Anti-metastatic and anti-allergic spirostanol saponins from Solanum macaonense and S. torvum

Twenty-five steroidal saponins isolated from Solanum macaonens (1-15) [1] and S. torvum (16-25) [2] were assayed for cytotoxicity, anti-metastatic, and anti-allergic activities. Spirostanols 1, 2, 5, and furostanol 10 have moderate cytotoxicities toward human lung (A549), breast (MCF-7), ovarian (SKOV3), colon (HCT116), prostate (DU145), and oral (Ca922) cancer cell lines (IC₅₀ 29.6 – 48.2µM). Spirostanols 1-5 and 7 showed inhibition against A549 cancer cell migrations at the concentration of 50µM, notably 1 and 2 that could remarkably suppressed wound migration by 71.7% and 73.0% in comparison with control cells, respectively. However, 1-5 and 7 did not have effect at the lower concentration of 25µM. In addition, 18 and 19 could lead to 26.0% and 60.3% healing at 20 µg/mL, respectively. Compounds 1-6 and 18-19 which showed antineutrophilic inflammatory effects [1,2], were not able to inhibit immediately allergic degranulation in rat basophilic leukemia RBL-2H3 cells, but 2, 4-6, and 18 could be significantly against interleukin-4 (IL-4) release at the concentration of 3.1µM that is a late-phase response of allergic inflammation reaction. In our studies, spirostanol saponins 2 and 18 have both anti-metastatic and anti-inflammatory effects in accordance with anti-inflammatory phytochemicals are potential candidates against tumor metastasis. Spirostanols 2 and 18 could be as the promising lead compounds against inflammation-associated tumors.

[1] Lee CL, Hwang TL, Yang JC, Cheng HT, He WJ, Yen CT, Kuo CL, Chen CJ, Chang WY, Wu YC. J Nat Prod 2014; 77: 1770 – 1783.

[2] Lee CL, Hwang TL, He WJ, Tsai YH, Yen CT, Yen HF, Chen CJ, Chang WY, Wu YC. Phytochemistry 2013; 95: 315 – 321.