Chemical constituents with cytotoxic and anti-inflammatoty activity in Hypericum sampsonii and the antitumor potential under the view of cancer-related inflammation.

Chronic inflammation has an important role in the development of cancers. Hypericum sampsonii, known as "Yuanbao Cao", is mainly distributed in the southwest of China. As a folk medicinal plant, "Yuanbao Cao" is traditionally used for treatment of various inflammation-related diseases including swelling, burns, arthritis, and dermatitis, etc. The plant is a promising anticancer herb. However, there is no research on the antitumor potential of this plant from the view of cancer-related inflammation strategy.To explore the H. sampsonii in relation to cancer-related chemical constituents with anti-inflammatory and cytotoxic activity in cancer-related inflammation.The chemical constituents of H. sampsonii were isolated by repeated chromatography techniques, and their structures were identified mainly by spectroscopic methods and compared to published data. The chemical profile of the herb was analyzed using HPLC. The cytotoxicities of compounds against five cancer cell lines: human melanoma cell (A375), human breast cancer cell (MDA-MB-231), human gastric cancer cell (SGC-7901), human colon cancer cell (SiHa), and human bone marrow neuroblastoma cell (SHSY-5Y), were tested using MTT assay; their anti-inflammatory activities were evaluated by inhibition on NO production in LPS-stimulated RAW 264.7, THP-1 and BV-2 microglial cells.

Twenty-five compounds, including four phenols (1-4), two anthraquinonoids (5 and 6), six xanthones (7-12), one benzophenone (13), one phloroglucinol (14), nine flavonoids (15-23), one sterol (24) and one alkaloid (25), were isolated from the EtOH extract of H. sampsonii. Of them, compounds 3, 4, 6, 7, 10-14, 17, 19, 22 and 23 were reported in H. sampsonii for the first time. HPLC analysis showed that flavonoids were the main constituents in the herb. MTT assay revealed that compounds 1, 2, 5-14, 15, 17, 18, 20, 21, 22 and 25 had selective cytotoxic activities (IC₅₀: 7.52-158.90 μM) against tested cancer cells, in which compound 5, 6, 13 and 14 displayed high activities against A375, MDA-MB-231, SiHa and SHSY-5Y. In the screening experiment of anti-inflammatory activity, most compounds (1-2, 5-23) showed considerable high anti-inflammatory activities (IC₅₀: 10.59-42.75 μM), in which compounds 5, 6, 13, 14, and 15 exhibited high anti-inflammatory activities in LPS-stimulated RAW264.7, THP-1 and BV-2 microglial cells.

Compounds 3, 4, 6, 7, 10-14, 17, 19, 22 and 23 were isolated for the first time from H. sampsonii. Compound 5, 6, 13 and 14 displayed high cytotoxic activities against the tested cancer cell lines. Compounds (1-2, 5-23) showed anti-inflammatory activities, of them, compounds 5, 6, 13, 14 and 15 exhibited the high activity. From the view of cancer-related inflammation point, not only the compounds with high cytotoxicity, but those compounds with anti-inflammatory activities, especially the flavonoids, contribute to the antitumor potential of H. sampsonii. The results and viewpoint of present study provide a different insight to better understand the antitumor potential of H. sampsonii, and may also promote the reasonable usage of this folk medical herb.