Semisynthesis and antitumor activity of endertiin B and related triterpenoids from Ganoderma lucidum.

Ganoderma lucidum, a fungus used in traditional Chinese medicine, is known for its medicinal value attributed to its active components called Ganoderma triterpenoids (GTs). However, the limited isolation rate of these GTs has hindered their potential as promising drug candidates. Therefore, it is imperative to achieve large-scale preparation of GTs. In this study, four GTs were effectively synthesised from lanosterol. The antitumor activity of these GTs was evaluated in vivo. Endertiin B exhibited potent inhibitory activity against breast cancer cells (9.85 ± 0.91 µM and 12.12 ± 0.95 µM). Further investigations demonstrated that endertiin B significantly upregulated p21 and p27 and downregulated cyclinD1 expression, arresting the cell cycle at the G0/G1 phase and inducing apoptosis by decreasing BCL-2 and increasing BAX and BAK levels. Additionally, endertiin B was found to reduce the expression of proteins associated with the PI3K-AKT signaling pathway. To summarize, endertiin B effectively inhibited cell proliferation by blocking the cell cycle and inducing apoptosis through the PI3K-AKT pathway.

Gut symbionts alleviate MASH through a secondary bile acid biosynthetic pathway.

The gut microbiota has been found to play an important role in the progression of metabolic dysfunction-associated steatohepatitis (MASH), but the mechanisms have not been established. Here, by developing a click-chemistry-based enrichment strategy, we identified several microbial-derived bile acids, including the previously uncharacterized 3-succinylated cholic acid (3-sucCA), which is negatively correlated with liver damage in patients with liver-tissue-biopsy-proven metabolic dysfunction-associated fatty liver disease (MAFLD). By screening human bacterial isolates, we identified Bacteroides uniformis strains as effective producers of 3-sucCA both in vitro and in vivo. By activity-based protein purification and identification, we identified an enzyme annotated as ß-lactamase in B. uniformis responsible for 3-sucCA biosynthesis. Furthermore, we found that 3-sucCA is a lumen-restricted metabolite and alleviates MASH by promoting the growth of Akkermansia muciniphila. Together, our data offer new insights into the gut microbiota-liver axis that may be leveraged to augment the management of MASH.

Design, syntheses and biological evaluation of natural product aiphanol derivatives and analogues: Discovery of potent anticancer agents.

The natural product aiphanol (1) is one of the substances with anticancer biological activity isolated from traditional Chinese medicines (TCM) Smilax glabra Roxb. (Tufuling). Our recent research found that aiphanol could suppress angiogenesis and tumor growth by dual-blocking VEGF/VEGFRs and COX2 signal pathway. In this study, four series of 40 aiphanol derivatives and analogues were designed, synthesized and evaluated for their anticancer activity. Among them, the analogues 10j and 14c exhibited the most potent inhibition and broad-spectrum antiproliferative activity toward nine tumor cell lines. The IC50 values of the analogues 10j and 14c range from 0.81 to 10 µmol/L which up to 80-fold vs. parent compound aiphanol. The structure-activity relationship (SAR) studies indicated that the substrate at 7-position of benzo 1,4-dioxane is very crucial for anticancer activity. Molecular docking indicated that the compound 14c (ent-14c) tightly binds to VEGFR2 and COX2, respectively. Therefore, compounds 10j and 14c could be promising candidates for the development of anticancer agents in the future.

Epidural Pulsation Accelerates the Drainage of Brain Interstitial Fluid.

Unhindered transportation of substances in the brain extracellular space (ECS) is essential for maintaining brain function. Regulation of transportation is a novel strategy for treating ECS blockage-related brain diseases, but few techniques have been developed to date. In this study, we established a novel approach for accelerating the drainage of brain interstitial fluid (ISF) in the ECS using minimally invasive surgery, in which a branch of the external carotid artery is separated and implanted epidurally (i.e., epidural arterial implantation [EAI]) to promote a pulsation effect on cerebrospinal fluid (CSF) in the frontoparietal region. Tracer-based magnetic resonance imaging was used to evaluate the changes in ISF drainage in rats 7 and 15 days post-EAI. The drainage of the traced ISF from the caudate nucleus to ipsilateral cortex was significantly accelerated by EAI. Significant increases in the volume fraction of the ECS and molecular diffusion rate were demonstrated using the DECS-mapping technique, which may account for the mechanisms underlying the changes in brain ISF. This study provides a novel perspective for encephalopathy treatment via the brain ECS.

Aiphanol, a multi-targeting stilbenolignan, potently suppresses mouse lymphangiogenesis and lymphatic metastasis.

