Pithecellobium eriorhachis Harms. (Fabaceae) has been used as a folk medicine to treat various diseases in Cameroon and other countries. The present study aimed to isolate and characterise compounds with cytotoxic activity against three glioblastoma cancer cell lines (U87-MG, U251-MG, LN229) from the stem bark of P. eriorachis. As a result, two new cerebrosides, trivially named Pithecellobioside A and B (1-2), together with seven known compounds, were isolated by silica gel column chromatography, including one alkaloid (3), four flavonoids (4-7) and two steroids (8-9). The structures of all isolated compounds were elucidated using extensive spectral data, including 1D and 2D NMR, HR-ESI-MS, and comparison of their NMR data with those of previously reported compounds. Both new compounds (1-2) were assessed in vitro using the MTT assay on three glioblastoma cancer cell lines (U87-MG, U251-MG, and LN229). U87-MG cells were the most sensitive to compound 1 (IC50 = 1.23 ± 0.06 μg/mL), while compound 2 showed the highest activity against LN229 cells (IC50 = 2.68 ± 0.08 μg/mL), exceeding that of the reference drug (oxaliplatin against LN229, IC50 = 4.78 ± 0.56 μg/mL). Pithecellobioside B (2) is identified as a potent cytotoxic compound that warrants further investigation for the development of novel antiproliferative drugs targeting LN229 epithelial-like glioblastoma cells. These findings indicate that Pithecellobiosides A and B (1-2) represent new cerebrosides with selective cytotoxicity against glioblastoma cells, highlighting P. eriorachis as a promising source of bioactive glycosphingolipids.
Melong et al. (Wed,) studied this question.