Four new xanthones and their cytotoxicity from the stems of Garcinia schomburgkiana.

Four new xanthones, named schomburgones C-F (1‒4), along with six known xanthones (5‒10) were isolated from the stems of Garcinia schomburgkiana. Their structures were determined by spectroscopic analysis especially 1D and 2D NMR spectroscopies. The isolated compounds were evaluated for their cytotoxicity against five human cancer cell lines. Furanoxanthones 4‒6 showed potent cytotoxicity against four cell lines (KB, HeLa S3, MCF-7 and Hep G2) with IC50 values in the range of 0.18‒9.95 µM.

Correction to: Two new xanthones from the roots of Cratoxylum cochinchinense and their cytotoxicity.

In the original publication of the article, figure 1 was published incorrectly. The correct version of figure 1 is provided below.

Two new xanthones from the roots of Cratoxylum cochinchinense and their cytotoxicity.

Two new xanthones namely cratochinone A (1) and cratochinone B (2), along with 16 known xanthones, were isolated from the roots of Cratoxylum cochinchinense. Their structures were characterized by spectroscopic methods, especially 1D and 2D NMR as well as comparison with those reported in the literature for known xanthones. All isolated compounds were evaluated for their cytotoxicity against five human cancer cell lines (KB, HeLa S-3, HT-29, MCF-7 and Hep G2 cell lines). Compounds 2, 5, and 7 showed significant cytotoxic effects against all cell lines with IC50 values in the range of 0.91-9.93 µM, while 10 exhibited cytotoxicity against the KB, HeLa S-3, and HT-29 cells with IC50 values of 7.39, 6.07, and 8.11 µM, respectively. Compound 12 exhibited cytotoxicity against both KB and HeLa S-3 cells with IC50 values of 7.28 and 9.84 µM.

Veluflavanones A-P, Cytotoxic Geranylated Flavanones from Dalbergia velutina Stems.

Sixteen new geranylated flavanones, named veluflavanones A-P (1-16), and a known analogue (17), were isolated from Dalbergia velutina. The chemical structures of 1-17, as well as their absolute configurations, were determined by spectroscopic analysis and experimental ECD data. All isolated compounds were tested for their cytotoxicity against five human cancer cell lines. Compound 9 showed cytotoxicity toward KB, HeLa S3, and MCF-7 cells with IC50 values of 9.9, 8.1, and 10.0 µM, respectively. In addition, compounds 10, 11, 14, and 16 exhibited selective cytotoxicity against HeLa S3 cells with IC50 values of 6.6-9.9 µM.

A sesquiterpenoid tropolone and 1,2,3,4-tetrahydronaphthalene derivatives from Olax imbricata roots.

The methanol extract of Olax imbricata roots afforded one new sesquiterpenoid tropolone and three new 1,2,3,4-tetrahydronaphthalene derivatives, olaximbrisides A-D (1-4). Their structures were determined by 1D and 2D NMR experiments in combination of HRESIMS. The relative configurations were assigned by the NOESY experiments. The absolute configurations were established by a combination of X-ray diffraction analysis and electronic circular dichroism (ECD) experiments. All isolated compounds were evaluated for their cytotoxic effects against some cancer cell lines. Among them, compound 1 exhibited the cytotoxicities against MCF-7, HepG2 and LU cell lines with IC50 values of 16.3, 34.3 and 8.0 µM, respectively.

Two new xanthones and cytotoxicity from the bark of Garcinia schomburgkiana.

Two new xanthone derivatives, named schomburgones A (1) and B (2), along with eight known compounds, including xanthones (3-8) and anthraquinones (9-10) were isolated from the bark of Garcinia schomburgkiana. Their structures were determined by spectroscopic analysis especially 1D and 2D NMR spectroscopies. All isolated compounds were evaluated for their cytotoxicity against five cancer cell lines (KB, HeLa S-3, HT-29, MCF-7 and HepG-2). Compounds 3-6 and 8 showed good cytotoxicity against all the five cancer cell lines with IC50 values in the range of 1.45-9.46 µM.

Calaxanthones A-C, three new xanthones from the roots of Calophyllum calaba and the cytotoxicity.

Three new xanthones, named calaxanthones A-C (1-3), along with 17 known xanthones (4-20) were isolated from the roots of Calophyllum calaba. Their structures were determined by spectroscopic analysis. All isolated compounds were evaluated for their cytotoxicity against five cancer cell lines (KB, HeLa S-3, HT-29, MCF-7 and HepG-2). Compound 3 showed potent cytotoxicity against all the five cancer cell lines with IC50 values in the range of 0.82-5.04 µM. Furthermore, compound 6 showed potent cytotoxicity against KB, HeLa S-3 and HepG2 cells with IC50 values of 7.06, 5.27 and 9.64 µM, respectively. Additionally, compound 7 showed potent cytotoxicity against KB cell with an IC50 value of 4.62 µM.

Xanthones and biphenyls from the stems of Garcinia cylindrocarpa and their cytotoxicity.

