Design, synthesis, and evaluation of antitumor activity in Pseudolaric acid B Azole derivatives: Novel and potent angiogenesis inhibitor via regulation of the PI3K/AKT and MAPK mediated HIF-1/VEGF signaling pathway.

Tumor proliferation and metastasis are intricately linked to blood vessel formation, with vascular endothelial growth factor (VEGF) playing a pivotal role in orchestrating angiogenesis throughout tumor progression. Pseudolaric acid B (PAB) has emerged as a potent inhibitor of tumor cell proliferation, migration, and angiogenesis. In efforts to enhance its efficacy, 37 derivatives of PAB were synthesized and assessed for their capacity to suppress VEGF secretion in SiHa cells under hypoxic conditions. Notably, majority of these derivatives exhibited significant inhibition of VEGF protein secretion without inducing cytotoxicity. Among them, compound M2 displayed the most potent inhibitory activity, with an IC50 value of 0.68 µM, outperforming the lead compound PAB (IC50 = 5.44 µM). Compound M2 not only curbed the migration and angiogenesis of HUVECs under hypoxic conditions but also hindered the invasion of SiHa cells. Mechanistic investigations unveiled that compound M2 may impede the accumulation and nuclear translocation of hypoxia-inducible factor 1α (HIF-1α) in SiHa cells, thereby downregulating VEGF expression. This inhibitory effect on HIF-1α was corroborated by experiments utilizing the protease inhibitor MG-132 and protein synthesis inhibitor CHX, indicating that compound M2 diminishes HIF-1α levels by reducing its synthesis. Furthermore, compound M2 was observed to modulate the PI3K/AKT/mTOR and MAPK signaling pathways in tumor cells, thereby regulating HIF-1α translation and synthesis. In vivo studies demonstrated that compound M2 exhibited low toxicity and effectively curbed tumor growth. Immunohistochemistry analyses validated that compound M2 effectively suppressed the expression of HIF-1α and VEGF in tumor tissues, underscoring its potential as a promising therapeutic agent for targeting tumor angiogenesis.

[Research progress on C_(20)-diterpenoid alkaloids and their bioactivities in Ranunculaceae].

C_(20)-diterpenoid alkaloids are mainly distributed in plants of genus Aconitum, Delphinium, and Consolida in the Ranunculaceae. Their chemical structures are mainly categorized into nine types such as atisines, denudatines, hetidines, and hetisines. Bioactivity studies have shown that C_(20)-diterpenoid alkaloids have exhibited superior anti-tumor, analgesic, antiarrhythmic, and anti-inflammatory effects. In this review, the chemical structures and biological activities of 190 C_(20)-diterpenoid alkaloids reported in the Ranunculaceae from 2002 to the present were summarized, so as to provide a reference for the subsequent research on C_(20)-diterpenoid alkaloids in plants of Ranunculaceae.

New Cytotoxic α-Aminoacylamide and bis-1,5-Disubstituted Tetrazole Adducts From Amino-Diterpene Molecules by Ugi Reaction.

In search for new molecules of diterpene origin with promising anticancer activity, two amino-derivatives (methyl maleopimarate aminoimide and methyl 1ß,13-epoxydihydroquinopimarate C4-hydrazone) were involved in the 4-component Ugi reaction (Ugi-4CR) and pseudo-7-component azido-Ugi condensation (azido-Ugi-7CR) to afford a series of adducts holding α-aminoacylamide and bis-1,5-disubstituted tetrazole substituents. The NCI-60 cancer cell panel screening revealed diterpene-type Ugi adducts 2, 5, and 6 with strong antiproliferative potency with GI50 in range of 1.2-15.4 µM. The high positive correlations with standard anticancer drugs suggest microtubules or progesterone and androgen receptors as possible targets of the synthesized compounds.

Antifungal Activity and Mechanism of Diaporthein B against Botryosphaeria dothidea in Prevention of Apple Ring Rot.

