A new mixed inhibitor of adenosine deaminase produced by endophytic Cochliobolus sp. from medicinal plant seeds.

Medicinal plants have been studied for potential endophytic interactions and numerous studies have provided evidence that seeds harbor diverse microbial communities, not only on their surfaces but also within the embryo. Adenosine deaminase (ADA) is known as a potential therapeutic target for the treatment of lymphoproliferative disorders and cancer. Therefore, in this study, 20 types of medicinal plant seeds were used to screen endophytic fungi with tissue homogenate and streak. In addition, 128 morphologically distinct endophyte strains were isolated and their ADA inhibitory activity determined by a spectrophotometric assay. The strain with the highest inhibitory activity was identified as Cochliobolus sp. Seven compounds were isolated from the strain using a chromatography method. Compound 3 showed the highest ADA inhibitory activity and was identified as 5-hydroxy-2-hydroxymethyl-4H-pyran-4-one, based on the results of 1H and 13C NMR spectroscopy. The results of molecular docking suggested that compound 3 binds to the active site and the nonspecific binding site of the ADA. Furthermore, we found that compound 3 is a mixed ADA inhibitor. These results indicate that endophytic strains are a promising source of ADA inhibitors and that compound 3 may be a superior source for use in the preparation of biologically active ADA inhibitor compounds used to treat cancer.

Reynoutria Japonica from Traditional Chinese Medicine: A Source of Competitive Adenosine Deaminase Inhibitors for Anticancer.

BACKGROUND: Adenosine deaminase (ADA) is an important enzyme in purine metabolism and is known as a potential therapeutic target for the treatment of lymphoproliferative disorders and cancer. Traditional Chinese Herbal Medicine (TCHM) is widely used alone or in combination with chemotherapy to treat cancer, due to its ability to deliver a broad variety of bioactive secondary metabolites as promising sources of novel organic natural agents. OBJECTIVE: In the present study, 29 varieties of medicinal plants were screened for the presence of ADA inhibitors. RESULTS: Extracts from Reynoutria japonica, Glycyrrhiza uralensis, Lithospermum erythrorhizon, Magnolia officinalis, Gardenia jasminoides, Stephania tetrandra, Commiphora myrrha, Raphanus sativus and Corydalis yanhusuo demonstrated strong ADA inhibition with rates greater than 50%. However, Reynoutria japonica possessed the highest ADA inhibitory activity at 95.26% and so was used in our study for isolating the ADA inhibitor to be further studied. Eight compounds were obtained and their structures were identified. The compound H1 had strong ADA inhibitory activity and was deduced to be emodin by 1H and 13C-NMR spectroscopic analysis with an IC50 of 0.629 mM. The molecular docking data showed that emodin could bind tightly to the active site of ADA. Our results demonstrated that emodin displayed a new biological activity which is ADA inhibitory activity with high cytotoxic activity against K562 leukemia cells. The bioactivity of cordycepin was significantly increased when used in combination with emodin. CONCLUSION: Emodin may represent a good candidate anti-cancer therapy and adenosine protective agent.

Flavonoids from Inula britannica reduces oxidative stress through inhibiting expression and phosphorylation of p47(phox) in VSMCs.

CONTEXT: Inula britanica Linn. (Compositae) is a traditional Chinese medicinal herb that has been used to treat bronchitis and inflammation. The total flavonoid extracts (TFEs) isolated from its flowers can inhibit neointimal formation induced by balloon injury in vivo. OBJECTIVE: To investigate the mechanism by which TFE suppresses oxidative stress generation and the subsequent inflammation response in vitro. MATERIALS AND METHODS: The cultured vascular smooth muscle cells (VSMCs) form rats were exposed to oxidative stress following pretreatment with or without TFE at different concentration. Then, fluorescence staining was used to detect superoxide anion (O2(˙-)) production, and the lever of maleic dialdehyde (MDA) and superoxide dismutase (SOD) was measured at the same time. Furthermore, tumor necrosis factor-α (TNF-α) was measured by enzyme linked immunosorbent assay (ELISA), reverse transcription-PCR and western blot were performed to detect the expression activity of p47(phox) gene, and immunoprecipitation was used to test the level of p47(phox) phosphorylation. RESULTS: TFE inhibited the production of O2(˙-) induced by H2O2 in VSMCs, with decrease in secretion of TNF-α; elevated the activity of SOD in the medium, similar to the effect of quercetin; reduced the level of MDA in culture medium of VSMCs. The pretreatment with TFE resulted in decrease the level of p47(phox) mRNA and protein, and even p47(phox) phosphorylation in VSMCs, compared with H2O2 control. DISCUSSION AND CONCLUSION: These findings demonstrate that TFE is capable of attenuating the oxidative stress generation and the subsequent inflammation response via preventing the overexpression and activation of p47(phox) and the increased TNF-α secretion in VSMCs in vitro.