Hainanxylogranolides A-F: New Limonoids isolated from the seeds of Hainan mangrove plant Xylocarpus granatum.

Six new limonoids, named hainanxylogranolides A-F (1-6), together with nineteen known ones (7-25) were isolated from the seeds of a Hainan mangrove Xylocarpus granatum. The structures of the new compounds were established by extensive NMR spectroscopic data combined with the DFT and TDDFT calculated electronic circular dichroism spectra. Hainanxylogranolide A (1) is the aromatic B-ring limonoid containing a central pyridine ring and a C-17 substituted γ(21)-hydroxybutenolide moiety. Hainanxylogranolide B (2) belongs to the small group of mexicanolides containing a C3-O-C8 bridge, whereas hainanxylogranolides C and D (3 and 4) are mexicanolides comprising a C1-O-C8 bridge. Compounds 9 and 25 posed obvious inhibition effect on the tube formation of HUVECs. There are only about 25% tube-like structures were observed at the concentration of 40.0 µM of compound 25. The antiviral activities of the isolates against herpes simplex virus-1 (HSV-1) and severe fever with thrombocytopenia syndrome virus (SFTSV) were tested in vitro. Compound 23 exhibited moderate anti-SFTSV activity with the IC50 value of 29.58 ± 0.73 µM. This is the first report of anti-angiogenic effect and anti-SFTSV activity of limonoids from the genus Xylocarpus.

Bismuth chelate as a contrast agent for X-ray computed tomography.

BACKGROUNDS: Due to the unexpected side effects of the iodinated contrast agents, novel contrast agents for X-ray computed tomography (CT) imaging are urgently needed. Nanoparticles made by heavy metal elements are often employed, such as gold and bismuth. These nanoparticles have the advantages of long in vivo circulation time and tumor targeted ability. However, due to the long residence time in vivo, these nanoparticles may bring unexpected toxicity and, the preparation methods of these nanoparticles are complicated and time-consuming. METHODS: In this investigation, a small molecular bismuth chelate using diethylenetriaminepentaacetic acid (DPTA) as the chelating agent was proposed to be an ideal CT contrast agent. RESULTS: The preparation method is easy and cost-effective. Moreover, the bismuth agent show better CT imaging for kidney than iohexol in the aspect of improved CT values. Up to 500 µM, the bismuth agent show negligible toxicity to L02 cells and negligible hemolysis. And, the bismuth agent did not induce detectable morphology changes to the main organs of the mice after intravenously repeated administration at a high dose of 250 mg/kg. The pharmacokinetics of the bismuth agent follows the first-order elimination kinetics and, it has a short half-life time of 0.602 h. The rapid clearance from the body promised its excellent biocompatibility. CONCLUSIONS: This bismuth agent may serve as a potential candidate for developing novel contrast agent for CT imaging in clinical applications.

Sasanquasaponin ΙΙΙ from Schima crenata Korth induces autophagy through Akt/mTOR/p70S6K pathway and promotes apoptosis in human melanoma A375 cells.

BACKGROUND: Melanoma is a high fatality skin cancer which lacks effective drugs. Sasanquasaponin, an important sort of constituents in theaceae, has been demonstrated to have potent anti-tumor effect in breast cancer and hepatocellular carcinoma. As a sasanquasaponin, we speculate that Sasanquasaponin III (SQS III) isolated from Schima crenata Korth may also have anti-tumor activity. PURPOSE: This study aims to investigate whether SQS III has anti-melanoma activity and examine the underlying mechanisms of SQS III against melanoma. METHODS/STUDY DESIGNS: The anti-proliferative effect of SQS III was assessed by cells viability assay. Annexin V-FITC/PI double staining assay was utilized for detection of apoptosis. Mitochondrial membrane potential and reactive oxygen species (ROS) production were detected using JC-1 and DCFH-DA assay, respectively. Autophagy was monitored using transmission electron microscopy (TEM) and GFP-LC3 transfection fluorescence analysis. Autophagosome-lysosome fusion and lysosomal degradation were determined using a GFP-LC3 & LAMP1 co-localization assay and DQ-BSA staining. Proteins related to apoptosis and autophagy were analyzed by Western blotting. RESULTS: Our results demonstrated that the SQS III exhibited potent anti-cancer activity in A375 cells by inducing both apoptosis and autophagy. In melanoma cells treated with SQS III, caspases were activated and PARP was cleaved, proving the occurrence of apoptosis. Mechanistic studies indicated that the pro-apoptosis activity of SQS III was mediated by death receptor pathway and mitochondrial dysfunction which was induced by ROS accumulation and reversed by the ROS inhibitor N-acetyl-cysteine (NAC). In addition to triggering apoptosis, SQS III may also cause autophagy in melanoma cells. Our results demonstrated that SQS III induced up-regulated expression of GFP-LC3, autophagosome-lysosomal fusion and lysosomal degradation. Additionally, the ROS accumulation was also involved in the activation of autophagy. Meanwhile, it was also found that after SQS III treatment, the expression of LC3-II was up-regulated and the AKT/mTOR signaling pathway was inhibited. The autophagy inhibitor 3-MA converted cytotoxicity and apoptosis of SQS III in A375 cells, which indicated that autophagy promoted the SQS III-induced apoptosis. CONCLUSION: SQS III showed potent anti-cancer activity by inducing apoptosis and autophagy, which provides insights into its possible use as a therapy for melanoma.

Acylphloroglucinol derivatives from the leaves of Syzygium samarangense and their cytotoxic activities.

Samarones A-D (1-4), four new acylphloroglucinol derivatives bearing a C17 alkyl side chain, along with five known analogues (5-9), were isolated from the leaves of Syzygium samarangense. Their structures were characterized on the basis of extensive spectroscopic methods including HR-ESI-MS/MS analysis. The cytotoxic activities of compounds 1-3 and 5-9 against HepG2 and MDA-MB-231 cells were also evaluated.

Fibroblast Activation Protein α Activated Tripeptide Bufadienolide Antitumor Prodrug with Reduced Cardiotoxicity.

Bufadienolides are the major pharmacologic constituents of traditional Chinese medicine Chan'su, which is frequently used clinically for cancer treatment in China. Motivated by reducing or avoiding the cardiac toxicity of bufadienolides, we have designed, synthesized, and evaluated the fibroblast activation protein α (FAPα) activated tripeptide arenobufagin prodrugs with the purpose of improving the safety of arenobufagin (a representative bufadienolide). Among these FAPα-activated prodrugs, 3f exhibited the best hydrolytic efficiency by recombinant human FAPα (rhFAPα) and was activated in tumors. The LD50 of 3f was 6.5-fold higher than that of arenobufagin. We also observed that there are nonapparent changes in echocardiography, pathological section of cardiac muscle, and the lactate dehydrogenase activities (LDH) in 3f-treatment tumor-bearing mice, even when the dose reached 3 times the amount of parent drug arenobufagin that was used. Compound 3f also exhibits significant antitumor activity in vitro and in vivo. The improved safety profile and favorable anticancer properties of 3f warrant further studies of the potential clinical implications. Our study suggests that FAPα prodrug strategy is an effective approach for successful increasing the therapeutic window of bufadienolides.