Evaluation of biomarkers for doxorubicin­induced cardiac injury in rats.

Drug-induced cardiotoxicity is a leading cause of failure in drug development and predicting its occurrence in non-clinical studies is the primary preventive measure. The present study aimed to evaluate the changes in biomarkers during acute and chronic myocardial injury induced by doxorubicin (DOX) in rats. A rat model of acute myocardial injury was established through a single-dose, intraperitoneal injection of DOX (40 mg/kg), the changes in biomarkers were measured at 2, 4, 8 and 24 h after administration, following DOX administration, creatine kinase (CK) and fatty acid-binding protein 3 (FABP3) levels increased between 8 and 24 h, whereas cardiac troponin I (cTnI) peaked at 8 h. To establish a chronic myocardial injury model, rats received 1, 2 or 3 mg/kg DOX weekly by caudal vein injection for 2, 4, 6 or 7 weeks, the changes in biomarkers were detected at 2, 4, 6 and 8 weeks, the results showed that cTnI increased significantly after 2 and 8 weeks of administration. A significant increase in FABP3 and microRNA (miR)-146b levels was observed after 8 weeks of administration. Receiver operating characteristic curve and correlation analysis showed that cTnI and miR-146b had relatively high predictive values for chronic myocardial injury (area under the curve, 0.83 and 0.71, respectively) and were closely correlated with myocardial damage. These data suggested that CK, cTnI and FABP3 were relatively sensitive to DOX-induced acute myocardial injury, whereas cTnI and miR-146b were relatively sensitive to DOX-induced chronic myocardial injury.

Diosgenin-3-O-alpha-L-rhamnopyranosyl-(1 --> 4)-beta-D-glucopyranoside obtained as a new anticancer agent from Dioscorea futschauensis induces apoptosis on human colon carcinoma HCT-15 cells via mitochondria-controlled apoptotic pathway.

Diosgenin-3-O-alpha-L-rhamnopyranosyl-(1 --> 4)-beta-D-glucopyranoside (DRG) is a well-known pentacyclic triterpene glycoside newly isolated from the rhizomes of Dioscorea futschauensis R. Kunth (Dioscoreaceae) by our group. In the present work, the inhibitory effect of DRG on the cell proliferation of human cancer cell lines was examined to reveal for the first time that DRG shows stronger anticancer activity than that of the positive control cisplatin. DRG inhibited the proliferation of human cancer cells, A431, A2780, A549, K562, and HCT-15, with IC50 (micromol L(-1)) values of 9.33 +/- 0.22, 18.7 +/- 0.16, 9.98 +/- 0.38, 6.44 +/- 0.10, and 5.86 +/- 0.14 respectively. It was then found, by morphological observation, "DNA ladder" detection and flow cytometric analysis, that DRG exerts its anticancer effect through inducing apoptosis on HCT-15 cells. Furthermore, it has been demonstrated that DRG triggers a mitochondria-controlled apoptotic pathway to induce apoptosis on HCT-15 cells, which involves the reduction of the mitochondrial potential (deltapsim), the release of cytochrome c from mitochondria into the cytosol, and the down-regulation of the ratio of Bcl-2/Bax expression level. The present results reasonably suggest that regulating the balance of Bcl-2/Bax expression level plays a key role in the DRG-induced apoptosis. Such findings provide novel knowledge to elucidate the biological properties of DRG, even though DRG was discovered early in the late 1960s. These results suggest that DRG may be a good candidate as a chemotherapeutic agent to treat human colon carcinoma.

New furostanol glycosides from the rhizomes of Dioscorea futschauensis R. Kunth.

