Paeoniae radix overcomes resistance to EGFR-TKIs via aurora B pathway suppression in lung adenocarcinoma.

Targeted therapies using epidermal growth factor receptor (EGFR) inhibitors have markedly improved survival rates and quality of life for patients with EGFR-mutant lung adenocarcinoma (LUAD). Despite these advancements, resistance to EGFR inhibitors remains a significant challenge, limiting the overall effectiveness of the treatment. This study explored the synergistic effects of combining Paeoniae Radix (PR) with first-generation EGFR-tyrosine kinase inhibitors (TKIs), erlotinib and gefitinib, to overcome this resistance. Transcriptomic analysis of EGFR-mutant LUAD cell lines revealed that PR treatment could potentially reverse the gene signatures associated with resistance to EGFR-TKIs, primarily through the suppression of the Aurora B pathway. Experimental validation demonstrated that combining PR with erlotinib and gefitinib enhanced drug responsiveness by inhibiting Aurora kinase activity and inducing apoptosis in LUAD cells. Additionally, gene expression changes confirmed these combined effects, with the suppression of the Aurora B pathway and upregulation of the apoptotic pathway, which was accompanied by increased expression of multiple pro-apoptotic genes. Our findings contribute to the development of natural product-based therapeutic strategies to mitigate drug resistance in LUAD.

Biological evaluation of signal transducer and activator of transcription 3 (STAT3) targeting by phaeosphaeride A and its analogs.

The inhibitory activities of phaeosphaeride A (PPA), phaeosphaeride B, and four synthetic derivatives against phosphorylation of signal transducer and activator of transcription 3 (STAT3) and cell proliferation in cervical (HeLa) and breast (MDA-MB-231) cancer cells were evaluated. PPA inhibited IL-6-induced STAT3 phosphorylation and cell proliferation at similar concentrations. The structure-activity relationship studies revealed that the enantiomer of PPA was the most potent of the evaluated phaeosphaerides in both inhibiting STAT3 phosphorylation and cell growth. PPA clearly inhibited the IL-6-activated STAT3 signaling pathway. However, the presence or absence of activation of the STAT3 signaling pathway in cells showed no relationship to the antiproliferative activity. Notably, the possible covalent bond-forming ability of PPA was critical for its biological activities.

Sinapinic acid as a potential therapeutic agent for epilepsy through targeting NMDA receptors and nitrite level.

Epilepsy, a widespread neural ailment considered by prolonged neuronal depolarization and repetitive discharge, has been linked to extreme stimulus of N-methyl-D-aspartate receptors (NMDARs). Despite the availability of approved anti-seizure medications (ASMs) in many developed nations, approximately 30% of epilepsy patients continue to experience drug-resistant seizures. Thus, a growing interest in discovering natural compounds as potential sources for new medications is growing. Sinapinic acid, a natural derivative of cinnamic acid found in food sources, is known for its neuroprotective properties. This study investigated how sinapinic acid interacts with NMDA receptors and its potential role in providing anticonvulsant effects. Male mice were randomly allocated into nine groups: a control group receiving normal saline (1 ml/kg), groups treated with sinapinic acid at doses of 1, 3, and 10 mg/kg, a group treated with diazepam at 10 mg/kg, a group treated with an NMDA agonist at 75 mg/kg, a group treated with an NMDA antagonist at 0.5 mg/kg, a group receiving the ineffective dose of sinapinic acid (1 mg/kg) along with the NMDA antagonist, and a group receiving the effective dose of sinapinic acid (10 mg/kg) along with the NMDA agonist. Sinapinic acid and other treatments were administered intraperitoneally 30 min prior to inducing seizures with PTZ injection. Seizure onset time was recorded following PTZ injection. Blood and brain samples were collected after anesthesia to determine serum and brain nitrite levels. Real-time PCR assessed NMDAR gene expression in the prefrontal cortex (PFC). Data were analyzed using Prism software. The time seizures began was notably extended in groups treated with sinapinic acid at doses of 3 and 10 mg/kg compared to those treated with saline (P < 0.05). Additionally, in the receiving group of an ineffective dose of sinapinic acid alongside ketamine, the beginning of seizure time was significantly prolonged compared to the group that received the ineffective dose of sinapinic acid alone (P < 0.05). Serum and prefrontal cortex (PFC) nitrite levels were significantly lower in mice treated with sinapinic acid at doses of 1, 3, and 10 mg/kg compared to the saline-treated group (P < 0.05). The gene expression of the NMDAR NR2B subunit in the PFC was decreased in groups treated with sinapinic acid at 1 and 10 mg/kg compared to the saline-treated group. Furthermore, co-administration of sinapinic acid (10 mg/kg) with NMDA resulted in significantly lower NR2A gene expression than the group treated with 10 mg/kg of sinapinic acid alone. Conversely, co-administration of ketamine with sinapinic acid (1 mg/kg) significantly increased NR2B subunit gene expression compared to the group treated with sinapinic acid at 1 mg/kg alone. Sinapinic acid showed anticonvulsant effects through reduced serum and PFC nitrite and modulation of glutamatergic signaling.

