Calotetrapterins A-C, three new pyranoxanthones and their cytotoxicity from the stem bark of Calophyllum tetrapterum Miq

Two new chromanone acids from the stem bark of Calophyllum peekelii Lauterb

Three chromanone acids were isolated from the stem bark of Calophyllum peekelii Lauterb. Among them are two new chromanone acids, calopeekelioic acids A (1) and B (2), along with calolongic acid (3), Their structures were established by analyzing a combination of HRESIMS, 1 D, and 2 D NMR spectra. Chromanone acids 1-3 were evaluated for their antiplasmodial activity against Plasmodium falciparum strain 3D7. Compounds 1-2 showed high activity with an IC50 value of 1.70 and 1.01 µg/mL, respectively.

Three novel quinolinone alkaloids from the leaves of Melicope denhamii

Three previously unreported quinolinone alkaloids: melicodenines J-L (1-3) and six known compounds (4-9), were isolated from the leaves of Melicope denhamii (Seem) T.G. Hartley. The structures of three quinolinone alkaloids were identified based on HRESIMS and NMR spectra. Compounds 1-9 were assayed in three cancer cells (MCF-7, HeLa, and P-388). Compounds 1 and 5 showed high cytotoxic activity against HeLa cells with IC₅₀ values of 1.8 and 0.8 µM, respectively.

A simple and practical solvent system selection strategy for high-speed countercurrent chromatography based on the HPLC polarity parameter model

The selection of an appropriate solvent system is the most crucial step in high-speed countercurrent chromatography (HSCCC) separation. The compound polarity plays an important role in HPLC analysis and HSCCC separation, and it can be calculated by the HPLC polarity parameter model and the average polarity of the HSCCC solvent system, respectively. However, flow rates, columns and methanol concentrations of the HPLC experiment can influence the calculation of the compound polarity. Therefore, the applicability and accuracy of the HPLC polarity parameter model still needed to be extensively validated. We chose 14 compounds to conduct the shake-flask experiments and HPLC analysis on, such as apigenin, honokiol, phloridzin and dihydromyricetin. The HPLC analysis results showed that different flow rates and columns have negligible effects on the calculated compound polarities. However, there was a certain variation trend in the calculated polarities with different methanol concentrations. Although the polarity values of some compounds showed a difference between the HPLC analysis and shake-flask experiments, their partition coefficients (K) in the HSCCC solvent systems were still located in the range of 0.5 < K < 2.0. Guided by the HPLC polarity parameter model, the appropriate HSCCC solvent systems for mangosteen peel and Hypericum sampsonii Hance were selected, and the two main components (mangostin and quercetin) were isolated from their extracts, respectively. The separation results showed that the predicted compound polarities were sufficient to meet the HSCCC separation requirements. Meanwhile, this method required only 1 to 2 HPLC analyses with reference compounds, greatly improved the efficiency of the HSCCC solvent system selection, and shortened the experimental time. The polarity parameter model was a fast and efficient analysis method for the selection of an appropriate HSCCC solvent system.

An Update on the Anticancer Activity of Xanthone Derivatives: A Review

The annual number of cancer deaths continues increasing every day; thus, it is urgent to search for and find active, selective, and efficient anticancer drugs as soon as possible. Among the available anticancer drugs, almost all of them contain heterocyclic moiety in their chemical structure. Xanthone is a heterocyclic compound with a dibenzo-γ-pyrone framework and well-known to have "privileged structures" for anticancer activities against several cancer cell lines. The wide anticancer activity of xanthones is produced by caspase activation, RNA binding, DNA cross-linking, as well as P-gp, kinase, aromatase, and topoisomerase inhibition. This anticancer activity depends on the type, number, and position of the attached functional groups in the xanthone skeleton. This review discusses the recent advances in the anticancer activity of xanthone derivatives, both from natural products isolation and synthesis methods, as the anticancer agent through in vitro, in vivo, and clinical assays.

Two new pyranoxanthones from the stem bark of Calophyllum pseudomolle P.F. Stevens

Two new pyranoxanthones, calotetrapterins D (1) and E (2), were isolated from the stem bark of Calophyllum pseudomolle P.F. Stevens along with α-mangostin (3). The structures of compounds 1-2 were determined based on 1D NMR (¹H, ¹³C) and 2D NMR (HMQC, HMBC), as well as HRESIMS spectroscopic analysis. Compounds 1-2 showed moderate activity against HeLa and murine leukaemia P-388 cells.