Tamarixetin 3-O-ß-d-Glucopyranoside from Azadirachta indica Leaves: Gastroprotective Role through Inhibition of Matrix Metalloproteinase-9 Activity in Mice.

Neem (Azadirachta indica) is a well-known medicinal and insecticidal plant. Although previous studies have reported the antiulcer activity of neem leaf extract, the lead compound is still unidentified. The present study reports tamarixetin 3-O-ß-d-glucopyranoside (1) from a methanol extract of neem leaves and its gastroprotective activity in an animal model. Compound 1 showed significant protection against indomethacin-induced gastric ulceration in mice in a dose-dependent manner. Moreover, ex vivo and circular dichroism studies confirmed that 1 inhibited the enzyme matrix metalloproteinase-9 (MMP-9) activity with an IC50 value of ca. 50 µM. Molecular docking and dynamics showed the binding of 1 into the pocket of the active site of MMP-9, forming a coordination complex with the catalytic zinc, thus leading to inhibition of MMP-9 activity.

Chemistry of withaferin-A: chemo, regio, and stereoselective synthesis of novel spiro-pyrrolizidino-oxindole adducts of withaferin-A via one-pot three-component [3+2] azomethine ylide cycloaddition and their cytotoxicity evaluation.

Withaferin-A (WA) has attracted the attention of chemists as well as biologists due to its interesting structure and various bio-activities. In light of the promising biological importance of WA as well as pyrrolidine-2-spiro-3'-oxindole ring system, we became interested in the synthesis of a combined motif involving both the ring systems via the 1,3-dipolar cycloaddition of WA at Δ(2)-bond of the α,ß-unsaturated carbonyl system. We now report a facile, atom-economic synthesis of novel spiro-pyrrolizidino-oxindole adducts of withaferin-A (10 compounds) via the intermolecular cycloaddition of azomethine ylides generated in situ from proline and isatins/acenaphthoquinone. The reaction is highly chemo, regio, and stereoselective affording the cis-fused products with ß-orienting hydrogen. The structures were determined by 1D/2D NMR spectroscopic data analysis and unequivocally confirmed by X-ray crystallographic analysis in some cases. Bioevaluation of the compounds against six cancer lines (e.g., CHO, HepG2, HeLa, HEK 293, MDCK-II, and Caco-2) identified 4 promising potential anticancer compounds.

Copper-phenanthroline catalysts for regioselective synthesis of pyrrolo[3',4':3,4]pyrrolo[1,2-a]furoquinolines/phenanthrolines and of pyrrolo[1,2-a]phenanthrolines under mild conditions.

A new series of pyrrolo[3',4':3,4]pyrrolo[1,2-a]furoquinolines/phenanthrolines and pyrrolo[1,2-a]phenanthrolines were efficiently built up from an 8-hydroxyquinoline derivative or phenanthroline via 1,3-dipolar cycloaddition reaction involving non-stabilized azomethine ylides, generated in situ from the parent furo[3,2-h]quinoliniums/phenanthroliums, in presence of a copper(II) chloride-phenanthroline catalytic system. The methodology combines general applicability with high yields.

Discovery of safe and orally effective 4-aminoquinaldine analogues as apoptotic inducers with activity against experimental visceral leishmaniasis.

