Discovery of Cytotoxic Nitric Oxide-Releasing Piperlongumine Derivatives Targeting Wnt/ß-Catenin in Colon Cancer Cells.

Piperlongumine (1) increases reactive oxygen species (ROS) levels and induces apoptosis in cancer cells through various pathways. Nitric oxide (NO) donors have demonstrated potent anticancer activities with exogenous NO being oxidized by ROS in the tumor microenvironment to form highly reactive N-oxides (RNOS). This amplifies oxidative stress cascade reactions, ultimately inducing cancer cell apoptosis. To exploit this synergy, a series of NO-releasing piperlongumine derivatives (2-5) were designed and synthesized. These compounds were expected to release NO in cancer cells, simultaneously generating piperlongumine derivative fragments to enhance the anticancer effects. Compound 6, structurally similar to compounds 2-5 but not releasing NO, served as a control. Among these derivatives, compound 5 exhibited the most potent antiproliferative activity against HCT-116 cells and efficiently released NO in this cell line. Further investigation revealed that compound 5 inhibited colon cancer cell proliferation by modulating ß-catenin expression, which is a pivotal protein in the Wnt/ß-catenin signaling pathway. These findings highlight compound 5 as a promising candidate for colon cancer treatment targeting the Wnt/ß-catenin pathway.

Eurochevalierines A-I, Sesquiterpene Alkaloid Hybrids with Anti-Triple Negative Breast Cancer Activity from Penicillium sp. HZ-5.

Nine new sesquiterpene alkaloids, eurochevalierines A-I (1-9), were separated from the rice cultures of the endophytic fungus Penicillium sp. HZ-5 originated from the fresh leaf of Hypericum wilsonii N. Robson. The structures' illumination was conducted by single-crystal X-ray diffraction, extensive spectroscopic analysis, alkaline hydrolysis reaction, and Snatzke's method. Importantly, the antitumor activities screen of these isolates indicated that 1 could suppress triple negative breast cancer (TNBC) cell proliferation and induce apoptosis, with an IC50 value of 5.4 µM, which is comparable to the positive control docetaxel (DXT). Flow cytometry experiments mentioned that compound 1 significantly reduced mitochondrial membrane potential (MMP) of TNBC cells. In addition, 1 could activate caspase-3 and elevated the levels of reactive oxygen species (ROS) and expressions of suppressive cytokines and chemokines. Further Western blot analysis showed that 1 could selectively induce mitochondria-dependent apoptosis in TNBC cells via the BAX/BCL-2 pathway. Remarkably, these finding provide a new natural product skeleton for the treatment of TNBC.

Spirohypertones A and B as potent antipsoriatics: Tumor necrosis factor-α inhibitors with unprecedented chemical architectures.

Tumor necrosis factor-α (TNF-α) is a promising target for inflammatory and autoimmune diseases. Spirohypertones A (1) and B (2), two unprecedented polycyclic polyprenylated acylphloroglucinols with highly rearranged skeletons, were isolated from Hypericum patulum. The structures of 1 and 2 were confirmed through comprehensive spectroscopic analysis, single-crystal X-ray diffraction and electronic circular dichroism calculations. Importantly, 2 showed remarkable TNF-α inhibitory activity, which could protect L929 cells from death induced by co-incubation with TNF-α and actinomycin D. It also demonstrated the ability to suppress the inflammatory response in HaCaT cells stimulated with TNF-α. Notably, in an imiquimod-induced psoriasis murine model, 2 restrained symptoms of epidermal hyperplasia associated with psoriasis, presenting anti-inflammatory and antiproliferative effects. This discovery positions 2 as a potent TNF-α inhibitor, providing a promising lead compound for developing an antipsoriatic agent.

Discovery of 23,24-diols containing ergosterols with anti-neuroinflammatory activity from Penicillium citrinum TJ507.

