Wen-Cai Ye

Antiviral flavonoids from the root bark of Morus alba L.

A prenylated flavonoid, moralbanone, along with seven known compounds kuwanon S, mulberroside C, cyclomorusin, eudraflavone B hydroperoxide, oxydihydromorusin, leachianone G and alpha-acetyl-amyrin were isolated from the root bark of Morus alba L. Leachianone G showed potent antiviral activity (IC(50) = 1.6 microg/ml), whereas mulberroside C showed weak activity (IC(50) = 75.4 microg/ml) against herpes simplex type 1 virus (HSV-1). Their structures were elucidated by spectroscopic methods.

Arenobufagin, a natural bufadienolide from toad venom, induces apoptosis and autophagy in human hepatocellular carcinoma cells through inhibition of PI3K/Akt/mTOR pathway

Hepatocellular carcinoma (HCC) is a deadly form of cancer without effective chemotherapy so far. Currently, only sorafenib, a multitargeted tyrosine kinase inhibitor, slightly improves survival in HCC patients. In searching for natural anti-HCC components from toad venom, which is frequently used in the treatment of liver cancer in traditional Chinese medicine, we discovered that arenobufagin, a bufadienolide from toad venom, had potent antineoplastic activity against HCC HepG2 cells as well as corresponding multidrug-resistant HepG2/ADM cells. We found that arenobufagin induced mitochondria-mediated apoptosis in HCC cells, with decreasing mitochondrial potential, as well as increasing Bax/Bcl-2 expression ratio, Bax translocation from cytosol to mitochondria. Arenobufagin also induced autophagy in HepG2/ADM cells. Autophagy-specific inhibitors (3-methyladenine, chloroquine and bafilomycin A1) or Beclin1 and Atg 5 small interfering RNAs (siRNAs) enhanced arenobufagin-induced apoptosis, indicating that arenobufagin-mediated autophagy may protect HepG2/ADM cells from undergoing apoptotic cell death. In addition, we observed the inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway by arenobufagin. Interestingly, inhibition of mTOR by rapamycin or siRNA duplexes augmented arenobufagin-induced apoptosis and autophagy. Finally, arenobufagin inhibited the growth of HepG2/ADM xenograft tumors, which were associated with poly (ADP-ribose) polymerase cleavage, light chain 3-II activation and mTOR inhibition. In summary, we first demonstrated the antineoplastic effect of arenobufagin on HCC cells both in vitro and in vivo. We elucidated the underlying antineoplastic mechanisms of arenobufagin that involve cross talk between apoptosis and autophagy via inhibition of the PI3K/Akt/mTOR pathway. This study may provide a rationale for future clinical application using arenobufagin as a chemotherapeutic agent for HCC.

Triterpenoids from Pulsatilla chinensis

A new lupane type triterpenic acid, pulsatillic acid, and two new lupane type triterpenoid glycosides, pulsatilloside A and B, along with the known 23-hydroxybetulinic acid were isolated from the roots of Pulsatilla chinensis. Their structures were characterized as 3-oxo-23-hydroxy-lup-20(29)-en-28-oic acid, 3 beta, 23-dihydroxy-lup-20(29)-en-28-oic acid 3-O-alpha-L-arabinopyranoside and 3 beta, 23-dihydroxy-lup-20(29)-en-28-oic acid 28-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside on the basis of hydrolysis and spectral evidence including two-dimensional relay HOHAHA, one-dimensional multiple relay COSY and ROESY NMR techniques. Pulsatillic acid exhibited cytotoxic activities against P-388, Lewis lung carcinoma and human large-cell lung carcinoma.

Phenolic compounds from Origanum vulgare and their antioxidant and antiviral activities

In the present study, six new phenolic compounds (1-6) along with five known ones were isolated from the ethanol extract of the whole plants of Origanum vulgare. The structures of the new compounds were identified on the basis of extensive spectroscopic analyses (UV, IR, NMR, and HRESIMS) and acid hydrolysis. Twenty-one phenolic compounds isolated from O. vulgare in our previous and present studies were evaluated for their in vitro antioxidant activity using 2,2-diphenyl-1-picryhydrazyl (DPPH) radical-scavenging and ferric-reducing antioxidant power (FRAP) assays; twelve of them including two new compounds exhibited significant antioxidant activity comparable to that of ascorbic acid. In addition, the antiviral effects against respiratory syncytial virus (RSV), Coxsackie virus B3 (CVB3) and herpes simplex virus type 1 (HSV-1) were tested by cytopathic effect (CPE) reduction assay.

Psiguadials A and B, two novel meroterpenoids with unusual skeletons from the leaves of Psidium guajava.

Psiguadials A (1) and B (2), two novel sesquiterpenoid-diphenylmethane meroterpenoids with unusual skeletons, along with a pair of known epimers, psidial A (3) and guajadial (4), were isolated from the leaves of Psidium guajava. Their structures with absolute configurations were elucidated by means of NMR, X-ray diffraction, and quantum chemical CD calculation. Compounds 1, 2, and 4 exhibited potent inhibitory effects on the growth of human hepatoma cells.

