In silico molecular docking and in vitro antioxidant activity studies of novel α-aminophosphonates bearing 6-amino-1,3-dimethyl uracil.

In the present study, a new series of α-Aminophosphonates bearing 6-amino-1,3-dimethyluracil was synthesized in good to excellent yields (78-95%) by one-pot, three-component reaction of 6-amino-1,3-dimethyluracil, aromatic aldehydes and diethylphosphite via Kabachnik-Fields reaction by using an eco-friendly Eaton's reagent. All the compounds were screened for in vitro antioxidant studies by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide (H2O2) methods. Among the synthesized bioactive molecules, 4a, 4d, 4g, and 4h exhibited promising antioxidant activity compared with the standard drug Ascorbic acid. Furthermore, in order to support the biological results of the compounds, molecular docking studies were performed against Aromatase enzyme for four compounds which revealed that the compounds 4a, 4d, 4g, and 4h have significant binding modes, with docking scores of -8.6, -8.4, -8.1 and -8.1 respectively and the compound 4b specifically has equal dock score of -8.0 when compared with the standard drug Exemestane.

Biogenesis of silver nanoparticles using leaf extract of Indigofera hirsuta L. and their potential biomedical applications (3-in-1 system).

The present study reports the biosynthesis of silver nanoparticles (IH-AgNPs) using aqueous leaf extract of Indigofera hisruta L. The biosynthesized IH-AgNPs were found to be FCC crystals, 5-10 nm in size, spherical in shape and stable. The biosynthesized IH-AgNPs showed dose-dependant cytotoxicity against prostate cancer (PC3) (IC50 = 68.5 µg/mL), colon cancer (COLO205) (IC50 = 85.2 µg/mL), and mouse melanoma (B16F10) (IC50 = 80.9 µg/mL). IH-AgNPs were found to be nontoxic towards normal CHO (Chinese hamster ovary) cells. The biosynthesized IH-AgNPs showed effective in vitro antioxidant activity against DPPH (IC50 = 63.43 µg/mL) and H2O2 (IC50 = 89.93 µg/mL) radicals. IH-AgNPs exhibited effective antibacterial activity against both Gram+ve and Gram-ve bacteria. MIC values of IH-AgNPs against S. aureus, B. subtilis, P. aeruginosa and E. coli were found to be 7.8 µg/mL, 3.9 µg/mL, 15.6 µg/mL and 15.6 µg/mL respectively. IH-AgNPs also showed inhibitory activity against fungal pathogens including C. albicans, C. nonalbicans and C. tropicalis. Considering the results together, we demonstrate that IH-AgNPs exhibits three different bioactivities (3-in-1 system) and they could be employed as future antimicrobial, antioxidant and anticancer agents/drug delivery vehicles in the field of biomedicine.

Potential anticancer activity of biogenic silver nanoparticles using leaf extract of Rhynchosia suaveolens: an insight into the mechanism.

The present study reports a simple and eco-friendly synthesis of silver nanoparticles (AgNPs) using leaf extract of Rhynchosia suaveolens. UV-Vis analysis of R. suaveolens synthesized AgNPs (RS-AgNPs) showed surface plasmon resonance (SPR) peak at 426 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis revealed that RS-AgNPs were 10-30 nm in size with spherical shape. X-ray diffraction (XRD) analysis of RS-AgNPs confirmed the crystalline nature with face-centered cubic (FCC) lattice. Fourier transform infrared (FTIR) interprets that polyphenols and proteins take part in bioreduction and capping of RS-AgNPs. RS-AgNPs exhibited dose-dependent inhibition of proliferation of different cancer cells including DU145 and PC-3(human prostate carcinoma cell lines), SKOV3 (human ovarian carcinoma) and A549 (human lung adenocarcinoma)with IC50 values of 4.35, 7.72, 4.2 and 24.7 µg/mL, respectively. The plausible reasons behind anticancer activity of RS-AgNPs were explained using different assays on the most susceptible SKOV3 cells. RS-AgNPs induced oxidative stress in SKOV3 cells by generating reactive oxygen species (ROS), enhancing lipid peroxidation (LPO) levels and decreasing glutathione (GSH) levels. RS-AgNPs induced the apoptosis of SKOV3 cells by up regulating the caspase-3, caspase -8, caspase -9, p53 and BAX and down regulating the antiapoptotic protein Bcl-2. Further, RS-AgNPs showed elevation of caspase 3/7 activity and also exhibited antimigratory effect by inhibiting the migration of SKOV3 cells into the wounded area. The findings suggested that biogenic RS-AgNPs provide an alternative approach to overcome several limitations of chemotherapy.

Biogenesis of silver nanoparticles using endophytic fungus Pestalotiopsis microspora and evaluation of their antioxidant and anticancer activities.

