Asmita Samadder

Biosynthesized silver nanoparticles by ethanolic extracts of Phytolacca decandra, Gelsemium sempervirens, Hydrastis canadensis and Thuja occidentalis induce differential cytotoxicity through G2/M arrest in A375 cells

The capability of crude ethanolic extracts of certain medicinal plants like Phytolacca decandra, Gelsemium sempervirens, Hydrastis canadensis and Thuja occidentalis used as homeopathic mother tinctures in precipitating silver nanoparticles from aqueous solution of silver nitrate has been explored. Nanoparticles thus precipitated were characterized by spectroscopic, dynamic light scattering, X-ray diffraction, atomic force and transmission electron microscopic analyses. The drug-DNA interactions of silver nanoparticles were analyzed from data of circular dichroism spectroscopy and melting temperature profiles using calf thymus DNA (CT-DNA) as target. Biological activities of silver nanoparticles of different origin were then tested to evaluate their effective anti-proliferative and anti-bacterial properties, if any, by exposing them to A375 skin melanoma cells and to Escherichia coli C, respectively. Silver nanoparticles showed differences in their level of anti-cancer and anti-bacterial potentials. The nanoparticles of different origin interacted differently with CT-DNA, showing differences in their binding capacities. Particle size differences of the nanoparticles could be attributed for causing differences in their cellular entry and biological action. The ethanolic extracts of these plants had not been tested earlier for their possible efficacies in synthesizing nanoparticles from silver nitrate solution that had beneficial biological action, opening up a possibility of having therapeutic values in the management of diseases including cancer.

Poly (lactide-co-glycolide) acid nanoencapsulation of a synthetic coumarin: cytotoxicity and bio-distribution in mice, in cancer cell line and interaction with calf thymus DNA as target.

Several naturally occurring coumarin compounds, including scopoletin (7 hydroxy-6 methoxycoumarin), of plant origin have been reported to have anti-cancer potentials. A related but chemically synthesized coumarin, 4-methyl-7-hydroxy coumarin (SC), was also shown to have similar anti-cancer potentials. In the present study, to test if nano-encapsulated SC could be a more potent anti-cancer agent, we encapsulated SC with poly lactide-co-glycolide acid (PLGA) nanoparticles (Nano Coumarin; NC) and tested its potentials with a variety of protocols. NC demonstrated greater efficiency of drug uptake and showed anti-cancer potentials in melanoma cell line A375, as revealed from scanning electronic and atomic force microscopies. To test its possible interaction with target DNA, the combined data of circular dichroism spectra (CD) and melting temperature profile (T(m)) of calf thymus DNA treated with NC were analyzed. Results indicated a concentration dependent interaction of NC with calf thymus DNA, bringing in effective change in structure and conformation, and forming a new complex that increased its stability. Particle size and morphology of NC determined through polydispersity index and zeta potential using dynamic light scattering qualified NC to be a more potent anti-cancer agent than SC. Further, SC and NC showed negligible cytotoxic effects on normal skin cells and peripheral blood mononuclear cells of mice. Distribution assay of PLGA nanoparticles in different tissues like brain, heart, kidneys, liver, lungs, and spleen in mice revealed the presence of nanoparticles in different tissues including brain, indicating that the particles could cross the blood brain barrier, significant information for drug design.

Rhodamine-based bis-sulfonamide as a sensing probe for Cu2+ and Hg2+ ions

A new rhodamine-based bis-sulfonamide 1 has been designed and synthesized. The receptor selectively recognizes Cu2+ and Hg2+ ions in CH3CN–water (4/1, v/v; 10 μM tris HCl buffer, pH 6.8) by showing different emission characteristics and color changes. While Cu2+ is sensed through increase in emission, Hg2+ is detected by a weak ratiometric change in emission of 1. The receptor shows in vitro detection of both the ions in human cervical cancer (HeLa) cells.

