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In the present study, we have evaluated fractionation based phytochemical constituents, antioxidant activity, DNA damage protecting potential and anticancerous properties of leaves of common Ficus species (namely Ficus virens, Ficus benghalensis, Ficus religiosa, Ficus elastica) along with GCMS analysis for identification of major bioactive constituents. Methanol fraction of F. virens contained maximum amount of phenolics (1267.35 mg GAE/g dry extract) and flavonoids (1080.61 mg QE/g dry extract) whereas hexane fraction of F. religiosa possessed highest amount of tannins (123.76 mg TAE/g dry extract). Least amount of phytochemicals was recovered from F. elastica. Highest DPPH radical scavenging activity (IC50 = 108.28 μg/ml) was detected by methanol fraction of F. benghalensis whereas highest ABTS activity (IC50 = 105.56 μg/ml) by F. benghalensis and highest ferric reducing power by F. virens (359.44 mg QE/g dry extract). Leaf methanol fraction of F. virens, F. religiosa and F. elastica were able to prevent oxidative DNA damage at 0.1 mg/ml,0.2 mg/ml and 0.3 mg/ml respectively. Viability of normal breast cells was unaffected by methanol fraction of tested Ficus species at doses less than 160 μg/ml, whereas survival of breast cancer cells was decreased by F. benghalensis at 5 μg/ml. GCMS analysis of the purified methanol fraction of tested species revealed the presence of potent bioactive compounds such as carvacrol, phytol, tocopherol, benzophenone, dibutyl phthalate, lycopersen etc. All our experimental results along with the identification of the bioactive compounds supported the fact that leaves of tested Ficus species as rich source of phytochemicals with nutraceutical potentialities.

Zoochoric plants usually produce fruits with a mechanical barrier in the exocarp, or chemical inhibitors in the fruit pulp (mesocarp) or seed coat (endocarp) to achieve required dormancy. Tamarindu...

Inhibiting sprouting of potatoes is an interesting subject needed for potato storage and industry. Sprouting degrades the quality of tuber along with releasing α-solanine and α-chaconine, which are harmful for health. Sprout suppressants, available in the market, are either costly or toxic to both health and environment. So, there is a need for developing countries to explore new sprouting suppressant compound which is cheap, non-toxic and reasonably efficient in comparison to commercial ones. We have established that simple maleic acid and l-tartaric acid are effective sprout suppressing agents. Both can hinder sprouting up to 6 weeks and 4 weeks post treatment respectively at room temperature in dark. These do not affect the quality parameters, retain the moisture content and maintain the stout appearance of the tubers along the total storage period. Thus maleic acid and l-tartaric acid would qualify as alternative, cheap, efficient sprout suppressant for potato storage and processing.

Vegetable oils are integral part in production of manufactured food both in domestic and industrial scale. Vegetable oil market is increasing upward with a CAGR of 3.25% during the forecast period (2019–2024) all around the world. Therefore, it is necessary to find alternative sources of vegetable oil to fulfil the scarcity in the market. Seeds of Sterculia foetida, L. yielded considerable amount of oil (58.7 g/100g) as compared to other vegetable oils (such as sunflower, ground nut, mustard, soybean). Fatty acids composition of all the five tested oils showed that total fatty acid as well as unsaturated fatty acid percentage is higher in Sterculia seed oil. Proximate and mineral composition analysis suggested that Sterculia oil is a good source of protein, lipids, macro and micronutrients. Lowest TOTOX value (2.67) and higher iodine value (132–144) indicated its higher oxidative stability and presence of greater number of unsaturated bands in the fatty acid moieties which is also beneficial for human health. Sterculia oil exhibited lower IC50 values in DPPH (825.73 μg/ml), and NO (111.98 μg/ml) radical scavenging assays. In case of ABTS radical scavenging activity, no significant differences were observed in groundnut, mustard, sterculia and soybean except sunflower. Sterculia oil did not exhibit any cytotoxic effect on both normal and cancerous cell lines even at concentrations of 40 μg/ml as evident from MTT assay. Thus, seed oil of Sterculia foetida may be a cost-effective and viable source of safe nutritious edible oils to combat the present market demand.