Acute oral toxicity and genotoxicity assessment of the essential oil from Croton pulegiodorus Baill (Euphorbiaceae) leaves in mice.

Essential oils obtained from Croton pulegiodorus leaf are renowned for their biological activities; however, data on their toxicity are limited. Therefore, this study aimed to evaluate the acute oral toxicity and genotoxicity of a C. pulegiodorus leaf essential oil (CPLEO). Chemical characterization of CPLEO was conducted by gas chromatography coupled to mass spectrometry (GC-MS). In vitro assay was performed to verify the hemolytic capacity of the oil in mice erythrocytes. Next, an acute oral toxicity study was conducted on female mice at CPLEO doses of 2000, 1000, 500, 250, 100, and 50 mg/kg. Hematological, biochemical, and histopathological markers were assessed in mice from groups were no death occurred. Relative consumption of water and food and the weight of animals and their organs were also recorded. Finally, a genotoxicity analysis was performed using the micronucleus and comet assays. The extraction yield of CPLEO was 1.149% and its major compounds were ascaridole (23.18%), eucalyptol (17.20%), camphor (14.20%), p-cymene (7.91%), α-terpineol (4.69%), and isobornyl acetate (4.57%). CPLEO showed a hemolytic effect only at high concentrations (185.5-1000 mg/mL). It showed acute oral toxicity in mice with a LD50 of 460.42 mg/kg. CPLEO (50-250 mg/kg) caused some significant changes in hematological and biochemical parameters. Histopathological evaluation indicated alterations in liver and kidneys but transaminases, urea and creatinine levels remained like the negative control. CPLEO administration impaired weight gain and reduced water and food consumption. Finally, it was not genotoxic by both comet and micronucleus tests. The results highlight the need for attention when choosing doses to evaluate the bioactivities of CPLEO.

The Diverse Activities and Mechanisms of the Acylphloroglucinol Antibiotic Rhodomyrtone: Antibacterial Activity and Beyond.

Background/Objectives: The rose myrtle Rhodomyrtus tomentosa is a medicinal plant used in traditional Asian medicine. The active compound in R. tomentosa leaf extracts is rhodomyrtone, a chiral acylphloroglucinol. Rhodomyrtone exhibits an impressive breadth of activities, including antibacterial, antiviral, antiplasmodial, immunomodulatory, and anticancer properties. Its antibacterial properties have been extensively studied. Methods: We performed a comprehensive literature review on rhodomyrtone and summarized the current knowledge about this promising acylphloroglucinol antibiotic and its diverse functions in this review. Results: Rhodomyrtone shows nano to micromolar activities against a broad range of Gram-positive pathogens, including multidrug-resistant clinical isolates, and possesses a unique mechanism of action. It increases membrane fluidity and creates hyperfluid domains that attract membrane proteins prior to forming large membrane vesicles, effectively acting as a membrane protein trap. This mechanism affects a multitude of cellular processes, including cell division and cell wall synthesis. Additionally, rhodomyrtone reduces the expression of inflammatory cytokines, such as TNF-α, IL-17A, IL1ß, and IL8. Generally showing low toxicity against mammalian cells, rhodomyrtone does inhibit the proliferation of cancer cell lines, such as epidermal carcinoma cells. The primary mechanism behind this activity appears to be the downregulation of adhesion kinases and growth factors. Furthermore, rhodomyrtone has shown antioxidant activity and displays cognitive effects, such as decreasing depressive symptoms in mice. Conclusions: Rhodomyrtone shows great promise as therapeutic agent, mostly for antibacterial but also for diverse other applications. Yet, bottlenecks such as resistance development and a better understanding of mammalian cell toxictiy demand careful assessment.

