Cytotoxic stilbenes from the roots of Paphiopedilum godefroyae

Abstract

Two new stilbenes, 2-(3′,5′-dimethoxyphenyl)-6-hydroxy-5-methoxybenzofuran (1) and 3′-hydroxy-2,5′-dimethoxystilbene (2), together with seven known stilbenes (3, 5–10) and one flavanone (4), were isolated from the roots of Paphiopedilum godefroyae. Their chemical structures were determined on the basis of their spectroscopic data. These isolated compounds were evaluated for their cytotoxicity against human small cell lung cancer (NCI-H187) cell lines and an arylbenzofuran derivative, 5,6-dimethoxy-2-(3-hydroxy-5-methoxyphenyl)benzofuran (6), was shown to be strongly cytotoxic with an IC₅₀ value of 5.10 μM.

Keywords:

• Paphiopedilum godefroyae
• Orchidaceae
• stilbenes
• cytotoxicity
• NCI-H187

Acknowledgment

The authors are thankful to Dr. Duangpen Pattamadilok of the Department of Medical Sciences, Ministry of Public Health, for providing mass spectral data.