Hot taste spices have enormous health benefits starting from kitchen to pharmaceutical laboratories. Our present study is focused on phytochemical and pharmacological screening of six hot taste spices namely Zingiber officinale (ginger), Capsicum annuum (chilli), Piper chaba (java long pepper), Piper nigrum (black pepper), Syzygium aromaticum (clove), Trachyspermum ammi (carom). Among all six spices, clove and ginger exhibited strong antioxidant activity owing to higher phytochemical contents. Significant antifungal activity (IZD ≥ 11 mm) was revealed by all six spices except hexane fraction of carom whereas strong antibacterial activity with lowest MIC was displayed by clove, ginger and chilli. DNA was successfully protected from oxidative damage by clove, ginger followed by chilli, java long pepper and carom but black pepper could only partially protect DNA damage even at 4 mg/ml concentration. Based on the DNA damage protecting potentials and antioxidant activities clove, ginger, java long pepper and carom may be utilized for neutraceuticals development. Antimicrobial activities suggested that clove, ginger, java long pepper and chilli may be useful as food preservatives. Fractionated bioactivity of the all the six HTS would help for targeted extraction and development of nutraceuticals from these commonly used medicinal spices.

Eclipta alba (L.) Hassk (Asteraceae) is a branched herbaceous plant known for its curative properties against various tropical and sub-tropical diseases. In India, it is commonly known as Bhringaraj and Karisilakanni and in Bengali it is called keshut. The extensive growth of the plant in moist areas of diverse topology indicates its invasiveness and signifies its intense allelopathic activity. Morphologically the plant bears soft and sessile stem. In view of this allelopathic potential, the roots of the plants are considered as a vital biochemical mediator to the environment. Hence, the present study attempts to evaluate the allelopathic activity of the root exudates of E. alba. Amongst the major solvent extracts from the roots, the methanol fraction was found to possess significant antimicrobial activity against microbes with multiple hosts and environment. Bioassay on crop germination establishes it as a natural agricultural resource for fertilizer. The experimental finding inferred statistical significance at 0.001 level and validates practical implication.

Alstonia scholaris, R. Br. (Apocynaceae, commonly known as Devil tree) is an elegant evergreen tree, which serves as a host for foliar galls caused by Pauropsylla tuberculata, Crawf. A. scholaris is useful both medicinally as well as being an important shade tree and gall formation being problematic for using this tree in the cities. Gall formation in mature plant does not much effect the plant but when the young plants are affected it harms the plant. Gall induction, mediated by insect-herbivore chemical stimuli, is the result of anatomical and biochemical alterations in the host-plant tissues. In order to understand the biochemical changes induced by P. tuberculata on Alstonia, we studied the chlorophyll content and secondary metabolites specially phenolics that apparently act as defense compounds and also the activity of two foliar antioxidant enzymes, catalase and peroxidase both experimentally and statistically. Activity of antioxidant enzymes and phenolics were found to be positively correlated with different stages of gall leaves whereas chlorophyll content exhibited strong negative correlation. Information from both the studies led us to suggest that antioxidant enzymes and phenolics act as biochemical markers of foliar gall resistance in Alstonia scholaris.

Objective: To explore the phytochemical profile of Artocarpus lakoocha Roxb. leaves both qualitatively and quantitatively, and validate its role as a potent antioxidant and antimicrobial agent. Methods: Extraction and isolation of different compounds were done from the leaves of Artocarpus lakoocha based on solvent fractionation method. Subsequently, quantitative and qualitative phytochemical profiling along with antioxidant, antimicrobial and antioxidative activities were tested following standard protocols. Results: Among the five fractions, methanol fraction of Artocarpus lakoocha exhibited higher content of phytochemical compounds [phenols = (3 175.21 ±290.43) mg GAE/g dry extract, flavonoids = (1 173.15±47.52) mg QE/g dry extract and tannins = (923.53±95.21) mg TAE/ g dry extract] as compared to other fractions. The methanol fraction showed the highest antioxidant activity in DPPH and ABTS radical scavenging assays with IC50 of (111.98±34.20) μg/mL and (138.26±0.66) μg/mL, respectively, and the best reduction potential with a value of (316.81±2.96) mg QE/g dry extract in reducing power assay. There was significant correlation between the amount of phytochemicals and antioxidant activities. Moreover, the extract successfully protected Lambda phage DNA from damage at 5 and 6 mg/mL concentration and exhibited substantial bactericidal as well as fungicidal activity. The GC-MS analysis of methanol fraction of Artocarpus lakoocha revealed diethyl phthalate as the main phytochemical compound, along with 3,4-dihydroxymandelic acid, 9-octyl eicosane and 7,8-didehydro-3- methoxy-17-methyl-6-methylene morphinan. Conclusions: The methanol fraction of Artocarpus lakoocha could be used as a potent antioxidant and antimicrobial agent for sustainable agriculture and pharmaceutical purposes.

