Derivatization of Abietane Acids by Peptide-like Substituents Leads to Submicromolar Cytotoxicity at NCI-60 Panel.

Natural compounds, including diterpenoids, play a critical role in various biological processes and are recognized as valuable components in cancer treatment. Isocyanides multicomponent reactions (IsMCRs) are one of the effective methods to obtain adducts at the carboxyl group with a peptide-like substituent. In this study, dehydroabietic acid and levopimaric acid diene adducts as the starting scaffolds were modified by the multicomponent Passerini (P-3CR) and Ugi (U-4CR) reactions to afford α-acyloxycarboxamides and α-acylaminocarboxamides. A group of twenty novel diterpene hybrids was subjected to NCI in vitro assessment, and a consistent structure-activity relationship was established. Eleven of the synthesized derivatives inhibited the growth of cancer cells of 4 to 39 cell lines in one dose assay, and the most active were derivatives 3d, 9d, and 10d holding a fragment of 1a,4a-dehydroquinopimaric acid. They were selected for a five-dose analysis and demonstrated a significant antiproliferative effect towards human cancer cell lines. The outstanding cytotoxic activity was observed for the P-3CR product 3d with growth inhibitory at submicromolar and micromolar concentrations (GI50 = 0.42-3 µM) against the most sensitive cell lines. The U-4CR products 9d and 10d showed selective activity against all leukemia cell lines with GI50 in the range of 1-17 µM and selectivity indexes of 5.49 and 4.72, respectively. Matrix COMPARE analysis using the GI50 vector showed a moderate positive correlation of compound 3d with standard anticancer agents that can influence kinase receptors and epidermal growth factor receptors (EGFRs). The ADMET analysis acknowledges the favorable prognosis using compounds as potential anticancer agents. The obtained results indicate that these new hybrids could be useful for the further development of anticancer drugs, and 1a,4a-dehydroquinopimaric acid derivatives could be recommended for in-depth studies and the synthesis of new antitumor analogs on their basis.

Antioxidation Activity Enhancement by Intramolecular Hydrogen Bond and Non-Browning Mechanism of Active Ingredients in Rosemary: Carnosic Acid and Carnosol.

Rosemary is one of the most promising, versatile, and studied natural preservatives. Carnosic acid (CA) and carnosol (CARN), as the primary active ingredients of rosemary extracts, have little difference in structure, but their antioxidant activities vary significantly, depending on the system studied. The underlying molecular mechanisms remain unclear. By means of optical spectroscopies, stopped-flow, laser photolysis, and density functional theory (DFT) calculations, we have compared CA and CARN between their reaction dynamics of radical scavenging, metal ion chelation, and oxidation inhibition in lipid emulsion and beef, as well as between their interactions with ß-carotene (ß-Car). For reference, 3-isopropyl catechol (IC), which is structurally similar to the active groups of CA and CARN, was studied in parallel. It is found for CA that the intramolecular hydrogen bond can boost the acidity of its phenol hydroxyl and that the synergistic effect with ß-Car can substantially enhance its antioxidation activity in the model systems of lipid and meat via the CA-to-ß-Car electron transfer reaction. The substitution of A and B rings on the catechol group in both CA and CARN limits browning caused by their formation of oxidative products as antioxidants.

Self-assembled Abietic acid encapsulated nanoparticles to improve the stability of Proanthocyanin B2.

Procyanidin B2 (Pac B2) has attracted much attention due to its strong antioxidant activity, but poor in vivo stability limits its wide application in food and medicine. In this paper, composite nanoparticles (NPs) were constructed using abietic acid (AA) as a carrier, which significantly enhanced Pac B2 stability. A spherical morphology and average diameter of 396.05 nm were observed in AA-Pac B2 NPs synthesized by solvent co-precipitation. Pac B2 encapsulation was 11.28 %, and thermal stability is improved. Infrared, Ultraviolet spectrum, and MD (molecular dynamics) spectroscopy revealed hydrogen bonding and hydrophobic interaction between AA and Pac B2. For up to 2 h at 37 °C, Pac B2 can be sustainably released in simulated gastric and intestinal fluids. In vitro, AA-Pac B2 NPs at the same concentration exhibited higher bioavailability and uptake efficiency than free Pac B2. The data demonstrate the potential of AA NPs for improving polyphenol thermal stability and bioavailability.

