Tumoral cytotoxic and antioxidative phenylpropanoid glycosides in Smilax riparia A. DC.

BACKGROUND

Smilax riparia A. DC., known as "Niu-Wei-Cai" in China, is distributed through the south and middle of China. The roots and rhizomes of Smilax riparia have been used not only as traditional Chinese medicines (TCMs) for the treatment of bronchitis, lumbago of renal asthenia, traumatic injury, asthenia edema, and cancer but also as edible wild herbs in some areas of China.

OBJECTIVE

To identify the phytochemicals in the roots and rhizomes of Smilax riparia and to investigate their antioxidant activities and cytotoxicities toward several tumor cell lines.

METHODS

Four fractions and five phenylpropanoid glycosides were obtained from roots and rhizomes of Smilax riparia under bioassay-guided screenings. The structures of five compounds were elucidated by spectroscopic methods and compared with published data. We evaluated their antioxidant activities and their cytotoxicities on five cancer cell lines: human promyelocytic leukemia (HL-60), human hepatocellular carcinoma (SMMC-7721), human lung cancer (A-549), human breast cancer (MCF-7), and human colon cancer (SW480).

RESULTS

Of the five glycosides, one new compound (3, smilaside P) was isolated from an EtOAc fraction. Compound 1 was cytotoxic toward HL-60, SMMC-7721, A-549, MCF-7, and SW480 (IC50 2.70, 3.80, 11.91, 3.79, and 3.93 μM, respectively). Moreover, compounds 1-3 showed moderate scavenging activities against the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical (IC50 339.58, 330.66, 314.49 μM, respectively).

CONCLUSIONS

Five phenylpropanoid glycosides were reported for the first time from this TCM. Each was studied, as observed here for the first time, in the cytotoxic experiments toward HL-60, SMMC-7721, and SW480 cell lines. Compound 1, bearing three feruloyl groups and three acetyl groups, had the greatest cytotoxicity toward the five tumor cell lines. Compounds 1-3 showed moderate antioxidant activities. All results reflect that compounds 1-3 are cytotoxic for a wide variety of cancer cell lines of differing tissue origins and that the cytotoxicities of these compounds may be related to their antioxidant activities.