A new Bromo isotopic compound has been isolated and purified from the Methanol Fraction of Teak leaves (MFTk). Chromatographic and spectral analyses (TLC, UV, MS, NMR, and IR) indicated the compound to be 2-bromo-1-(2-hydroxypheny1)-3, 4-dimethylpentan-1-one, in short, BrHPDMP with molecular weights 285 and 287. The whole leaf leachate of teak showed strong inhibitory activity in bioassay. But when fraction-4 (Methanolic fraction of teak leaf) was isolated and purified, it showed concentration dependent stimulatory activity on rice seeds. At 1000 ppm concentration, it showed 12.820% inhibition in shoot and 15.59% stimulation in root length. Below this concentration, it showed stimulatory effects on both shoot and root length. At 500ppm, it revealed 10.040% stimulation in shootlength and 34.16% stimulation in root length. At a concentration of 31.25ppm, it revealed maximum stimulatory effects i.e. 16.260% stimulation in shoot length and 42.78% stimulation in rootlength.

Cleome viscosa L. (Capparidaceae) is well known for its medicinal properties. Lactam nonanoic acid (LNA) [2-amino-9-(4-oxoazetidin-2-yl)-nonanoic acid; C12H22N2O3, mol. wt. 242] has been isolated and purified from the root exudates of Cleome viscosa. The aqueous solution of this pure compound has been tested on bacteria (Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus) and fungi (Aspergillus fumigatus, A. niger and A. tamarii). At a dosage of 500 ppm and above, P. aeruginosa and S. aureus were totally inhibited while E. coli remained unaffected. On the other hand, growth of A. niger and A. tamarii was stimulated while there was no effect on A. fumigatus. This pure compound showed concentration-dependent inhibitory activity on rice, gram and mustard seeds.

Because the local microstructure plays a pivotal role for many biological functions, a wide range of methods have been developed to design precisely engineered substrates for both fundamental biological studies and biotechnological applications. However, these techniques have been by-and-large limited to flat surfaces. Herein, we use electrohydrodynamic co-spinning to prepare biodegradable three-dimensional fiber scaffolds with precisely engineered, micrometre-scale patterns, wherein each fiber is comprised of two distinguishable compartments. When bicompartmental fiber scaffolds are modified via spatially controlled peptide immobilization, highly selective cell guidance at spatial resolutions (

A combination of PEG-based surface passivation techniques and spatially addressable SPPS (solid phase peptide synthesis) was used to demonstrate a highly specific cell-peptide adhesion assay on a microfluidic platform. The surface of a silicon-glass microchip was modified to form a mixed self-assembled monolayer that presented PEG moieties interspersed with reactive amino terminals. The PEG provided biomolecular inertness and the reactive amino groups were used for consequent peptide synthesis. The cytophobicity of the surface was characterized by on-chip fluorescent binding assays and was found to be resistant to non-specific attachment of cells and proteins. An integrated system for parallel peptide synthesis on this reactive amino surface was developed, using photogenerated acid chemistry and digital microlithography. A constant synthesis efficiency of >98% was observed for up to 7mer peptides. To demonstrate specific cell adhesion on these synthetic peptide arrays, variations of a 7mer cell binding peptide that binds to murine B lymphoma cells were synthesized. Sequence specific binding was observed on incubation with fluorescently labeled, intact murine B lymphoma cells and key residues for binding were identified by deletional analysis.

Root exudates (RE) of Leonurus sibiricus L. show the stimulatory effect of a bioassay on rice, wheat and mustard. Root exudate shows concentration-dependent activity. A stock solution (one seedling in 200 mL of 0.1% Knop’s solution for 4 days) is denoted as (1). A 10-fold higher concentration (10) was made by using a rotary vacuum evaporator; for example, 100 mL stock solution was reduced to 10 mL. For bioassay, (25), (50), (75) and (100)-fold concentrations have been used. The stimulatory effect increases with concentration (peak at 10), decreases thereafter, and at (50) (75) and (100), the effect is inhibitory (almost 100% at 75 and 100). Paper chromatography and staining suggest the presence of phenolics including caffeic acid in RE. Caffeic acid also shows the same concentration-dependent activity on rice seeds. An ether extract of acid hydrolyzed leaves shows a number of phenolics on thin layer chromatography. Among these phenolics, three are common with RE. One highly fluorescent band occurs in a much larger amount (both RE and acid hydrolyzed leaf extract), and coincides with standard caffeic acid. On ultraviolet spectrometer analysis after elution, the putative caffeic acid compound shows two characteristic peaks similar to that of caffeic acid at 277 and 231 nm, respectively. Gas liquid chromatography retention time of both standard caffeic acid and the fluorescent spot is the same.