Novel antileishmanials are urgently required to overcome emergence of drug resistance, cytotoxic effects, and difficulties in oral delivery. Toward this, we investigated a series of novel 4-aminoquinaldine derivatives, a new class of molecules, as potential antileishmanials. 4-Aminoquinaldine derivatives presented inhibitory effects on L. donovani promastigotes and amastigotes (50% inhibitory concentration range, 0.94 to 127 µM). Of these, PP-9 and PP-10 were the most effective in vitro and demonstrated strong efficacies in vivo through the intraperitoneal route. They were also found to be effective against both sodium antimony gluconate-sensitive and -resistant Leishmania donovani strains in BALB/c mice when treated orally, resulting in more than 95% protection. Investigation of their mode of action revealed that killing by PP-10 involved moderate inhibition of dihydrofolate reductase and elicitation of the apoptotic cascade. Our studies implicate that PP-10 augments reactive oxygen species generation, evidenced from decreased glutathione levels and increased lipid peroxidation. Subsequent disruption of Leishmania promastigote mitochondrial membrane potential and activation of cytosolic proteases initiated the apoptotic pathway, resulting in DNA fragmentation and parasite death. Our results demonstrate that PP-9 and PP-10 are promising lead compounds with the potential for treating visceral leishmaniasis (VL) through the oral route.

Evaluation of safety margins of Chenopodium album seed decoction: 14-day subacute toxicity and microbicidal activity studies.

BACKGROUND: Sperm immobilizing activity and plausible mechanism of action of Chenopodium album seed decoction (CAD) have been elucidated in our earlier studies. The present study has been carried out to explore the safety standards of CAD along with microbicidal properties as prerequisite for its use as a topically applicable vaginal contraceptive. METHODS: The safety standards of CAD were assessed by a) Hemolytic index determination using rabbit erythrocytes, to set the doses of the other experiments, b) Dermal irritancy test using refined version of Draize scoring system on rabbits, c) Possible effect on local tissues and reproductive performance in female rats after fourteen daily single dose application, d) PCNA staining- to evaluate the effect of CAD on vaginal tissue proliferation, e) TUNEL assay- to examine its ability to induce in situ apoptosis in the vaginal tissue sections of the treated animals, and f) Microbicidal activity- to explore the effect of CAD on the growth of Lactobacillus acidophilus and Candida albicans. RESULTS: In vitro irritation studies on rabbit erythrocytes revealed the hemolytic index of CAD to be 8.2 mg/ml. The dermal irritation test showed it to be a non-irritant even at higher doses. Intra vaginal application of CAD in rat vagina for 14 consecutive days caused slight reversible inflammation on vaginal epithelial cells at doses as high as 82 mg/ml. However, at this dose level it neither had any adverse effect on vaginal tissue proliferation nor did it cause in situ apoptosis as evident from PCNA staining and TUNEL assay. Fertility and fecundity were restored 4-15 days after withdrawal of CAD application. At dose level 10 times that of its spermicidal MEC (minimum effective concentration), CAD did not block the growth of Lactobacillus, although the size of individual colony was marginally reduced. However, growth of the pathogenic fungus Candida albicans was completely inhibited with 20 mg/ml of CAD. CONCLUSION: The overall result evolved from the study strengthens the candidature of CAD as a safe microbicidal spermicide. It is almost non-irritant to rabbit skin and rat vaginal tissues at doses 10 fold higher than its hemolytic index. The effect of CAD on Lactobacillus culture was not highly encouraging but it prevented the growth of the fungal pathogen Candida albicans at 20 mg/ml of CAD.

Efficient synthesis of 3,3-diheteroaromatic oxindole analogues and their in vitro evaluation for spermicidal potential.

Syntheses of 3,3-diheteroaromatic oxindole derivatives has been achieved by coupling indole-2,3-dione (isatin) with differently substituted indoles and pyrrole in presence of I(2) in i-PrOH. The in vitro spermicidal potentials and the mode of spermicidal action of the synthesized analogues were evaluated and the derivative, 3,3-bis (5-methoxy-1H-indol-3-yl) indolin-2-one (3d) exhibited most significant activity.

Therapeutic effect of a novel anilidoquinoline derivative, 2-(2-methyl-quinoline-4ylamino)-N-(2-chlorophenyl)-acetamide, in Japanese encephalitis: correlation with in vitro neuroprotection.

