Thirty-two enmein-type ent-kaurane diterpenoids, including 13 new compounds, were isolated from the aerial parts of Isodon phyllostachys. Compounds 1 and 2 are the first examples of 3,20:6,20-diepoxyenmein-type ent-kauranoids, and the structures of these new compounds were established mainly by analyzing NMR and HREIMS data. The absolute configurations of 1 and 8 and the relative configuration of 9 were determined using single-crystal X-ray diffraction. Compounds 11, 15, 20, and 21 were active against five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW-480), with IC50 values ranging from 1.2 to 5.0 μM. Compounds 3, 11, 15, 17, 20, 21, 25, and 29 strongly inhibited NO production in LPS-stimulated RAW264.7 cells, with IC50 values ranging from 0.74 to 4.93 μM.

Medicinal plants are becoming an important research area for novel and bioactive molecules for drug discovery. Novel therapeutic strategies and agents are urgently needed to treat different incurable diseases. Many plant derived active compounds are in human clinical trials. Currently ursolic acid is in human clinical trial for treating cancer, tumor, and skin wrinkles. This review includes the clinical use of ursolic acid in various diseases including anticancer, antitumor, and antiwrinkle chemotherapies, and the isolation and purification of this tritepernoid from various plants to update current knowledge on the rapid analysis of ursolic acid by using analytical methods. In addition, the chemical modifications of ursolic acid to make more effective and water soluble derivatives, previous and current information regarding, its natural and semisynthetic analogs, focusing on its anticancer, cytotoxic, antitumor, antioxidant, anti-inflammatory, anti-HIV, acetyl cholinesterase, α-glucosidase, antimicrobial, and hepatoprotective activities, briefly discussion is attempted here for its research perspectives. This review article contains fourteen medicinally important ursolic acid derivatives and 351 references.

Isodon species (Labiatae) are widely distributed plants, many of which are used in folk medicine. Over the past twenty years, they have received considerable phytochemical and biological attention. Thestructures of their many diterpenoids constituents, especially those with an ent-kaurane skeleton, have been elucidated. The significant phytochemical and pharmacological diterpenoids form the subject of this review. There are 290 references.

ent-Kaurene diterpenoids, phyllostachysins D-H (1-5), together with nine known compounds, rabdoloxins A-B (6-7), rabdoinflexin B (8), amethystoidin A (9), rabdokunmin D (10), macrocalyxin E (11), 5,7-dihydroxy-4'-hydroxylflavone (12), oleanolic acid (13) and daucosterol (14), were isolated from aerial parts of Isodon phyllostachys. Structures were elucidated on the basis of spectroscopic methods, especially using 2D-NMR spectroscopic analyses. All ent-kaurenoids were tested for their cytotoxic effects against K562 cells. Compound 9 was the most potent with an IC50 value of 0.69 microg/ml.

Ursolic acid (UA) and oleanolic acid (OA) are triperpene acids having a similar chemical structure and are distributed wildly in plants all over the world. In recent years, it was found that they had marked anti-tumor effects. There is little literature currently available regarding their effects on colon carcinoma cells. The present study was designed to investigate their inhibitory effects on human colon carcinoma cell line HCT15.

HCT15 cells were cultured with different drugs. The treated cells were stained with hematoxylin-eosin and their morphologic changes observed under a light microscope. The cytotoxicity of these drugs was evaluated by tetrazolium dye assay. Cell cycle analysis was performed by flow cytometry (FCM). Data were expressed as means +/-SEM and Analysis of variance and Student' t-test for individual comparisons.

Twenty-four to 72 h after UA or OA 60 micromol/L treatment, the numbers of dead cells and cell fragments were increased and most cells were dead at the 72nd hour. The cytotoxicity of UA was stronger than that of OA. Seventy-eight hours after 30 micromol/L of UA or OA treatment, a number of cells were degenerated, but cell fragments were rarely seen. The IC(50) values for UA and OA were 30 and 60 micromol/L, respectively. Proliferation assay showed that proliferation of UA and OA-treated cells was slightly increased at 24h and significantly decreased at 48 h and 60 h, whereas untreated control cells maintained an exponential growth curve. Cell cycle analysis by FCM showed HCT15 cells treated with UA 30 and OA 60 for 36 h and 72 h gradually accumulated in G(0)/G(1) phase (both drugs P<0.05 for 72 h), with a concomitant decrease of cell populations in S phase (both drugs P<0.01 for 72 h) and no detectable apoptotic fraction.

UA and OA have significant anti-tumor activity. The effect of UA is stronger than that of OA. The possible mechanism of action is that both drugs have an inhibitory effect on tumor cell proliferation through cell-cycle arrest.