Possible pharmaceutical applications can be developed from naturally occurring phenanthroindolizidine and phenanthroquinolizidine alkaloids.

Naturally occurring phenanthroindolizidine and phenanthroquinolizidine alkaloids (PIAs and PQAs) are two small groups of herbal metabolites sharing a similar pentacyclic structure with a highly oxygenated phenanthrene moiety fused with a saturated or an unsaturated N-heterocycle (indolizidine/quinolizidine moieties). Natural PIAs and PQAs only could be obtained from finite plant families (such as Asclepiadaceae, Lauraceae and Urticaceae families, etc.). Up to date, more than one hundred natural PIAs, while only nine natural PQAs had been described. PIA and PQA analogues have been applied to the development of potent anticancer agents all along because of their excellent cytotoxic activity. However, in the last two decades, other great biological properties, such as anti-inflammatory and antiviral activities were revealed successively by different pharmacological assays. Especially because of their potent antiviral activity against coronavirus (TGEV, SARS CoV and MHV) and tobacco mosaic virus, PIA and PQA analogues have attracted much pharmaceutical attention again, some of them have been used to present interesting targets for total or semi synthesis, and structure-activity relationship (SAR) study for the development of antiviral agents. In this review, natural PIA and PQA analogues obtained in the last two decades with their herbal origins, key spectroscopic characteristics for structural identification, biological activity with possible SARs and application prospects were systematically summarized. We hope this paper can stimulate further investigations on PIA and PQA analogues as an important source for potential drug discovery.

[A new triterpenoid from Pittosporum glabratum Lindl].

The roots of Pittosporum glabratum Lindl. (Pittosporaceae) have been used as a folk medicine for the treatment of rheumatic arthritis, insomnia and hypertension. Only a few chemical or biological studies on P. glabratum have been reported. As part of our ongoing phytochemical research on this plant, four compounds were isolated. Their structures were identified as 3beta, 6beta, 19alpha, 21alpha, 24-pentahydroxy-12-en-28-oleanolic acid (1), 3-O-beta-D-glucuronopyranosyl-28-O-beta-D-glucopyranosyl siaresinolic acid (2), 3, 4, 5-trimethoxyphenyl-1-O-beta-D-(5-O-syringoyl)-apiofuranosyl-(1 --> 6)-beta-D-glucopyranoside (3) and 3, 4, 5-trimethoxyphenol-1-O-beta-D-apiofuranosyl-(1 --> 6)-beta-D-glucopyranoside (4) on the basis of physical evidence and spectroscopic analysis. Among them, compound 1 is a new triterpenoid, and compounds 2-4 are isolated from the genus Pittosporum for the first time.

[The up-regulation of hypoxia inducible factor-1α by hypoxic postconditioning reduces hypoxia/reoxygenation-induced injury in heart-derived H9c2 cells].

The aim of the present study was to explore the effects of hypoxic postconditioning (PostC) on heart-derived H9c2 cells injury induced by hypoxia/reoxygenation (H/R) and the expression of hypoxia inducible factor-1α (HIF-1α), and to analyze the relationship between them. Cultured H9c2 cardiac muscle cells were subjected to 3-hour hypoxia and 2-hour reoxygenation to simulate ischemia and reperfusion, or underwent 3 cycles of 5-min reoxygenation and 5-min hypoxia preceding the long reoxygenation to simulate ischemic postconditioning. Cell viability, lactate dehydrogenase (LDH) activity, and caspase-3 activity were detected respectively to investigate the cell injury induced by H/R. The level of HIF-1α mRNA was measured by real-time PCR. Western blot was used to determine HIF-1α protein level. The results showed that postconditioning significantly increased H9c2 cell viability, reduced the activity of LDH and caspase-3. Simultaneously, postconditioning up-regulated the HIF-1α protein level. Moreover, after DMOG, an inhibitor of proline hydroxylase (PHD) which targeted to HIF-1α degradation, was used to stabilize HIF-1α protein level, the reduction of H9c2 cells injury was comparable to that by postconditioning. There was a significant linear positive relationship between HIF-1α protein level and cell viability (r = 0.743, P < 0.01). After HIF-1α gene was silenced by siRNA, the cardio-protective effects of postconditioning was significantly weakened. These data suggest that up-regulation of HIF-1α plays an important role in the cardio-protection of postconditioning.

[The attenuation of myocardial susceptibility to ischemia/reperfusion injury by ischemic postconditioning in hypercholesteremia rats and the role of hypoxia inducible factor-1alpha].