Astaxanthin Is a Novel Candidate for Glioblastoma Treatment? A Review.

Glioblastoma (GBM) is a malignant primary brain tumor with a poor prognosis and high recurrence rates. At present, the current treatments available for GBM patients can only prolong their overall survival and cannot provide a complete cure. Discovering an effective therapy against the disease is a challenge due to its recurrence and resistance to common available treatments for GBM. Several natural products have been documented to possess the potential to function as anticancer agents through diverse mechanisms. Astaxanthin (AXT) is an orange-red pigment that is a natural lipophilic and xanthophyll carotenoid derived mostly from microalgae. Numerous studies have examined that AXT impacts GBM cells in laboratory settings and animal models. This review aims to provide the latest information about the potential of astaxanthin as a novel therapeutic option for GBM. AXT has been targeted more on reactive oxygen species (ROS), and suppressed tumor growth in vitro and in vivo conditions. The available data suggests that AXT might serve as a key component in the development of innovative cancer therapies, especially for glioblastoma.

First report on exploration of structural features of natural compounds (NPACT database) for anti-breast cancer activity (MCF-7): QSAR-based virtual screening, molecular docking, ADMET, MD simulation, and DFT studies.

Due to the high toxicity, poor efficacy and resistance associated with current anti-breast cancer drugs, there's growing interest in natural products (NPs) for their potential anti-cancer properties. Computational modelling of NPs to identify key structural features can aid in developing novel natural inhibitors. In this study, we developed statistically significant QSAR models based on NPs from the NPACT database, which have shown potential anticancer activity against the MCF-7 cancer cell lines. All the developed QSAR models were statistically robust, meeting both internal (R 2 = 0.666-0.669, R 2 adj = 0.657-0.660, Q 2 Loo = 0.636-0.638) and external (Q 2 F n = 0.686-0.714, CCC ext = 0.830-0.847) validation criteria. Consequently, they were utilized to virtually screen a series of NPs from the COCONUT database in the search for novel natural inhibitors. Molecular docking studies were conducted on the identified compounds against the human HER2 protein (PDB ID: 3PP0), which is a crucial target in breast cancer. Molecular docking analysis demonstrated that compounds 4608 and 2710 achieved the highest docking scores, with CDOCKER interaction energies of -72.67 kcal/mol and - 72.63 kcal/mol respectively. Compounds 4608 and 2710 were identified as the most promising candidates upon performing triplicate 100 ns MD simulation study using the CHARMM36 force field. DFT studies was performed to evaluate their stability and reactivity as potential drug molecules. This research contributes to the development of new natural inhibitors for breast cancer. Supplementary Information: The online version contains supplementary material available at 10.1007/s40203-024-00266-5.

Exploring marine natural products for identifying putative candidates as EBNA1 inhibitors: An insight from molecular docking, molecular dynamics, and DFT computations.

