
Parasuraman JaisankarIndian Institute of Chemical Biology | IICB · Organic and Medicinal Chemistry
Parasuraman Jaisankar
M.Sc., Ph.D., FIC.FAScT.
Currently at St. Jude Children's Research Hospital, Memphis, TN, USA as Fulbright Visiting Scientist
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Introduction
Publications
Publications (166)
Biocatalysis plays an important role in the synthesis of complex organic molecules. Wedelolactone, a natural coumestan, has been reported to have many bioactive properties. A novel and efficient enzyme obtained from sweet potato juice was used for condensation of 4-hydroxycoumarins with catechols to produce wedelolactone and its structurally divers...
Chronic obstructive pulmonary disease (COPD) along with asthma is a major and increasing global health problem. Smoking contributes to about 80%–90% of total COPD cases in the world. COPD leads to the narrowing of small airways and destruction of lung tissue leading to emphysema primarily caused by neutrophil elastase. Neutrophil elastase plays an...
Leishmaniasis is a group of neglected tropical diseases (NTDs) caused by about 20 species of obligate intracellular protozoan parasites of the genus Leishmania, which occurs in cutaneous, mucocutaneous, and visceral forms. Many researchers have sought to utilize natural products for novel and effective treatments to combat many infectious diseases,...
Nanoscale self-assembly of peptide constructs represents a promising means to present bioactive motifs to develop new functional materials. Here, we present a series of peptide amphiphiles which form hydrogels based on β-sheet nanofibril networks, several of which have very promising anti-microbial and anti-parasitic activities, in particular again...
The aim of the present study is to explore the spermicidal potential of the synthetic spirooxindole derivatives and to examine the pathway behind the spermicidal action of the compounds. The in vitro spermicidal activities of the compounds were examined against human sperm by the modified Sander‐Cramer test. The pathway behind the spermicidal actio...
The formation and accumulation of amyloid beta (Aβ) peptide are considered the crucial events that are responsible for the progression of Alzheimer's disease (AD). Herein, we have designed and synthesized a series of fluorescent probes by using electron acceptor-donor end groups interacting with a π-conjugating system for the detection of Aβ aggreg...
SARS-CoV-2, a new coronavirus emerged in 2019, causing a global healthcare epidemic. Although a variety of drug targets have been identified as potential antiviral therapies, and effective candidate against SARS-CoV-2 remains elusive. One of the most promising targets for combating COVID-19 is SARS-CoV-2 Main protease (Mpro, a protein responsible f...
A comparative study of two Andrographis species have been done, and it was found that Andrographis nallamalayana J.L.Ellis is phytochemically and biologically different from Andrographis paniculata (Burm. f.) Nees.
Two novel cyanobacteria (AP3 and AP3b) with thin cells and simple morphology were isolated from two islands of the Indian Sundarbans. The 16S rRNA phylogeny data revealed the distinct lineage of AP3b which was nearest to the clade incorporating the genus Oculatella and Tildeniella. Strain AP3 shared a common ancestor with the species Euryhalinema m...
Chagas disease and leishmaniasis are neglected diseases caused by parasites of the Trypanosomatidae family and together they affect millions of people in the five continents. The treatment of Chagas disease is based on benznidazole, whereas for leishmaniasis few drugs are available, such as amphotericin B and miltefosine. In both cases, the current...
Mangrove forests occupy the estuarine ecotone and harbor a wide range of microorganisms along with a rich diversity of flora and fauna. Marine and estuarine organisms are known to produce unique molecules due to the aggressive, exigent, and competitive surroundings that are unlike those produced in the terrestrial environment. Marine cyanobacteria...
A series of heterocyclic C5-Curcuminoid (bis(arylmethylidene) acetones) (PJ1-PJ6) having large Stokes shift (λ = 104-173 nm) have been synthesized for selective detection of cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) in living cells. The compounds were synthesized by a new methodology via deacetylation under microwave condition. The...
This review deals with the recent applications of the indium trichloride (InCl3) catalyst in the synthesis of a broad spectrum of heterocyclic compounds. Over the years, a number of reviews on the applications of InCl3-catalyzed organic synthesis have appeared in the literature. It is evident that InCl3 has emerged as a valuable catalyst for a wide...
Molecular data based revision of Leptolyngbya, the largest polyphyletic genus of the family Leptolyngbyaceae (Synechococcales) is imperative. Polyphasic approach to the taxonomic analysis of two (AP9F and AP25) cyanobacteria, tentatively designated positions in the “LPP-group” is described. Cell shapes of AP9F and AP25 were highly elongated whereas...