2-(2-Methyl-quinoline-4ylamino)-N-(2-chlorophenyl)-acetamide, a novel anilidoquinoline derivative, was synthesised and evaluated for its therapeutic efficacy in treating Japanese encephalitis. The compound showed significant antiviral and antiapoptotic effects in vitro. Significant decreases in viral load (P<0.01) combined with an increase in survival was observed in Japanese encephalitis virus-infected mice treated with 2-(2-methyl-quinoline-4ylamino)-N-(2-chlorophenyl)-acetamide.

Synthesis and assessment of fertility-regulating potential of 2-(2''-chloroacetamidobenzyl)-3-(3'-indolyl) quinoline in adult rats as a male contraceptive agent.

BACKGROUND: The purpose of this study was to investigate the fertility-regulating potential of the compound 2-(2''-chloroacetamidobenzyl)-3-(3'-indolyl) quinoline in male rats. STUDY DESIGN: Rats of proven fertility were treated with the compound by oral gavage for 1 to 8 consecutive weeks. Functional fertility, testicular, epididymal and seminal vesicular weight, epididymal sperm count and spermatogenesis were quantitated. Reproductive hormones and some biochemical parameters were measured. RESULTS: Functional fertility was reduced significantly as revealed by a fall in fertility and pregnancy rate. The weight of the reproductive organs was reduced significantly. A reduction of sperm count and number of different types of testicular cells was observed. The treatment with the compound resulted in decline of testosterone and an increase of FSH hormone levels. The compound effectively reduced testicular protein, glycogen and epididymal glyceryl phosphorylcholine. Increase in testicular alkaline phosphatase and cholesterol was also observed. Fertility and other effects were regained gradually after cessation of treatment. CONCLUSION: The results revealed from the study indicate that the compound has reversible antifertility activity and can be explored as male contraceptive agent.

Chenopodium album seed extract-induced sperm cell death: exploration of a plausible pathway.

BACKGROUND: This study was conducted for to explore the plausible pathway of Chenopodium album seed extract (CAE)-mediated sperm cell death. STUDY DESIGN: The role of CAE for its spermicidal action was assessed by (a) measuring lipid peroxidation, protein carbonyl content and intracellular glutathione content in CAE exposed sperm cells; (b) assaying antioxidant enzymes like catalase and superoxide dismutase (SOD); (c) analyzing protein expressions by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis; (d) fluorimetric measurement of intracellular H(2)O(2) level and generation of reactive oxygen species (ROS) in CAE-treated sperm cells; and (e) DNA ladder formation study. RESULTS: CAE-induced sperm death is due to (a) lipid peroxidation of the sperm cell membrane, oxidation of some critical cellular proteins and depletion of intracellular reduced gluthathione, indicating production of ROS; (b) activation of Mn-SOD and inactivation of catalase favoring endogenous accumulation of H(2)O(2); (c) generation of O(2)(*-) at an enhanced rate during oxidative stress as evidenced by increased Mn-SOD activity and protein expression; (d) accumulation of ROS in spermatozoa reflected in the fluorimetric experiments; and (e) increased production of O(2)(*-) and H(2)O(2) induced apoptosis-like death in sperm cells as observed by DNA ladder formation. CONCLUSION: The sperm death mediated by CAE is due to oxidative damage of cellular macromolecules by in situ generation of ROS.

Synthesis of diversely substituted bis-pyrrolizidino/ thiopyrrolizidino oxindolo/acenaphthyleno curcuminoids via sequential azomethine ylide cycloaddition.

Curcumin has been transformed to several diversely substituted bis-pyrrolizidino/thiopyrrolizidino oxindolo/acenaphthyleno curcuminoids via a sequential azomethine ylide cycloaddition reaction using isatins/acenaphthoquinone and proline/thioproline as the reagents. The products were separated via extensive chromatography and characterized by 1D/2D NMR and HRMS analysis.

Racemoside A, an anti-leishmanial, water-soluble, natural steroidal saponin, induces programmed cell death in Leishmania donovani.