Epstein-Barr virus (EBV), namely a DNA neoplasm virus, is liable for over 1 % of malignant neoplasms involving Hodgkin's and Burkitt's lymphoma as well as ventral cancer. Despite the crucial role of EBV in carcinoma evolution, no treatment has been discovered yet against EBV. Epstein-Barr nuclear antigen 1 (EBNA1), the EBV-encoded latent protein, is produced in all EBV-linked neoplasms and is the only latent protein in these cancer types. EBNA1 protein has multiple roles in the upkeep, reproduction, and EBV genome separation and can thus act as an attractive therapeutic target for treating EBV-related malignancies. In the past few decades, attempts have been made to develop specialized EBNA1 inhibitors to reduce EBNA1 expression or obstruct EBNA1-relied processes, but none has been approved yet. Marine natural products (MNPs) have garnered significant interest as potential sources of antiviral drug candidates. In seeking potent drug candidates to inhibit EBV reproduction, an MNP database containing >14,000 compounds was mined to hunt putative EBNA1 inhibitors using docking computations and molecular dynamics simulations (MDS). On the basis of binding energy (ΔGbinding) estimations over 200 ns MDS, UMHMNP351444649 and UMHMNP134128179 revealed a greater binding affinity towards EBNA1 compared to KWG, with ΔGbinding values of -35.6, -33.3, and -32.4 kcal/mol, respectively. Structural and energetical investigations of UMHMNP351444649 and UMHMNP134128179 complexed with EBNA1 were inspected, unveiling the great constancy of these inhibitors within the EBNA1 binding site. Moreover, the identified MNPs demonstrated favorable physicochemical and medicinal chemistry characteristics. Finally, density functional theory calculations were executed, and the results assured the outcomes obtained from docking computations and MDS. These findings proposed UMHMNP351444649 and UMHMNP134128179 as potential anti-EBV drug candidates that warrant further in-vitro and in-vivo assays.

Advances in the pharmacological mechanisms of berberine in the treatment of fibrosis.

The rising incidence of fibrosis poses a major threat to global public health, and the continuous exploration of natural products for the effective treatment of fibrotic diseases is crucial. Berberine (BBR), an isoquinoline alkaloid, is widely used clinically for its anti-inflammatory, anti-tumor and anti-fibrotic pharmacological effects. Until now, researchers have worked to explore the mechanisms of BBR for the treatment of fibrosis, and multiple studies have found that BBR attenuates fibrosis through different pathways such as TGF-ß/Smad, AMPK, Nrf2, PPAR-γ, NF-κB, and Notch/snail axis. This review describes the anti-fibrotic mechanism of BBR and its derivatives, and the safety evaluation and toxicity studies of BBR. This provides important therapeutic clues and strategies for exploring new drugs for the treatment of fibrosis. Nevertheless, more studies, especially clinical studies, are still needed. We believe that with the continuous implementation of high-quality studies, significant progress will be made in the treatment of fibrosis.

Anticancer Drug Discovery from Natural Compounds Targeting PI3K/AKT/mTOR Signaling Pathway.

The term cancer is used to describe a complex pathology characterized by the uncontrollable proliferation of cells, which displays a fast metastatic spread, being a disease with difficult treatment. In this context, Phosphatidylinositol 3-kinase (PI3K) represents a promising pathway to be inhibited, aiming to develop anticancer agents, since it performs a pivotal role in regulating essential cellular processes, including cell proliferation, growth, autophagy, and apoptosis. In parallel, natural compounds can effectively represent a therapeutic strategy to fight against malignant cells. Then, compounds derived from various plant sources, such as flavonoids, terpenoids, alkaloids, coumarins, and lignans, have exhibited remarkable in vitro and in vivo anticancer properties. This review focused in the exploration of natural products targeting the PI3K/AKT/m-TOR signaling pathway, demonstrating that these compounds could even further investigated to reveal novel and effective anticancer drugs in the future.

The Second Methylation in Psilocybin Biosynthesis Is Enabled by a Hydrogen Bonding Network Extending into the Secondary Sphere Surrounding the Methyltransferase Active Site.

The Psilocybe cubensis SAM-dependent methyltransferase, PsiM, catalyzes the last step in the biosynthesis of psilocybin. Likely evolved from monomethylating RNA methyltransferases, PsiM acquired a key amino acid exchange in the secondary sphere of the active site, M247N, which is responsible for its capacity to dimethylate. Two variants, PsiMN247M and PsiMN247A, were generated to further examine the role of Asn247 for mono- and dimethylation in PsiM. Herein, we present the kinetic profiles of both variants and crystal structures at resolutions between 0.9 and 1.0 Å. Each variant was crystallized as a ternary complex with the non-methylated acceptor substrate, norbaeocystin and S-adenosyl-l-homocysteine, and in a second complex with the cofactor analog, sinefungin, and the monomethylated substrate, baeocystin. Consistent with the inability of the variants to catalyze a second methyl transfer, these structures reveal catalytically non-productive conformations and a high level of disorder of the methylamine group of baeocystin. Additionally, both variants exhibit destabilization in the ß5-ß7 sheets and a conserved ß-turn of the core Rossmann fold, causing 20-fold reduced substrate binding and 2-fold lower catalytic efficiency even with norbaeocystin.