OBJECTIVE: To explore whether ischemic postconditioning can attenuate the myocardial injury induced by ischemia/reperfusion (I/R) in hypercholesteremic rats and whether hypoxia inducible factor-1alpha (HIF-1alpha) play a role in the protection. METHODS: Adult male Wistar rats received a high fat diet for 8 weeks to prepare the hypercholesteremic models. Myocardial damage induced by ischemia/reperfusion was evaluated by infarct size, creatine kinase (CK) activity and myocardial apoptosis. HIF-1alpha mRNA level was detected by real time-RT-PCR and the protein level was detected by Western blot. RESULTS: Myocardial infarct size, CK activity, and caspase-3 activity induced by I/R were markedly increased in hypercholesteremic rats compared with those in normal rats. Ischemic postconditioning attenuated the myocardial injury in both normal rats and hypercholesteremic rats, and increased HIF-1alpha protein level. There was a significant linear inverse relationship between HIF-1alpha protein level and infarct size (r = -0.802, P <0.01). CONCLUSION: Hypercholesteremia enhanced the susceptibility of myocardia to ischemia/reperfusion injury. While ischemic postconditioning markedly attenuated the increase of myocardial susceptibility to I/R induced by hypercholesteremia. HIF-1alpha might be one of the mechanisms of protection by ischemic postconditioning.

A new triterpenoid saponin from Sanguisorba officinalis.

A new 19-oxo-18,19-seco-ursane-type triterpenoid saponin, named sanguisoside A (1), along with nine known triterpenoid saponins (2-10), was isolated from the roots of Sanguisorba officinalis. Their structures were determined on the basis of spectroscopic analysis and chemical method. Compounds 2 and 3 showed cytotoxic activity against SGC-7901, SMMC-7721, A549, and DU145 cell lines.

[Study on lignans of Polygonum capitatum].

OBJECTIVE: To study the lignan of Polygonum capitatum. METHODS: The compounds were isolated and purified by using of SiO2, Sephadex LH-20 column chromatography and pre-HPLC. The structures of the compounds were determined on the basis of their physical properties and the spectral data. RESULTS: Four compounds were isolated and identified as schizandriside (1), (-)-isolariciresinol-2a-O-beta-D-xylopyranoside (2), (-) -5 '-methoxyisolariciresinol-2a-O-beta-D-xylopyranoside (3) and nudiposide (4). CONCLUSION: Compounds 1 - 4 are isolated from the genus for the first time.

Attenuation of myocardial injury by postconditioning: role of hypoxia inducible factor-1alpha.

Postconditioning (PostC) has regenerated interest as a mechanical intervention against myocardial ischemia/reperfusion injury, but its molecular mechanisms remain elusive. This study tested the hypothesis that hypoxia inducible factor-1alpha (HIF-1alpha) plays a role in PostC-induced cardioprotection. Male Wistar rats were subjected to 30 min ischemia followed by 3 h of reperfusion (Control). PostC with 3 cycles of 10 s reperfusion and 10 s re-occlusion was applied at the onset of reperfusion. Relative to the Sham group, HIF-1alpha protein level was increased by 2.9-fold in the Control group, but its level was enhanced by 5.8-fold with PostC (P < 0.01 vs. Control). However, HIF-1alpha protein level was further augmented by 2.0-fold and 3.3-fold, respectively, when the prolyl hydroxylase inhibitor, dimethyloxalylglycine (DMOG, 40 mg/kg, i.p.) was given at 24 h before ischemia in both Control and PostC groups. PostC reduced infarct size by 24% compared with the Control (27 +/- 4.2% vs. 36 +/- 5.2%, P < 0.01), consistent with significant lower levels of plasma creatine kinase activity, index of cardiomyocyte apoptosis and caspase-3 activity. Although pretreatment with DMOG significantly reduced infarct size relative to the Control, the infarct-sparing effect of PostC was remarkably enhanced when DMOG was given before PostC (18 +/- 2.0% vs. 27 +/- 4.2% in PostC alone, P < 0.05). There was a significant linear inverse relationship between HIF-1alpha protein level and infarct size (r = -0.799, P < 0.01) among all groups. Furthermore, along with up-regulated HIF-1alpha expression, the levels of iNOS mRNA and protein were significantly increased in the PostC alone and DMOG plus PostC groups. In conclusion, these data suggest that HIF-1alpha is involved in cardioprotection by PostC and pharmacological augmentation of HIF-1alpha expression that enhances the infarct-sparing effect of PostC; iNOS, the downstream gene of HIF-1alpha, may participate in signaling pathways in mediating PostC's protection.