Flavonoid constituents,cytotoxic and antioxidant activities of Gleditsia triacanthos L. leaves

Gleditsia triacanthos L. is a deciduous tree belonging to the family Fabaceae. It possesses important biological activities as anti-mutagenic, anticancer, cytotoxic and treating rheumatoid arthritis. The total ethanol extract (EtOHE) and successive extracts (petroleum ether, chloroform, ethyl acetate, and aqueous ethanol) were prepared from the leaves. Eight flavone glycosides and two flavone aglycones named vicenin-I (1), vitexin (2), isovitexin (3), orientin (4), isoorientin (5), luteolin-7-O-ß-glucopyranoside (6), luteolin-7-O-ß-galactopyranoside (7), apigenin-7-O-ß-glucopyranoside (8), luteolin (9) and apigenin (10) were isolated from the aqueous ethanol extract of G. triacanthos L. leaves. Potent cytotoxic activity of the EtOHE extract was observed against the liver (IC₅₀ = 1.68 μg), breast (IC₅₀ = 0.74 μg), cervix (IC₅₀ = 1.28 μg), larynx (IC₅₀ = 0.67 μg) and colon (IC₅₀ = 2.50 μg) cancer cell lines. Cytotoxic activity of compounds 2, 4, 6 and 8 against, the liver, breast and colon cancer cell lines was also proved. Evaluation of the in-vivo antioxidant activity of the EtOHE and successive extracts revealed that the highest activity was exhibited by 100 mg of EtOHE (97.89% potency) as compared with vitamin E (100% potency). Compound 6 showed 91.8% free radical scavenging activity.     

Characterisation of lepidopteran-active Bacillus thuringiensis isolates recovered from infected larvae

Abstract

As a part of an ongoing nationwide programme focused on finding novel strains of Bacillus thuringiensis (Bt) that are toxic to some of the major pests that impact economically important crops, we initiated a search for Bt isolates native to Syria. We succeeded in assembling a collection of 40 Bt isolates recovered from infected larvae of Galleria mellonella, Helicoverpa armigera and Ephestia kuehniella. Light microscopy showed that all isolates produce bipyramidal and cuboidal crystal proteins. The 50% lethal concentration of the spore-crystal mixture of the 40 isolates against E. kuehniella larvae varied from 3 to more than 200 µg g^?1. A comparison of the LC₅₀ values of the tested isolates with the reference strain Bt kurstaki HD-1 (20.55 µg g^?1), showed that some of these isolates have a similar or up to six times higher toxicity potential. PCR screening revealed that all obtained isolates contain cry1 and cry2 genes, whereas only four contain cry9. Moreover, the proteins of 130 and 65/70 Kda encoded by these genes were detected in the SDS-PAGE of the purified parasporal bodies. Flagellar serotyping classified 30 as serovar kurstaki, six isolates serovar aizawai, one isolate cross-reacted with more than one H3 antisera and three were not typeable. Assays of toxicity of the aizawai isolates against third instar of G. mellonella showed that four, which contain cry9, have almost similar toxicity to the commercial strain Bt aizawai B401. Therefore, these isolates could be adopted for future applications to control G. mellonella. Moreover, this study contributes to our knowledge of Bt diversity in Syria where to date very few collections have been described.     

Effect of fungi–termite interaction on the chlorophyll content of three rice varieties grown on ultisol soil of Ikenne,south-west Nigeria

The effect of fungi–termite interaction on three rice varieties was conducted in a screen house at the Africa Rice Center (AfricaRice) Ibadan, Nigeria. Of the 10 fungi species (Fusarium verticilloides, Trichoderma sp., Aspergillus niger, Aspergillus flavus, Macrophoma sp., Neurospora sp., Botryodiplodia theobromae, Penicillum sp., Rhizopus sp. and Sclerotium rolfsii) isolated from termites, soil and rice plants, F. verticilloides, Trichoderma sp. and B. theobromae were used for the interaction study. Each fungus was inoculated singly and in combinations with termite into the root of each rice variety in potted soil. Leaf samples were taken to measure the chlorophyll content which is a major parameter to estimate effect of termite–fungi interaction. The chlorophyll content of the inoculated rice plants was significantly reduced when compared with the control. Fungi interaction with termite had significant reduction on the chlorophyll content. The synergistic relationship between the fungi and the termite was discussed.     

Cucurbitacins from Ecballium elaterium juice increase the binding of bilirubin and ibuprofen to albumin in human plasma

Ecballium elaterium, a medicinal plant, whose fruit juice is used for the treatment of jaundice in folk medicine, has been reported as being capable of decreasing bilirubinemia in animals with jaundice [H.H. Elayan, M.N. Garaibeh, S.M. Zmeili, S.A. Salhab, Effects of Ecballium elaterium juice on serum bilirubin concentration in male rats, Int. J. Crude Drug Res. 27 (1989) 227-234]. The aim of this study is to identify the Ecballium elaterium components, which are able to modify the binding of bilirubin to albumin. The juice is fiber-free but contains proteins, lipids, sugars, and minerals. The extract of the juice, analyzed by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS), contains cucurbitacins (Cuc) B, D, E, and I as well as several glycosylated compounds. Human plasma containing no or serial concentrations of Ecballium elaterium components were prepared and the direct bilirubin (DB) and total bilirubin (TB) were determined by the Jendrassik and Grof method. Our results showed that Cuc D, E, and B decreased the levels of DB and TB in plasma, while Cuc I, glycosyl derivatives, and proteins of the juice did not modify the bilirubin levels. The binding of domain specific ligands to HSA, bilirubin (domain IIA), and ibuprofen (domain IIIA), were studied in the absence and presence of Cuc D, E, and I, by fluorescence spectroscopy. The values of binding constant K(a) and binding site number n, determined by Scatchard method, increased for the both ligands only in the presence of Cuc E and D. Cuc I decreased slightly the K(a) of ibuprofen, suggesting an interaction with the domain IIIA of the protein. As a conclusion, Cuc E, D, and B produce rearrangement in the structure of albumin leading to increase the binding of domain specific ligands, ibuprofen and bilirubin.     

Osteoactivin promotes breast cancer metastasis to bone

The skeleton is a preferred site of metastasis in patients with disseminated breast cancer. We have used 4T1 mouse mammary carcinoma cells, which metastasize to bone from the mammary fat pads of immunocompetent mice, to identify novel genes involved in this process. In vivo selection of parental cells resulted in the isolation of independent, aggressively bone metastatic breast cancer populations with reduced metastasis to the lung. Gene expression profiling identified osteoactivin as a candidate that is highly and selectively expressed in aggressively bone metastatic breast cancer cells. These cells displayed enhanced migratory and invasive characteristics in vitro, the latter requiring sustained osteoactivin expression. Osteoactivin depletion in these cells, by small interfering RNA, also lead to a loss of matrix metalloproteinase-3 expression, whereas forced osteoactivin expression in parental 4T1 cells was sufficient to elevate matrix metalloproteinase-3 levels, suggesting that this matrix metalloproteinase may be an important mediator of osteoactivin function. Overexpression of osteoactivin in an independent, weakly bone metastatic breast cancer cell model significantly enhanced the formation of osteolytic bone metastases in vivo. Finally, high levels of osteoactivin expression in primary human breast cancers correlate with estrogen receptor-negative status and increasing tumor grade. Thus, we have identified osteoactivin as a protein that is expressed in aggressive human breast cancers and is capable of promoting breast cancer metastasis to bone.