Studies On The Constituents Of Hedyotis Diffusa Willd

Hedyotis diffusa Willd., locally named "Bai-hua-she-she-cao", is an annual herbaceous plant of the genus Hedyotis Linn. (Rubiaceae). Its herbs are used as the traditional Chinese medicine for the treatment of several tumors and inflammations. Modern pharmacological studies showed that the extract of this whole plant possessed series of bioactivities, such as anticancer, antimicrobial, immunoloregulation effects and et al.In our study on the chemical constituents of H. diffusa,22 compounds were obtained from the subfraction of HEDI-B (50% v/v ethanol eluent of 60% ethanol extract of the whole plant over an HP-20 macroporous resin column) through various chromatographic techniques. Their structures were elucidated on the basis of their physico-chemical properties and modern spectroscopic analysis, including UV, IR, MS, 1D-and 2D-NMR. Among them, two were new compounds, and five of them were isolated for the first time from this genus.The MMT assay against HepG2, MCF-7, HCT-116 cell lines were carried out to evaluate the cytotoxic activity of the isolated compounds, however, none of them showed cytotoxic effects. Combined with other investigation results reported, it suggested that these compounds might execute anti-tumor activity through stimulating the immune system.Moreover, some of the iridoid glycosides were also evaluated for their effects on enhancement of short-term learning/memory abilities in human Aβ42 transgenic flies. The results showed that six compounds could improve short-term learning/memory abilities of transgenic flies, suggesting that these compounds might have antagonism effects against Alzheimer's disease.The HPLC fingerprint chromatogram of the extract of H. diffusa was established, and the main peaks in the HPLC chromatogram were identified by the reference components isolated from H. diffusa. It would contribute to the development of quality control methods of TCM "Bai-hua-she-she-cao".