Poly (lactide-co-glycolide) encapsulated extract of Phytolacca decandra demonstrates better intervention against induced lung adenocarcinoma in mice and on A549 cells

We tested relative efficacy of the extract of Phytolacca decandra (PD) and its PLGA nano-encapsulated form (NPD) in mice intoxicated with benzo[a]pyrene (BaP) (25 mg/kg b.w.) plus sodium-arsenite (SA) (10 mg/kg b.w.) and on A549 lung cancer cells in vitro. We characterized nanoparticles by physico-chemical and morphological studies using dynamic light scattering, scanning electron and atomic force microscopies. We also conducted FTIR and (1)H NMR studies to determine if NPD had a co-polymeric nature and analyzed drug-DNA interaction through circular dichroism spectra (CD) and melting temperature profiles (T(m)) taking calf thymus DNA as target. An oral dose of 0.3mg/kg b.w. for NPD and 30 mg/kg b.w. for PD in mice showed chemopreventive effects in regard to DNA fragmentation, comet tail length and toxicity biomarkers like ROS generation, NFκβ, p53, PARP, CYP1A1 and caspase 3. NPD showed greater effects than that by PD. Results of in vivo studies showed similar effects on A549 in regard to cell viability, DAPI and PI staining, Comet tail length, DNA fragmentation. To further confirm the biological molecule present in PD we analyzed its chromatographic fraction through mass spectroscopy, NMR and FT-IR studies and characterized it to be a tri-terpenoid, a derivative of betulinic acid with a molecular formula C(30)H(46)O(2.) Thus, overall results suggest that nano-encapsulation of PD (NPD) increases drug bioavailability and thereby has a better chemo-preventive action against lung cancer in vivo and on A549 cells in vitro than that of PD.

Apigenin-induced apoptosis in A375 and A549 cells through selective action and dysfunction of mitochondria

We isolated apigenin (5,7,4’-trihydroxy flavone) from ethanolic extract of Lycopodium clavatum (LC) used as a homeopathic mother tincture for treatment of various diseases. We assessed the anticancer potentials of the compound using human malignant melanoma cell line A375 and a lung carcinoma cell line A549 and focussed on its putative molecular mechanism of action on apoptosis induction. We examined the cytotoxicity of apigenin in both cancer cells and normal peripheral blood mononuclear cells (PBMC). A375 cells were more prone to apigenin-induced apoptosis, as compared with A549 cells after 24 h of treatment, while PBMC showed little or no cytotoxicity to apigenin. We also evaluated the effects of apigenin on interaction with DNA by comparative analysis of circular dichroism spectral data and melting temperature profiles (Tm) of calf thymus DNA (CT-DNA) treated with or without apigenin. Reactive oxygen species (ROS) accumulation in mitochondria, super-oxide dismutase and total thiol group (GSH) activities were also analyzed. The apoptotic process involved mitochondrial pathway associated with apigenin-DNA interaction, DNA fragmentation, ROS accumulation, cytochrome c (cyt c) release and mitochondrial transmembrane potential depolarization, Bax, caspase 3, 9, PARP, up-regulation, Bcl-2 down-regulation and down-regulation of cyt c in the mitochondrial fraction. Results of mitochondrial inner membrane swelling measurements, intracellular ADP/ATP ratio and ATPase activity showed that in A549 cells, apigenin did not appear to directly target the mitochondrial oxidative phosphorylation system but rather acted at an upstream step to activate the mitochondrial apoptotic pathway. However, apigenin could directly target and impair mitochondrial function in A375 cells by breaking down their oxidative phosphorylation system. Collectively, these results suggest that apigenin exhibits anticancer potential in A375 and A549 cells that may be mediated through DNA interaction, damage and mitochondrial dysfunction either by direct or indirect action on mitochondrial oxidative phosphorylation system.

