Importance of Neem Leaf: An insight into its role in combating diseases.

The neem (Azadirachta indica A. Juss) is a tropical evergreen tree (Fam. Meliacae; Subfam. Melioideae) traditionally well known for its medicinal value. Beneficialt effects of different parts of neem are attributed to its biologically active principle 'Azadirachtin'. Apart from Indian subcontinent, neem is widely used in African countries as therapeutics, preservatives and insecticides. Neem leaves, natural source of flavonoids, polyphenols, isoprenoids, sulphurous and polysaccharides, play important role in scavenging the free radical and subsequently arresting disease pathogenesis. Considerable research has gone into neem for developing cost effective and non-toxic products. The present review has compiled different phytochemicals isolated from neem leaves, methods of extraction and their therapeutic use in preventing several diseases. Here, we highlighted the mechanism of anti-inflammatory and antioxidant activity of neem leaf that underscores the disease through regulation of physiological responses. Also, multiple roles of neem leaf and commercial use of neem formulation as an alternative in paving a frontier in the field of drug discovery are discussed.

Identification of a sulfonoquinovosyldiacylglyceride from Azadirachta indica and studies on its cytotoxic activity and DNA binding properties.

Chromatographic separation of the methanolic extract of the leaves of Azadirachta indica led to the isolation of a sulfonoglycolipid characterized as a sulfonoquinovosyldiacylglyceride (SQDG), by extensive 2D NMR and mass spectral analysis. SQDG induces apoptosis in a dose dependent manner with IC(50) 8.3 µM against acute lymphoblastic leukemia (ALL) MOLT-4 cell lines. The compound showed significant DNA binding properties as evidenced by the enhancement of melting temperature and perturbation of the characteristic B-form in CD evidence of calf thymus DNA. The DNA binding was also characterized by isothermal calorimetry where a predominantly enthalpy driven binding to CT DNA was revealed.

Synthesis and characterizations of novel quinoline derivatives having mixed ligand activities at the kappa and mu receptors: Potential therapeutic efficacy against morphine dependence.

Based on an established 3D pharmacophore, a series of quinoline derivatives were synthesized. The opioidergic properties of these compounds were determined by a competitive binding assay using (125)I-Dynorphine, (3)H-DAMGO and (125)I-DADLE for kappa, mu, and delta receptors, respectively. Results showed varying degree of activities of the compounds to kappa and mu opioid receptors with negligible interactions at the delta receptor. The compound, S4 was the most successful in inhibiting the two most prominent quantitative features of naloxone precipitated withdrawal symptoms - stereotyped jumping and body weight loss. Determination of IC(50) of S4 revealed a greater affinity towards mu compared to kappa receptor. In conclusion, quinoline derivatives of S4 like structure offer potential tool for treatment of narcotic addictions.

Ultrastructural changes in Raillietina (Platyhelminthes: cestoda), exposed to sulfonoquinovosyldiacylglyceride (SQDG), isolated from Neem (Azadirachta indica).

Neem (Azadirachta indica), has been known to be a curative for various ailments and diseases in the traditional Indian medicinal system from times immemorial. A glycolipid sulfonoquinovosyldiacylglyceride (SQDG) isolated from the leaves of neem has been found to be a proactive antibacterial and antiviral agent in previous studies. The current communication pertains to the anthelmintic activity of SQDG in vitro against a model cestode Raillietina spp. The results of efficacy tests showed a paralysis time of 1.0 ± 0.1 and 0.7 ± 0.01 h, whereas death time of 1.6 ± 0.3 and 0.9 ± 0.02 h, following treatments with dosages of 0.5 and 1.0 mg/mL, respectively. The scanning electron microscopic studies showed significant and unique changes in the ultrastructure of the worms with prominent breakages and furrows on the surface.

The quinoline compound, S4 effectively antagonizes alcohol intake in mice: Possible association with the histone H3 modifications.

Opioidergic system plays an important role in controlling alcohol seeking behavior. We have previously shown that a quinoline compound, S4 (2-(2-methylquinolin-4-ylamino)-N-phenyl acetamide), having dual affinity for µ- and κ-opioid receptors, could successfully inhibit withdrawal symptoms in mice rendered dependent on morphine. Accordingly, in the present study, we sought to determine the potential of S4 in attenuating voluntary alcohol intake in alcohol-preferring (AP) mice and the mechanism thereof. The study was conducted in different mice strains initially screened for AP and alcohol-avoiding (AA) behavior. S4 was injected subcutaneously (20 mg/kg) to evaluate its efficacy in reducing voluntary alcohol consumption along with prevention of body weight loss during withdrawal from alcohol after discontinuation of the drug. The results showed that S4 significantly reduced the alcohol intake in AP mice and also in a dose dependent manner. Mechanistic studies on the post translational histone H3 modifications in brain of AP mice compared to the AA mice were determined. Compared to AA mice, histone H3 trimethylation at lys9 and its regulators, jumonji domain containing 2A and phosphorylated histones H3 at thr11 as well as the expression of 14-3-3 protein and phosphorylated histones H3 at ser28, were altered in the AP animals, most of which were restored post S4 treatment in the AP mice. Together, the present results suggest that S4 effectively blocked alcohol drinking behavior by restoring the altered epigenetic signature in the AP mice. The study provides a novel compound which could lead to developing effective drugs against alcoholism/alcohol abuse.