Flueggines A and B, Two New Dimeric Indolizidine Alkaloids from Flueggea virosa

Two unprecedented C,C-linked dimeric indolizidine alkaloids, flueggines A (1) and B (2), were isolated from the twigs and leaves of Flueggea virosa. The structures and absolute configurations were elucidated by means of NMR, single-crystal X-ray diffraction, and CD analyses. Compound 1 is the first example of Securinega alkaloids bearing an isoxazolidine ring, the plausible biogenetic pathway of which is also proposed. Compound 2 exhibited growth inhibitory activity against MCF-7 and MDA-MB-231 human breast cancer cells.

Oleanane saponins from Gymnema sylvestre.

Six oleanane-type saponins, along with two known triterpene saponins, were isolated from the leaves of Gymnema sylvestre. The structures of the oleanane triterpene glycosides were characterized as longispinogenin 3-O-beta-D-glucuronopyranoside, 21 beta-benzoylsitakisogenin 3-O-beta-D-glucuronopyranoside, 3-O-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl ester, oleanolic acid 3-O-beta-D-xylopyranosyl(1-->6)-beta-D-glucopyranosyl(1-->6)-beta-D- glucopyranoside, 3-O-beta-D-xylopyranosyl(1-->6)-beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl ester and 3-O-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl oleanolic acid 28-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl ester on the basis of hydrolysis and spectral evidence, including 1D- and 2D-NMR (TOCSY, ROESY, HMQC and HMBC) and FABMS analyses.

Bufotalin from Venenum Bufonis inhibits growth of multidrug resistant HepG2 cells through G2/M cell cycle arrest and apoptosis

Venenum Bufonis, a traditional Chinese medicine, is widely used in the treatment of liver cancer in modern Chinese medical practices. In our search for anti-hepatoma constituents in Venenum Bufonis, bufotalin, bufalin, telocinobufagin and cinobufagin were obtained. Bufotalin was the most potent active compound among these four bufadienolides, and it exerted stronger inhibitory effect on the viability of doxorubicin-induced multidrug resistant liver cancer cells (R-HepG2) than that of their parent cells HepG2. Structure-activity relationship analysis indicated that the acetyl group linked to C-16 of bufadienolides might be useful for increasing anti-hepatoma activity. Further mechanistic studies revealed that bufotalin treatment induced cell cycle arrest at G(2)/M phase through down-regulation of Aurora A, CDC25, CDK1, cyclin A and cyclin B1, as well as up-regulation of p53 and p21. Bufotalin treatment also induced apoptosis which was accompanied by decrease in mitochondrial membrane potential, increases in intracellular calcium level and reactive oxygen species production, activations of caspase-9 and -3, cleavage of poly ADP-ribose polymerase (PARP) as well as changes in the expressions of bcl-2 and bax. It was also found that the inhibition of Akt expression and phosphorylation was involved in apoptosis induction, and specific Akt inhibitor LY294002 or siRNA targeting Akt can synergistically enhanced bufotalin-induced apoptosis. In vivo study showed that bufotalin significantly inhibited the growth of xenografted R-HepG2 cells, without body weight loss or marked toxicity towards the spleen. These results indicate that bufotalin has a promising potential to become a novel anti-cancer agent for the treatment of liver cancer with multidrug resistance.

Betulinic Acid and its Derivatives as Potential Antitumor Agents

Betulinic acid (BA) is a lupane‐type pentacyclic triterpene, distributed ubiquitously throughout the plant kingdom. BA and its derivatives demonstrate multiple bioactivities, particularly an antitumor effect. This review critically describes the recent research on isolation, synthesis, and derivatization of BA and its natural analogs betulin and 23‐hydroxybetulinic acid. The subsequent part of the review focuses on the current knowledge of antitumor properties, combination treatments, and pharmacological mechanisms of these compounds. A 3D‐QSAR analysis of 62 BA derivatives against human ovarian cancer A2780 is also included to provide information concerning the structure–cytotoxicity relationships of these compounds.

Copy number variations of interleukin-17F, interleukin-21, and interleukin-22 are associated with systemic lupus erythematosus.

OBJECTIVE Systemic lupus erythematosus (SLE) represents the classic prototype of systemic autoimmune disease. The identification of the Th17 cell subset has provided new understanding regarding the underlying mechanisms of autoimmunity. Copy number variations (CNVS) have been discovered to have phenotypic consequences and are associated with various types of diseases. We undertook this study to explore a possible association between CNVS of Th17 cell-related genes and the risk of SLE. METHODS We extracted genomic DNA and RNA from 938 SLE patients and 1,017 healthy controls. We examined CNVS of Th17 cell-related genes, including retinoic acid receptor-related orphan nuclear receptor γt, STAT-3, interleukin-6 (IL-6), transforming growth factor β, tumor necrosis factor α, IL-17A, IL-17F, IL-21, IL-22, IL-23A, CCL20, and CCR6, and levels of messenger RNA (mRNA) for IL-17F, IL-21, and IL-22. RESULTS Genotype and allele frequencies for copy number amplifications of IL-17F, IL-21, and IL-22 were found to be significantly higher in SLE patients than in healthy controls. CNVS of IL-17F, IL-21, and IL-22 had no synergistic contribution to SLE. The mRNA expression of IL-17F, IL-21, and IL-22 in the samples with >2 copies of DNA was significantly higher than that in those with 2 copies of DNA. CONCLUSION Our findings indicate that CNVS of IL-17F, IL-21, and IL-22 are associated with the risk of SLE.