Phenylpropanoid-conjugated pentacyclic triterpenoids from the whole plants of Leptopus lolonum induced cell apoptosis via MAPK and Akt pathways in human hepatocellular carcinoma cells.

Our present and previous phytochemical investigations on Leptopus lolonum have resulted in the isolation of almost 30 phenylpropanoid-conjugated pentacyclic triterpenoids (PCPTs). During the continuous study on PCPTs, this kind of triterpenoid ester is considered as a natural product with low toxicity because of it's widely distribution in natural plants and edible fruits including kiwi fruit, durian, jujube, pawpaw, apple and pear. In the present work, we report the isolation, structural elucidation and cytotoxic evaluation of four new PCPTs (1-4) which obtained from L. lolonum. In addition, the possible biosynthesis pathway for 28-norlupane triterpenoid and potent effect of phenylpropanoid moiety for increasing the cytotxic effect of triterpenoids were also discussed. Among these compounds, compound 1 exhibited the highest cytotoxic effect on HepG2 cells with IC50 value of 11.87 µM. Further flow cytometry and western blot analysis demonstrated that 1 caused G1 cell cycle arrest by up-regulated the expression of phosphorylated p53 protein in HepG2 cells and induced cell apoptosis via MAPK and Akt pathways. These results emphasized the potential of PCPTs as lead compounds for developing anti-cancer drugs.

New phenylpropanoid-conjugated pentacyclic triterpenoids from the whole plants of Leptopus lolonum with their antiproliferative activities on cancer cells.

Most of Euphorbiaceae plants are considered as folk medicinal plants because of their various pharmacological effects. However, there are eight Leptopus genus plants which belong to Euphorbiaceae have never be investigated. Thus, four Leptopus genus plants were collected to study their chemical constituents and pharmacological activities. In the present work, the cytotoxicities of the extracts of four Leptopus genus plants were evaluated before phytochemical experiments. And nine new phenylpropanoid-conjugated pentacyclic triterpenoids, along with twenty-two known compounds were isolated from the whole plants of Leptopus lolonum. The structures of these new compounds were unequivocally elucidated by HRESIMS and 1D/2D NMR data. All triterpenoids were screened for their cytotoxicities against four cancer cell lines including HepG2, MCF-7, A549 and HeLa. Among these isolates, the triterpenoid with a phenylpropanoid unit showed increasing cytotoxicity on cancer cells, which suggested the importance of the phenylpropanoid moiety.

Morphological and cytohistological observations of seed germination and protocorm development of Bletilla striata / 中国中药杂志

In order to investigate the mechanism of growth for Bletilla striata, which could be applied for rapid propagation, morphological and cytohistological of seed germination and protocorm development in vitro culture were observed using paraffin section techniques. In this study, we have found that the development of B. striata goes through four stages： embryo, protocorm, rhizome and pseudobulb. The end away from embryo suspensor is able to differentiate green buds after the seed of B. striata swelling, growing point. At the same time, the other end of embryo grows many white villous roots, with the green bud differentiating into cotyledon, the embryo breaking through seed coat and being protocorm. The shoot apical meristem of protocorm consists of tunica, corpus and leaf primordium, whose developmental flowing tunica-corpus theory. After more vascular bundle appeared from the leaf primordium, B. striata grows into the stage of rhizome. While in the stage of rhizome, the root primordium of tissue culture seedlings are differentia initially that derived from rhizome vascular bundle, belonging to internal origin. Subsequently, the pseudobulb forms by the inner meristem growing into mature parenchymatous tissue and the rhizome enlargement gradually.