Euodia rutaecarpa is a common traditional Chinese medicine (TCM) in clinical practice, having the ability to suppress pain and cease coughing; however, with the increasing reports showing that it is toxic, particularly hepatotoxic, the concerns raised by what cause its toxicity is growing. In the current study, an analysis method based on the spectrum effect has been employed to screen the major hepatotoxic components in Euodia rutaecarpa so that the toxic material’s basis would be elucidated. A fingerprinting method of the Euodia rutaecarpa extracts (which were petroleum ether, chloroform, ethyl acetate, n-butanol, and water) using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometer (UHPLC-QTOF/MS) has been developed. Orthogonal partial least squares (OPLS) was used to establish the spectrum-toxicity relationship with the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in mice serum as evaluation indices for liver injury. The UHPLC-MS fingerprint was established and the OPLS analytical results suggested that coniferin, 1-methyl-2-undecyl-4(1H)-quinolone, 1-methyl-2-[(6Z,9Z,12E)-pentadeca triene]-4(1H)-quinolone, evocarpine, 1-methyl-2-[(Z)-7-tridecenyl]-4(1H)-quinolone, dihydroevocarpine, and 1-methyl-2-tetradecy-4-(1H)-quinolone probably associated with the hepatotoxicity of Euodia rutaecarpa. This paper offered considerable methods and insight for the fundamental research of the toxic material basis of similar toxic TCMs.

In this study, a combination of quadrupole time-of-flight mass spectrometry (Q-TOF-MS) and linear trap quadrupole orbitrap mass spectrometry (LTQ-Orbitrap-MS) was performed to investigate the fragmentation behaviors of prenylated flavonoids (PFs) from Artocarpus plants. Fifteen PFs were selected as the model molecules and divided into five types (groups A–E) according to their structural characteristics in terms of the position and existing form of prenyl substitution in the flavone skeleton. The LTQ-Orbitrap-MSⁿ spectra of the [M − H]⁻ ions for these compounds provided a wealth of structural information on the five different types of compounds. The main fragmentation pathways of group A were the ortho effect and retro Diels–Alder (RDA), and common losses of C₄H₁₀, CO, and CO₂. The compounds in group B easily lose C₆H₁₂, forming a stable structure of a 1,4-dienyl group, unlike those in group A. The fragmentation pathway for group C is characterized by obvious ^1,4A⁻, ^1,4B⁻ cracking of the C ring. The diagnostic fragmentation for group D is obvious RDA cracking of the C ring and the successive loss of CH₃ and H₂O in the LTQ-Orbitrap-MSⁿ spectra. Fragmentation with successive loss of CO or CO₂, ·CH₃, and CH₄ in the LTQ-Orbitrap-MSⁿ spectra formed the characteristics of group E. The summarized fragmentation rules were successfully exploited to identify PFs from Artocarpus heterophyllus, a well-known Artocarpus plant, which led to the identification of a total of 47 PFs in this plant.

In an effort to identify agents from natural products that inhibit protein tyrosine phosphatase 1B (PTP1B), 5 new prenylated stilbenes, (±)-styrastilbene A (1), styrastilbene B (2), and (±)-styrastilbenes C – E (3, 4, and 7), along with 4 known structurally related compounds (5, 6, 8, and 9), were isolated from the roots of Artocarpus styracifolius. Their structures were elucidated by spectroscopic methods, including 1D and 2D nuclear magnetic resonance (NMR), high-resolution electrospray ionization mass spectrometry (HRESIMS), ultraviolet (UV), and infrared (IR). Based on these isolates, a new plausible biosynthetic pathway for the unusual stilbene derivatives 3–8 with a tetracyclic ring system is proposed. Among these compounds, 1–3, 8, and 9 displayed significant PTP1B inhibitory effects with IC₅₀ values ranging from 2.40 (95% confidence interval [CI]: 2.21 – 2.59) to 8.80 (95% CI: 8.28 – 9.32) µM. Moreover, kinetic analysis and molecular docking simulations were performed to provide insight into the inhibition type as well as the interaction and binding mode of these active isolates with PTP1B. Our results revealed mixed-type PTP1B inhibition for all compounds tested. Docking simulations of these stilbene derivatives showed negative binding energies and close proximity to residues at the allosteric and catalytic sites of PTP1B. These findings suggest that these compounds may have a potential to be further developed as agents for the management of type 2 diabetes mellitus.

Nine compounds were isolated from leaves of Dendrobium officinale, including 1 new bibenzyl derivative, denofficin (1), and 8 known structurally related compounds, dendrocandin B (2), dendrocandin U (3), 3,4-dihydroxy-5,4′-dimethoxy bibenzyl (4), moscatilin (5), 4,4′-dihydroxy-3,5-dimethoxy bibenzyl (6), (S)-3,4,α-trihydroxy-5,4′-dimethoxy bibenzyl (7), gigantol (8), densiflorol A (9). The structures of these compounds were identified by spectroscopic methods. All isolated compounds were screened for their cytotoxicity against human cervical cancer cell line HeLa cells. Of them, compounds 1-3, 5, 6, and 8 were found to have the capabilities of proliferation inhibition against HeLa cells with half-maximal inhibitory concentration values ranging from 8.0 to 92.4 μM.