The high incidence of lymphatic metastasis is closely related to poor prognosis and mortality in cancers. Potent inhibitors to prevent pathological lymphangiogenesis and lymphatic spread are urgently needed. The VEGF-C-VEGFR3 pathway plays a vital role in driving lymphangiogenesis and lymph node metastasis. In addition, COX2 in tumor cells and tumor-associated macrophages (TAMs) facilitates lymphangiogenesis. We recently reported that aiphanol, a natural stilbenolignan, attenuates tumor angiogenesis by repressing VEGFR2 and COX2. In this study, we evaluated the antilymphangiogenic and antimetastatic potency of aiphanol using in vitro, ex vivo and in vivo systems. We first demonstrated that aiphanol directly bound to VEGFR3 and blocked its kinase activity with an half-maximal inhibitory concentration (IC50) value of 0.29 µM in an in vitro ADP-GloTM kinase assay. Furthermore, we showed that aiphanol (7.5-30 µM) dose-dependently counteracted VEGF-C-induced proliferation, migration and tubular formation of lymphatic endothelial cells (LECs), which was further verified in vivo. VEGFR3 knockdown markedly mitigated the inhibitory potency of aiphanol on lymphangiogenesis. In 4T1-luc breast tumor-bearing mice, oral administration of aiphanol (5 and 30 mg· kg-1 ·d-1) dose-dependently decreased lymphatic metastasis and prolonged survival time, which was associated with impaired lymphangiogenesis, angiogenesis and, interestingly, macrophage infiltration. In addition, we found that aiphanol decreased the COX2-dependent secretion of PGE2 and VEGF-C from tumor cells and macrophages. These results demonstrate that aiphanol is an appealing agent for preventing lymphangiogenesis and lymphatic dissemination by synergistically targeting VEGFR3 and inhibiting the COX2-PGE2-VEGF-C signaling axis.

A multi-targeting natural product, aiphanol, inhibits tumor growth and metastasis.

Cancer is one of the main causes of death in humans worldwide, the development of more effective anticancer drugs that can inhibit the malignant progression of cancer cells is of great significance. Aiphanol is a natural product identified from the seeds of Arecaceae and the rhizome of Smilax glabra Roxb. Our preliminary studies revealed that it had potential antiangiogenic and antilymphangiogenic activity by directly targeting VEGFR2/3 and COX2 in endothelial cells. However, the influence of aiphanol on cancer cells per se remains largely undefined. In this study, the effects and related mechanisms of aiphanol on cancer growth and metastasis were evaluated in vitro and in vivo. Acute toxicity assay and pharmacokinetic analysis were utilized to investigate the safety profile and metabolism characteristics of aiphanol. We revealed that aiphanol inhibited the proliferation of various types of cancer cells and the growth of xenograft tumors in mice and zebrafish models. The possible mechanism was associated with the inactivation of multiple kinases, including FAK, AKT and ERK, and the upregulation of BAX and cleaved caspase-3 to promote cancer cell apoptosis. Aiphanol significantly inhibited cancer cell migration and invasion, which was related to the inhibition of epithelial-mesenchymal transition (EMT) and F-actin aggregation. Aiphanol effectively attenuated the metastasis of several types of cancer cells in vivo. In addition, aiphanol exerted no significant toxicity and had fast metabolism. Collectively, we demonstrated the anticancer effects of aiphanol and suggested that aiphanol has potential as a safe and effective therapeutic agent to treat cancer.

Natural product incarvillateine aggravates epileptic seizures by inhibiting GABAA currents.

A natural monoterpene alkaloid incarvillateine isolated from the plant Incarvillea sinensis is known to relieve inflammatory and neuropathic pain. However, the molecular target for the action of incarvillateine remains elusive. Here, we report that incarvillateine exacerbates epileptic seizures by inhibiting subtypes of γ-Aminobutyric acid type A (GABAA) receptors. Two-electrode voltage clamp recordings of α1ß3γ2, α2ß3γ2, α3ß3γ2 and α5ß3γ2 subtypes expressed in Xenopus oocytes revealed that incarvillateine inhibited the GABAA currents with IC50 of 25.1 µM, 43.1 µM, 105.1 µM and 93.7 µM, respectively. Whole-cell patch clamp recordings of hippocampal slices confirmed that incarvillateine inhibited spontaneous inhibitory postsynaptic currents (IPSCs), and miniature IPSCs and tonic currents. Moreover, inhibition of GABAA currents and spontaneous IPSCs by incarvillateine persisted even in the presence of blockers of adenosine receptors. In addition, incarvillateine enhanced epileptic discharges induced by Mg2+-free artificial cerebrospinal fluid (ACSF) in hippocampal slices. Furthermore, intracerebral ventricular injections of incarvillateine increased the severity of seizures induced by kainic acid in a dose-dependent manner. Taken together, our data demonstrate that incarvillateine aggravates seizures by inhibition of GABAA currents and GABAergic synaptic transmissions.