Medicinal plant-based therapies can be important for treatment of cancer owing to high efficiency, low cost and minimal side effects. Here, we report the anti-cancer efficacy of Ricinus communis L. fruit extract (RCFE) using estrogen positive MCF-7 and highly aggressive, triple negative MDA-MB-231 breast cancer cells. RCFE induced cytotoxicity in t...
Background:
Many of present chemotherapeutics are inadequate and also resistant against visceral leishmaniasis (VL), an immunosuppressive ailment caused by Leishmania donovani. Despite the interest in plant-based drug development, no antileishmanial drugs from plant source are currently available. Glinus oppositifolius had been reported in favor o...
Cancer chemoprevention invokes the adoption of natural or man-made agents for the inhibition, delay, or reversal of carcinogenesis before an invasion. It is predicted that roughly one-third of all cancer deaths might be prevented through proper dietary alteration. Chemopreventives should be defined by low toxicity in therapeutic drugs and the possi...
The immune system is the most complex and important biological system of the human body, and good health requires it to be strong and well-functioning. Imbalance or malfunction of the immune system leads to a wide range of chronic diseases, including allergies, cancers, autoimmune diseases, and others. Immunogenicity mainly refers to any changes in...
Introduction of axial chirality in bioactive 3-indolyl furanoids has been achieved by systematic alteration of functional groups around the stereogenic axis, keeping in mind that atropisomerically pure analogues may possess different binding affinities and selectivities towards a target protein. The kinetics of racemization of axially chiral 3-indo...
Partial characterisation of secondary metabolites of a potent antagonistic bacterium Pseudomonas aeruginosa FARP72 (NCBI GenBank Accession No. KC570343) isolated from the skin mucus of catfish Clarias batrachus was attempted in this study. The antagonistic activity of P. aeruginosa was confirmed by cross and parallel streaking methods against three...
Bioactive molecules from medicinal plants can be important weapon in the arsenal of cancer therapy due to their high efficiency, low cost and minimal side effects. Nonetheless, current therapeutic regimen available for treatment of the disease, studies are ongoing to find more safe and potent therapies. In this report, we evaluated efficiency of fr...
Taxonomic characterization by a polyphasic approach was carried out on two cyanobacteria, AP17 and AP24 isolated from soil biofilms of two separate islands, Lothian and Sagar respectively, of the Indian Sundarbans. The strains were studied morphologically by light microscopy, scanning and transmission electron microscopy. Growth responses to variou...
Present chemotherapeutics are inadequate against visceral leishmaniasis (VL) an immunosuppressive ailment caused by Leishmania donovani. Despite the interest in plant-based drug development, an antileishmanial drug from plant source is unavailable. Glinus oppositifolius had been reported in favor of being immunomodulators along with other tradition...
Purpose
Orcinol glucoside (OG) - loaded nanostructured lipid carrier (NLC), coated with polyethylene glycol-25/55-stearate (PEG-25/55-SA), were explored for delivering OG to improve in vitro cytotoxicity against gastrointestinal tract (GIT), colon and hepatoma carcinoma cell lines. It is being expected that the PEGylated formulations would possess...
Kinetoplast DNA (kDNA) bearing unusual mitochondrion of trypanosomatid parasites offers a new paradigm in chemotherapy modality. Topoisomerase II of Leishmania donovani (LdTopII), a key enzyme associated with kDNA replication, is emerging as a potential drug target. However, mode of action of LdTopII targeted compounds in the parasites at sub-cellu...
Enzyme from Daucus carota root catalyzed Henry reaction of substituted benzaldehydes and nitromethane in phosphate buffer of pH 7 at 28 °C to afford β-nitroalcohols in excellent yields (up to 94%).
Background/aims:
Hypercholesterolemia is recently considered a risk factor for Parkinson's disease (PD), the most consistent neurodegenerative movement disorder. The study aimed to investigate the effect of exogenous cholesterol on 1-methyl-4-phenylpyridinium (MPP+) parkinsonian neurotoxin-induced cell death, loss of mitochondrial membrane potenti...
Fiaud’s acid (trans-1-hydroxy-2,5-diphenylphospholane 1-oxide), a phospholane-based phosphinic acid, is introduced as an efficient chiral Brønsted acid catalyst that mediates the asymmetric Friedel–Crafts alkylation of indoles with 2-butene-1,4-diones. With a catalyst loading of 10 mol %, the reaction proceeded smoothly to afford 2-(indol-3-yl)buta...