Identification of Potential Inhibitors of TGFßR1 for the treatment of Cancer through Structure-based virtual screening and Molecular dynamics simulations.

Globally, cancer is one of the leading causes of death. Resistance to conventional medications, such as chemotherapy and radiation, continues to be a significant challenge in the treatment of cancer despite the availability of numerous medicines. Therefore, the highest priority is to hunt for new therapeutic agents. Transforming growth factor-beta is a pivotal regulatory cytokine that exerts significant influence over cellular processes, particularly emphasizing its role in facilitating and modulating cell proliferation. TGFß1, identified as most promising active site of the TGF-ß signaling, is a potent drug target site that has garnered wide attention for developing new anticancer agents. The present investigation investigates the potential phytochemicals as TGFßR1 inhibitors. The SB431542 complexed TGFßR1 protein model was used to screen the natural product database to obtain a compound with high binding potential. NPC247629 has emerged as the best-scored compound among all the screened compounds, demonstrating the highest affinity towards the TGFßR1 regarding docking score -17.54 kcal/mol. The MD simulation study indicated that all proposed hits are retained inside the receptor in dynamic states. The best-screened hits, NPC247629 and NPC60735, have excellent binding affinity and hold a massive potential for TGFßR1 inhibition, paving the way for promising future investigations in cancer treatment.

Molecular Networking-Guided Discovery of a New Antitumor Pyranonaphthoquinone from Streptomyces tanashiensis DSM 731: Insights from Single-Molecule Stretching Assays.

Guided by molecular networking based on single-molecule stretching assay, an unprecedented pyranonaphthoquinone, methyl kalafunginate (1) and five known compounds 2-6 were isolated from Streptomyces tanashiensis DSM 731. Compound 1 was characterized through a combination of spectroscopic techniques, including 1D and 2D NMR analysis, ECD calculation, and X-ray crystallography. Interestingly, we discovered that compound 1 was spontaneously converted from kalafungin (4) in methanol solution. All isolated compounds were assessed for their cytotoxic potential against a panel of five human cancer cell lines: A549, HepG2, BxPC-3, SW620, and C4-2B. Compounds 1, 2, 4, and 5 exhibited remarkable cytotoxicity with IC50 values below 2.382 µM, suggesting their potential as promising anticancer agents. These findings highlight the significance of using a combined approach of single-molecule stretching assays and molecular networking for efficiently discovering novel natural products with potential therapeutic applications.

Construction of a Bifunctional Nanoelectrode for Intracellular Natural Product Delivery and Monitoring Anticancer Efficiency in Single Cells.

Natural products play a significant role in new drug discovery and anticancer therapy, making the evaluation of their anticancer efficiency crucial for clinical application. However, delivering natural products to single cells and in situ monitoring of induced signaling molecule fluctuation to evaluate anticancer efficiency remain significant challenges. Hence, we proposed a universal and straightforward strategy to construct a bifunctional nanoelectrode that integrates drug loading and monitoring of signal molecule fluctuations at the single-cell level. Platinum (Pt) nanoparticles/reduced graphene oxide (rGO) composites were first electrochemically deposited on the carbon fiber nanoelectrode (CFNE@Pt/rGO) to serve as electrocatalytic materials for the monitoring of natural-product-induced reactive oxygen species (ROS) generation. The GO/natural product complex, formed by π-π stacking and hydrophobic interactions, was further electrochemically reduced on the surface of CFNE@Pt/rGO to enable the CFNE drug-loading function. Using this bifunctional functional nanoelectrode, a series of natural products (such as capsaicin, curcumin, and chrysin) were delivered into single cancer cells, and their anticancer efficiency was evaluated by measuring ROS generation. The results showed that intracellular ROS production induced by chrysin was 1.5-fold greater than that of curcumin and 2.1-fold greater than that of capsaicin. This work proposes an effective tool to evaluate the anticancer efficiency of various natural products. Additionally, this nanotool can be expanded to monitor the fluctuation of other biomolecules (such as RNS, GSH, NADH, etc.) by replacing Pt nanoparticles with other electrocatalytic materials, which is significant for comprehensively exploring the anticancer efficiency of new drugs and for the clinical treatment of various diseases.