An endophytic fungal strain isolated from the leaves of Gymnema sylvestre was identified as Pestalotiopsis microspora VJ1/VS1 based on nucleotide sequencing of internal transcribed spacer region (ITS 1-5.8S-ITS 2) of 18S rRNA gene (NCBI accession number KX213894). In this study, an efficient and ecofriendly approach has been reported for the synthesis of silver nanoparticles (AgNPs) using aqueous culture filtrate of P. microspora. Ultraviolet-visible analysis confirmed the synthesis of AgNPs by showing characteristic absorption peak at 435 nm. Fourier transform infrared spectroscopy analysis revealed the presence of phenolic compounds and proteins in the fungal filtrate, which are plausibly involved in the biosynthesis and capping of AgNPs. Transmission electron microscopy (TEM) showed that the AgNPs were spherical in shape of 2-10 nm in size. Selected area electron diffraction and X-ray diffraction studies determined the crystalline nature of AgNPs with face-centered cubic (FCC) lattice phase. Dynamic light scattering analysis showed that the biosynthesized AgNPs possess high negative zeta potential value of -35.7 mV. Biosynthesized AgNPs were proved to be potential antioxidants by showing effective radical scavenging activity against 2,2'-diphenyl-1-picrylhydrazyl and H2O2 radicals with IC50 values of 76.95±2.96 and 94.95±2.18 µg/mL, respectively. The biosynthesized AgNPs exhibited significant cytotoxic effects against B16F10 (mouse melanoma, IC50 =26.43±3.41 µg/mL), SKOV3 (human ovarian carcinoma, IC50 =16.24±2.48 µg/mL), A549 (human lung adenocarcinoma, IC50 =39.83±3.74 µg/mL), and PC3 (human prostate carcinoma, IC50 =27.71±2.89 µg/mL) cells. The biosynthesized AgNPs were found to be biocompatible toward normal cells (Chinese hamster ovary cell line, IC50 =438.53±4.2 µg/mL). Cytological observations on most susceptible SKOV3 cells revealed concentration-dependent apoptotic changes that include cell membrane blebbing, cell shrinkage, pyknotic nuclei, karyorrhexis followed by destructive fragmentation of nuclei. The results together in this study strongly provided a base for the development of potential and versatile biomedical applications of biosynthesized AgNPs in the near future.

Endophytic fungal isolate mediated biosynthesis of silver nanoparticles and their free radical scavenging activity and anti microbial studies.

The present study reports that the biosynthesis of AgNPs using an endophytic fungus isolated from the ethnomedicinal plant Centella asiatica. The endophytic fungus was identified as Aspergillus versicolor ENT7 based on 18S rRNA gene sequencing (NCBI Accession number KF493864). The AgNPs synthesized were characterized by UV-visible spectroscopy, Fourier transform infra-red spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), particle size analyzer, and zeta potential measurements. The UV-Vis absorption spectra showed the peak at 429 nm which confirmed the synthesis of AgNPs. TEM analysis revealed that the AgNPs were spherical in shape with 3-40 nm in size; similar results were also obtained by Horiba particle size analyzer with 5-40 nm in size. The synthesized AgNPs were highly stable due to their high negative zeta potential value of -38.2 mV. XRD studies showed (111), (200), (220), (311), and (222) planes of the face-centered cubic (FCC) lattice, indicating the crystalline nature of the AgNPs. Selected area electron diffraction (SAED) pattern of the AgNPs showed five circular fringes which were in accordance with XRD data and confirmed the formation of high crystalline nature of AgNPs. FTIR measurements indicated the peaks at 3273, 2925, 1629, 1320, and 1020 cm-1 corresponding to different functional groups possibly involved in the synthesis and stabilization of AgNPs. The synthesized AgNPs exhibited effective free radical scavenging activity with the IC50 value of 60.64 µg/ml. The synthesized AgNPs were found to be highly toxic against both gram-positive and gram-negative bacteria and also showed a very good antifungal activity.

Elicitation of gymnemic acid production in cell suspension cultures of Gymnema sylvestre R.Br. through endophytic fungi.

