Euphejolkinolide A, a new ent-abietane lactone from Euphorbia peplus L. with promising biological activity in activating the autophagy-lysosomal pathway

TFEB activator tanshinone IIA and derivatives derived from Salvia miltiorrhiza Bge. Attenuate hepatic steatosis and insulin resistance

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia miltiorrhiza Bge. (SMB) is an herbal medicine extensively used for improving metabolic disorders, including Nonalcoholic fatty liver disease (NAFLD). However, the potential material basis and working mechanism still remained to be elucidated.

AIM OF THE STUDY

To find potential ingredients for therapy of NAFLD by high content screening and further verify the efficacy on restoring hepatic steatosis and insulin resistance, and clarify the potential working mechanism.

MATERIALS AND METHODS

The mouse transcription factor EB (Tfeb) in preadipocytes was knocked out by CRISPR-Cas9 gene editing. High content screening of TFEB nuclear translocation was performed to identify TFEB activators. The effect of candidate compounds on reducing lipid accumulation was evaluated using Caenorhabditis elegans (C. elegans). Then the role of Salvia miltiorrhiza extract (SMB) containing Tanshinone IIA and the derivatives were further investigated on high-fat diet (HFD) fed mice. RNA-seq was performed to explore potential molecular mechanism of SMB. Finally, the gut microbiota diversity was evaluated using 16S rRNA sequencing to investigate the protective role of SMB on regulating gut microbiota homeostasis.

RESULTS

Knockout of Tfeb led to excessive lipid accumulation in adipocytes while expression of TFEB homolog HLH-30 in C. elegans (MAH240) attenuated lipid deposition. Screening of TFEB activators identified multiple candidates from Salvia miltiorrhiza, all of them markedly induced lysosome biogenesis in HepG2 cells. One of the candidate compounds Tanshinone IIA significantly decreased lipid droplet deposition in HFD fed C. elegans. Administration of SMB on C57BL/6J mice via gastric irrigation at the dose of 15 g/kg/d markedly alleviated hepatic steatosis, restored serum lipid profile, and glucose tolerance. RNA-seq showed that gene expression profile was altered and the genes related to lipid metabolism were restored. The disordered microbiome was remodeled by SMB, Firmicutes and Actinobacteriotawere notably reduced, Bacteroidota and Verrucomicrobiota were significantly increased.

CONCLUSION

Taken together, the observations presented here help address the question concerning what were the main active ingredients in SMB for alleviating NAFLD, and established that targeting TFEB was key molecular basis for the efficacy of SMB.

Diterpenoids from Euphorbia peplus possessing cytotoxic and anti-inflammatory activities

Phytochemical investigation into the medium polar fraction of the ethanol extract of Euphorbia peplus led to the identification of 32 diterpenoids with five structural types. Compounds 1-5 and 7-11 are reported for the first time, while the configuration of 6,7-epoxy group of 6 was revised to be β-oriented. Compounds 1-5 feature a rare structural variation of the double bond at Δ1 migrating to Δ1(10) in the tigliane-type diterpenoid family. Biologically, compound 21 was found to be the only one to show moderate cytotoxic activity, associated with the presence of a benzoyloxy residue at C-16. Besides, compounds 4, 8, 12, 13, 16, and 19 show significant inhibitory activities against NO production induced by LPS in RAW264.7 macrophage cells, with IC50 values within 2-5 μM. Structure-activity relationship (SAR) analysis revealed that the ingenane-type diterpenoids have the best anti-inflammatory activity, and the esterification at 3-OH or 5-OH is crucial. Further biological researches demonstrated that 13, the predominant metabolite in this plant, exerts anti-inflammatory effects by blocking the activation of NF-κB and MAPK signaling pathways.

Corydecusines A-H, new phthalideisoquinoline hemicetal alkaloids from the bulbs of Corydalis decumbens inhibit Tau pathology by activating autophagy mediated by AMPK-ULK1 pathway

Twelve phthalideisoquinoline hemiacetal alkaloids including eight new ones (1-8) and one natural alkaloid characterized by an aziridine moiety with unassigned NMR data (9), were isolated and identified from the bulbs of Corydalis decumbens. Their structures were established by comprehensive analyses of HRESIMS, NMR, X-ray crystallography, and ECD analyses. The unambiguously established structures of the phthalideisoquinoline hemiacetal alkaloids indicated that the absolute configurations of C-1, C-9, and C-7' were confusable only relied on coupling constants. A summary of their ECD spectra was concluded and provided an insight for C-1, C-9, and C-7' absolute configuration assignment. These new compounds were evaluated to induce autophagy flux through flow cytometry analysis. Moreover, compounds 2 and 6 could significantly induce autophagy and inhibit Tau pathology by AMPK-ULK1 pathway activation, which provided an avenue for anti-AD lead compounds discovery.

Quassinoids from Twigs of Harrisonia perforata (Blanco) Merr and Their Anti-Parkinson's Disease Effect

Six new C-20 and one new C-19 quassinoids, named perforalactones F-L (1-7), were isolated from twigs of Harrisonia perforata. Spectroscopic and X-ray crystallographic experiments were conducted to identify their structures. Through oxidative degradation of perforalactone B to perforaqussin A, the biogenetic process from C-25 quassinoid to C-20 via Baeyer-Villiger oxidation was proposed. Furthermore, the study evaluated the anti-Parkinson's disease potential of these C-20 quassinoids for the first time on 6-OHDA-induced PC12 cells and a Drosophila Parkinson's disease model of PINK1B9. Perforalactones G and I (2 and 4) showed a 10-15% increase in cell viability of the model cells at 50 μM, while compounds 2 and 4 (100 μM) significantly improved the climbing ability of PINK1B9 flies and increased the dopamine level in the brains and ATP content in the thoraces of the flies.