Jasvinder Singh

Synthesis and biological evaluation of novel isoxazoles and triazoles linked 6-hydroxycoumarin as potent cytotoxic agents.

A new series of diverse isoxazoles and triazoles linked 6-hydroxycoumarin (1) were synthesized using click chemistry approach. All the derivatives were subjected to 3-(4,5-dimethylthiazol-yl)-diphenyl tetrazoliumbromide (MTT) cytotoxicity screening against a panel of five different human cancer cell lines viz. prostate (PC-3), colon (HCT-116 and Colo-205), leukemia (HL-60) and lung (A-549) to check their cytotoxic potential. Interestingly, among the tested molecules, some of the analogs displayed better cytotoxic activity than the parent 6-hydroxycoumarin (1). Of the synthesized isoxazoles, compounds 10 and 13 showed the best activity with IC50 of 8.2 and 13.6 μM against PC-3 cancer cell line, while as, among the triazoles, compounds 23 and 25 were the most active with the IC50 of 10.2 and 12.6 μM against A-549 cancer cell line. The other derivatives showed almost comparable activity with that of the parent molecule. The present study resulted in identification of ortho substituted isoxazole and triazole derivatives of 6-hydroxycoumarin as effective cytotoxic agents against prostate (PC-3) and lung (A-549) cancer cell lines, respectively.

Iron (FeII) Chelation, Ferric Reducing Antioxidant Power, and Immune Modulating Potential of Arisaema jacquemontii (Himalayan Cobra Lily)

This study explored the antioxidant and immunomodulatory potential of ethnomedicinally valuable species, namely, Arisaema jacquemontii of north-western Himalayan region. The tubers, leaves, and fruits of this plant were subjected to extraction using different solvents. In vitro antioxidant studies were performed in terms of chelation power on ferrous ions and FRAP assay. The crude methanol extract of leaves was found to harbour better chelating capacity (58% at 100 μg/mL) and reducing power (FRAP value 1085.4 ± 0.11 μMFe3+/g dry wt.) than all the other extracts. The crude methanol extract was thus further partitioned with solvents to yield five fractions. Antioxidant study of fractions suggested that the methanol fraction possessed significant chelation capacity (49.7% at 100 μg/mL) and reducing power with FRAP value of 1435.4 μM/g dry wt. The fractions were also studied for immune modulating potential where it was observed that hexane fraction had significant suppressive effect on mitogen induced T-cell and B-cell proliferation and remarkable stimulating effect on humoral response by 141% and on DTH response by 168% in immune suppressed mice as compared to the controls. Therefore, it can be concluded that A. jacquemontii leaves hold considerable antioxidant and immunomodulating potential and they can be explored further for the identification of their chemical composition for a better understanding of their biological activities.

Cladosporol A triggers apoptosis sensitivity by ROS-mediated autophagic flux in human breast cancer cells

BackgroundEndophytes have proven to be an invaluable resource of chemically diverse secondary metabolites that act as excellent lead compounds for anticancer drug discovery. Here we report the promising cytotoxic effects of Cladosporol A (HPLC purified >98%) isolated from endophytic fungus Cladosporium cladosporioides collected from Datura innoxia. Cladosporol A was subjected to in vitro cytotoxicity assay against NCI60 panel of human cancer cells using MTT assay. We further investigated the molecular mechanism(s) of Cladosporol A induced cell death in human breast (MCF-7) cancer cells. Mechanistically early events of cell death were studied using DAPI, Annexin V-FITC staining assay. Furthermore, immunofluorescence studies were carried to see the involvement of intrinsic pathway leading to mitochondrial dysfunction, cytochrome c release, Bax/Bcl-2 regulation and flowcytometrically measured membrane potential loss of mitochondria in human breast (MCF-7) cancer cells after Cladosporol A treatment. The interplay between apoptosis and autophagy was studied by microtubule dynamics, expression of pro-apoptotic protein p21 and autophagic markers monodansylcadaverine staining and LC3b expression.ResultsAmong NCI60 human cancer cell line panel Cladosporol A showed least IC50 value against human breast (MCF-7) cancer cells. The early events of apoptosis were characterized by phosphatidylserine exposure. It disrupts microtubule dynamics and also induces expression of pro-apoptotic protein p21. Moreover treatment of Cladosporol A significantly induced MMP loss, release of cytochrome c, Bcl-2 down regulation, Bax upregulation as well as increased monodansylcadaverine (MDC) staining and leads to LC3-I to LC3-II conversion.ConclusionOur experimental data suggests that Cladosporol A depolymerize microtubules, sensitize programmed cell death via ROS mediated autophagic flux leading to mitophagic cell death.Graphical abstractThe proposed mechanism of Cladosporol A -triggered apoptotic as well as autophagic death of human breast cancer (MCF-7) cells. The figure shows that Cladosporol A induced apoptosis through ROS mediated mitochondrial pathway and increased p21 protein expression in MCF-7 cells in vitro.