Carnosic Acid: A Novel Selective Inhibitor of ERAP1 by Direct Binding and Its Modulation of Antigen Processing and Presentation.

ERAP1 is an emerging target for a large subclass of severe autoimmune diseases known as "MHC-I-opathy", together with tumor immunity. Nevertheless, effective inhibitors targeting ERAP1 remain a challenge. In this study, a novel food-derived natural product ERAP1-targeting inhibitor, carnosic acid, was identified, and to our knowledge, it is one of the best active compounds among the highly selective inhibitors targeting the orthosteric site of ERAP1. The results reveal that carnosic acid could bind strongly, like a key to the ERAP1 active site in the biased S1' pocket, which is different from the binding mode of the existing orthosteric site inhibitors. HLA-B27-mediated cell modeling validated that carnosic acid has the activity to reverse the AS-associated cellular phenotype brought on by ERAP1 through inhibition. Our findings provide insights into the design of potent inhibitors against the ERAP1 orthosteric site and the discovery of a key direct target of carnosic acid.

Dehydroabietylamine-substituted trifluorobenzene sulfonamide rhodamine B hybrids as anticancer agents overcoming drug resistance.

Attachment of a conjugate assembled from a novel fluorinated carbonic anhydrase inhibitor and rhodamine B onto dehydroabietylamine (DHA) or cyclododecylamine led to first-in-class conjugates of good cytotoxicity; thereby IC50 values (from SRB assays; employed tumor cell lines A2780, A2780Cis, A549, HT29, MCF7, and non-malignant human fibroblasts CCD18Co) between 0.2 and 0.7 µM were found. Both conjugates showed similar cytotoxic activity but the dehydroabietylamine derived conjugate outperformed its cyclododecyl analog in terms of tumor cell/non-tumor cell selectivity. Both conjugates accumulate intracellular, and the DHA conjugate was able to overcome drug resistance which is effective independent of the expression status of carbonic anhydrase IX.

Five pimarane diterpenoids from Kaempferia champasakensis and their cytotoxic activities.

A phytochemical investigation of Kaempferia champasakensis rhizomes led to the isolation of five new pimarane diterpenes, kaempferiols E-I (1-5). The structures of 1-5 were elucidated by extensive spectroscopic techniques, including HR-ESI-MS, UV, IR, and 1D and 2D NMR. The absolute configurations of 1-3 were determined by the modified Mosher method, and those of 4 and 5 were established by ECD calculations. Further cytotoxic assay for all isolated compounds against three human cancer cell lines, lung cancer (A549), cervical cancer (HeLa), and breast cancer (MCF-7) indicated that 5 showed moderate cytotoxic activities against the three tested cell lines, with IC50 values of 44.78, 25.97, and 41.39 Mµ for A549, HeLa, and MCF-7 cell lines, respectively.

Characterization of pectin-zein nanoparticles encapsulating tanshinone: Antioxidant activity, controlled release properties, physicochemical stability to environmental stresses.

Tanshinone compounds, natural antioxidants found in the roots of Salvia subg Perovskia plants, offer various health benefits and can serve as natural food additives, replacing synthetic antioxidants. In this study, the nanoparticles were created using the antisolvent method, which were then evaluated for their antioxidant and antibacterial properties, as well as their ability to release tanshinone and withstand environmental stress. The results of the study demonstrated a significant improvement in the antioxidant capabilities of tanshinone with the nanoparticle coating. The T/Z/P NPs exhibited enhanced tanshinone release under simulated gastrointestinal conditions compared to T/Z nanoparticles. These nanoparticles displayed remarkable stability against fluctuations in environmental pH and thermal conditions. The study also revealed that the critical flocculation concentration of the system was 0.5 M of salt. Furthermore, the T/Z/P NPs showed good stability during storage at 4°C for 30 days, making them an excellent candidate for use in various food products.