Efficacy of PLGA-loaded apigenin nanoparticles in Benzo[a]pyrene and ultraviolet-B induced skin cancer of mice: Mitochondria mediated apoptotic signalling cascades

Skin cancer is increasing at an alarming rate and becoming resistant to conventional chemotherapy necessitating improved drug delivery system. We loaded apigenin (Ap), a dietary flavonoid having anti-cancer property, with poly (lactic-co-glycolide) (PLGA) nanoparticles (NAp) to explore if nano-encapsulation could enhance anti-carcinogenic effect against ultra-violet B (UVB) and Benzo(a)pyrene (BaP) induced skin tumor and mitochondrial dysfunction in mice. Particle size, morphology and zeta potential of NAp were determined using dynamic light scattering and atomic force microscopy. Tumor incidence and multiplicity in UVB-BaP induced mice with/without NAp treatment were ascertained and their histolopathological sections and chromosomal aberrations were studied. ROS accumulation and mitochondrial functioning through relevant markers like mitochondrial transmembrane potential were analyzed. Mitochondrial volume changes/swelling, cytochrome c (cyt c) release, mRNA and protein expressions of Apaf-1, bax, bcl-2, cyt c, cleaved caspase-9 and 3 were studied. Results showed that NAp produced better effects than Ap, due to their smaller size, and faster mobility. NAp reduced tissue damage and frequency of chromosomal aberrations, increased ROS accumulation to mediate mitochondrial-apoptosis through modulation of several apoptotic markers and mitochondrial matrix swelling. NAp showed ameliorative potentials in combating skin cancer and therefore has greater prospect of use in therapeutic management of skin cancer.

Strategic formulation of apigenin-loaded PLGA nanoparticles for intracellular trafficking, DNA targeting and improved therapeutic effects in skin melanoma in vitro.

The aim of the present study was the evaluation of anti-proliferative potentials of apigenin (Ap), (a dietary flavonoid) loaded in poly (lactic-co-glycolide) nanoparticles (NAp) in A375 cells in vitro. NAp was characterized for particle size, morphology, zeta potential, drug release and encapsulation. Cellular entry and intracellular localization of NAp were assessed by transmission electron and confocal microscopies. Circular dichroic spectral analysis and stability curve for Gibbs free energy of dsDNA of A375 cells were also analyzed. DNA fragmentation, intracellular ROS accumulation, superoxide-dismutase activity, intracellular glutathione-reductase content and mitochondrial functioning through relevant markers like mitochondrial transmembrane potential, ATPase activity, ATP/ADP ratio, volume changes/swelling, cytochrome-c release, expressions of Apaf-1, bax, bcl-2, caspase-9, 3, and PARP cleavage were analyzed. NAp produced better effects due to their smaller size, faster mobility and site-specific action. Photostability studies revealed that PLGA encapsulations were efficient at preserving apigenin ultraviolet-light mediated photodegradation. NAp readily entered cancer cells, could intercalate with dsDNA, inducing conformational change. Corresponding increase in ROS accumulation and depletion of the antioxidant enzyme activities exacerbated DNA damage, mediating apoptosis through mitochondrial dysfunction. Overall results indicate that therapeutic efficacy of NAp may be enhanced by PLGA nanoparticle formulations to have better ameliorative potentials in combating skin melanoma.

Cytotoxicity and apoptotic signalling cascade induced by chelidonine-loaded PLGA nanoparticles in HepG2 cells in vitro and bioavailability of nano-chelidonine in mice in vivo

Poor oral bioavailability of chelidonine, a bio-active ingredient of Chelidonium majus, showing anti-cancer potentials against cancer cells with multidrug resistance, makes its optimal use rather limited. To address this problem, we encapsulated chelidonine in biodegradable poly(lactide-co-glycolide) (PLGA) polymers and evaluated nano-chelidonines (NCs) anti-cancer efficacy vis-à-vis free chelidonine (FC) against HepG2 cells and also evaluated its bioavailability in mice. Physicochemical characteristics indicated that stable spherical NC were formed in nanometer size range (123±1.15 nm) with good yield (86.34±1.91%), better encapsulation efficiency (82.6±0.574%), negative surface charge (-19.6±2.48 mV) and ability of prolonged and sustained release of chelidonine. Fourier transform infrared analysis revealed that NC resembled similar peaks as that of FC suggesting effective encapsulation in PLGA. NC exhibited rapid cellular uptake and stronger apoptotic effect (∼46.6% reduced IC₅₀ value) than FC, blocking HepG2 cells at G2/M phase. p53, cyclin-D1, Bax, Bcl-2, cytochrome c, Apaf-1, caspase-9 and caspase-3 expressions also corroborated well to suggest greater anticancer potentials of NC. Our in vivo studies demonstrated NC to be more bio-available than FC and showed a better tissue distribution profile without inducing any toxicity (100 mg/kg bw) in mice. Unlike FC, NC could permeate into brain tissue, indicating thereby NCs better potentials for use in therapeutic oncology.