A convergent synthesis of novel alkyne–azide cycloaddition congeners of betulinic acid as potent cytotoxic agent ☆

&NA; In an endeavour to develop potent anti‐tumor agents from betulinic acid (BA), a series of C‐28 derived 1,2,3‐triazolyl derivatives were designed and synthesized by employing Cu(I) catalyzed Huisgen 1,3‐dipolar cycloaddition reaction. All the derivatives were evaluated for cytotoxic activity by MTT assay against five different human cancer cell lines: lung (A549), colon (HCT116), prostate (PC3), pancreatic (MIA PaCa‐2) and breast (T47D). The data revealed that compounds 11c, 11d, 11g, 11h and 13a possess most promising cytotoxic potential. The compound 11h was one of the most active compounds, with IC50 values in the range of 4–6 &mgr;M against all the five cancer cell lines. The results of this study suggested that derivatives with free –OH (11c, 11d and 11g) and free –COOH (11h and 13a) substitutions in the triazole moiety introduced at the C‐28 position significantly improved the anti‐tumor activity and may be the favourable position to synthesize potent anticancer leads from BA. Introduction of a non polar alkyl groups at C‐28 position (10, 12 and 14) resulted in the significant loss of the activity. Further, DAPI staining, ROS generation and wound healing experiments revealed that compound 11h induces apoptosis in HCT‐116 cells. Graphical abstract Design and synthesis of C‐28 derived 1,2,3‐triazolyl betulonic acid as apoptotic agents. Figure. No caption available. HighlightsSynthesis of 22 betulinic acid/betulonic acid derivatives.Several derivatives were active against human cancer cell lines.The molecule 11h is apoptotic inducer on HCT‐116 cells.

Immunostimulatory activity of plumieride an iridoid in augmenting immune system by targeting Th-1 pathway in balb/c mice

Abstract Plumieride, an iridoid glucoside isolated from Plumieria acutifolia leaves was investigated for its immunostimulatory activity on humoral, cell mediated and intracellular cytokine levels in sensitized and unsensitised balb/c mice. Plumieride restores the suppressed cell mediated, humoral immune response and also enhances the release of TNF‐ &agr;, IFN‐&ggr;, and IL‐2 (Th‐1) in immune compromised cyclosporine and cyclophosphamide treated balb/c mice. It does not stimulate the IL‐4 (Th‐2) expression. Plumieride demonstrates significant augmentation of Th‐1 response in immunosuppressed balb/c mice. Results of the present study suggested that plumieride can be developed as an immunostimulatory adjuvant to treat the immune suppression in various disease condition(s). Graphical abstract Figure. No caption available. HighlightsPlumieride, an iridoid stimulated the immune system in immune suppressed Balb/c mice.Plumieride stimulated the T cells by increasing the expression of TNF‐ &agr;, IFN‐&ggr;, and IL‐2.Plumieride stimulated the immune system by Th‐1 pathway.

Isolation of isoxanthanol and synthesis of novel derivatives as potential cytotoxic agents

AbstractNovel synthetic derivatives of sesquiterpene lactone isoxanthanol (1) have been prepared and bioevaluated against four human cancer cell lines viz. T98G (glioblastoma), A431 (epidermoid carcinoma), NCI-H322 (bronchioloalveolar carcinoma), and A549 (lung adeno carcinoma) for their cytotoxic potential using paclitaxel as the standard. This has resulted in the identification of potent molecules displaying IC50 1.9 and 5.0 µM, respectively against the A549 cancer cell line. The study has resulted in the identification of potential cytotoxic activity of the analog (compound 10) bearing electron donating aryl alkenoic substituent. Furthermore, the induction of cell death has been assessed for the most active compound (10) using flow cytometric method and sub-G1 cell population determination by propidium iodide staining. The concentration dependent inhibitory effect of 10 on the A549 cells ability did not reproduce and form colonies at 20 µM concentration.Graphical AbstractSynthesis of isoxanthanol derivatives and their cytotoxic study resulted in identification of potential cytotoxic agents. Compound 10, one of its aryl alkenoic substituent showed potency against NCI-H322 (bronchioloalveolar carcinoma), and A549 (lung adeno carcinoma) cell lines.

Antioxidant and Immunomodulatory Potential of Cobra lily Species of North-western Himalayan Region: A Comparative Analysis

Abstract This study explored the antioxidant and immunomodulatory potential of two ethno-medicinally valuable species belonging to genus Arisaema viz., Arisaema flavum and Arisaema propinquum. The arial parts and tubers of these species were subjected to polarity based extraction using different solvents. In vitro antioxidant studies were performed in terms of DPPH radical scavenging, chelation power on ferrous ions, reducing power and FRAP assays. Immunomodulatory studies were also determined by evaluating Humoral antibody response (Hab) and Delayed type hypersensitivity response (DTH). The results depicted that A. flavum exhibited relatively better antioxidant and immunomodulatory potential than A. propinquum. Methanol extract of A. flavum leaves demonstrated promising antioxidant activity with DPPH radical scavenging IC value of 0.406±0.43 mg/ml (R2 = 0.9643), FRAP value of 2176 mM of Fe2+/mg extract (R2 = 0.9962) and reducing power with EC 1.25±0.27mg/ml (R2 = 0.9948) than the extracts of A.propinquum. Chelation capacity of methanol extracts of A. flavum (55 %) leaves was found to be quite significant as compared to that of A. propinquum (51 %) at 100 µg/ml concentration. A. flavum leaf methanol extract was also found have immune enhancing effect by increasing the humoral response by 83 % and DTH response by 100 % in immune suppressed mice. The present work concludes that the antioxidative power of A. flavum surpasses that of A. propinquum whereas in case of immunomodulation, A. flavum has considerable enhancing effect on humoral response and A. propinquum demonstrated better DTH response.