We developed fast and readily applicable microarray chips to detect PSA by designing a novel conjugated polymer (energy donor) and combining it with on-chip peptide synthesis. The selective cleavage of a probing peptide labelled with a dye or a quencher (energy acceptor) produced a fluorescence sensory signal via fluorescent energy resonance transfer (FRET).

C12H22N2O3 [2-amino-9-(4-oxoazetidin-2-yl) nonanoic acid or 2-amino-9-β-lactum nonanoic acid(LNA), mol.wt. 242] has been isolated and purified from the root exudates of Cleome viscosa. Aqueous solution of this pure compound has been tested on bacteria ( Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus ) and fungi ( Aspergillus fumigatus, Aspergillus niger and Aspergillus tamarii ). At a dosage of 500ppm and above, P. aeruginosa and S. aureus were totally inhibited while E. coli remained unaffected. On the other hand, growth of A. niger and A. tamarii was stimulated while there was no effect on A. fumigatus. In A. tamarii, however, a dosage of 500ppm exerted the minimal stimulatory effect while maximal stimulation occurred at 1000ppm and above whereas in A. niger maximal stimulation was observed at 500ppm but at 2000ppm there was no effect. In rice, it caused complete inhibition of germination from 1000ppm to 125ppm concentration while in the case of mustard seeds, complete inhibition was noticed only at 1000ppm concentration. At 500ppm, 17.22% and 66.01% inhibition on shoot and root length respectively was detected. In case of gram seeds, MFCV exerted complete inhibition of germination up to 500ppm concentration. At 250ppm, it showed 100% inhibition in shoot length and 50.41% inhibition in root length. Keywords: Cleome viscosa , Allelochemical, Antimicrobial activity, Lactam nonanoic acid (LNA)

Biocompatible anisotropic polymer particles with bipolar affinity towards human endothelial cells are a novel type of building blocks for microstructured biohybrid materials, report Joerg Lahann and co-workers on p. 4920. Functional polarity due to two biologically distinct hemispheres has been achieved by synthesis of anisotropic particles via electro-hydrodynamic co-jetting of two different polymer solutions and subsequent selective surface modification.

Biocompatible anisotropic polymer particles with bipolar affinity towards human endothelial cells are a novel type of building blocks for microstructured bio-hybrid materials. Functional polarity due to two biologically distinct hemispheres has been achieved by synthesis of anisotropic particles via electro-hydrodynamic co-jetting of two different polymer solutions and subsequent selective surface modification.

Potent biopesticides with strong antimicrobial activity as well growth inhibitory activity has been isolated and purified from the Ethyl Acetate Fraction (TrEAF) of tamarind leaves. Chromatographic analyses (TLC, UV, MS, NMR, and IR) indicated the presence of putative caffeic acid derivative in Tamarind leaves. Aspergillus tamarii was highly sensitive to TrEAF compound at all concentrations (500 ppm, 1000 ppm, 1500 ppm and 2000 ppm) than Aspergillus fumigatus, Aspergillius niger. In Aspergillus tamarii and Aspergillius niger, 1500ppm concentration was very much sensitive to TrEAF compound. Cercina lutia, Staphylococcus aureus, Micrococcus roseus and Pseudomonas sp were much more sensitive to TrEAF compound than Escherichia coli. No effect of TrEAF compound was detected in E.coli at concentration of 1000ppm. When isolated and purified by fractionation and column chromatography, this active TrEAF compound showed concentration-dependent inhibitory/stimulatory activity on rice seeds. At concentration of 1000ppm, it showed 53.81% inhibition on shoot length and 58.85% inhibition in root length. At 500ppm concentration, 29.01% inhibition in shoot length and 38.82% inhibition in root length have been detected. Very slight stimulation on shoot length was observed at 7.81ppm. It showed no effect on the germination of rice seed.