Apigenin, a Bioactive Flavonoid from Lycopodium clavatum, Stimulates Nucleotide Excision Repair Genes to Protect Skin Keratinocytes from Ultraviolet B-Induced Reactive Oxygen Species and DNA Damage

In this study, we examined the antioxidative and the DNA protective potentials of apigenin, a flavonoid polyphenol isolated from Lycopodium clavatum, in both in-vitro (HaCaT skin keratinocytes) and in-vivo (mice) models against UV-B radiation. We used DAPI staining in UV-B-irradiated HaCaT skin keratinocytes pre-treated with and without apigenin to assess DNA damage. We also used a flow-cytometric analysis in mice exposed to UV-B radiation with or without topical application of apigenin to assess, through a comet assay, chromosomal aberrations and quanta from reactive oxygen species (ROS) generation. Data from the stability curves for the Gibbs free energy determined from a melting-temperature profile study indicated that apigenin increased the stability of calf thymus DNA. Immunofluorescence studies revealed that apigenin caused a reduction in the number of cyclobutane pyrimidine dimers (CPDs) after 24 h, the time at which the nucleotide excision repair (NER) genes were activated. Thus, apigenin accelerated reversal of UV-B-induced CPDs through up-regulation of NER genes, removal of cyclobutane rings, inhibition of ROS generation, and down-regulation of NF-κB and MAPK, thereby revealing the precise mechanism of DNA repair.

Diarylheptanoid–myricanone isolated from ethanolic extract of Myrica cerifera shows anticancer effects on HeLa and PC3 cell lines: signalling pathway and drug-DNA interaction

OBJECTIVE To test if myricanone (C21H24O5), a cyclic diarylheptanoid, has anticancer effects on two different cancer cell lines HeLa and PC3. The present study was conducted with a note on the drug-DNA interaction and apoptotic signalling pathway. METHODS Several studies like cytotoxicity, nuclear damage, annexin-V-fluorescein isothiocyanate (FITC)/propidium iodide (PI)-labelled apoptotic assay and cell cycle arrest, immunoblot and reverse transcriptase-polymerase chain reaction (RT-PCR) were used following standard protocols. Circular dichroism (CD) spectroscopy was also done to evaluate whether myricanone effectively interacted with DNA to bring about conformational changes that could strongly inhibit the cancer cell proliferation. RESULTS Myricanone showed a greater cytotoxic effect on PC3 cells than on HeLa cells. Myricanone promoted G0/G1 arrest in HeLa cells and S phase arrest in PC3 cells. Nuclear condensation and annexin V-FITC/PI studies revealed that myricanone promoted apoptotic cell death. CD spectroscopic data indicated that myricanone had an interaction with calf thymus DNA that changed DNA structural conformation. RT-PCR and immunoblot studies revealed that myricanone activated the apoptotic signalling cascades through down-regulation of transcription factors like nuclear factor-κB (NF-κB) (p65), and signal transducers and activators of transcription 3 (STAT3); cell cycle regulators like cyclin D1, and survivin and other signal proteins like Bcl-2 and up-regulation of Bax, caspase-9 and caspase-3. CONCLUSION Myricanone induced apoptosis in both types of cancer cells by triggering caspase activation, and suppression of cell proliferation by down-regulation of NF-κB and STAT3 signalling cascades, which makes it a suitable candidate for possible use in the formulation of therapeutic agent for combating cancer.