Abietane Diterpenes from Medusantha martiusii and Their Anti-Neuroinflammatory Activity.

Seven new abietane diterpenoids, comprising medusanthol A-G (1-3, 5, 7-9) and two previously identified analogs (4 and 6), were isolated from the hexane extract of the aerial parts of Medusantha martiusii. The structures of the compounds were elucidated by HRESIMS, 1D/2D NMR spectroscopic data, IR spectroscopy, NMR calculations with DP4+ probability analysis, and ECD calculations. The anti-neuroinflammatory potential of compounds 1-7 was evaluated by determining their ability to inhibit the production of nitric oxide (NO) and the proinflammatory cytokine TNF-α in BV2 microglia stimulated with LPS and IFN-γ. Compounds 1-4 and 7 exhibited decreased NO levels at a concentration of 12.5 µM. Compound 1 demonstrated strong activity with an IC50 of 3.12 µM, and compound 2 had an IC50 of 15.53 µM; both compounds effectively reduced NO levels compared to the positive control quercetin (IC50 11.8 µM). Additionally, both compounds significantly decreased TNF-α levels, indicating their potential as promising anti-neuroinflammatory agents.

Abietane diterpenoids from Isodon amethystoides and their biological activities.

Seven undescribed abietane diterpenoids [abietamethinols A-G (1-7)] were isolated from the twigs and leaves of Isodon amethystoides. Their structures were elucidated on the basis of spectroscopic methods including 2D NMR, and they were further confirmed by X-ray crystallographic data. Lophanic acid was considered as the precursor of 1-7 in the biosynthesis pathway hypothesis. These compounds were evaluated for their cytotoxic, anti-bacterial and anti-AIV (avian influenza virus) activities. Compound 5 showed 42.9% inhibitory activity against the cancer cell line SMMC-7721 at the concentration of 40 µM, 3 and 4 could inhibit the bacterial growth of Streptococcus sobrinus by 55.3% and 63.2% at the concentrations of 148.6 and 141.9 µM, respectively, and 4 was demonstrated with antiviral activity against AIV with the inhibitory effect of 68.4% at 25 µM.

Tanshinone IIA Liposomes Treat Doxorubicin-Induced Glomerulonephritis by Modulating the Microenvironment of Fibrotic Kidneys.

Renal fibrosis plays a key role in the pathogenesis of chronic kidney disease (CKD), in which the persistent high expression of transforming growth factor ß1 (TGF-ß1) and α-smooth muscle actin (α-SMA) contributes to the progression of CKD to renal failure. In order to improve the solubility, bioavailability, and targeting of tanshinone IIA (Tan IIA), a novel targeting material, aminoethyl anisamide-polyethylene glycol-1,2-distearoyl-sn-glycero-3-phosphate ethanolamine (AEAA-PEG-DSPE, APD) modified Tan IIA liposomes (APD-Tan IIA-L) was constructed. An animal model of glomerulonephritis induced by doxorubicin in BALB/c mice was established. APD-Tan IIA-L significantly decreased blood urea nitrogen and serum creatinine (SCr), and the consequences of renal tissue oxidative stress indicators showed that APD-Tan IIA-L downregulated malondialdehyde, upregulated superoxide dismutase, catalase, and glutathione peroxidase. Masson's trichrome staining showed that the deposition of collagen in the APD-Tan IIA-L group decreased significantly. The pro-fibrotic factors (fibronectin, collagen I, TGF-ß1, and α-SMA) and epithelial-mesenchymal transition marker (N-cadherin) were significantly inhibited by APD-Tan IIA-L. By improving the microenvironment of fibrotic kidneys, APD-Tan IIA-L attenuated TGF-ß1-induced excessive proliferation of fibroblasts and alleviated oxidative stress damage to the kidney, providing a new strategy for the clinical treatment of renal fibrosis.

