Scuteflorins A and B, Dihydropyranocoumarins from Scutellaria lateriflora L.

Scutellaria lateriflora L. (skullcap) is native to North America, but now widely cultivated in Europe and other areas of the world. It has been used for over two hundred years as an effective therapy for anxiety, nervous tension, and convulsions [1]. In America, skullcap is regulated as a dietary supplement and has been classified as an “Herb of Undefined Safety” by the FDA. Despite its extensive use, little data exist regarding the chemical constituents of Scutellaria lateriflora. In order to provide the scientific support for the uses of this plant, a systematical chemical study has been conducted. Two new dihydropyranocoumarins, named scuteflorins A and B, together with the known compounds, decursin, chrysin, oroxylin A, wogonin, 5,7-dihydroxy-2ʹ,8-dimethoxyflavone, dihydrochrysin, dihydrooroxylin A, lupenol, 3α,24-dihydroxy-olean-12-en-28-oic acid, 3β,19α-dihydroxy-urs-12-en-28-oic acid, ursolic acid, β-sitosterol, daucosterol, palmitic acid, a mixture of arachidic acid, behenic acid and lignoceric acid in a ratio of 2:1:0.3, and a mixture of 1-triacontanol and 1-dotriacontanol in a ratio of 2:1, were isolated from the aerial parts of this plant. Their structures were established by means of extensive 1D and 2D NMR spectra as well as HRMS data. The absolute configuration of dihydropyranocoumarins was determined by a comparison of the experimental and theoretical CD spectra. All the compounds except for wogonin and chrysin are reported for the first time from this plant. Acknowledgement: This work is funded in part by the Food Drug Administration contract “Biotanical Dietary Supplement: Science-Base for Authentication” FD-U-002071-07. Authors are thankful to Dr. Vaishali Joshi for the authentication of plant material. References: [1] Foster S, (1996), The Business of Herbs, May/June, p.14–16.