A series of N-substituted amide linked triazolyl β-D-glucopyranoside derivatives (4a-l) were synthesized and their in vitro inhibitory activity against yeast α-glucosidase enzyme [EC.3.2.1.20] was assessed. Compounds 4e (IC50=156.06 µM), 4f (IC50=147.94 µM), 4k (IC50 =127.71 µM) and 4l (IC50 =121.33 µM) were identified as the most potent inhibitors...
A number of 2-methyl-4- (2-oxo-2-phenyl-ethyl)-5-phenyl-furan-3-carboxylic acid alkyl ester derivatives (3a-j) were synthesized and evaluated for their in vitro inhibitory activity on soybean lipoxygenase enzyme. Among the screened compounds, 5-(4-bromo-phenyl)-4-[2-(4-bromo-phenyl)-2-oxo-ethyl]-2-methyl-furan-3-carboxylic acid methyl ester (3g) ha...
Poor aqueous solubility and unfavourable de-esterification of olmesartan medoxomil (a selective angiotensin II receptor blocker), results in low oral bioavailability of less than 26%. Improvement of oral bioavailability with prolonged pharmacodynamics activity of olmesartan in Wistar rats had been approached by nanoemulsification strategy in our pr...
A novel enzyme was isolated from specific variety of Daucus carota root catalyzed asymmetric cross aldol reaction of aromatic aldehydes with acetone to afford cross aldol products with excellent yield (up to 95%) and enantioselectivity (up to 99%). A plausible mechanism of the reaction has also been proposed.
Plant-derived natural products have made their own niche in the treatment of neurological diseases since time immemorial. Parkinson’s disease (PD), the second most prevalent neurodegenerative disorder, has no cure and the treatment available currently is symptomatic. This chapter thoughtfully and objectively assesses the scientific basis that suppo...
Visceral Leishmaniasis is a fatal parasitic disease and there is an emergent need for development of effective drugs against this neglected tropical disease. We report here development of a novel spirooxindole derivative N-benzyl 2, 2’ α 3, 3’, 5’, 6’, 7’, 7α,α'-octahydro-2methoxycarbonyl-spiro [indole-3, 3’ -pyrrolizidine]-2 one (Compound 4c) whic...
The significant rotational energy barrier about the stereogenic carbon–carbon bond of axially chiral 3,3′-bipyrroles has been investigated by electronic circular dichroism (ECD) spectroscopy, time dependent HPLC analysis, and computational modeling. The results elucidate pathways and transition states involved in configurational inversion, thereby...
Flavonoids are one of the most common groups of plant’s secondary metabolites. They are the low molecular weight polyphenolic compounds with a composition of various substituted three-ring structure and responsible for the vibrant colors of many plants. Flavonoids are recognized for their participation in plant’s defensive mechanisms by preventing...
Nanodomain Pd(0) mediated regio- and stereo-selective synthesis of (Z)-3-methyleneisoindoline-1-ones and furo[3,2-h]quinolines in water was achieved in high yield. The novel one-pot domino-Sonogashira-cyclization protocol is environment friendly as it eliminates the use of ligands, copper, organic solvents or ionic liquids and homogeneous catalysts...
Asthma, like many inflammation related disorders, has a complex etiology. Drugs targeting multiple pathways may prove more efficacious in these complex disorders. Cyclic 3′,5′-adenosine monophosphate (cAMP) phosphodiesterase IV (PDE IV) is one of the validated targets in bronchial asthma and despite availability of some therapeutic molecules target...
Leishmania, a protozoan parasite, causes a wide range of human diseases ranging from the localized self-healing cutaneous lesions to fatal visceral leishmaniasis. Toxicity of traditional first line drugs and emergence of drug-resistant strains have worsened the situation. DNA topoisomerase II in kinetoplastid protozoan parasites are of immense inte...
Microwave promoted indium trichloride (10 mol %) catalyzed sp3 C–H bond functionalization of 2-alkyl azaarenes 1 or 4 has been observed to construct C–C bond either with but-2-ene-1,4-diones 2 or (E)-3-(2-oxo-2-phenylethylidene)indolin-2-one (6) giving access to 2-((quinolin-2-yl)methyl)butane-1,4-diones 3, 2-((pyridin-2-yl)methyl)butane-1,4-diones...
Figure S1. Clearance of internalized SbS (AG83) and SbR (GE1) Leishmania donovani parasite from in vitro infected mouse macrophage in culture. Macrophages (Mϕ) were isolated from BALB/c mice 36–48 h post injection (intraperitoneal) with 2% (w/v) hydrolyzed starch by peritoneal lavage with ice-cold phosphate-buffered saline and infected with early-p...