The enhancement of plant secondary metabolite production in cell suspension cultures through biotic or abiotic elicitation has become a potential biotechnological approach for commercialization or large-scale production of bioactive compounds. Gymnema sylvestre R.Br. is an important medicinal plant, rich in a group of oleanane triterpenoid saponins called gymnemic acid, well known for its anti-diabetic activity. Two endophytic fungal strains were isolated from the leaves of G. sylvestre and identified as Polyancora globosa and Xylaria sp. based on the PCR amplification and internal transcribed spacer (ITS 1-5.8S-ITS 2) sequencing of 18S rRNA gene. The process of elicitation of cell suspension cultures of G. sylvestre with dried powder of fungal mycelia (DPFM) and extracellular culture filtrate (ECF) of endophytic fungi consistently enhanced the accumulation of gymnemic acid and the DPFM was proved to be an effective elicitor when compared to the ECF. The DPFM elicited the gymnemic acid content in the range of 2.57-10.45-fold, while the ECF elicited the gymnemic acid content in the range of 2.39-7.8-fold. P. globosa, a novel and a rare endophytic fungal strain, has shown a great influence on the production of gymnemic acid. Cell suspension cultures elicited with DPFM of P. globosa produced higher amount of gymnemic acid content (124.23 mg/g dried cell weight) compared to the cultures elicited with DPFM of Xylaria sp. (102.24 mg/g DCW). But the cultures treated with consortium of DPFM of both fungi showed great influence on the production of gymnemic acid (139.98 mg/g DCW) than the cultures treated with DPFM alone. Similarly, cultures treated with consortium of ECF of both fungi produced more gymnemic acid content (94.86 mg/g DCW) compared with cultures treated with ECF of Xylaria sp. (77.93 mg/g DCW) and ECF of P. globosa (78.65 mg/g DCW) alone.

Protective effect of centella triterpene saponins against cyclophosphamide-induced immune and hepatic system dysfunction in rats: its possible mechanisms of action

This study was designed to investigate the protective effects of the centella triterpene saponins (EXT) on cyclophosphamide (CYP)-induced hepatotoxicity and immunosuppression in rats. The phytochemical profile of EXT was analyzed for centella saponins by using high-performance liquid chromatographic (HPLC). Therapeutic efficacy of EXT (250 mg/kg/day p.o) on hematological profile of blood, liver function markers, and cytokine profiles in CYP (10 mg/kg/day p.o)-treated rats. In addition, weights of immune organs (spleen and thymus) and histopathological changes in the liver, intestine, and spleen were also evaluated. The active principles in EXT were identified as madecassoside, asiaticoside, and asiatic acid by HPLC analysis. Upon administration of EXT, enhanced levels of glutamate pyruvate transaminase, alkaline phosphatase, and lipid peroxidation were found reduced while the levels of reduced glutathione and hematological parameters and relative weights of immune organs were restored to normal in CYP-treated rats. The hepatic mRNA level of TNF-α, which was increased during CYP administration, was significantly decreased by the EXT treatment. The decreased levels of mRNA expression of other cytokines like IFN-γ, IL-2, GM-CSF, after CYP treatment, were also found elevated upon administration of the EXT. Histopathological examination of the intestine, liver, and spleen indicated that the extract could attenuate the CYP-induced hepatic and immune organ damage. These results indicated that EXT modulated the immune and hepatic system function of rats against CYP-induced immunosuppression and hepatotoxicity by restoring the cytokine production, antioxidant system, and multiorgan injury. Thus, triterpene saponins may provide protective and/or therapeutic alternative against the immune-mediated liver diseases

Protective effect of centella triterpene saponins against cyclophosphamide-induced immune and hepatic system dysfunction in rats: its possible mechanisms of action.

This study was designed to investigate the protective effects of the centella triterpene saponins (EXT) on cyclophosphamide (CYP)-induced hepatotoxicity and immunosuppression in rats. The phytochemical profile of EXT was analyzed for centella saponins by using high-performance liquid chromatographic (HPLC). Therapeutic efficacy of EXT (250 mg/kg/day p.o) on hematological profile of blood, liver function markers, and cytokine profiles in CYP (10 mg/kg/day p.o)-treated rats. In addition, weights of immune organs (spleen and thymus) and histopathological changes in the liver, intestine, and spleen were also evaluated. The active principles in EXT were identified as madecassoside, asiaticoside, and asiatic acid by HPLC analysis. Upon administration of EXT, enhanced levels of glutamate pyruvate transaminase, alkaline phosphatase, and lipid peroxidation were found reduced while the levels of reduced glutathione and hematological parameters and relative weights of immune organs were restored to normal in CYP-treated rats. The hepatic mRNA level of TNF-α, which was increased during CYP administration, was significantly decreased by the EXT treatment. The decreased levels of mRNA expression of other cytokines like IFN-γ, IL-2, GM-CSF, after CYP treatment, were also found elevated upon administration of the EXT. Histopathological examination of the intestine, liver, and spleen indicated that the extract could attenuate the CYP-induced hepatic and immune organ damage. These results indicated that EXT modulated the immune and hepatic system function of rats against CYP-induced immunosuppression and hepatotoxicity by restoring the cytokine production, antioxidant system, and multiorgan injury. Thus, triterpene saponins may provide protective and/or therapeutic alternative against the immune-mediated liver diseases.