New hemisynthetic derivatives of sphaeropsidin phytotoxins triggering severe endoplasmic reticulum swelling in cancer cells.

Sphaeropsidins are iso-pimarane diterpenes produced by phytopathogenic fungi that display promising anticancer activities. Sphaeropsidin A, in particular, has been shown to counteract regulatory volume increase, a process used by cancer cells to avoid apoptosis. This study reports the hemi-synthesis of new lipophilic derivatives obtained by modifications of the C15,C16-alkene moiety. Several of these compounds triggered severe ER swelling associated with strong proteasomal inhibition and consequently cell death, a feature that was not observed with respect to mode of action of the natural product. Significantly, an analysis from the National Cancer Institute sixty cell line testing did not reveal any correlations between the most potent derivative and any other compound in the database, except at high concentrations (LC50). This study led to the discovery of a new set of sphaeropsidin derivatives that may be exploited as potential anti-cancer agents, notably due to their maintained activity towards multidrug resistant models.

Development of Lipid Polymer Hybrid Nanoparticles of Abietic Acid: Optimization, In-Vitro and Preclinical Evaluation.

The objective of the current research was to develop abietic acid (AA)-loaded hybrid polymeric nanoparticles (HNPs) for anti-inflammatory and antioxidant activity after oral administration. AAHNPs were developed by microinjection technique and optimized by 3-factor 3-level Box-Behnken design. The AAHNPs were evaluated for morphology, FTIR, X-ray diffraction, in-vitro release, ex-vivo permeation, in-vitro antioxidant, and in-vivo anti-inflammatory activity. The optimized AAHNPs (AAHNPsopt) displayed 384.5 ± 6.36nm of PS, 0.376 of PDI, 23.0 mV of ZP, and 80.01 ± 1.89% of EE. FTIR and X-ray diffraction study results revealed that AA was encapsulated into a HNPs matrix. The AAHNPsopt showed significant (P < 0.05) high and sustained release of AA (86.72 ± 4.92%) than pure AA (29.87 ± 3.11%) in 24h. AAHNPsopt showed an initial fast release of AA (20.12 ± 3.07% in 2h), which succeeded in reaching the therapeutic concentration. The AAHNPsopt showed 2.49-fold higher ex-vivo gut permeation flux than pure AA due to the presence of lipid and surfactant. The AAHNPsopt exhibited significantly (P < 0.05, P < 0.01, P < 0.001) higher antioxidant activity as compared to pure AA at each concentration. AAHNPsopt formulation displayed a significantly (P < 0.05) higher anti-inflammatory effect (21.51 ± 2.23% swelling) as compared to pure AA (46.51 ± 1.74% swelling). From the in-vitro and in-vivo finding, it was concluded that HNPs might be a suitable carrier for the improvement of the therapeutic efficacy of the drug.

Abietane diterpenoids from Caryopteris incana (Thunb.) Miq. And their HIF-2α inhibitory activities in vitro.

Eleven previously undescribed abietane-type diterpenoids, named caryopincanoids A-K (1-11), together with five known compounds, were isolated from the EtOH extract of the aerial parts of Caryopteris incana (Thunb.) Miq. Their structures were elucidated on the basis of comprehensive spectroscopic data, NMR calculations, and ECD calculations. The inhibitory activities of all compounds against HIF-2α gene expression in 786-O cells were tested by luciferase assay. Compounds 7, 9, 15, and 16 showed significant inhibitory effects with IC50 values ranging from 12.73 to 23.80 µM. The preliminary structure-activity relationship of these compounds was also discussed.

Abietane-Type Diterpenoids from the Arils of Torreya grandis.

A chemical investigation of the arils of Torreya grandis led to the isolation of seven abietane-type diterpenoids (compounds 1-7) including three previously undescribed compounds, one unreported natural product, and three known analogs. The structures of these compounds were determined by means of spectroscopy, single-crystal X-ray diffraction, and ECD spectra. An antibacterial activity assay showed that compounds 5 and 6 had significant inhibitory effects on methicillin-resistant Staphylococcus aureus, with MIC values of 100 µM. Moreover, compounds 1, 3, 4, and 7 exhibited anti-neuroinflammatory activity in LPS-stimulated BV-2 microglia cells, with the IC50 values ranging from 38.4 to 67.9 µM.