3,3′-Diindolylmethane (DIM) derivatives 3a–k, prepared in one-pot from indoles 1a–k and hexamethylenetetramine (2) using ionic liquid [Bmim]BF4 as eco-friendly recyclable solvent as well as catalyst, showed good plant growth promoting activity on Oryza sativa. Among the DIM derivatives synthesized 3c shows potent auxin like growth promoting activity.

A new dammarane-type pseudojujubogenin glycoside, bacopasaponin H, has been isolated from the reputed Indian medicinal plant Bacopa monniera and characterized as 3-O-[α-1-arabinopyranosyl] pseudojujubogenin by spectral and chemical studies.

Picrorhiza kurroa Royle ex Benth, commonly known as kutki is used as a crude drug reported in Indian pharmacopoeia. Acetyl derivative of a new iridoid glucoside, picroside V (6-m-methoxybenzoyl catalpol) along with three known iridoid glucosides picroside I, picroside II and catalpol have been isolated from the roots of Picrorhiza kurroa Royle ex Benth.

Flavonoids are a broad class of plant phenolics that are known to possess a well-established protective effect against membrane lipoperoxidative damages. Oxidative damage of erythrocytes has been implicated in the reduced survival of erythrocytes during leishmanial infection. This study reveals the efficacy of five naturally occurring flavonoids in arresting the development of anemia during the postinfection period. Among the compounds studied, quercetin was most successful in inhibiting the oxidation of proteins and lipids on the red cell membranes of infected animals. Apart from its antianemic property, quercetin also seemed to be highly potent in lowering the parasite load in the spleen. Combination therapy of quercetin with the antileishmanial drug stibanate produced a better decay of OH in the erythrocytes of the infected animals compared to that induced by quercetin or drug treatment alone. Similar results were obtained in successful prevention of proteolytic degradation resulting in an aversion to early lysis of red cells after simultaneous treatment with quercetin and stibanate. Subsequent studies demonstrated the therapeutic efficacy of the combination treatment in the abatement of both anemia and parasitemia under the diseased condition.

Chemotherapy is still a major challenge for in vivo drug targeting to macrophages. Toxicity remains the major obstacle for the most potent drugs already known in the therapy of leishmaniasis. Thus, new drugs and new delivery systems are sought. By using different vesicular delivery modes e.g. liposomes, niosomes, microspheres and nanoparticles, attempts have been made to deliver an indigenous antileishmanial compound, quercetin, to treat experimental leishmaniasis in the hamster model so as to increase its efficacy as well as to reduce the toxicity. At equivalent quercetin concentration, the nanocapsulated quercetin was found to be the most potent in reducing the parasite burden in the spleen as well as in reducing hepatotoxcity and renaltoxicity compared to free drug or drug in other vesicular forms. An inverse relationship between the efficacy and the size of the vesicles was established. Such a drug vehicle formulation especially in the nanocapsulated form may be considered for clinical trials.

The efficacy of mannosylated liposome formulations with Quercetin (QC, a flavonoid antioxidant isolated from indigenous origin) has been tested in vivo against carbon tetrachloride(CCl(4))-induced liver oxidative damage in rats. Single subcutaneous injection of CCl(4) (40% v/v in olive oil; 1 ml/kg) induces the generation of toxic oxygen radicals and results in hepatocellular damage. The increased serum enzyme levels (glutamate pyruvate transaminase, alkaline phosphatase) and hepatocellular conjugated diene levels by CCl(4) induction were significantly lowered due to pretreatment with mannosylated liposomal QC (MLQ) (0.5 ml liposomal suspension containing 0.27 mg QC), whereas the same amount of free QC was found to be ineffective. In addition, the effectiveness of MLQ on CCl(4)-induced acute liver damage also was evaluated by tissue histopathological examination. Damage produced by CCl(4) in liver reverted to normal with pretreatment of MLQ.