Synthesis, structural modification, and biological activity of a novel bisindole alkaloid iheyamine A.

Diseases caused by plant viruses and pathogens pose a serious threat to crop yield and quality. Traditional pesticides have gradually developed drug resistance and brought certain environmental safety issues during long-term overuse. There is an urgent need to discover new candidate compounds to address these issues. In this study, we achieved the efficient synthesis of iheyamine A and its derivatives, and discovered their excellent antiviral activities against tobacco mosaic virus (TMV). Most compounds displayed higher antiviral activities against TMV than commercial ribavirin at 500 µg/mL, with compounds 3a (Inactive effect IC50: 162 µg/mL), 3d (Inactive effect IC50: 249 µg/mL), 6p (Inactive effect IC50: 254 µg/mL), and 7a (Inactive effect IC50: 234 µg/mL) exhibiting better antiviral activities than ningnanmycin at 500 µg/mL (Inactive effect IC50: 269 µg/mL). Meanwhile, the structure-activity relationships of this type of compounds were systematically studied. We chose 3a for further antiviral mechanism research and found that it can directly act on viral coat protein (CP). The interaction of 3a and CP was further verified via molecular docking. These compounds also showed broad-spectrum fungicidal activities against 8 plant pathogenic fungi, especially for P. piricola. This study provides a reference for the role of iheyamine alkaloids in combating plant pathogenic diseases.

Development of natural product-based targeted protein degraders as anticancer agents.

Targeted protein degradation (TPD) has emerged as a powerful approach for eliminating cancer-causing proteins through an "event-driven" pharmacological mode. Proteolysis-targeting chimeras (PROTACs), molecular glues (MGs), and hydrophobic tagging (HyTing) have evolved into three major classes of TPD technologies. Natural products (NPs) are a primary source of anticancer drugs and have played important roles in the development of TPD technology. NPs potentially expand the toolbox of TPD by providing a variety of E3 ligase ligands, protein of interest (POI) warheads, and hydrophobic tags (HyTs). As a promising direction in the TPD field, NP-based degraders have shown great potential for anticancer therapy. In this review, we summarize recent advances in the development of NP-based degraders (PROTACs, MGs and HyTing) with anticancer applications. Moreover, we put forward the challenges while presenting potential opportunities for the advancement of future targeted protein degraders derived from NPs.

Systematic Review and Meta-analysis Indicating Curcumin to Enhance the Synergistic Potential of Paclitaxel and Reduce Cell Viability, Tumor Volume, and Drug Resistance in Different Cancers.

BACKGROUND: To treat diseases like cancer, conventional Paclitaxel (PTX)- based monotherapy treatment regimens are becoming less effective due to the development of resistance. In this aspect, the phytomolecule curcumin (Cur), having ethnopharmacological importance in traditional South Asian remedies, like Ayurveda and Chinese traditional medicine, has been studied as a promising chemo-sensitizing and synergistic partner of PTX. AIM: This study aimed to evaluate the combined effect of PTX and Cur compared to PTX therapy alone in the in vitro and in vivo environments. MATERIAL AND METHODS: An extensive PubMed search was performed wherein 169 papers were shortlisted and screened to identify 30 studies that have reported the effect of PTX and Cur either in vitro, in vivo, or both. The pooled Odds Ratio (OR) was calculated at a 95% Confidence Interval (CI) for determining the effect of combination therapy. RESULTS: The meta-analysis has indicated PTX and Cur combination therapy to be associated with a significant decrease in cell viability (OR: 0.37, 95% CI: 0.27-0.51; p < 0.01) and tumor volume (OR: 0.32, 95% CI: 0.15-0.71; p = 0.01). Additionally, the effect of this combination on drug-resistant cell lines has exhibited a significant decrease in the odds of cell viability (OR: 0.45, 95% CI: 0.35-0.57; p < 0.01). CONCLUSION: Overall, the current meta-analysis has shown PTX and Cur combination to effectively inhibit the viability of cancer cells, reduce tumor volume, and diminish the growth of drug-resistant cancer cells.

