Three New Compounds from Delphinium kamaonense Hunth and Their in Vitro Cytotoxic and Potential Antioxidant Activities

A new amide (1), two new phenylpropanoid derivatives (2, 3), along with three new natural products, including three nitrogen chirality compounds, N-(3-methoxy-1,3-dioxopropyl)-D-phenylalanine methyl ester (4), N-(3-methoxy-1,3-dioxopropyl)-L-phenylalanine methyl ester (5), and N-acetyl-L-phenylalanine methyl ester (6), as well as dimethyl (2R,3R)-2-hydroxy-3-(((E)-3-(4-hydroxyphenyl)acryloyl)oxy)succinate (7) and dimethyl (S,E)-2-((3-(4-hydroxy-3-methoxyphenyl)acryloyl)oxy)succinate (8) were isolated from Delphinium kamaonense Hunth. Their structures were elucidated by extensive analysis of 1D and 2D NMR, and HR-ESI-MS experiments, and the absolute configurations were determined by comparative analysis of specific optical rotation. Compound 1 exhibited a moderate cytotoxicity effect against Hep-3B cancer cell lines (IC50 41.39 +/- 0.13 mu M) and an excellent antioxidant activity (IC50 0.527 +/- 0.06 mu M in ABTS assay, and 1.235 +/- 0.09 mu M in DPPH assay, respectively), which was superior to vitamin C in ABTS (IC50 1.670 +/- 0.07 mu M) and DPPH (IC50 19.10 +/- 0.40 mu M) methods.

Automated summary

In this study, a new amide and two phenylpropanoid derivatives, along with three new natural products, were isolated from Delphinium kamaonense Hunth. Their structures and absolute configurations were determined by various analytical techniques. Compound 1 showed moderate cytotoxicity against Hep-3B cancer cells and excellent antioxidant activity.