Six new compounds including four new xanthones, cylindroxanthones D-G (1-4), and two new biphenyls, cylindrobiphenyls A and B (5 and 6), were isolated from the stems of Garcinia cylindrocarpa together with 28 known compounds (7-34). The structures of the new compounds were established on the basis of extensive 1D and 2D NMR and HRESIMS spectroscopic analysis. Their cytotoxicity was evaluated against five human cancer cell lines including KB, HeLa S-3, MCF-7, Hep G2, and HT-29. Compound 23 showed strong cytotoxicity against KB, HeLa S-3, MCF-7, and Hep G2 cells with IC50 values in the range of 2.20-6.00 µM. Furthermore, compound 25 selectively exhibited good cytotoxicity against MCF-7 cells with IC50 value of 8.77 µM, while 31 showed good cytotoxicity against HT-29 cells with IC50 value of 9.18 µM.

Cytotoxic Flavones from the Stem Bark of Bougainvillea spectabilis Willd.

Five new flavones possessing a fully substituted A-ring with C-6 and C-8 methyl groups, bougainvinones I - M (1: -5: ), along with three known congeners, 2'-hydroxydemethoxymatteucinol (6: ), 5,7,3',4'-tetrahydroxy-3-methoxy-6,8-dimethylflavone (7: ) and 5,7,4'-trihydroxy-3-methoxy-6,8-dimethylflavone (8: ), were isolated from the EtOAc extract of the stem bark of Bougainvillea spectabilis. Their structures were established by means of spectroscopic data (ultraviolet, infrared, high-resolution electrospray ionization mass spectrometry, and one-dimensional and two-dimensional nuclear magnetic resonance) and single-crystal X-ray crystallographic analysis. The in vitro cytotoxicity of all isolated compounds against five cancer cell lines (KB, HeLa S-3, MCF-7, HT-29, and HepG2) was evaluated. Compound 5: showed promising cytotoxic activity against the KB and HeLa S-3 cell lines, with IC50 values of 7.44 and 6.68 µM. The other compounds exhibited moderate cytotoxicity against the KB cell line.

Identification of highly potent α-glucosidase inhibitory and antioxidant constituents from Zizyphus rugosa bark: enzyme kinetic and molecular docking studies with active metabolites.

CONTEXT: Previous studies have shown that extracts of Zizyphus rugosa Lam. (Rhamnaceae) bark contained phytoconstituents with antidiabetic potential to lower blood glucose levels in diabetic rats. However, there has been no report on the active compounds in this plant as potential antidiabetic inhibitors. OBJECTIVE: We evaluated the α-glucosidase inhibitory and antioxidant activities of Z. rugosa extract. Moreover, the active phytochemical constituents were isolated and characterized. MATERIALS AND METHODS: The α-glucosidase inhibition of crude ethanol extract obtained from the bark of Z. rugosa was assayed as well as the antioxidant activity. Active compounds (1-6) were isolated, the structures were determined, and derivatives (2a-2 l) were prepared. All compounds were tested for their α-glucosidase inhibitory (yeast and rat intestine) and antioxidant (DPPH) activities. RESULTS: The active α-glucosidase inhibitors (1-6) were isolated from Z. rugosa bark and 12 derivatives (2a-2 l) were prepared. Compound 2 showed the most powerful yeast α-glucosidase inhibitory activity (IC50 16.3 µM), while compounds 3 and 4 display only weak inhibition toward rat intestinal α-glucosidase. Moreover, compound 6 showed the most potent antioxidant activity (IC50 42.8 µM). The molecular docking results highlighted the role of the carboxyl moiety of 2 for yeast α-glucosidase inhibition through H-bonding. DISCUSSION AND CONCLUSIONS: These results suggest the potential of Z. rugosa bark for future application in the treatment of diabetes and active compounds 1 and 2 have emerged as promising molecules for therapy.

A novel pyrrole alkaloid from the fruit peels of Strychnos nux-blanda.

A novel pyrrole alkaloid, strychnuxin (1), along with five known compounds (2-6) was isolated from the fruit peels of Strychnos nux-blanda. The structures of all the isolated compounds (1-6) were fully characterised using spectroscopic data, as well as comparison with the previous literature data. Moreover, all isolated compounds were assessed for their α-glucosidase and acetylcholinesterase inhibitory activities.

Cytotoxicities of two new isoflavanes from the roots of Dalbergia velutina.

Two new isoflavanes, dalvelutinanes A (1) and B (2), along with three known isoflavanes (3-5) were isolated from the roots of Dalbergia velutina. Their chemical structures, including their absolute configurations, were determined by spectroscopic analysis (1D and 2D NMR, HRESIMS, and CD). All isolated compounds were evaluated for their in vitro cytotoxicities against five human cancer cell lines (KB, HeLa-S3, MCF-7, HepG-2, and HT-29). Compound 5 showed significant cytotoxicity against all of the tested cancer cell lines, with IC50 values in the range 3.47-9.76 µM. In addition, compound 3 showed significant cytotoxicity against the KB and HeLa-S3 cells, with IC50 values of 8.29 and 9.54 µM, respectively, and compound 2 showed significant cytotoxicity against the MCF-7 cell line, with an IC50 value of 4.69 µM.