Leishmaniasis remains a major health problem of the tropical and subtropical world. The visceral form causes the most fatalities if left untreated. Dramatic increases in the rates of infection and drug resistance and the non-availability of safe vaccines have highlighted the need for identification of novel and inexpensive anti-leishmanial agents. This study reports that racemoside A, a water-soluble steroidal saponin purified from the fruits of Asparagus racemosus, is a potent anti-leishmanial molecule effective against antimonial-sensitive (strain AG83) and -unresponsive (strain GE1F8R) Leishmania donovani promastigotes, with IC(50) values of 1.15 and 1.31 microg ml(-1), respectively. Incubation of promastigotes with racemoside A caused morphological alterations including cell shrinkage, an aflagellated ovoid shape and chromatin condensation. This compound exerts its leishmanicidal effect through the induction of programmed cell death mediated by the loss of plasma membrane integrity as detected by binding of annexin V and propidium iodide, loss of mitochondrial membrane potential culminating in cell-cycle arrest at the sub-G(0)/G(1) phase, and DNA nicking shown by deoxynucleotidyltransferase-mediated dUTP end labelling (TUNEL). Racemoside A also showed significant activity against intracellular amastigotes of AG83 and GE1F8R at a 7-8-fold lower dose, with IC(50) values of 0.17 and 0.16 microg ml(-1), respectively, and was non-toxic to murine peritoneal macrophages up to a concentration of 10 microg ml(-1). Hence, racemoside A is a potent anti-leishmanial agent that merits further pharmacological investigation.

Chenopodium album seed extract: a potent sperm-immobilizing agent both in vitro and in vivo.

PURPOSE: Aqueous decoction of Chenopodium album seeds (CAD) was assessed for its sperm-immobilizing and contraceptive efficacy in laboratory mammals. METHOD: Spermicidal efficacy was evaluated in vitro by a modified Sander-Cramer test. The mode of spermicidal action was assessed by (a) supravital and double fluoroprobe staining of sperm, (b) hypoosmotic swelling tests and (c) transmission electron microscopy. Contraceptive efficacy was evaluated by intrauterine and vaginal application of CAD in rats and rabbits, respectively, followed by their mating and evaluation of pregnancy outcomes. RESULTS: The minimum effective concentration of CAD that induced instantaneous immobilization of rat spermatozoa in vitro was 2 mg/mL. The mechanism of CAD action involved disintegration of sperm plasma membrane and dissolution of acrosomal cap causing sperm death. Fertilization of oocytes and establishment of implantation were prevented in the uterine horn that was administered with CAD, while these events occurred unhindered in the untreated contralateral side. In rabbit, intravaginal application of CAD significantly blocked the establishment of pregnancy. CONCLUSION: CAD possesses appreciable spermicidal potential, which may be explored as an effector constituent of vaginal contraceptive.

Steroidal saponins from the fruits of Asparagus racemosus.

Three steroidal saponins, racemosides A (1), B (2) and C (3), were isolated from the methanolic extract of the fruits of Asparagus racemosus, and characterized as (25S)-5beta-spirostan-3beta-ol-3-O-{beta-D- glucopyranosyl (1-->6)-[alpha-L-rhamnopyranosyl (1-->6)-beta-D-glucopyranosyl (1-->4)]-beta-D-glucopyranoside}, (25S)-5beta-spirostan-3beta-ol-3-O-alpha-L-rhamnopyranosyl (1-->6)-beta-D-glucopyranosyl (1-->6)-beta-D-glucopyranoside and (25S)-5beta-spirostan-3beta-ol-3-O-{alpha-L-rhamnopyranosyl-(1-->6)-[alpha-L-rhamnopyranosyl (1-->4)]-beta-D-glucopyranoside}, respectively, by spectrometric analysis and some chemical strategies.

Critical evaluation of the therapeutic potential of bassic acid incorporated in oil-in-water microemulsions and poly-D,L-lactide nanoparticles against experimental leishmaniasis.

