Targeting the PD-1/PD-L1 axis with small-molecular inhibitors is a promising approach for immunotherapy. Here, we identify a natural pentacyclic triterpenoid, Pygenic Acid A (PA), as a PD-1 signaling inhibitor. PA exerts anti-tumor activity in hPD-1 knock-in C57BL/6 mice and enhances effector functions of T cells to promote immune responses by disrupting the PD-1 signaling transduction.
View Article and Find Full Text PDFThree undescribed hybrid flavan-chalcones, caesalpinflavans D-F, and an unreported normonoterpene-chalcone heterodimer, caesalpinnone B, along with three known biflavonoids were isolated from the twigs and leaves of Caesalpinia digyna. Their structures were elucidated based on extensive spectroscopic analysis and quantum chemical calculations. Caesalpinflavan F was identified as a bis-(hybrid flavan-chalcone), its natural occurrence was supported by HPLC-IT-TOF-MS analysis.
View Article and Find Full Text PDFTwo undescribed eudesmane-type sesquiterpenoids together with four known compounds were isolated from Clonostachys sp. Y6-1 associated. Their chemical structures were unambiguously determined by NMR, mass spectrometry, and C-NMR calculation as well as DP4+ probability analyses.
View Article and Find Full Text PDFThree new lanostane triterpenoids () along with two new amides fatty compounds () were isolated from the ethyl acetate extract of a culture of the endophytic fungus gx-2. Their structures were identified by 1D and 2D NMR spectral data and HRESIMS. Compounds were evaluated for their anti-inflammatory and tyrosinase inhibition activities.
View Article and Find Full Text PDFTwo new compounds, including a norsesquiterpenoid, annuionone H (), and a quassinoid, picraqualide G (), along with eleven known compounds (), were isolated from the twigs and leaves of . Comprehensive spectroscopic analyses and NMR calculation with DP4+ analysis were used to identify their structures. Moreover, of all these compounds, compound showed a week inhibition rate in the anti-inflammatory screening results against mouse macrophage J774A.
View Article and Find Full Text PDFTwo new compounds verboncin A () and verboncin B () and 14 known compounds ( and ) were isolated from , and these 14 compounds were first obtained from this plant. Their chemical structures were established by one and two-dimensional NMR and HRESIMS analysis and the results were compared with literature values. The absolute configuration of was determined by calculating electronic circular dichroism (ECD).
View Article and Find Full Text PDFTwo new C-benzylated chalcones, 2',4'-dihydroxy-3'-(2-hydroxylbenzyl) chalcone (1) and 2',4'-dihydroxy-5'-(2-hydroxybenzyl) chalcone (2), one new and one known mimosin-type homoisoflavonoid, mimosol H (7) and mimosol G (8), together with four known chalcones (3-6) and four known sappanin-type homoisoflavonoids (9-12), were isolated from the twigs and leaves of Caesalpinia digyna. Their structures were characterized by comprehensive spectroscopic analyses (including NMR and HRESIMS). Compounds 1, 2 and 8 exhibited moderate cytotoxicity against SMMC-7721, A-549 and/or MDA-MB-231 cell lines with IC values ranging from 11.
View Article and Find Full Text PDFFour previously undescribed erythrinan alkaloids, 8α-acetonylerythristemine, 8α-acetonylerysotrine, 10β-hydroxy-11β-methoxyerysotramidine and 3-epierysotrine, one undescribed pyrrolidine derivative, S-1-(4-hydroxy-3-methoxyphenethyl)-5-hydroxy pyrrolidin-2-one, and one undescribed amide, N-(3-hydroxy-4-methoxyphenethyl)-4-hydroxylbutanamide, along with thirteen known alkaloids were isolated from the stem barks of Erythrina strica Roxb. (Leguminosae). Their structures were identified by extensive analysis of physical, spectroscopic and spectrometric data.
View Article and Find Full Text PDFTwo new cassane ditepenoid lactams, caesmimotam A (1) and B (2), along with eight known compounds (3-10) were isolated from the fruits of Caesalpinia mimosoides Lam. Their structures were identified by 1D and 2D NMR spectral data. Compounds 1 and 2 were evaluated for their cytotoxicity on HL-60, SMMC-7721, A-549, MCF-7 and SW-480 human cancer cell lines, but they were inactive.
View Article and Find Full Text PDF