New Isoflavanes from Spatholobus suberectus and Their Cytotoxicity against Human Breast Cancer Cell Lines

The rattans of Spatholobus suberectus Dunn are a traditional Chinese medicine activating blood circulation and removing stasis. They have often been used for the traditional Chinese medicinal treatment of breast cancer in modern China. In this study, four novel isoflavanes (1–3 and 5) and four known analogues (4 and 6–8) were isolated from an ethanolic extract of the rattans of S. suberectus. Their structures were elucidated by extensive spectroscopic analyses and electronic circular dichroism studies. MCF-7 and MDA-MB-231 human breast cancer cell lines were used to evaluate the cytotoxic effects of the isolates. Interestingly, compounds 1 and 2 only inhibited the proliferation of MCF-7 cells, while compound 6 showed a selective cytotoxicity against MDA-MB-231 cells. However, compound 4 had significant cytotoxicity against both MCF-7 and MDA-MB-231 cell lines.

Two new 8-isopentenyl isoflavane derivatives from Astragalus dolichochaete diels

Astragali Radix (Huangqi) is one of the well-known traditional Chinese medicines and has been used in China for more than two thousand years. As a close species, Astragalus dolichochaete Diels was found to possess cytotoxicity during our preliminary study of Astragalus plants from Yunnan Province, China. To better understand the chemical foundation of the cytotoxicity, the major constituents of A. dolichochaete were studied. As a result, two new 8-isopentenyl isoflavane derivatives, dolichochaeteins A and B (1 and 2), together with ten known constituents were isolated, and their structures were elucidated by means of spectroscopy, mainly 1D and 2D NMR techniques. The cytotoxic activities were evaluated for the raw extract, ethyl acetate fraction, compound 2 and glyasperin H (3) against human gastric carcinoma cell line SGC-7901, human hepatoma cell line SMMC-7721 and human leukemic cell line K562. All the samples exhibited significant cytotoxicity.

Antiplasmodial Isoflavanes and Pterocarpans from Apoplanesia paniculata

Bioassay-guided fractionation of an EtOH extract of the roots of the plant Apoplanesia paniculata (Fabaceae) led to the isolation of the three known compounds amorphaquinone (1), pendulone (2), and melilotocarpan C (3), and the two new pterocarpans 4 and 5. Compounds 1 and 2 exhibited good antiplasmodial activity with IC50 values of 5.7 ± 1.5 and 7.0 ± 0.8 µM, respectively. Compound 3 exhibited weak antiplasmodial activity (41.8 ± 5.2 µM), while compounds 4 and 5 were inactive. Compound 6 was synthesized to confirm the structure of 5, and it showed enhanced antiplasmodial activity (15.8 ± 1.4 µM) compared to its analogues 3-5.