Bassic acid, an unsaturated triterpene acid isolated from Mimusops elangii, was tested for its antileishmanial properties both in vitro and in vivo. The in vitro antileishmanial activity of bassic acid being encouraging, its activity in vivo was evaluated in hamster models of visceral leishmaniasis, both in free form, as well as incorporated in two different delivery systems, viz microemulsions and polylactide nanoparticles. The delivery systems were prepared by published protocols. The percentage intercalation of bassic acid in nanoparticles and microemulsion was found to be about 50 and 100, respectively, when determined at its absorption maxima (lambda(max)) 285 nm (epsilon(m) = 2.3 x 10(2) M(-1) cm(-1)). At an equivalent dose of 2 mg kg(-1) body weight, when injected subcutaneously for a total of six doses in 15 days, bassic acid was found to reduce spleen parasite loads by 45, 62 and 78% in free, microemulsion-incorporated and nanoparticle-incorporated forms, respectively. A comparison of specific biochemical tests related to normal liver and kidney functions revealed that the nanoparticulate form was successful in significantly reducing the hepatotoxicity and nephrotoxicity of the free drug, but the microemulsion delivery system was less effective and toxic to liver and kidney to some extent. Confocal microscopic images of Leishmania donovani promastigotes treated with bassic acid revealed that the drug induced necrotic cell death due to non-specific membrane damage. Because of its high efficacy as well as non-hepatotoxicity and non-nephrotoxicity, the nanoparticulate form of bassic acid may be considered for clinical application in humans rather than the microemulsion incorporated form.

New flavonoid glycosides and other chemical constituents from Clerodendrum phlomidis leaves: isolation and characterisation.

Phytochemical investigation of the plant Clerodendrum phlomidis Linn. F. (Lamiaceae) has now led to the isolation of two new flavonoid glycosides (1, 2) together with six known compounds identified as pectolinaringenin (3), pectolinaringenin-7-O-ß-D-glucopyranoside (4), 24ß-ethylcholesta-5,22E,25-triene-3ß-ol (5), 24ß-ethylcholesta-5,22E,25-triene-3ß-O-ß-D-glucopyranoside (6), (2S,3S,4R,10E)-2-[(2'R)-2'-hydroxytetracosanoylamino]-10-octadecene-1,3,4-triol (7) and andrographolide (8) mainly by spectroscopic analysis. Compounds 4 and 6-8 are reported for the first time from C. phlomidis.

Synthesis of Bis-pyrrolizidine-Fused Dispiro-oxindole Analogues of Curcumin via One-Pot Azomethine Ylide Cycloaddition: Experimental and Computational Approach toward Regio- and Diastereoselection.

Curcumin has been transformed to racemic curcuminoids via an azomethine ylide cycloaddition reaction using isatin/acenaphthoquinone and proline as the reagents. The products were characterized by extensive 1D/2D NMR analysis and single-crystal X-ray crystallographic studies. The enantiomers of one racemic product were separated by HPLC on a Chiralcel OD-H column and were indeed confirmed by the CD spectra of the separated enantiomers.

Isolation, structural elucidation and cytotoxicity evaluation of a new pentahydroxy-pimarane diterpenoid along with other chemical constituents from Aerva lanata.

