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

Phytochemical investigation of the rhizomes and the leaves of <i>Curculigo orchioides</i> led to the isolation of fourteen compounds. They consist of one undescribed dihydrobenzofuran, curcorchidihydrobenzofuran A (<b>1</b>), two undescribed benzyl benzoate glycosides, curculigoside J (<b>2</b>) and K (<b>3</b>), and eleven known compounds (<b>4</b>-<b>14</b>). The structures of the isolated compounds were elucidated by thorough analysis of spectroscopic (IR, NMR and ECD) and spectrometric (MS) data. Compound <b>1</b> 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 <i>Vero</i> cells. Compound <b>1</b> also inhibited the tyrosinase enzyme in a moderate manner (IC₅₀ = 120.8 µM). Eventually, its permethylated synthetic analog <b>1a</b> showed a significant suppression of lipopolysaccharide (LPS)-induced NO production in murine macrophage RAW 264.7 (IC₅₀ = 23.4 µM).