Anticancer Effects of Abietane Diterpene 7α-Acetoxy-6ß-hydroxyroyleanone from Plectranthus grandidentatus and Its Semi-Synthetic Analogs: An In Silico Computational Approach.

The abietane diterpenoid 7α-acetoxy-6ß-hydroxyroyleanone (Roy) isolated from Plectranthus grandidentatus demonstrates cytotoxicity across numerous cancer cell lines. To potentiate anticancer attributes, a series of semi-synthetic Roy derivatives were generated and examined computationally. ADMET predictions were used to evaluate drug-likeness and toxicity risks. The antineoplastic potential was quantified by PASS. The DFT models were used to assess their reactivity and stability. Molecular docking determined cancer-related protein binding. MS simulations examined ligand-protein stability. Additionally, network pharmacology was used to identify potential targets and signaling pathways. Favorable ADME attributes and acceptable toxicity profiles were determined for all compounds. Strong anticancer potential was shown across derivatives (Pa 0.819-0.879). Strategic modifications altered HOMO-LUMO gaps (3.39-3.79 eV) and global reactivity indices. Favorable binding was revealed against cyclin-dependent kinases, BCL-2, caspases, receptor tyrosine kinases, and p53. The ligand exhibited a stable binding pose in MD simulations. Network analysis revealed involvement in cancer-related pathways. In silico evaluations predicted Roy and derivatives as effective molecules with anticancer properties. Experimental progress is warranted to realize their chemotherapeutic potential.

New pimarane diterpenoids with antibacterial activity from fungus Arthrinium sp. ZS03.

A comprehensive chemical study of the endophytic fungus Arthrinium sp. ZS03, associated with Acorus tatarinowii Schott, yielded eleven pimarane diterpenoids (compounds 1-11), including seven novel compounds designated arthrinoids A-G (1-7). The determination of their structures and absolute configurations was achieved through extensive spectroscopic techniques, quantum chemical calculations of electronic circular dichroism (ECD), and single-crystal X-ray diffraction analysis. Furthermore, 7 demonstrated inhibitory activity against Klebsiella pneumoniae, comparable to the reference antibiotic amikacin, with a minimum inhibitory concentration (MIC) of 8 µg·mL-1.

Structural modification of tanshinone IIA and their α-glucosidase inhibitory activity.

α-Glucosidase is one of the therapeutic approaches for treating type 2 diabetes mellitus. Almost 95 % of diabetes patients worldwide have been diagnosed with type 2 diabetes, resulting in 1.5 million fatalities each year. Newly synthesized oxazole-based tanshinone IIA derivatives (1a-n) were designed and evaluated for their inhibitory activity against α-glucosidase enzyme. Eight compounds (1a-d, 1f-g, 1j, and 1m) demonstrated excellent inhibition with IC50 values ranging from 0.73 ± 0.11 to 9.46 ± 0.57 µM as compared to tanshinone IIA (IC50 = 11.39 ± 0.77 µM) and standard acarbose (IC50 = 100.00 ± 0.95 µM). Among this series, 1j bearing two hydroxyls group over the phenyl ring was identified as the most potent α-glucosidase inhibitor with IC50 value of 0.73 ± 0.11 µM. Molecular docking simulations were done for the most active compound to identify important binding modes responsible for inhibition activity of α-glucosidase. In addition, the kinetic study was also performed to understand the mode of inhibition.

Discovery of Dehydroabietylamine Derivatives as Antibacterial and Antifungal Agents.

