Antitumor and Immunostimulatory Activity of Two Chromones and Other Constituents from Cassia Petersiana

Phytochemical and biological investigation of the leaves of Cassia petersiana afforded two new chromones (1, 2), in addition, to the known glyceryl-1-hexacosanoate (3) and stigmasterol-3-O-β-D-glucoside (4). The structures of the compounds were determined by comprehensive NMR studies, including DEPT, COSY, HMQC, HMBC and IR spectroscopy and MS. 1–4 were investigated against different types of cell lines, including solid tumor cells (Hep-G2, and MCF-7 cells) and leukemia (1301) cells for their cytotoxic effects. 1–3 possessed a dose-dependent cytotoxic effect against Hep-G2 cells, but in relatively high concentrations; 4 was the most cytotoxic with the lowest IC 50 value of 82.7 μM. The calculated IC 50 values against MCF-7 cells were 112.2 μM, 143.7 μM, 68.1 μM, and 114.3 μM for 1, 2, 3, and 4, respectively. The alteration in the macrophage proliferation index, using Raw 264.7 cells, was monitored. 1 and 3 were the highest stimulators of macrophage proliferation in a dose-dependent manner, whereas 2 and 4 showed a peak point of stimulation at 20 μM. The effect of these compounds on pre-induced NO was explored. 1–4 inhibited the LPS-induced NO, with inhibition percentages of 80.5%, 89.3%, 82.1%, and 92.1%, respectively, at a concentration of 20 μM. The antioxidant capacity of 1–4, using the DPPH assay was also investigated. 1–3 possessed weak scavenging activity; while 4 had an effective SC 50 value as low as 36 μM. These results indicated that 4 possessed the highest anti-tumor, immunoproliferative, macrophage proliferation, anti-inflammatory, and antioxidant activities.