Two new furostanol glycosides, 26-O-beta-D-glucopyranosyl-3beta,26-dihydroxy-23(S)-methoxyl-25(R)-furosta-5,20(22)-dien-3-O-alpha-L-rhamnopyranosyl(1 --> 2)-[beta-D-glucopyranosyl(1 --> 3)]-beta-D-glucopyranoside (dioscoreside E, 1) and 26-O-beta-D-glucopyranosyl-3beta,26-dihydroxy-25(R)-furosta-5,20(22)-dien-3-O-alpha-Lrhamnopyranosyl(1 --> 2)-[beta-D-glucopyranosyl (1 --> 3)]-beta-D-glucopyranoside (prtotogracillin, 2), together with 11 known furostanol glycosides were isolated from the rhizomes of Dioscorea futshauensis R. Kunth. Their structures were elucidated on the basis of spectroscopic analysis (NMR and FABMS). Their anti-fungal activity against the plant pathogenic fungus Pyricularia oryzae and cytotoxic activity on K562 cancer cell line were evaluated in vitro.

[Apoptosis of human chronic myeloid leukemia k562 cell induced by prosapogenin B of dioscin (P.B) in vitro].

BACKGROUND & OBJECTIVE: The authors have isolated prosapogenin B of dioscin (P.B) newly from Dioscorea futschauensis R. Kunth (Dioscoreaceae) and found that P.B could significantly inhibit the cell proliferation of several human cancer cell lines for the first time. The objective of this paper was designed to investigate whether P.B could inhibit cancer cell proliferation by inducing apoptosis. METHODS: Morphological changes of cell nuclei were observed under invert fluorescence microscope and transmission electron microscope. The changes in the cell size distribution were analyzed by Coulter Multisizer II particle analyzer. DNA ladder and apoptotic cells were analyzed respectively by DNA agarose gel electrophoresis and flow cytometry. RESULTS: The K562 cells treated with 10 micromol/L P.B for 24 hours showed morphological characteristics of apoptotic cells, such as decrease in cellular volume, nuclear chromatin condensation, nuclear fragmentation, and plasma membrane bleb formation. The treatment of K562 cells with 10 micromol/L P.B for 6, 12,and 24 hours caused the increase of the detected DNA ladder and the decrease of normal size cells both in a time-dependent manner. The percentage of apoptotic bodies detected in the sub-G(0)/G(1) peak region by flow cytometry was also increased time-dependently as analyzed as 6.12% for 6 hours, 35.6% for 12 hours and 45.7% for 24 hours treatments, respectively. CONCLUSION: These results suggested that P.B exerts its anti-proliferative effect on K562 cells through inducing apoptosis of the cells.

Steroidal saponins from rhizomes of Tupistra wattii Hook. f.

Chemical examination of the fresh rhizomes of Tupistra wattii HOOK. f. led to the isolation of three new steroidal saponins, wattoside G (1), H (2), and I (3), together with one known steroidal saponin, (25S)-1beta,3beta,4beta-trihydroxyspirotan-5beta-yl-O-beta-D-glucopyranoside (4). The structures of 1-3 were established to be (25R)-1beta,2beta,3beta,5beta-tetrahydroxyspirostan-4beta-yl-O-beta-D-xylopyranoside (1), (24S,25S)-24-[(beta-D-glucopyranosyl)oxy]-1beta,2beta,3beta,4beta,5beta,7beta-hexahydroxyspirostan-6-one (2), and (24S,25S)-1beta,3beta-dihydroxy-5beta-spirostan-24-yl-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (3) on the basis of detailed analyses of physical, chemical, and spectral data. The isolated compounds were evaluated for cytotoxic activity against the cancer cell line K562 in vitro.

A new ergostanol saponin from Dioscorea deltoidea Wall var. orbiculata.

From the fresh rhizomes of Dioscorea deltoidea Wall var. orbiculata, a novel ergostanol saponin, orbiculatoside A (1), was isolated and identified as 3-O-beta-D-glucopyranosyl-ergost-5-ene-3beta, 26-diol-26-O-beta-D-glucopyranosyl(1-->3)-[beta-D-glucopyranosyl(1-->2)-beta-D-glucupyranosyl(1-->6)]-beta-D-glucopyranoside by various NMR techniques in combination with chemical methods. The new saponin showed strong activity against Pyricularia oryzae, with a MMDC (minimum morphological deformation concentration) value of 28.04 micromol/l and was cytotoxic to cancer cell line K562, HCT-15, A549, HT1080, and A2780a in vitro.