New Anthraquinone and Iridoid Glycosides from the Stems of Hedyotis hedyotidea

Introduction. – The genus Hedyotis (Rubiaceae family) contains 69 species distributed in China [1], some of which have been used as Traditional Chinese Medicines (TCM), such as Hedyotis diffusa for treating cancer, and Hedyotis chrysotricha for treating enteritis [2]. The characteristic chemical constituents of this genus are anthraquinones, flavonoids, iridoids, and triterpenoids [3]. Plants of this genus have been found to exhibit anti-inflammatory and anticancer activities [3]. Hedyotis hedyotidea (DC.) Merr. [4], a 3 – 5-m tall shrub growing in the south of China [1], has been traditionally used for the treatment of cold, cough, gastro-enteritis, heatstroke, Herpes zoster, rheumatoid arthritis, etc. [5]. Previously, some iridoids have been identified from H. hedyotidea, and meanwhile the activity of the crude extract of this herb against stress ulcer in mice was mentioned [6], but the bioactive components were unknown. As part of our ongoing effort to discover new bioactive agents from Chinese medicinal plants, the stems ofH. hedyotidea were investigated. We report here on the isolation and characterization of seven anthraquinones, including five new glycosides, 1 – 5, together with six iridoids, which comprise two new glycosides, 6 and 7. Inhibitory activities of compounds obtained to NF-kB induced by the NF-kB-activating cytokine TNF-a (tumor necrosis factor a) was investigated, but all turned out to be inactive.