Dykellic acid inhibits cell migration and tube formation by RhoA-GTP expression.

Dykellic acid, a novel factor initially identified from the culture broth of Westerdykella multispora F50733, has been shown to inhibit matrix metalloprotease 9 activity, caspase-3 activity, B cell proliferation and LPS-induced IgM production, suggesting that this factor may have anti-cancer effects. In an effort to further address the possible anti-tumoral effects of dykellic acid, we used wound healing, invasion and RhoA-GTP assays to examine the effects of dykellic acid on cell migration, invasion and angiogenesis. Our results revealed that dykellic acid dose-dependently inhibits B16 cell migration and motility, and inhibits HUVEC tube formation. Western blot analysis of the active form of RhoA (RhoA-GTP) showed that dykellic acid treatment decreased the levels of RhoA-GTP. These findings collectively suggest that dykellic acid may have both anti-metastatic and anti-angiogenic acitivites, and provides the first evidence for the involvement of RhoA in dykellic acid-induced effects.

The coffee diterpene kahweol suppress the inducible nitric oxide synthase expression in macrophages.

Excessive nitric oxide production by inducible nitric oxide synthase (iNOS) in stimulated inflammatory cells is thought to be a causative factor of cellular injury in cases of inflammation. In recent studies, it has been shown that kahweol, coffee-specific diterpene, exhibit chemoprotective effects. In this study, we investigated the effects of kahweol on the production of and the expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages. The nitrite production induced by LPS was markedly reduced in a dose-dependent manner. In addition, kahweol suppressed the expression of iNOS protein and iNOS mRNA. Since iNOS transcription has been shown to be under the control of the transcription factor, NF-kappaB, the effects of kahweol on NF-kappaB activation were examined. Transient transfection experiments showed that kahweol inhibited NF-kappaB-dependent transcriptional activity. Moreover, electrophoretic mobility shift assay experiments indicated that kahweol blocked the LPS-induced activation of NF-kappaB. The results of these studies suggest that the suppression of the transcriptional activation of iNOS by kahweol might be mediated through the inhibition of NF-kappaB activation. Taken together, the results of our study provide evidence that kahweol possess an anti-inflammatory potential, which constitutes a previously unrecognized biologic activity, and which may provide new insights into the inflammatory process.

Dykellic acid inhibits phorbol myristate acetate-induced matrix metalloproteinase-9 expression by inhibiting nuclear factor kappa B transcriptional activity.

Proteolytic degradation of the extracellular matrix and tumor metastasis correlate with expression of endopeptidases known as matrix metalloproteinases (MMPs). Expression of MMPs is regulated by cytokines and signal transduction pathways, including those activated by phorbol myristate acetate. We found that dykellic acid, a fungal metabolite, significantly inhibits the phorbol myristate acetate-induced increase in MMP-9 expression and activity. These effects of dykellic acid are time- and dose-dependent, and correlate with decreased MMP-9 promoter activity and mRNA expression. Whereas this compound does not affect DNA binding activity of nuclear factor kappa B (NF kappa B), dykellic acid does inhibit transactivation of NF kappa B. These data demonstrate a role for NF kappa B in the regulation of MMP-9 expression and the ability of dykellic acid to suppress this action of NF kappa B.

Dykellic acid inhibits drug-induced caspase-3-like protease activation.

Dykellic acid is a novel microbial metabolite isolated from the broth of Westerdykella multispora F50733. Investigations on the molecular function of dykellic acid revealed that this compound partially inhibits calcium influx, resulting in a decrease in Ca(2+)-dependent endonuclease activation and DNA fragmentation induced by camptothecin. In our experiments, active caspase-3-like protease cleavage of procaspase-3, PARP, and cytosolic cytochrome c was inhibited by dykellic acid in a concentration-dependent manner when the apoptosis was induced by camptothecin as well as doxorubicin. We confirmed that dykellic acid did not bind to camptothecin using surface plasmon resonance analysis. These results suggest that dykellic acid inhibits drug-induced apoptosis via a caspase-3-like protease-suppressing mechanism. Our data provide important information on the mechanism of action of dykellic acid and indicate that this compound may be employed in the treatment of specific caspase-3-like protease-mediated diseases.

Brine shrimp lethality of the compounds from Phryma leptostachya L.

Brine shrimp assay-guided fractionation and isolation of the EtOAc soluble fraction of Phryma leptostachya L. (Phrymacaceae) gave two active compounds, phrymarolin II (1) and ursolic acid (2), which were identified by physicochemical and spectroscopic methods. Compound 1 exhibited potent lethality with LD50 value of 0.0013 microg/ml, whereas 2 showed moderate lethality with LD50 value of 27.0 microg/ml against brine shrimp. The cytotoxic activities of 1 and 2 were also evaluated against one murine and five human cancer cell lines employing the sulforhodamin B (SRB) method. Compound 2 exhibited cytotoxic activity against L1210 and SK-MEL-2 cells with ED50 values of 3.70 and 9.27 mg/ml, respectively, whereas 1 was devoid of any cytotoxic activity against all cancer cells tested.

Eucosterol oligoglycosides isolated from Scilla scilloides and their anti-tumor activity.

Two new eucosterol oligoglycosides, 15-deoxo-30-hydroxyeucosterol 3-O-alpha-L-rhamnopyranosyl-(1-->2)-[(beta-D-glucopyranosyl-(1-->3)]-beta-D-glucopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-beta-D-glucopyranoside (scillanoside L-1, 1) and 3beta,31-dihydroxy-17alpha,23-epoxy-5alpha-lanost-8-en-23,26-olactone 3-O-alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->3)]-beta-D-glucopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)-beta-D-glucopyranoside (scillanoside L-2, 2), were isolated from the bulbs of Scilla scilloides, together with four that were known (3-6), have been isolated from the bulbs of Scilla scilloides. The structures of the new compounds were determined on the basis of spectroscopic and chromatographic methods, and some chemical transformations were discussed. Amongst the isolated compounds, 3 showed the most significant cytotoxicity against tumor cells tested several types with ED(50) value of 1.53-3.06 nM. In vivo experiments, 3 apparently increased the life span of mice bearing Sarcoma 180 tumor cell with T/C value of 239% at dose of 3 mg/kg.

Agastinol and agastenol, novel lignans from Agastache rugosa and their evaluation in an apoptosis inhibition assay.

Investigation of the whole plant of Agastache rugosa resulted in the isolation of two new lignan compounds. Their structures were elucidated as (8S,7'R,8'S)-4-hydroxybenzoic acid 4-(4-hydroxy-3-methoxybenzyl)-2-(4-hydroxy-3-methoxyphenyl)tetrahydrofuran-3-ylmethyl ester (agastinol, 1) and (7'R,8'S)-4-hydroxybenzoic acid 4-(hydroxy-3-methoxybenzylidene)-2-(4-hydroxy-3-methoxyphenyl)-tetrahydrofuran-3-ylmethyl ester (agastenol, 2). Agastinol and agastenol inhibited etoposide-induced apoptosis in U937 cells with IC50 values of 15.2 and 11.4 microg/mL, respectively.