Apple ring rot, caused by the pathogenic fungus Botryosphaeria dothidea, has inflicted substantial economic losses and caused significant food safety concerns. In this study, a pimarane-type diterpenoid, diaporthein B (DTB), isolated from a marine-derived fungus, exhibited significant antifungal activity against B. dothidea, with an EC50 value of 8.8 µg/mL. Transcriptome, metabolome, and physiological assays revealed that DTB may target mitochondria and disrupt the tricarboxylic acid (TCA) cycle and oxidative phosphorylation processes. This interference led to increased accumulation of reactive oxygen species and subsequent lipid peroxidation, ultimately inhibiting fungal growth. Furthermore, DTB exhibited an inhibitory potency against apple ring rot at a concentration of 31.2 µg/mL, achieving rates ranging from 67.7 to 81.6% across four distinct apple cultivars. These results indicated that DTB could serve as a novel fungicide for controlling apple ring rot in apple cultivation, transportation, and storage.

Engineering Yarrowia lipolytica for Efficient Synthesis of Geranylgeraniol.

Geranylgeraniol (GGOH) is a crucial component in fragrances and essential oils, and a valuable precursor of vitamin E. It is primarily extracted from the oleoresin of Bixa orellana, but is challenged by long plant growth cycles, severe environmental pollution, and low extraction efficiency. Chemically synthesized GGOH typically comprises a mix of isomers, making the separation process both challenging and costly. Advancements in synthetic biology have enabled the construction of microbial cell factories for GGOH production. In this study, Yarrowia lipolytica was engineered to efficiently synthesize GGOH by expressing heterologous phosphatase genes, enhancing precursor supplies of farnesyl diphosphate, geranylgeranyl pyrophosphate, and acetyl-CoA, and downregulating the squalene synthesis pathway by promoter engineering. Additionally, optimizing fermentation conditions and reducing reactive oxygen species significantly increased the GGOH titer to 3346.47 mg/L in a shake flask. To the best of our knowledge, this is the highest reported GGOH titer in shaking flasks to date, setting a new benchmark for terpenoid production.

A kalihinol analog disrupts apicoplast function and vesicular trafficking in P. falciparum malaria.

We report the discovery of MED6-189, an analog of the kalihinol family of isocyanoterpene natural products that is effective against drug-sensitive and drug-resistant Plasmodium falciparum strains, blocking both asexual replication and sexual differentiation. In vivo studies using a humanized mouse model of malaria confirm strong efficacy of the compound in animals with no apparent hemolytic activity or toxicity. Complementary chemical, molecular, and genomics analyses revealed that MED6-189 targets the parasite apicoplast and acts by inhibiting lipid biogenesis and cellular trafficking. Genetic analyses revealed that a mutation in PfSec13, which encodes a component of the parasite secretory machinery, reduced susceptibility to the drug. Its high potency, excellent therapeutic profile, and distinctive mode of action make MED6-189 an excellent addition to the antimalarial drug pipeline.

An Overview of Secondary Metabolites from Soft Corals of the Genus Capnella over the Five Decades: Chemical Structures, Pharmacological Activities, NMR Data, and Chemical Synthesis.

There has been no specific review on the secondary metabolites from soft corals of the genus Capnella till now. In this work, all secondary metabolites from different species of the title genus were described. It covered the first work from 1974 to May 2024, spanning five decades. In the viewpoint of the general structural features, these chemical constituents were classified into four groups: sesquiterpenes, diterpenes, steroids, and lipids. Additionally, the 1H and 13C NMR data of these metabolites were provided when available in the literature. Among them, sesquiterpenes were the most abundant chemical compositions from soft corals of the genus Capnella. A variety of pharmacological activities of these compounds were evaluated, such as cytotoxic, antibacterial, antifungal, and anti-inflammatory activities. In addition, the chemical synthesis works of several representative sesquiterpenes were provided. This review aims to provide an up-to-date knowledge of the chemical structures, pharmacological activities, and chemical synthesis of the chemical constituents from soft corals of the genus Capnella.

Sphaerococcenol A Derivatives: Design, Synthesis, and Cytotoxicity.