Sulfonoquinovosyl diacylglyceride selectively targets acute lymphoblastic leukemia cells and exerts potent anti-leukemic effects in vivo.

DNA topoisomerase II inhibitors e.g. doxorubicin and etoposide are currently used in the chemotherapy for acute lymphoblastic leukemia (ALL). These inhibitors have serious side effects during the chemotherapy e.g. cardiotoxicity and secondary malignancies. In this study we show that sulfonoquinovosyl diacylglyceride (SQDG) isolated from Azadirachta indica exerts potent anti-ALL activity both in vitro and in vivo in nude mice and it synergizes with doxorubicin and etoposide. SQDG selectively targets ALL MOLT-4 cells by inhibiting catalytic activity of topoisomerase I enzyme and inducing p53 dependent apoptotic pathway. SQDG treatment induces recruitment of ATR at chromatin and arrests the cells in S-phase. Down-regulation of topoisomerase I or p53 renders the cells less sensitive for SQDG, while ectopic expression of wild type p53 protein in p53 deficient K562 cells results in chemosensitization of the cells for SQDG. We also show that constant ratio combinations of SQDG and etoposide or SDQG and doxorubicin exert synergistic effects on MOLT-4 cell killing. This study suggests that doses of etoposide/doxorubicin can be substantially reduced by combining SQDG with these agents during ALL chemotherapy and side effects caused can be minimized. Thus dual targeting of topoisomerase I and II enzymes is a promising strategy for improving ALL chemotherapy.

Spermicidal and contraceptive potential of desgalactotigonin: a prospective alternative of nonoxynol-9.

Crude decoction of Chenopodium album seed showed spermicidal effect at MIC 2 mg/ml in earlier studies. Systematic isolation, characterization and evaluation revealed that the major metabolite Desgalactotigonin (DGT) is the most effective principle in both in vitro and in vivo studies. The in vitro studies comprises (a) rat and human sperm motility and immobilizing activity by Sander-Cramer assay; (b) sperm membrane integrity was observed by HOS test and electron microscopy; (c) microbial potential was examined in Lactobacillus broth culture, and (d) the hemolytic index was determined by using rat RBCs. The in vivo contraceptive efficacy was evaluated by intra uterine application of DGT in rat. Lipid peroxidation and induction of apoptosis by DGT on human spermatozoa were also studied. The minimum effective concentration (MEC) of DGT that induced instantaneous immobilization in vitro was 24.18 µM for rat and 58.03 µM for human spermatozoa. Microbial study indicated DGT to be friendly to Lactobacillus acidophilus. Implantation was prevented in DGT treated uterine horn while no hindrance occurred in the untreated contra lateral side. At the level of EC50, DGT induced apoptosis in human spermatozoa as determined by increased labeling with Annexin-V and decreased polarization of sperm mitochondria. Desgalactotigonin emerged 80 and 2×10(4) times more potent than the decoction and Nonoxynol-9 respectively. It possesses mechanism based detrimental action on both human and rat spermatozoa and spares lactobacilli and HeLa cells at MEC which proves its potential as a superior ingredient for the formulation of a contraceptive safer/compatible to vaginal microflora.

Cytotoxic activity and apoptosis-inducing potential of di-spiropyrrolidino and di-spiropyrrolizidino oxindole andrographolide derivatives.

Anticancer role of andrographolide is well documented. To find novel potent derivatives with improved cytotoxicity than andrographolide on cancer cells, two series of di-spiropyrrolidino- and di-spiropyrrolizidino oxindole andrographolide derivatives prepared by cyclo-addition of azomethine ylide along with sarcosine or proline (viz. sarcosine and proline series respectively) and substitution of different functional groups (-CH3, -OCH3 and halogens) were examined for their cytotoxic effect on a panel of six human cancer cell lines (colorectal carcinoma HCT116 cells, pancreatic carcinoma MiaPaCa-2 cells, hepatocarcinoma HepG2 cells, cervical carcinoma HeLa cells, lung carcinoma A549 and melanoma A375 cells). Except halogen substituted derivatives of proline series (viz. CY2, CY14 and CY15 for Br, Cl and I substitution respectively), none of the other derivatives showed improved cytotoxicity than andrographolide in the cancer cell lines examined. Order of cytotoxicity of the potent compounds is CY2>CY14>CY15>andrographolide. Higher toxicity was observed in HCT116, MiaPaCa-2 and HepG2 cells. CY2, induced death of HCT116 (GI50 10.5), MiaPaCa-2 (GI50 11.2) and HepG2 (GI50 16.6) cells were associated with cell rounding, nuclear fragmentation and increased percentage of apoptotic cells, cell cycle arrest at G1 phase, ROS generation, and involvement of mitochondrial pathway. Upregulation of Bax, Bad, p53, caspases-3,-9 and cleaved PARP; downregulation of Bcl-2, cytosolic NF-κB p65, PI3K and p-Akt; translocation of P53/P21, NF-κB p65 were seen in CY2 treated HCT116 cells. Thus, three halogenated di-spiropyrrolizidino oxindole derivatives of andrographolide are found to be more cytotoxic than andrographolide in some cancer cells. The most potent derivative, CY2 induced death of the cancer cells involves ROS dependent mitochondrial pathway like andrographolide.