cell apoptosis.

Synthesis and Cytotoxicity Evaluation of Dehydroabietic Acid Derivatives Bearing Nitrate Moiety

Synthesis and Cytotoxicity Evaluation of Dehydroabietic Acid Derivatives Bearing Nitrate Moiety

Toxic phthalate-free and highly plasticized polyvinyl chloride materials from non-timber forest resources in plantation

In this study, dehydroabietic acid derivatives containing primary amine groups were synthezied from one of the most important non-timber forest resources in plantation. Phthalate-free and highly plasticized polyvinyl chloride (PVC) materials were produced via substituting chlorine of PVC with dehydroabietic acid derivatives containing primary amine groups. Performance of phthalate-free and highly plasticized PVC materials including pyrolysis and tensile property, solvent extraction resistance and lattice structure, the relationship between plasticizing property and hydrogen bond were investigated and compared with plasticized PVC materials containing toxic phthalate plasticizers. The phthalate-free and highly plasticized PVC materials exhibited more flexible than PVC and higher solvent extraction performance than plasticized PVC materials with phthalate plasticizers. Some environmental performance such as releasing less asphyxiating gases during thermal degradation than PVC, not containing toxic phthalate esters and no plasticizer migration was obtained. The highly plasticized PVC materials are promising to find application in various fields as a replacement of plasticized PVC materials containing toxic phthalate plasticizers. The study provides new way for chemical transformation and improving added value of non-timber forest resources in plantation.

Synthesis and biological evaluation of novel N-(piperazin-1-yl)alkyl-1H-dibenzo[a,c]carbazole derivatives of dehydroabietic acid as potential MEK inhibitors

In this paper, a series of novel 1H-dibenzo[a,c]carbazole derivatives of dehydroabietic acid bearing different N-(piperazin-1-yl)alkyl side chains were designed, synthesised and evaluated for their in vitro anticancer activities against three human hepatocarcinoma cell lines (SMMC-7721, HepG2 and Hep3B). Among them, compound 10g exhibited the most potent activity against three cancer cell lines with IC50 values of 1.39 ± 0.13, 0.51 ± 0.09 and 0.73 ± 0.08 µM, respectively. In the kinase inhibition assay, compound 10g could significantly inhibit MEK1 kinase activity with IC50 of 0.11 ± 0.02 µM, which was confirmed by western blot analysis and molecular docking study. In addition, compound 10g could elevate the intracellular ROS levels, decrease mitochondrial membrane potential, destroy the cell membrane integrity, and finally lead to the oncosis and apoptosis of HepG2 cells. Therefore, compound 10g could be a potent MEK inhibitor and a promising anticancer agent worthy of further investigations.