Betulinic acid, a naturally abundant, plant derived, pentacyclic triterpenoid possesses anti-HIV, anti-malarial and anti-inflammatory properties and has recently emerged as a potent anti-tumor compound. This study explores the mode of action of betulinic acid on eukaryotic topoisomerase I and identifies the major functional group responsible along with more potent derivatives.Topoisomerase I relaxation activity was electrophoretically measured by the decreased mobility of the relaxed monomers followed by ethidium bromide staining. DNA cleavage was studied by electrophoretic separation of the nicked monomers from the relaxed and supercoiled monomers in presence of ethidium bromide. In-vivo DNA cleavage was studied in blasted mouse splenocytes by the SDS-K+ trapping of 3H-DNA-topoisomerase I-camptothecin ternary complex.Betulinic acid exerts its inhibitory effect by preventing topoisomerase I-DNA interaction as a result of which the 'cleavable complex' is not formed. In consequence, it also acts as an antagonist to camptothecin-mediated cleavage. A series of analogues modified at C-3, C-17 and C-20 positions of betulinic acid were subsequently assayed for inhibition of topoisomerase I catalytic activity. Replacement of the 17-carboxylic group reduces the inhibitory effect and decarboxylation leads to the complete loss of inhibitory effect.This study is the first detail report of betulinic acid as a very potent inhibitior of eukaryotic topoisomerase I and highlights the necessity of the carboxylic functional group. Dihydro betulinic acid is the most potent (IC50=0.5 mM) pentacyclic triterpenoid to inhibit eukaryotic topoisomerase I till date and can be exploited as a strong candidate for anti-tumor drug designing.

Luteolin, a naturally occurring flavonoid, is abundant in our daily dietary intake. It exhibits a wide spectrum of pharmacological properties, but little is known about its biochemical targets other than the fact that it induces topoisomerase II-mediated apoptosis. In the present study, we show that luteolin completely inhibits the catalytic activity of eukaryotic DNA topoisomerase I at a concentration of 40μM, with an IC50 of 5μM. Preincubation of enzyme with luteolin before adding a DNA substrate increases the inhibition of the catalytic activity (IC50 = 0.66μM). Treatment of DNA with luteolin before addition of topoisomerase I reduces this inhibitory effect. Subsequent fluorescence tests show that luteolin not only interacts directly with the enzyme but also with the substrate DNA, and intercalates at a very high concentration (>250μM) without binding to the minor groove. Direct interaction between luteolin and DNA does not affect the assembly of the enzyme–DNA complex, as evident from the electrophoretic mobility-shift assays. Here we show that the inhibition of topoisomerase I by luteolin is due to the stabilization of topoisomerase-I DNA-cleavable complexes. Hence, luteolin is similar to camptothecin, a class I inhibitor, with respect to its ability to form the topoisomerase I-mediated ‘cleavable complex'. But, unlike camptothecin, luteolin interacts with both free enzyme and substrate DNA. The inhibitory effect of luteolin is translated into concanavalin A-stimulated mouse splenocytes, with the compound inducing SDS–K+-precipitable DNA–topoisomerase complexes. This is the first report on luteolin as an inhibitor of the catalytic activity of topoisomerase I, and our results further support its therapeutic potential as a lead anti-cancer compound that poisons topoisomerases.

BACKGROUND: Plant-derived flavonoids, which occur abundantly in our daily dietary intake, possess antitumor, antibacterial, and free radical scavenging properties. They form active constituents of a number of herbal and traditional medicines. Several flavonoids have been shown to exert their action by interacting with DNA topoisomerases and promoting site-specific DNA cleavage. Therefore, flavonoids are potential candidates in drug design. We report here that, although the flavonoids luteolin and quercetin are potent antileishmanial agents, luteolin has great promise for acting as a lead compound in the chemotherapy of leishmaniasis, a major concern in developing countries. MATERIALS AND METHODS: Kinetoplast DNA (kDNA) minicircle cleavage in drug-treated parasites was measured by electrophoresis of the total cellular DNA, followed by Southern hybridization using 32P labeled kDNA as a probe. Cell cycle progression and apoptosis were measured by flow cytometry using propidium iodide and fluorescein isothiocyanate (FITC)-labeled Annexin V. RESULTS: Luteolin and quercetin inhibited the growth of Leishmania donovani promastigotes and amastigotes in vitro, inhibited DNA synthesis in promastigotes, and promoted topoisomerase-II-mediated linearization of kDNA minicircles. The IC50 values of luteolin and quercetin were 12.5 microM and 45.5 microM, respectively. These compounds arrest cell cycle progression in L. donovani promastigotes, leading to apoptosis. Luteolin has no effect on normal human T-cell blasts. Both luteolin and quercetin reduced splenic parasite burden in animal models. CONCLUSION: Luteolin and quercetin are effective antileishmanial agents. Quercetin has nonspecific effects on normal human T cells, but luteolin appears nontoxic. So, luteolin can be a strong candidate for antileishmanial drug design.