Citristerones A-E (1-5), five new 23,24-diols containing ergosterols, along with three known analogues, were isolated from the endophytic fungus Penicillium citrinum TJ507 obtained from Hypericum wilsonii N. Robson. Their structures and absolute configurations were determined by NMR, HRESIMS, Snatzke's method, X-ray diffraction analyses and ECD calculation. Subsequently, the anti-neuroinflammatory effects of these isolates were screened using lipopolysaccharide (LPS)-induced BV-2 microglial cells, and citristerone B (2) showed outstanding anti-neuroinflammatory activity, with IC50 value of 0.60 ± 0.04 µM. Moreover, immunofluorescence and western blot analysis suggested that citristerone B not only reduced the release of nitric oxide (NO) and proinflammatory cytokines in LPS-induced BV-2 microglial cells, but also significantly inhibited the expression of TNF-α, iNOS and NF-κB, along with the production of cellular ROS.

Patumantanes A-D, seco-Polycyclic Polyprenylated Acylphloroglucinols with Diverse Carbon Skeletons from Hypericum patulum.

Patumantanes A-D (1-4), four new seco-polycyclic polyprenylated acylphloroglucinols (PPAPs) were isolated from Hypericum patulum. Patumantane A (1) was an unprecedented 1,2-seco-homoadamantane-type PPAP bearing a new 3,7-dioxatetracyclo[7.7.0.01,6.111,15]heptadecane architecture based on a 6/7/5/6 ring system. Patumantane B (2) was a unique 1,9-seco-adamantane-type PPAP with a tricyclo[4.4.4.0.02,12]tridecane core formed by a 6/6/6 carbon skeleton, and the further breakage between C-5 and C-9 decorated patumantane C (3) with the 9-nor-adamantane skeleton. More importantly, compounds 2 and 3 exhibited moderate immunosuppressive activity on Con A-induced T-lymphocyte proliferation in vitro, with IC50 values of 5.6 ± 1.2 and 11.2 ± 1.2 µM, respectively.

Cryptic piperazine derivatives activated by knocking out the global regulator LaeA in Aspergillus flavipes.

Genome sequencing on an intertidal zone-derived Aspergillus flavipes strain revealed its great potential to produce secondary metabolites. To activate the cryptic compounds of A. flavipes, the global regulator flLaeA was knocked out, leading to substantial up-regulation of the expression of two NRPS-like biosynthetic gene clusters in the ΔflLaeA mutant. With a scaled-up fermentation of the ΔflLaeA strain, five compounds, including two previously undescribed piperazine derivatives flavipamides A and B (1 and 2), along with three known compounds (3-5), were obtained by LC-MS guided isolation. The new compounds were elucidated by spectroscopic analysis and electronic circular dichroism (ECD) calculations, and the biosynthetic pathway was proposed on the bias of bioinformatic analysis and 13C isotope labeling evidence. This is the first report to access cryptic fungi secondary metabolites by inactivating global regulator LaeA and may provide a new approach to discovering new secondary metabolites by such genetic manipulation.

Hyparillums A and B: polycyclic polyprenylated acylphloroglucinols from Hypericum patulum.

Hyparillums A (1) and B (2), two previously unidentified polycyclic polyprenylated acylphloroglucinols (PPAPs) with intricate architectures, were isolated from Hypericum patulum Thunb. Hyparillum A was the first PPAP with eight-carbon rings based on an unprecedented 6/6/5/6/6/5/6/4 octocyclic system featuring a rare heptacyclo[10.8.1.11,10.03,8.08,21.012,19.014,17]docosane core. In contrast, hyparillum B featured a novel heptacyclic architecture (6/6/5/6/6/5/5) based on a hexacyclo[9.6.1.11,9.03,7.07,18.011,16]nonadecane motif. Furthermore, hyparillums A and B demonstrated promising inhibitory effects on the proliferation of murine splenocytes stimulated by anti-CD3/anti-CD28 monoclonal antibodies and lipopolysaccharide, exhibiting half-maximal inhibitory concentration (IC50) values ranging from 6.13 ± 0.86 to 12.69 ± 1.31 µmol·L-1.

Hyperatins A-D, highly oxidized polycyclic polyprenylated acylphloroglucinols from Hypericum perforatum L. with hypoglycemic potential in liver cells.