A New Non-glucosidic Iridoid from the Roots of Strychnos nux-blanda.

Strychnuxin (1), a new non-glucosidic iridoid, together with four known compounds, IX (2), loganetin (3), loganin (4) and sweroside (5), were isolated from the roots of Strychnos nux-blanda. The structures of all isolated compounds (1-5) were elucidated through their physical properties and by the use of spectroscopic methods, as well as comparisons with the previous literature. To the best of our knowledge, this is the first isolation of compounds 1-5 from this plant. All isolated compounds were evaluated for their in vitro cytotoxicity against five human cancer cell lines.

New depsidones and xanthone from the roots of Garcinia schomburgkiana.

Two new depsidones, schomburgdepsidones A and B (1 and 2), and one new xanthone, schomburgxanthone A (3), together with eight known compounds (4-11) were isolated from the roots of Garcinia schomburgkiana. Their chemical structures were established on the basis of spectroscopic analysis. The in vitro cytotoxicity of all 11 compounds was evaluated against the KB, HeLa S-3, HT-29, MCF-7 and Hep G2 human cancer cell lines. Compound 7 performed a good cytotoxicity against the KB, Hela S-3 and MCF-7 cell lines with IC50 values in the range of 3.17-6.07µM. Compound 3 exhibited a good cytotoxicity against the KB cell line only, with an IC50 value of 8.14µM.

A New Coumarin from the Stems of Pterocarpus indicus.

The chemical investigation of the crude ethyl acetate extract from Pterocarpus indicus stems led to isolation of a new coumarin, indicusane (1), together with eleven known compounds (2-12). To the best of our knowledge, all isolated coumarins (1-12) are reported for the first time from this plant. Their structures were identified on the basic of spectroscopic data (NMR, MS and ECD) as well as a chemical reaction (Mosher's method). In addition, all isolates were also evaluated for their cholinesterase (ChEs) inhibitory activities, in which only compound 4 exhibited the moderate activity toward AChE and BChE.

Dalvelutinoside, a new isoflavone glycoside from the methanol extract of Dalbergia velutina roots.

A new isoflavone glycoside, dalvelutinoside (1), together with one known isoflavone (2) and five known isoflavone glycosides (3-7) were isolated from the methanol extract of the roots of Dalbergia velutina. Their structures were determined by spectroscopic analysis. All isolated compounds were evaluated for their cytotoxicity against KB and HeLa cell lines.

Cylindroxanthones A-C, three new xanthones and their cytotoxicity from the stem bark of Garcinia cylindrocarpa.

Three new xanthones, cylindroxanthones A-C (1-3), were isolated from the stem bark of Garcinia cylindrocarpa. The structures were established on the basis of spectroscopic analysis. The molecular structure of 1 was unequivocally confirmed by single-crystal X-ray diffraction analysis. These three xanthones were evaluated regarding their cytotoxicity against KB, HeLa S-3, HT-29, MCF-7, and Hep G2 cancer cell lines. Compound 1 exhibited good cytotoxicity against KB cell with IC50 value of 2.36 µM.

Velucarpins A-C, three new pterocarpans and their cytotoxicity from the roots of Dalbergia velutina.

Three new pterocarpans, named velucarpins A-C (1-3), along with three known pterocarpans (4-6) were isolated from the roots of Dalbergia velutina. Their structures were determined by spectroscopic analysis. All isolated compounds were evaluated for their cytotoxicity against KB and HeLa cell lines. Compounds 3 and 5 showed good cytotoxicity against KB and HeLa cells with IC50 values of 8.22, 8.09 µM and 5.99, 8.69 µM, respectively.

Chemical constituents and derivatization of melodorinol from the roots of Melodorum fruticosum.

Chemical investigation of the CH2Cl2 and MeOH crude extracts of the roots of Melodorum fruticosum Lour. led to the isolation of 15 known compounds, of which 5, 10, and 12-15 are reported for the first time from this plant. In addition, melodorinol (7) was derivatized to afford six new (7a-7d and 7f-7g) analogues and one known compound (7e). Their structures were identified on the basic of spectroscopic data Most of them were evaluated for their cytotoxicity against KB, HeLa, MCF-7 and HepG-2 cell lines. Compounds 4 and 7b were the most potent to all cell lines.

Kaennacowanols A-C, three new xanthones and their cytotoxicity from the roots of Garcinia cowa.

Three new xanthones, named kaennacowanols A-C (1-3), along with nineteen known xanthones were isolated from the roots of Garcinia cowa Roxb. Their structures were determined by spectroscopic analysis. All isolated compounds were evaluated for their cytotoxicity against KB and HeLa cell lines. Compounds 17 and 22 showed good cytotoxicity against KB cell with IC50 values of 7.97 and 9.10µM, respectively. On the other hand, compound 15 showed good cytotoxicity against HeLa cell with IC50 value of 9.34µM.