A diverse array of biologically active derivatives was derived by modifying the chemically active sites of dehydroabietylamine. Herein, we describe the synthesis of a new series of C-19-arylated dehydroabietylamine derivatives using a palladium-catalyzed C(sp3)-H activation reaction. Five analogues (3b, 3d, 3h, 3n, and 4a) exhibited antibacterial activity against Escherichia coli. Compound 4a exhibited strong inhibitory activity against DNA Topo II and Topo IV. Molecular docking modeling indicated that it can bind effectively to the target through interactions with amino acid residues. The synthesized compounds were tested in vitro for their antifungal activity against six common phytopathogenic fungi. The mechanism of action of compound 4c against Rhizoctorzia solani was investigated, revealing that it disrupts the morphology of the mycelium and enhances cell membrane permeability.

Tanshinone IIA Against Cerebral Ischemic Stroke and Ischemia- Reperfusion Injury: A Review of the Current Documents.

Stroke is a well-known neurological disorder that carries significant morbidity and mortality rates worldwide. Cerebral Ischemic Stroke (CIS), the most common subtype of stroke, occurs when thrombosis or emboli form elsewhere in the body and travel to the brain, leading to reduced blood perfusion. Cerebral Ischemia/Reperfusion Injury (CIRI) is a common complication of CIS and arises when blood flow is rapidly restored to the brain tissue after a period of ischemia. The therapeutic approaches currently recognized for CIS, such as thrombolysis and thrombectomy, have notable side effects that limit their clinical application. Recently, there has been growing interest among researchers in exploring the potential of herbal agents for treating various disorders and malignancies. One such herbal agent with medicinal applications is tanshinone IIA, an active diterpene quinone extracted from Salvia miltiorrhiza Bunge. Tanshinone IIA has shown several pharmacological benefits, including anti-inflammatory, antioxidant, anti-apoptotic, and neuroprotective properties. Multiple studies have indicated the protective role of tanshinone IIA in CIS and CIRI. This literature review aims to summarize the current findings regarding the molecular mechanisms through which this herbal compound improves CIS and CIRI.

Structure, Absolute Configuration, Antiproliferative and Phytotoxic Activities of Icetexane and Abietane Diterpenoids from Salvia carranzae and Chemotaxonomic Implications.

From the aerial parts of Salvia carranzae Zamudio and Bedolla, three new icetexane-type diterpenoids were isolated. Their structures were established through spectroscopic methods and named the following: salvicarranzanolide (1), 19-deoxo-salvicarranzanolide (2) and 19-deoxo-20-deoxy-salvicarranzanolide (3). In addition, the known icetexane-type diterpenoids, 6,7,11,14-tetrahydro-7-oxo-icetexone (4), iso-icetexone (5), 19-deoxo-iso-icetexone (6), icetexone (7), 19-deoxo-icetexone (8) and 7α-acetoxy-6,7-dihydroicetexone (9), were also isolated, along with the abietanes sessein (10) and ferruginol (11). α-Tocopherol was also identified. Compounds 5, 6 and 8 were tested for their antiproliferative activity using the sulforhodamine B assay on six cancer and one normal human cell lines. Diterpenoids 5 and 6 showed noteworthy antiproliferative activity, exhibiting an IC50 (µM) = 0.43 ± 0.01 and 1.34 ± 0.04, respectively, for U251 (glioblastoma), an IC50 (µM) = 0.45 ± 0.01 and 1.29 ± 0.06 for K5621 (myelogenous leukemia), 0.84 ± 0.07 and 1.03 ± 0.10 for HCT-15 (colon cancer), and 0.73 ± 0.06 and 0.95 ± 0.09 for SKLU-1 (lung adenocarcinoma) cell lines. On the other hand, the phytotoxicity of compounds 5-7 and 9-10 was evaluated on seed germination and root growth in some weeds such as Medicago sativa, Panicum miliaceum, Amaranthus hypochondriacus and Trifolium pratense as models. While compounds 5 and 10 exhibited a moderate inhibitory effect on the root growth of A. hypochondriacus and T. pratense at 100 ppm, the diterpenoids 6, 7 and 9 were ineffective in all the plant models. Taxonomic positions based on the chemical profiles found are also discussed.