Sphaerococcenol A is a cytotoxic bromoditerpene biosynthesized by the red alga Sphaerococcus coronopifolius. A series of its analogues (1-6) was designed and semi-synthesized using thiol-Michael additions and enone reduction, and the structures of these analogues were characterized by spectroscopic methods. Cytotoxic analyses (1-100 µM; 24 h) were accomplished on A549, DU-145, and MCF-7 cells. The six novel sphaerococcenol A analogues displayed an IC50 range between 14.31 and 70.11 µM on A549, DU-145, and MCF-7 malignant cells. Compound 1, resulting from the chemical addition of 4-methoxybenzenethiol, exhibited the smallest IC50 values on the A549 (18.70 µM) and DU-145 (15.82 µM) cell lines, and compound 3, resulting from the chemical addition of propanethiol, exhibited the smallest IC50 value (14.31 µM) on MCF-7 cells. The highest IC50 values were exhibited by compound 4, suggesting that the chemical addition of benzylthiol led to a loss of cytotoxic activity. The remaining chemical modifications were not able to potentiate the cytotoxicity of the original compounds. Regarding A549 cell viability, analogue 1 exhibited a marked effect on mitochondrial function, which was accompanied by an increase in ROS levels, Caspase-3 activation, and DNA fragmentation and condensation. This study opens new avenues for research by exploring sphaerococcenol A as a scaffold for the synthesis of novel bioactive molecules.

An Ingenane-Type Diterpene from Euphorbia kansui Promoted Cell Apoptosis and Macrophage Polarization via the Regulation of PKC Signaling Pathways.

Euphorbia kansui, a toxic Chinese medicine used for more than 2000 years, has the effect of "purging water to promote drinking" and "reducing swelling and dispersing modules". Diterpenes and triterpenes are the main bioactive components of E. kansui. Among them, ingenane-type diterpenes have multiple biological activities as a protein kinase C δ (PKC-δ) activator, which have previously been shown to promote anti-proliferative and pro-apoptotic effects in several human cancer cell lines. However, the activation of PKC subsequently promoted the survival of macrophages. Recently, we found that 13-hydroxyingenol-3-(2,3-dimethylbutanoate)-13-dodecanoate (compound A) from E. kansui showed dual bioactivity, including the inhibition of tumor-cell-line proliferation and regulation of macrophage polarization. This study identifies the possible mechanism of compound A in regulating the polarization state of macrophages, by regulating PKC-δ-extracellular signal regulated kinases (ERK) signaling pathways to exert anti-tumor immunity effects in vitro, which might provide a new treatment method from the perspective of immune cell regulation.

Design, Synthesis, and Anticancer Activity of Novel Enmein-Type Diterpenoid Derivatives Targeting the PI3K/Akt/mTOR Signaling Pathway.

The enmein-type diterpenoids are a class of anticancer ent-Kaurane diterpnoids that have received much attention in recent years. Herein, a novel 1,14-epoxy enmein-type diterpenoid 4, was reported in this project for the first time. A series of novel enmein-type diterpenoid derivatives were also synthesized and tested for anticancer activities. Among all the derivatives, compound 7h exhibited the most significant inhibitory effect against A549 cells (IC50 = 2.16 µM), being 11.03-folds better than its parental compound 4. Additionally, 7h exhibited relatively weak anti-proliferative activity (IC50 > 100 µM) against human normal L-02 cells, suggesting that it had excellent anti-proliferative selectivity for cancer cells. Mechanism studies suggested that 7h induced G0/G1 arrest and apoptosis in A549 cells by inhibiting the PI3K/AKT/mTOR pathway. This process was associated with elevated intracellular ROS levels and collapsed MMP. In summary, these data identified 7h as a promising lead compound that warrants further investigation of its anticancer properties.

The Cytoprotective Effect of C60 Derivatives in the Self-Microemulsifying Drug Delivery System against Triptolide-Induced Cytotoxicity In Vitro.

