A new benzoquinone and a new stilbenoid from Paphiopedilum exul (Ridl.) Rolfe.

One new alkyl benzoquinone, paphionone (1), one new trans-stilbenoid, (E)-6,5'-dihydroxy-2,3'-dimethoxystilbene (2), and eight known stilbenoids and flavonoids (3-10) were isolated from the leaves and roots of Paphiopedilum exul (Orchidaceae). Their chemical structures were determined based on IR, ECD, MS and NMR analyses. Cytotoxicity of all isolated compounds towards human hepatocellular carcinoma (HepG2) cell line was examined in vitro by MTT assay. The para-hydroxybenzyl substituted stilbene 10 was potently cytotoxic to the cancer cells, with an IC50 value of 4.80 ± 1.10 µM (selectivity index = 20.83). All compounds were non-toxic to normal human embryo fibroblast (OUMS-36) cell line.

Cytotoxic Polyprenylated Benzoylphloroglucinol Derivatives from the Branches of Garcinia schomburgkiana.

Five undescribed polyprenylated benzoylphloroglucinol derivatives (1:  - 5: ), named garschomcinols A - E, and five known analogues (6:  - 10: ) were isolated from the branches of Garcinia schomburgkiana. Their structures were determined on the basis of 1D and 2D NMR and HRESIMS analyses. The absolute configuration of the bicyclo [3.3.1]nonane core structure of the polyprenylated benzoylphloroglucinols was assigned by comparison of its experimental electronic circular dichroism data with that of related compounds. All isolated compounds were evaluated for their cytotoxicity in vitro against five cancer cell lines. Compound 6: showed potent cytotoxicity against five cancer cell lines including KB, HeLa S3, HT-29, MCF-7, and Hep G2 with IC50 values in the range of 5.05 - 7.03 µM.

Antidiabetic, cytotoxic and antioxidant activities of Rhodomyrtus tomentosa leaf extracts.

As part of our project on exploring Indonesian medicinal plants for antidiabetic and anticancer agents, this study was conducted to investigate the total phenolic and flavonoid contents, and antioxidant, cytotoxic and antidiabetic properties of R. tomentosa leaf extracts. The antioxidant activity was tested using DPPH, ABTS, and FRAP methods. In vitro cytotoxic assay was performed against MCF-7, HeLa, A549, and B16 cancer cell lines. The in vitro antidiabetic testing was determined using α-glucosidase and α-amylase inhibitory evaluation, while STZ-induced diabetic rats were used for in vivo study. The highest values of total phenolic (191.97 ± 0.19 mg GAE g-1) and flavonoid (29.11 ± 0.05 mg QE g-1) contents were recorded in methanolic extract. This extract also showed the highest DPPH and ABTS activities with IC50 values of 7.79 ± 0.03 and 4.03 ± 0.02 µg mL-1, respectively, as well as the highest FRAP activity with a value of 64.05 ± 0.54 µM Fe2+ g-1. The methanol extract had cytotoxicity against MCF-7, HeLa, A549, and B16 cancer cell lines with IC50 values of 123.49 ± 0.79, 28.28 ± 0.17, 168.88 ± 1.14, and 42.44 ± 0.18 µg mL-1, respectively. In vitro antidiabetic evaluation indicated that the MeOH extract inhibited α-glucosidase and α-amylase with IC50 values of 45.73 ± 1.06 and 41.31 ± 1.12 µg mL-1, respectively. A dose of 400 mg kg-1 body weight of the MeOH extract reduced rats' blood glucose rate and serum blood glucose by 48.51% and 17.73%, respectively after 15 days of treatment. Taken together, these findings suggested that the methanolic extract of R. tomentosa leaves can be used as a potential source of antioxidant, cytotoxic, and antidiabetic agents.

Evaluation of the Antioxidant, Antidiabetic, and Antiplasmodial Activities of Xanthones Isolated from Garcinia forbesii and Their In Silico Studies.

This study aimed to isolate xanthones from Garcinia forbesii and evaluated their activity in vitro and in silico. The isolated compounds were evaluated for their antioxidant activity by DPPH, ABTS and FRAP methods. The antidiabetic activity was performed against α-glucosidase and α-amylase enzymes. The antiplasmodial activity was evaluated using Plasmodium falciparum strain 3D7 sensitive to chloroquine. Molecular docking analysis on the human lysosomal acid-alpha-glucosidase enzyme (5NN8) and P. falciparum lactate dehydrogenase enzyme (1CET) and prediction of ADMET for the active compound, were also studied. For the first time, lichexanthone (1), subelliptenone H (2), 12b-hydroxy-des-D-garcigerrin A (3), garciniaxanthone B (4) and garcigerin A (5) were isolated from the CH2Cl2 extract of the stem bark of G. forbesii. Four xanthones (Compounds 2-5) showed strong antioxidant activity. In vitro α-glucosidase test showed that Compounds 2 and 5 were more active than the others, while Compound 4 was the strongest against α-amylase enzymes. In vitro antiplasmodial evaluation revealed that Compounds 2 and 3 showed inhibitory activity on P. falciparum. Molecular docking studies confirmed in vitro activity. ADMET predictions suggested that Compounds 1-5 were potential candidates for oral drugs. The isolated 2-5 can be used as promising phytotherapy in antidiabetic and antiplasmodial treatment.

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.

Velucarpin D, a new pterocarpan from the stems of Dalbergia velutina and its cytotoxicity.

A new pterocarpan, named velucarpin D (1), along with nine known pterocarpans (2-10) were isolated from the stems of Dalbergia velutina. Their structures were determined by spectroscopic analysis. All isolated compounds were evaluated for their cytotoxicity against five human cancer cell lines (KB, HeLa S-3, MCF-7, Hep G2, and HT-29). Compound 2 showed potent cytotoxicity against all the five human cancer cell lines with IC50 values in the range of 4.74-8.46 µM. In addition, compounds 1, 3, 4, 5 and 9 showed moderate cytotoxicity against both KB and HeLa S-3 cells with IC50 values in the range of 14.23-29.35 µM.

Tetrandraxanthones A-I, Prenylated and Geranylated Xanthones from the Stem Bark of Garcinia tetrandra.

Nine new xanthones, tetrandraxanthones A-I (1-9), and 22 known xanthones (10-31) were isolated from Garcinia tetrandra stem bark. The structures of 1-9 were characterized through detailed spectroscopic analysis, including HRESIMS and 2D NMR data. Among the compounds tested for their cytotoxicity, 26 showed significant cytotoxic effects against five human cancer cell lines, including MCF-7, HT-29, KB, Hep G2, and HeLa S3, with IC50 values in the range of 1.6-3.4 µM, while 10 and 11 were cytotoxic against the MCF-7, HeLa S3, and KB cell lines, with IC50 values of 4.3-9.0 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.

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.

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.

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.