Structural Optimization of Isoquinoline Derivatives from Lycobetaine and Their Inhibitory Activity against Neuroendocrine Prostate Cancer Cells.

Neuroendocrine prostate cancer (NEPC) is a highly aggressive cancer that is resistant to hormone therapy and characterized by poor prognosis, as well as limited therapeutic options. Since the natural product lycobetaine was reported to exhibit good antitumor activities against various types of cancers, we initially simplified the scaffold of lycobetaine to obtain the active compound 1, an isoquinoline derivative with an aryl moiety substitution at the 4-position, which showed apparent antiproliferative activities against NPEC cell line LASCPC-01 in vitro. Subsequently, we carried out structural optimization and systematic structure-activity relationship (SAR) studies on compound 1, leading to the discovery of compound 46, which demonstrated potent inhibitory activities against the LASCPC-01 cell line with an IC50 value of 0.47 µM. Moreover, compound 46 displayed remarkable selectivity over prostate cancer cell line PC-3 with a selectivity index greater than 190-fold. Further cell-based mechanism studies revealed that compound 46 and lycobetaine can effectively induce G1 cell cycle arrest and apoptosis dose dependently. However, lycobetaine inhibited the expression of neuroendocrine markers, while compound 46 slightly upregulated these proteins. This suggested that compound 46 might exert its antitumor activities through a different mechanism than lycobetaine, warranting further study.

Parallel evolution of methyltransferases leads to vobasine biosynthesis in Tabernaemontana elegans and Catharanthus roseus.

Monoterpenoid indole alkaloids (MIA) are one of the largest and most complex alkaloid class in nature, boasting many clinically significant drugs such as anticancer vinblastine and antiarrhythmic ajmaline. Many MIAs undergo nitrogen N-methylation, altering their reactivity and affinity to the biological targets through a straightforward reaction. Remarkably, all known MIA N-methyltransferases (NMT) originate from the neofunctionalization of ancestral γ-tocopherol C-methyltransferases (γTMTs), a phenomenon seemingly unique to the Apocynaceae family. In this study, we unveil and characterize a new γTMT-like enzyme from the plant Tabernaemontana elegans (toad tree): perivine Nß-methyltransferase (TePeNMT). TePeNMT and other homologs form a distinct clade in our phylogenetic study, setting them apart from other γTMTs and γTMT-like NMTs discovered to date. Enzyme kinetic experiments and enzyme homology modeling studies reveal the significant differences in enzyme active sites between TePeNMT and CrPeNMT, a previously characterized perivine Nß-methyltransferase from Catharanthus roseus (Madagascar periwinkle). Collectively, our findings suggest that parallel evolution of ancestral γTMTs may be responsible for the occurrence of perivine N-methylation in T. elegans and C. roseus.

Uncovering the Potent Antiviral Activity of the Sesterterpenoids from the Sponge Ircinia felix against Human Adenoviruses: from the Natural Source to the Total Synthesis.

Human Adenovirus (HAdV) infections in immunocompromised patients can result in disseminated diseases with high morbidity and mortality rates due to the absence of available treatments for these infections. Ircinia felix sponge was selected for the significant anti-HAdV activity displayed by its organic extracts. Its chemical analysis yielded three novel sesterterpene lactams, ircinialactams J-L, along with three known sesterterpene furans which structures were established by a deep spectrometric analysis. Ircinialactam J displayed significant antiviral activity against HAdV without significant cytotoxicity, showing an effectiveness 11 times greater than that of the standard treatment, cidofovir®. Some structure-activity relationships were deduced. Mechanistic assays suggest that ircinialactam J targets an early step of the HAdV replicative cycle before HAdV genome reaches the nucleus of the host cell. The first total synthesis of ircinialactam J was also accomplished to prove the structure and to provide access to analogues. Key steps are a regio- and stereoselective construction of the trisubstituted Z-olefin at Δ7 by iron-catalyzed carbometallation of a homopropargylic alcohol, a stereoselective methylation to generate the stereogenic center at C18, and the formation of the (Z)-Δ20 by stereoselective aldol condensation to introduce the tetronic acid unit. Ircinialactam J is a promising antiviral drug against HAdV infections.