Pyranonaphthoquinones (PNQs) are important structural scaffolds found in numerous natural products. Research interest in these specialized metabolites lies in their natural occurrence and therapeutic activities. Nonetheless, research progress has thus far been hindered by the lack of analytical standards and analytical methods for both qualitative and quantitative analysis. We report here that various parts of Ventilago harmandiana are rich sources of PNQs. We developed an ultraperformance liquid chromatography–electrospray ionization multiple reaction monitoring/mass spectrometry method to quantitatively determine six PNQs from leaves, root, bark, wood, and heartwood. The addition of standards in combination with a stable isotope of salicylic acid-D6 was used to overcome the matrix effect with average recovery of 82% ± 1% (n = 15). The highest concentration of the total PNQs was found in the root (11,902 μg/g dry weight), whereas the lowest concentration was found in the leaves (28 μg/g dry weight). Except for the root, PNQ-332 was found to be the major compound in all parts of V. harmandiana, accounting for ∼48% of the total PNQs quantified in this study. However, PNQ-318A was the most abundant PNQ in the root sample, accounting for 27% of the total PNQs. Finally, we provide novel MS/MS spectra of the PNQs at different collision induction energies: 10, 20, and 40 eV (POS and NEG). For structural elucidation purposes, we propose complete MS/MS fragmentation pathways of PNQs using MS/MS spectra at collision energies of 20 and 40 eV. The MS/MS spectra along with our discussion on structural elucidation of these PNQs should be very useful to the natural products community to further exploring PNQs in V. harmandiana and various other sources.

The combination of ion mobility mass spectrometry (IM-MS) and chromatography is a valuable tool for identifying compounds in natural products. In this study, using an ultra-performance liquid chromatography system coupled to a high-resolution quadrupole/traveling wave ion mobility spectrometry/time-of-flight MS (UPLC-TWIMS-QTOF), we have established and validated a comprehensive TWCCSN2 and MS database for 112 plant specialized metabolites. The database included 15 compounds that were isolated and purified in-house and are not commercially available. We obtained accurate m/z, retention times, fragment ions, and TWIMS-derived CCS (TWCCSN2) values for 207 adducts (ESI+ and ESI–). The database included novel 158 TWCCSN2 values from 79 specialized metabolites. In the presence of plant matrix, the CCS measurement was reproducible and robust. Finally, we demonstrated the application of the database to extend the metabolite coverage of Ventilago harmandiana Pierre. In addition to pyranonaphthoquinones, a group of known specialized metabolites in V. harmandiana, we identified flavonoids, xanthone, naphthofuran, and protocatechuic acid for the first time through targeted analysis. Interestingly, further investigation using IM-MS of unknown features suggested the presence of organonitrogen compounds and lipid and lipid-like molecules, which is also reported for the first time. Data are available on the MassIVE (, data set identifier MSV000090213).

The first phytochemical investigation of the leaves and twigs of Santisukia pagetii (Bignoniaceae) using a bioassay-guided fractionation led to the isolation and identification of seventeen known compounds, including four triterpenoids, 3-O-acetylpomolic acid (1), ursolic acid (2), 3-O-acetylursolic acid (3) and siaresinolic acid (4), three iridoid glycosides, specioside (5), verminoside (6) and ambiguuside (7), three flavonoid glycosides, luteolin-7-O-neohesperidoside (8), apigenin-7-O-neohesperidoside (9) and isoquercitrin (10), two phenolic compounds, p-coumaric acid (11) and caffeic acid (12), one monoterpenoid, (6S)-menthiafolic acid (13), together with α-D-glucose (14), β-D-maltose (15), β-sitosterol 3-O-β-D-glucopyranoside (16), a mixture of β-sitosterol (17A) and stigmasterol (17B). Compounds 113 were isolated from Santisukia genus for the first time. In addition, compounds 17, 9 and 10 were found to be active against HIV-1 in anti-syncytium assay, while only compounds 1 and 3 were found to be active (84.4% and 87.2% inhibition at 200 µg/mL, with IC 50 values of 290.96 and 210.34 µM, respectively) against HIV-1 reverse transcriptase. Moreover, anti-HIV-1 activities of compounds 1, 38, and 13 were reported for the first time.