Cytotoxic Natural Products Isolated from Cryptogramma crispa (L.) R. Br

Parsley fern, Cryptogramma crispa, is a common fern in arctic-alpine regions, and even though this species has been known since ancient times and has been presumed to cause the poisoning of horses, its natural products have not previously been investigated. Here, we characterise 15 natural products isolated from the aerial parts of Cryptogramma crispa, including the previously undescribed compound 3-malonyl pteroside D. The structure determinations were based on several advanced 1D and 2D NMR spectroscopic techniques, Circular Dichroism spectroscopy and high-resolution mass spectrometry. The pteroside derivatives exhibited selective moderate cytotoxic activity against the acute myeloid leukaemia MOLM13 cell line and no cytotoxicity against the normal heart and kidney cell lines, suggesting that their potential anticancer effect should be further investigated.