Curculigosides J–K and curcorchidihydrobenzofuran A, a dihydrobenzofuran with anti-proliferative properties from Curculigo orchioides

Phytochemical investigation of the rhizomes and the leaves of Curculigo orchioides led to the isolation of fourteen compounds. They consist of one undescribed dihydrobenzofuran, curcorchidihydrobenzofuran A (1), two undescribed benzyl benzoate glycosides, curculigoside J (2) and K (3), and eleven known compounds (4–14). The structures of the isolated compounds were elucidated by thorough analysis of spectroscopic (IR, NMR and ECD) and spectrometric (MS) data. Compound 1 displayed significant anti-proliferative activities against cervical cancer cells (HelaS3, IC50 = 3.6 µM) and breast cancer cells (MCF-7, IC50 = 13.9 µM) while showing moderate activities against lung cancer cells (A549, IC50 = 29.8 µM). Importantly, it was non-toxic to Vero cells. Compound 1 also inhibited the tyrosinase enzyme in a moderate manner (IC50 = 120.8 µM). Eventually, its permethylated synthetic analog 1a showed a significant suppression of lipopolysaccharide (LPS)-induced NO production in murine macrophage RAW 264.7 (IC50 = 23.4 µM).