Aervalanata possesses various useful medicinal and pharmaceutical activities. Phytochemical investigation of the plant has now led to the isolation of a new 2α,3α,15,16,19-pentahydroxy pimar-8(14)-ene diterpenoid (1) together with 12 other known compounds identified as ß-sitosterol (2), ß-sitosterol-3-O-ß-D-glucoside (3), canthin-6-one (4), 10-hydroxycanthin-6-one (aervine, 5), 10-methoxycanthin-6-one (methylaervine, 6), ß-carboline-1-propionic acid (7), 1-O-ß-D-glucopyranosyl-(2S,3R,8E)-2-[(2'R)-2-hydroxylpalmitoylamino]-8-octadecene-1,3-diol (8), 1-O-(ß-D-glucopyranosyl)-(2S,3S,4R,8Z)-2-[(2'R)-2'-hydroxytetracosanoylamino]-8(Z)-octadene-1,3,4-triol (9), (2S,3S,4R,10E)-2-[(2'R)-2'-hydroxytetracosanoylamino]-10-octadecene-1,3,4-triol (10), 6'-O-(4″-hydroxy-trans-cinnamoyl)-kaempferol-3-O-ß-D-glucopyranoside (tribuloside, 11), 3-cinnamoyltribuloside (12) and sulfonoquinovosyldiacylglyceride (13). Among these, six compounds (8-13) are reported for the first time from this plant. Cytotoxicity evaluation of the compounds against five cancer cell lines (CHO, HepG2, HeLa, A-431 and MCF-7) shows promising IC50 values for compounds 4, 6 and 12.

Towards the development of anticancer drugs from andrographolide: semisynthesis, bioevaluation, QSAR analysis and pharmacokinetic studies.

Isolation of andrographolide from Andrographis paniculata, preparation of a library of derivatives via 1,3-dipolar cycloaddition of andrographolide with azomethine ylides generated from isatin derivatives or acenaphthoquinone and seconday α-amino acids, evaluation of the anticancer potential of the products, quantitative structure activity relationship studies and pharmacokinetic parameter determination have been described. 2D QSAR studies revaled that steric effects and van der Waals interactions play major roles in the determination of antiproliferative activity of these derivatives. 3D QSAR study predicted that the benzyl substitution at N20 position may be important for higher steric interaction. Pharmacokinetic studies with two most potent analogues revealed moderate chemical stability but poor aqueous solubility, metabolic stability and permeability with significant CYP3A4 inhibition.

Search for a potent microbicidal spermicide from the isolates of Shorea robusta resin.

BACKGROUND: An alarming increase in global population is the root cause of poverty, malnutrition, sexually transmitted infections (STIs) and many other social problems. Microbicidal spermicides possessing dual function of contraception and STI protection can effectively combat this problem, and their development is of utmost importance at present. STUDY DESIGN: A major metabolite isolated from Shorea robusta resin was spectroscopically characterized as asiatic acid. Spermicidal efficacy of the isolate was evaluated in vitro by a modified Sander-Cramer test. The mode of spermicidal action was assessed by (a) double fluoroprobe staining, (b) hypoosmotic swelling test and (c) scanning electron microscopy. Antimicrobial efficacy was assessed by disc diffusion and broth dilution methods using human isolates of bacteria (Escherichia coli ATCC 25938 and Pseudomonas aeruginosa 71) and fungus (Candida tropicalis). RESULTS: The minimum effective concentration of asiatic acid that induced instantaneous immobilization of rat spermatozoa in vitro was 125 mcg/mL. The mechanism of action involved disruption of sperm plasma membrane. The microbicidal efficacy was found to be moderate for vaginal pathogens, with no effect on normal vaginal flora. CONCLUSION: Asiatic acid possesses appreciable spermicidal and microbicidal potential and may be explored as an effective microbicidal spermicide.

Regio- and stereoselective synthesis of a library of bioactive dispiro-oxindolo/acenaphthoquino andrographolides via 1,3-dipolar cycloaddition reaction under microwave irradiation.

Dispiro-pyrrolidino/pyrrolizidino fused oxindoles/acenaphthoquinones have been derived from andrographolide via azomethine ylide cycloaddition to the conjugated double-bond under microwave (MW) irradiation. The reactions are chemo-, stereo-, and regioselective in nature. Change in amino acid from sarcosine/N-benzyl glycine to l-proline changes the regiochemistry. A representative library of 40 compounds along with in vitro anticancer evaluation is reported.