Hyperatins A-D (1-4), four previously undescribed polycyclic polyprenylated acylphloroglucinols, were isolated from Hypericum perforatum L. (St. John's wort). Compound 1 possessed a unique octahydroindeno[1,7a-b]oxirene ring system with a rare 2,7-dioxabicyclo[2.2.1]heptane fragment. Compounds 2-4 had an uncommon decahydrospiro[furan-3,7'-indeno[7,1-bc]furan] ring system. Their structures were established by spectroscopic analyses and X-ray crystallography. Plausible biosynthetic pathways of 1-4 were also proposed. Compounds 1 and 2 exerted promising hypoglycemic activity by inhibiting glycogen synthase kinase 3 expression in liver cells.

Discovery of adamantane-type polycyclic polyprenylated acylphloroglucinols that can prevent concanavalin A-induced autoimmune hepatitis in mice.

Hyperadamans A-G (1-7), seven new adamantane type polycyclic polyprenylated acylphloroglucinols (PPAPs), were isolated from Hypericum wilsonii N. Robson. Structurally, 1-4 were the first adamantanes bearing an unusual 2,7-dioxabicyclo-[2.2.1]-heptane fragment, and compound 5 was the first adamantane with a rare 1,6-dioxaspiro[4.4]nonane section. Importantly, 1-7 exhibited significant immunosuppressive activity on Con A-induced T-lymphocyte proliferation in vitro, with IC50 values ranging from 3.97 ± 0.10 to 18.12 ± 1.07 µM. Pretreatment with 1 in Con A-challenged autoimmune hepatitis mice could dramatically ameliorate the levels of hepatic injury indexes (ALT and AST) and reduce the product of proinflammatory cytokines (COX-2, IL-6, IL-1ß, IL-18, IL-23A and TNF-α). Furthermore, the protective effect of 1 on the Con A-induced liver injury was corroborated by the histological analysis and the immunohistochemistry.

Maydistacins A-G, Terpestacin-type Sesterterpenoids with Anti-inflammatory Activity from the Phytopathogenic Fungus Bipolaris maydis.

Seven undescribed terpestacin-type sesterterpenoids, maydistacins A-G (1-7), along with two known congeners (8 and 9), were isolated from the phytopathogenic fungus Bipolaris maydis collected from the leaves of Hypericum longistylum. The structures of 1-7 were elucidated based on extensive spectroscopic analysis, chemical methods, NMR calculations with DP4+ probability analysis, and comparison of experimental and calculated electronic circular dichroism (ECD) calculations. In vitro anti-inflammatory effects of these compounds were tested in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Compound 1 exhibited inhibition of the production of nitric oxide in LPS-induced macrophages, with an IC50 value of 19 ± 2 µM. A dexamethasone control displayed an IC50 value of 6.7 ± 0.6 µM. Compound 1 is the first terpestacin-type sesterterpenoid reported to display anti-inflammatory activity and may provide a novel chemical scaffold for the discovery of new anti-inflammatory drugs.

Discovery of bioactive polycyclic polyprenylated acylphloroglucinols with adamantine/homoadamantane skeletons from Hypericum wilsonii.

In this work, nine previous undescribed polycyclic polyprenylated acylphloroglucinols with adamantine/homoadamantane skeletons, cumilcinols A-I (1-9), along with six known analogues, were isolated and identified from the stems, leaves and flowers of Hypericum wilsonii. Their structures were determined by HRESIMS, NMR spectroscopic analysis, single-crystal X-ray crystallography as well as electronic circular dichroism calculations and comparisons. Compound 2 formed a unique furan ring bearing a rare acetal functionality. In bioassays, hyperacmosin G (13) could significantly inhibit the production of NO in LPS-stimulated RAW264.7 cell (IC50 = 4.350 ± 1.146 µM), and increased expression of related transcription factors at the gene level, inhibit the nuclear translocation of NF-κBp65, and reduce the protein expression of COX-2. Additionally, compound 5 showed significant inhibitory activity on Con A-induced T-lymphocyte proliferation (IC50 = 4.803 ± 3.149 µM), and treatment of 5 could reduce the increased ratio of CD4 and CD8 subpopulations induced by Con A in vitro. Those results indicated 13 possesses potential anti-inflammatory activity, and 5 exhibits a certain degree of immunosuppressive activity.