BackgroundBreast cancer is considered as an increasing major life-threatening concern among the malignancies encountered globally in females. Traditional therapy is far from satisfactory due to drug resistance and various side effects, thus a search for complementary/alternative medicines from natural sources with lesser side effects is being emphasized. Andrographis paniculata, an oriental, traditional medicinal herb commonly available in Asian countries, has a long history of treating a variety of diseases, such as respiratory infection, fever, bacterial dysentery, diarrhea, inflammation etc. Extracts of this plant showed a wide spectrum of therapeutic effects, such as anti-bacterial, anti-malarial, anti-viral and anti-carcinogenic properties. Andrographolide, a diterpenoid lactone, is the major active component of this plant. This study reports on andrographolide induced apoptosis and its possible mechanism in highly proliferative, invasive breast cancer cells, MDA-MB-231 lacking a functional p53 and estrogen receptor (ER). Furthermore, the pharmacokinetic properties of andrographolide have also been studied in mice following intravenous and oral administration.ResultsAndrographolide showed a time- and concentration- dependent inhibitory effect on MDA-MB-231 breast cancer cell proliferation, but the treatment did not affect normal breast epithelial cells, MCF-10A (>80 %). The number of cells in S as well as G2/M phase was increased after 36 h of treatment. Elevated reactive oxygen species (ROS) production with concomitant decrease in Mitochondrial Membrane Potential (MMP) and externalization of phosphatidyl serine were observed. Flow cytometry with Annexin V revealed that the population of apoptotic cells increased with prolonged exposure to andrographolide. Activation of caspase-3 and caspase-9 were also noted. Bax and Apaf-1 expression were notably increased with decreased Bcl-2 and Bcl-xL expression in andrographolide-treated cells. Pharmacokinetic study with andrographolide showed the bioavailability of 9.27 ± 1.69 % with a Cmax, of 0.73 ± 0.17 μmol/L and Tmax of 0.42 ± 0.14 h following oral administration. AG showed rapid clearance and moderate terminal half lives (T1/2) of 1.86 ± 0.21 and 3.30 ± 0.35 h following IV and oral administration respectively.ConclusionThis investigation indicates that andrographolide might be useful as a possible chemopreventive/chemotherapeutic agent for human breast cancers.Electronic supplementary materialThe online version of this article (doi:10.1186/s12929-016-0257-0) contains supplementary material, which is available to authorized users.

This study focuses on the isolation and characterization of a high cadmium (Cd)-resistant bacterial strain, and possible exploitation of its Cd-accumulation and Cd-induced siderophore production property to improve plant growth in cadmium-contaminated soil through root colonization. The bacterial strain could tolerate up to 8 mM of Cd and could accumulate Cd intracellularly. The strain showed Cd-induced siderophore production maximally at 1.75 mM of Cd concentration under culture condition. It stimulated the growth of mustard and pumpkin plants in Cd-added soil through its establishment in rhizosphere. Through biochemical characterization and 16S rDNA sequence analysis, the strain KUCd1, as the name given to it, was identified as a strain of Pseudomonas aeruginosa.

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Increasing bacterial resistance to common drugs is a major public health concern for the treatment of infectious diseases. Certain naturally occurring compounds of plant sources have long been reported to possess potential antimicrobial activity. This study was aimed to investigate the antibacterial activity and possible mechanism of action of andrographolide (Andro), a diterpenoid lactone from a traditional medicinal herb Andrographis paniculata. Extent of antibacterial action was assessed by minimal bactericidal concentration method. Radiolabeled N-acetyl glucosamine, leucine, thymidine, and uridine were used to determine the effect of Andro on the biosyntheses of cell wall, protein, DNA, and RNA, respectively. In addition, anti-biofilm potential of this compound was also tested. Andro showed potential antibacterial activity against most of the tested Gram-positive bacteria. Among those, Staphylococcus aureus was found to be most sensitive with a minimal inhibitory concentration value of 100 μg/mL. It was found to be bacteriostatic. Specific inhibition of intracellular DNA biosynthesis was observed in a dose-dependent manner in S. aureus. Andro mediated inhibition of biofilm formation by S. aureus was also found. Considering its antimicrobial potency, Andro might be accounted as a promising lead for new antibacterial drug development.

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A cadmium (8 mM) resistant Pseudomonas aeruginosa strain KUCd1 exhibiting high Cd accumulation under in vitro aerobic condition has been reported. The isolate showed a significant ability to remove more than 75% and 89% of the soluble cadmium during the active growth phase from the growth medium and from Cd-amended industrial wastewater under growth supportive condition. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDXS) suggest the presence of Cd in the cells from mid-stationary phase. The cell fractionation study revealed membrane and periplasm to be the major accumulating site in this strain. The chemical nature of the accumulated Cd was studied by X-ray powder diffraction analysis.

This article reports on the isolation and characterization of a Cr(VI) resistant bacterial strain, having plant growth promoting properties to improve general growth of plant in chromium-contaminated soil through rhizosphere colonization. The strain was isolated from the sludge of waste canal carrying industrial effluents. The minimum inhibitory concentration of chromium to this strain was found to be 450 and 400 mM in complex and minimal media, respectively. The strain also showed varied degree of resistance to Cd, Co, As, Ni and Zn. It exhibited potential Cr(VI) reducing ability under aerobic culture conditions, and the factors affecting Cr(VI) reduction by this strain were evaluated. The optimum pH and temperature required to achieve maximum Cr(VI) reduction values were 7 and 35°C, respectively. Higher concentration of Cr(VI) slowed down the reduction, but with longer incubation time it reduced nearly all detectable amount of Cr(VI). The strain showed positive response to IAA production and phosphate solubilization. It promoted the growth of chilli plants in waste-fed soil with or without additional Cr through its establishment in rhizosphere. The successful establishment of KUCr3 in the rhizosphere of chilli plants helped to reduce Cr uptake by the test plant. This strain shows a promise that the multifarious role of this strain would be useful in the Cr-contaminated rhizosphere soil as a good bioremediation and plant growth promoting agent as well. Through biochemical characterization and 16S rDNA sequence analysis, the strain KUCr3, as the name given to it, was identified as a strain of Cellulosimicrobium cellulans.

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