OBJECTIVE: The aim of this study was to optimize the formulation of a C60-modified self-microemulsifying drug delivery system loaded with triptolide (C60-SMEDDS/TP) and evaluate the cytoprotective effect of the C60-SMEDDS/TP on normal human cells. RESULTS: The C60-SMEDDS/TP exhibited rapid emulsification, an optimal particle size distribution of 50 ± 0.19 nm (PDI 0.211 ± 0.049), and a near-neutral zeta potential of -1.60 mV. The release kinetics of TP from the C60-SMEDDS/TP exhibited a sustained release profile and followed pseudo-first-order release kinetics. Cellular proliferation and apoptosis analysis indicated that the C60-SMEDDS/TP (with a mass ratio of TP: DSPE-PEG-C60 = 1:10) exhibited lower toxicity towards L02 and GES-1 cells. This was demonstrated by a higher IC50 (40.88 nM on L02 cells and 17.22 nM on GES-1 cells) compared to free TP (21.3 nM and 11.1 nM), and a lower apoptosis rate (20.8% on L02 cells and 26.3% on GES-1 cells, respectively) compared to free TP (50.5% and 47.0%) at a concentration of 50 nM. In comparison to the free TP group, L02 cells and GES-1 cells exposed to the C60-SMEDDS/TP exhibited a significant decrease in intracellular ROS and an increase in mitochondrial membrane potential (ΔψM). On the other hand, the C60-SMEDDS/TP demonstrated a similar inhibitory effect on BEL-7402 cells (IC50 = 28.9 nM) and HepG2 cells (IC50 = 107.6 nM), comparable to that of the free TP (27.2 nM and 90.4 nM). The C60-SMEDDS/TP group also exhibited a similar intracellular level of ROS and mitochondrial membrane potential compared to the SMEDDS/TP and free TP groups. METHOD: Fullerenol-Grafted Distearoyl Phosphatidylethanolamine-Polyethylene Glycol (DSPE-PEG-C60) was synthesized and applied in the self-microemulsifying drug delivery system. The C60-SMEDDS/TP was formulated using Cremophor EL, medium-chain triglycerides (MCT), PEG-400, and DSPE-PEG-C60, and loaded with triptolide (TP). The toxicity and bioactivity of the C60-SMEDDS/TP were assessed using normal human liver cell lines (L02 cells), normal human gastric mucosal epithelial cell lines (GES-1 cells), and liver cancer cell lines (BEL-7402 cells and HepG2 cells). The production of reactive oxygen species (ROS) after the C60-SMEDDS/TP treatment was assessed using 2',7'-dichlorofluorescein diacetate (DCFDA) staining. The alterations in mitochondrial membrane potential (ΔψM) were assessed by measuring JC-1 fluorescence. CONCLUSIONS: The cytoprotection provided by the C60-SMEDDS/TP favored normal cells (L02 and GES-1) over tumor cells (BEL-7402 and HepG2 cells) in vitro. This suggests a promising approach for the safe and effective treatment of TP.

Diterpenoids with Potent Anti-Psoriasis Activity from Euphorbia helioscopia L.

Psoriasis, an immune-mediated inflammatory skin disorder, seriously affects the quality of life of nearly four percent of the world population. Euphorbia helioscopia L. is the monarch constituent of Chinese ZeQi powder preparation for psoriasis, so it is necessary to illustrate its active ingredients. Thus, twenty-three diterpenoids, including seven new ones, were isolated from the whole herb of E. helioscopia L. Compounds 1 and 2, each featuring a 2,3-dicarboxylic functionality, are the first examples in the ent-2,3-sceo-atisane or the ent-2,3-sceo-abietane family. Extensive spectroscopic analysis (1D, 2D NMR, and HRMS data) and computational methods were used to confirm their structures and absolute configurations. According to the previous study and NMR data from the jatropha diterpenes obtained in this study, some efficient 1H NMR spectroscopic rules for assigning the relative configurations of 3α-benzyloxy-jatroph-11E-ene and 7,8-seco-3α-benzyloxy-jatropha-11E-ene were summarized. Moreover, the hyperproliferation of T cells and keratinocytes is considered a key pathophysiology of psoriasis. Anti-proliferative activities against induced T/B lymphocytes and HaCaT cells were tested, and IC50 values of some compounds ranged from 6.7 to 31.5 µM. Compounds 7 and 11 reduced the secretions of IFN-γ and IL-2 significantly. Further immunofluorescence experiments and a docking study with NF-κB P65 showed that compound 13 interfered with the proliferation of HaCaT cells by inhibiting the NF-κB P65 phosphorylation at the protein level.

Discovery of antitumor diterpenoids from Casearia graveolens targeting VEGFR-2 to inhibit angiogenesis.

