Sesquiterpene lactones from Tithonia diversifolia with ferroptosis-inducing activities.

Eight previously undescribed sesquiterpene lactones (1-8), together with six known ones (9-14) were isolated from the aerial parts of Tithonia diversifolia (Hemsl.) A. Gray. The absolute configurations of these compounds were elucidated using HRMS, NMR spectroscopy, optical rotation measurements, X-ray crystallography, and ECD. Among them, sesquiterpene lactones 2-4 share a unique carbon skeleton with a rare C-3/C-4 ring-opened structure. Compounds 1 and 8 showed moderate inhibitory effects toward CT26 murine colon carcinoma cells by promoting lipid ROS production, highlighting their potential as ferroptosis inducers.

Novel Jatrophane Diterpenoids from Euphorbia esula Promotes Lipid Clearance by Transcriptional Regulation of PCSK9.

PCSK9 has been recognized as an efficient target for hyperlipidemia and related cardiovascular/cerebrovascular diseases. However, PCSK9 inhibitors in the clinic are all biological products, and no small molecules are available yet. In the current work, we discovered that the crude extract of Euphorbia esula (E. esula) promoted LDL uptake in vitro and then obtained 8 new and 12 known jatrophane diterpenoids by activity-guided isolation. After summarized their structure-activity relationship of PCSK9 inhibition, we selected compound 11 (C11) with potent activity and high abundance to investigate its mechanism and in vivo efficacy. Mechanistically, C11 bound with HNF1α to influence its nuclear distribution and subsequently inhibit PCSK9 transcription, thereby enhancing LDLR and promoting LDL uptake. Moreover, C11 demonstrated obvious lipid-lowering activity in HFD mouse model. In conclusion, we first revealed the novel application of E. esula in the discovery of a lipid-lowering candidate and highlighted the potential of C11 in the treatment of hyperlipidemia.

Haperforatones A-M, thirteen undescribed limonoids from Harrisonia perforata with anti-inflammatory activity.

UPLC-Q-TOF-MS combined with mass defect filtering strategies were applied for the phytochemical investigation of Harrisonia perforata, leading to the isolation of thirteen undescribed limonoids named haperforatones A-M (1-13) and seventeen known compounds (14-30). Particularly, haperforatones D-E (4-5) have an unprecedented A, B, C, D-seco-6, 7-nor-C-24-limonoid skeleton, structurally stripped of the five-membered lactone ring B and formed a double bond at the C-5 and C-10 positions. Their 2D structures and relative configurations were identified using spectroscopic data. The absolute configurations of 1, 4, and 6 were established via X-ray diffraction crystallography. All 30 compounds were evaluated for anti-inflammatory potential in LPS-induced Raw 264.7 cell lines. Among those tested compounds, the most potent activity against LPS-induced NO generation was demonstrated by haperforatone F (6), with the IC50 value of inhibition NO production of 7.2 µM. Additionally, 6 could significantly inhibit IL-1ß and IL-6 release and markedly downregulate the protein expression level of iNOS in the LPS-stimulated RAW264.7 cells at 10 µM. The possible mechanism of NO inhibition of 6 was also investigated using molecular docking, which revealed the interaction of compound 6 with the iNOS protein.

Amide alkaloids and neolignans from Piper hongkongense and their inhibitory activities of PCSK9 expression.

Four undescribed amide alkaloids hongkongensines A-C and 1-(1-oxo-6-hydroxy-2E,4E-dodecadienyl)-piperidine, five known amide alkaloids, and three known neolignans were isolated from the aerial part of Piper hongkongense. The planar structures of these compounds were determined by detailed analyses of HR-ESI-MS and NMR data. The absolute configurations of hongkongensines A-C were elucidated by single-crystal X-ray diffraction analysis and ECD calculations. Moreover, the inhibitory activities of PCSK9 expression in vitro for all compounds were assessed by PCSK9 AlphaLISA screening. Kadsurenone (10) displayed a significant inhibitory activity at 5 µM with an inhibition rate of 51.98%, compared with 55.55% of berberine (BBR 5 µM).

Dimeric ent-kauranoids isolated from Isodon japonica var. Glaucocalyx and their anti-inflammatory activities.

The phytochemical investigation of the aerial parts of Isodon japonica var. glaucocalyx afforded four undescribed (glaucocalyxin O-R, 1-4) and six known ent-kauranoids (5-10). Their structures were established using NMR and MS measurements. Compounds 1 and 2 are dimeric ent-kaurane-type diterpenoids. Moreover, the plausible biogenetic pathways for compounds 1 and 2 were proposed as Michael addition between two monomers. Eight compounds were assayed for their anti-inflammatory activity by evaluating NO production in LPS-induced RAW 267.4 cells, and compounds 7, 8 and 9 exhibited relatively remarkable anti-inflammatory activities at 10 µM.

Eighteen iridoids from the roots and rhizomes of Valeriana jatamansi and their protective effects against α-hemolysin.

Thirteen previously undescribed iridoids (1-13), together with five known iridoids (14-18) were isolated from the roots and rhizomes of Valeriana jatamansi Jones. Their structures with absolute configurations were elucidated by analysis of MS, NMR, optical rotation and their experimental and calculated electronic circular dichroism spectra. All of the isolated compounds were tested for their protective effects against α-hemolysin-induced cell death in A549 cells. Compounds 14, 16 and 17 showed moderate protective effects, and compounds 15 and 18 showed weak protective effects.

Lindenane sesquiterpenoid dimers from Chloranthus japonicus improve LDL uptake by regulating PCSK9 and LDLR.

UPLC-TOF-MS/MDF directed phytochemical research of Chloranthus japonicus led to the isolation of 46 lindenane sesquiterpenoid dimers, which included 13 new analogs. Their structures with absolute configurations were elucidated by analysis of spectroscopic data. Fourteen compounds with ester chains significantly decreased PCSK9 protein level in medium of HepG2 cells, especially for compounds 14 and 29 (5 µM) with inhibition rates of 69.0% and 72.8%, respectively. Compound 14 in HepG2 cells was evaluated via DiI-LDL uptake assays and found to increase LDL uptake by upregulating LDLR mRNA and protein level. Meanwhile, 14 decreased the secretion of PCSK9 protein in medium and downregulated intracellular PCSK9 protein and mRNA level. The discovery of these natural small molecule compounds provides a novel structure basis for design PCSK9 regulators, making them a promising lead for development of new lipid-lowering agents.