Alterations of growth, antioxidant system and gene expression in Stylosanthes guianensis during Colletotrichum gloeosporioides infection.

Anthracnose caused by Colletotrichum gloeosporioides is one of the most destructive fungal diseases of many plants, including stylo (Stylosanthes spp.), which is an important tropical forage legume. Although C. gloeosporioides-caused anthracnose is the major constraint limiting the growth and yield of stylo, little information is available regarding the responses of stylo during the infection process of this pathogen. This study investigated the changes in growth, the antioxidant system and gene expression in stylo in response to C. gloeosporioides treatment. Negative effects of C. gloeosporioides were observed in inoculated stylo plants, as reflected by the formation of necrotic disease lesions and the decrease in shoot fresh weight. Reactive oxygen species (ROS) accumulation increased in stylo leaves during the C. gloeosporioides infection process. The activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione peroxidase (GPX) and glutathione reductase (GR), as well as the concentrations of the antioxidant compounds ascorbate (AsA) and glutathione (GSH), increased in leaves under C. gloeosporioides treatment. Furthermore, transcriptional analysis showed that the expression of stress response genes, including NADPH oxidase (Nox), thioredoxin (Thi), pathogenesis related genes (PR1 and PR5), phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), chalcone synthase (CHS) and chitinase (Cht), was differentially enhanced in stylo leaves by C. gloeosporioides. Taken together, this study provides novel information regarding the alterations during the infection process of C. gloeosporioides in stylo at the levels of antioxidant system and gene expression.

Antinociceptive effects of incarvillateine, a monoterpene alkaloid from Incarvillea sinensis, and possible involvement of the adenosine system.

Incarvillea sinensis is a Bignoniaceae plant used to treat rheumatism and relieve pain in traditional Chinese medicine. As a major component of I. sinensis, incarvillateine has shown analgesic activity in mice formalin tests. Using a series of animal models, this study further evaluated the effects of incarvillateine against acute, inflammatory, and neuropathic pain. Incarvillateine (10 or 20 mg/kg, i.p.) dose-dependently attenuated acetic acid-induced writhing, but did not affect thermal threshold in the hot plate test. In a Complete Freund's Adjuvant model, incarvillateine inhibited both thermal hyperalgesia and paw edema, and increased interleukin-1ß levels. Additionally, incarvillateine attenuated mechanical allodynia induced by spared nerve injury or paclitaxel, whereas normal mechanical sensation was not affected. Incarvillateine did not affect locomotor activity and time on the rotarod at analgesic doses, and no tolerance was observed after 7 consecutive daily doses. Moreover, incarvillateine-induced antinociception was attenuated by theophylline, 1,3-dipropyl-8-cyclopentylxanthine, and 3,7-dimethyl-1-propargylxanthine, but not naloxone, indicating that the effects of incarvillateine on chronic pain were related to the adenosine system, but not opioid system. These results indicate that incarvillateine is a novel analgesic compound that is effective against inflammatory and neuropathic pain, and that its effects are associated with activation of the adenosine system.

Stereocontrolled and efficient total synthesis of (-)-stephanotic acid methyl ester and (-)-celogentin C.

A highly stereocontrolled and efficient total synthesis of (-)-stephanotic acid methyl ester and (-)-celogentin C was accomplished in longest linear 14 steps (4.6% overall yield) and in 20 steps (1.6% overall yield) from l-tryptophan, respectively. Highlights of the synthesis include a tandem asymmetric Michael addition/bromination/azidation strategy for a ready access to the leucine-tryptophan moiety (Leu-Trp linkage) and an oxidative coupling reaction to form the indole-imidazole linkage.

Synthesis of DEFG ring of complestatin and chloropeptin I: highly atropdiastereoselective macrocyclization by intramolecular Suzuki-Miyaura reaction.

Palladium-catalyzed intramolecular Suzuki-Miyaura reaction of linear tripeptide (23) afforded the 16-membered DEFG ring of complestatin (3) in good yield with an excellent atropdiastereoselectivity. Acidic treatment of 3 triggers a stereospecific rearrangement leading to the corresponding DEFG ring 4 of chloropeptin I.