Eight novel clerodane diterpenoids (1-8) were isolated from the twigs of Casearia graveolens. Their structures were elucidated through comprehensive nuclear magnetic resonance (NMR), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), and electronic circular dichroism (ECD) analyses. In addition to structural determination, surface plasmon resonance (SPR) assays were conducted to investigate molecular interactions, revealing that compound 8 exhibited high affinity for vascular endothelial growth factor receptor 2 (VEGFR2), a key regulator of tumor angiogenesis. Subsequent in vivo experiments demonstrated that compound 8 effectively inhibited angiogenesis and displayed significant antitumor activity by suppressing tumor proliferation and metastasis in zebrafish xenograft models. These findings suggest that compound 8 holds promise as an anticancer lead compound targeting VEGFR-2 to obstruct tumor angiogenesis.

Three new diterpenoids from the roots of Euphorbia fischeriana and their cytotoxicity.

Euphorbiabietane F (1), a novel abietane diterpenoid with the unprecedented 6/6/5/6/5 carbon skeleton, one new strobane diterpenoid (2), together with one new pimarane diterpenoid (3) were isolated from the roots of Euphorbia fischeriana. The structures were elucidated by the extensive spectroscopic data, gauge-independent atomic orbital (GIAO) NMR calculations, the comparison of experimental and calculated ECD spectra, as well as single crystal X-ray diffraction. The cytotoxicity result suggested the moderate inhibition rate of 1 on the cell lines of HepG2 and A549.

Phytotoxic Isocassadiene-Type Diterpenoids from Tomato Fusarium Crown and Root Rot Pathogen Fusarium oxysporum f. sp. radicis-lycopersici.

Fusarium crown and root rot (FCRR) has emerged as a highly destructive soil-borne disease, posing a significant threat to the safe cultivation of tomatoes in recent years. The pathogen of tomato FCRR is Fusarium oxysporum f. sp. radicis-lycopersici (Forl). To explore potential phytotoxins from Forl, eight undescribed diterpenoids namely fusariumic acids A-H (1-8) were isolated. Their structures were elucidated by using spectroscopic data analyses, quantum chemical calculations, and X-ray crystallography. Fusariumic acids A (1) and C-H (3-8) were typical isocassadiene-type diterpenoids, while fusariumic acid B (2) contained a cage-like structure with an unusual 7,8-seco-isocassadiene skeleton. A biosynthetic pathway of 2 was proposed. Fusariumic acids A (1) and C-H (3-8) were further assessed for their phytotoxic effects on tomato seedlings at 200 µg/mL. Among them, fusariumic acid F (6) exhibited the strongest inhibition against the hypocotyl and root elongation of tomato seedlings, with inhibitory rates of 61.3 and 45.3%, respectively.

Inhibition of Soluble Epoxide Hydrolase by Cembranoid Diterpenes from Soft Coral Sinularia maxima: Enzyme Kinetics, Molecular Docking, and Molecular Dynamics.

Soluble epoxide hydrolase (sEH) is essential for converting epoxy fatty acids, such as epoxyeicosatrienoic acids (EETs), into their dihydroxy forms. EETs play a crucial role in regulating blood pressure, mediating anti-inflammatory responses, and modulating pain, making sEH a key target for therapeutic interventions. Current research is increasingly focused on identifying sEH inhibitors from natural sources, particularly marine environments, which are rich in bioactive compounds due to their unique metabolic adaptations. In this study, the sEH inhibitory activities of ten cembranoid diterpenes (1-10) isolated from the soft coral Sinularia maxima were evaluated. Among them, compounds 3 and 9 exhibited considerable sEH inhibition, with IC50 values of 70.68 µM and 78.83 µM, respectively. Enzyme kinetics analysis revealed that these two active compounds inhibit sEH through a non-competitive mode. Additionally, in silico approaches, including molecular docking and molecular dynamics simulations, confirmed their stability and interactions with sEH, highlighting their potential as natural therapeutic agents for managing cardiovascular and inflammatory diseases.

Design, synthesis, and in vivo and in vitro biological screening of pseudolaric acid B derivatives as potential anti-tumor agents.

Pseudolaric Acid B (PAB), a natural product with remarkable anti-tumor activity, is a starting point for new anticancer therapeutics. We designed and synthesized 27 PAB derivatives and evaluated their anti-proliferative activities against four cancer cell lines: MCF-7, HCT-116, HepG2, and A549. Compared with unmodified PAB, the PAB derivatives showed stronger anti-proliferative activity. The ability of compound D3 (IC50 = 0.21 µM) to inhibit HCT-116 cells was approximately 5.3 times that of PAB (IC50 = 1.11 µM) and the antiproliferative action was unrelated to cytotoxicity (SI=20.38), indicating its superior safety profile (PAB; SI=0.95). Compound D3 effectively suppressed the EdU-positive rate and reduced colony formation, arrested HCT-116 cells in the S and G2/M phases and induced apoptosis. In vivo experiments further demonstrated low toxicity of compound D3 while suppressing tumor growth in mice. In summary, given its strong anti-proliferative effect and relative safety, further development of compound D3 is warranted.

Lathyrane diterpenoids with multidrug resistance reversal activity from the tubers of Euphorbia antiquorum.

Nine previously unreported lathyrane diterpenoids named euphorantesters A-I, along with 16 known analogues, have been separated from the tubers of Euphorbia antiquorum. Their structures were established by means of spectroscopic analyses, time-dependent density functional theory based electronic circular dichroism calculation and single crystal X-ray crystallography. Their reversal ability against P-glycoprotein-mediated multidrug resistance (MDR) in MCF-7/ADR cell line was then evaluated, and 15 ones exhibited moderate MDR reversal activity with reversal fold falling in the range of 1.12-13.15. The most active euphorantester B could effectively increase the sensitivity of MCF-7/ADR cell to adriamycin comparably to the reference drug verapamil.

Identification of diterpenoids from Salvia castanea Diels f. tomentosa Stib and their antitumor activities.

Four new diterpenoid tropolones, salvirrddones A-D (1-4), and four new icetexanes, salvirrddices A-D (9-12), along with thirteen new 11,12-seco-norabietane diterpenoids, salvirrddnor A-M (14-24, 31, 32) and sixteen known compounds (5-8, 13, 25-30, 33-37), were isolated from the roots and rhizomes of Salvia castanea Diels f. tomentosa Stib. Their structures were elucidated by comprehensive spectroscopic analyses, quantum chemical calculations, and X-ray crystallography. Structurally, compounds 1-8 represent a class of rare natural products featuring a unique cyclohepta-2,4,6-trienone moiety with diterpenoid skeletons. Bioassays showed that only diterpenoid tropolones 3, 5, 6, and 7 exhibited significant activity against several human cancer cell lines with IC50 values ranging from 3.01 to 11.63 µM. Additionally, 3 was shown to inhibit Hep3B cell proliferation, block the G0/G1 phase of the cell cycle, induce mitochondrial dysfunction and oxidative stress, promote apoptosis, as well as inhibit migration and invasion in vitro. Meanwhile, 3 demonstrated anti-proliferative, pro-apoptotic, and migration-inhibitory effects in the Hep3B xenograft zebrafish model in vivo. Network pharmacological analysis and molecular docking results suggested that 3 may treat hepatocellular carcinoma (HCC) through the PI3K-Akt signaling pathway, as well as by binding PARP1 and CDK2 targets. Overall, the present results extremely expand the repertoire of diterpenoids from natural products and may provide a novel chemical scaffold for the discovery of new antitumor drugs.

Identification of three novel P450 enzymes involved in the oxidative modification of a newly discovered fusicoccane diterpene.

Fusicoccane (FC)-type diterpenoids are a class of diterpenoids characterized by a unique 5-8-5 ring system and exhibit diverse biological activities. Recently, we identified a novel FC-type diterpene synthase MgMS, which produces a myrothec-15(17)-en-7-ol (1) hydrocarbon skeleton, however, its tailoring congeners have not been elucidated. Here, we discovered two additional gene clusters Bn and Np, each encoding a highly homologous terpene synthase to MgMS but distinct tailoring enzymes. Heterologous expression of the terpene synthases BnMS and NpMS yielded the same product as MgMS. Subsequent introduction of three P450 enzymes MgP450, BnP450 and NpP450 from individual gene clusters resulted in four new FC-type diterpenoids 2-5. Notably, MgP450 serves as the first enzyme responsible for hydroxylation of the C19 methyl group, whereas NpP450 functions as a multifunctional P450 enzyme involved in the oxidations at C5, C6, and C19 positions of the 5-8-5 tricyclic skeleton. C5 oxidation of the hydrocarbon skeleton 1 led to broadening of the NMR signals and incomplete spectra, which was resolved by high-temperature NMR spectral analysis.