Figure S6. Effect of isobenzofuranone derivatives on LdTOPII–DNA binary complex formation. Effect of isobenzofuranone derivatives on DNA-binding activity of LdTOPII proteins was analyzed by EMSA analysis. Lane 1, labeled 36-mer duplex oligonucleotide; lane 2, 36-mer oligonucleotide incubated with of LdTOPII; lanes 3 and 4 same as lane 2, but incuba...
Figure S2. Isobenzofuranone derivatives induced the generation of ROS and fragmentation of genomic DNA in Leishmania donovani. ROS generation for the promastigotes treated with JVPH3/JVPH4 for different times was measured by flurometric analysis of H2DCFDA at 530 nm (A). The level of fluorescent products of lipid peroxidation was measured at 430 nm...
Figure S3. Effect of isobenzofuranone derivatives on hTOPIIα activity. hLdTOPIIα was incubated with 200 ng kDNA in presence of different concentrations of JVPH3 and JVPH4. Lane 1, kDNA only; lane 2, kDNA treated with LdTOPII; lane 3, same as lane 2 but in presence of DMSO. KN indicates kDNA network. M II and M I indicate the released minicircles su...
Figure S5. Effect of isobenzofuranone derivatives on DNA unwinding. Unwinding assay was performed with supercoiled and relaxed plasmid DNA. Negatively supercoiled pBS (SK+) DNA was treated with LdTOPIB in presence of different concentrations of JVPH3 and JVPH4 (A). Relaxed pBS(SK+) DNA was treated with LdTOPIB in presence of different concentration...
Figure S7. In vivo generation of ROS and NO from infected and isobenzofuranone derivatives treated BALB/c mice. Splenocytes (2.0 × 106) from different experimental mice groups were pulsed with SLA for 48 h in 5% CO2 incubator at 37°C. Level of ROS in splenocytes was measured by H2DCFDA probe (A) and NO content in the culture supernatant was measure...
Figure S4. Effect of isobenzofuranone derivatives on LdTOPIB activity. The type I DNA topoisomerase was assayed by decreased mobility of the relaxed isomers of supercoiled pBS (SK+) [pBluescript (SK+)] DNA in agarose gel. Different concentrations (2, 5, 10, 20, and 50 μmol/L) of JVPH3 and JVPH4 were incubated with LdTOPIB followed by electrophoresi...
Interaction of the 9-O-N-aryl/arylalkyl amino carbonyl methyl substituted analogs of the anticancer isoquinoline alkaloid berberine with RNA triplex, poly(U)-poly(A)·poly(U) has been studied in comparison to the duplex poly(A)-poly(U), using multiple biophysical techniques. Spectrophotometric and spectrofluorimetric studies established the non-coop...
Studies on the molecular aspects of alkaloid-RNA complexation are of prime importance for the development of rational RNA targeted drug design strategies. Towards this goal, the binding aspects of three novel 9-O-N-aryl/arylalkyl amino carbonyl methyl substituted berberine analogs to four single stranded ribonucleotides, poly(G), poly(I), poly(C) a...
Olmesartan medoxomil (OM) is hydrolyzed to its active metabolite olmesartan by the action of aryl esterase to exert its antihypertensive actions by selectively blocking angiotensin II–AT1 receptor. Poor aqueous solubility and uncontrolled enzymatic conversion of OM to its poorly permeable olmesartan limits its oral bioavailability. The aim of the c...
Various 3,3′-diindolylmethane (DIM) derivatives were synthesized and the antibacterial activity of these compounds were tested against ten bacterial strains and their minimum inhibitory concentration (MIC) values were determined. The MIC values of derivatives 3a–d and 5a–e were ranging from 125 to 500 μg/mL. Among these derivatives, 2-(di(1H-indol-...
The unicellular organism Leishmania undergoes apoptosis-like cell death in response to external stress or exposure to antileishmanial agents. Here, we showed
that 3-O,28-O-disuccinyl betulin (DiSB), a potent topoisomerase type IB inhibitor, induced parasitic cell death by generating oxidative
stress. The characteristic feature of the death process...
Lignans are diphenyl propanoids with vast range of biological activities. The present study provides an important insight into the anti-leishmanial activities of two lignan glycosides viz. lyoniside and saracoside. These compounds inhibit catalytic activities of topoisomerase IB (LdTopIB) of Leishmania donovani in non-competitive manner and stabili...
Mammalian target of rapamycin (mTOR) is a central kinase that regulates cell survival, proliferation and translation. Reactive oxygen species (ROS) are second messengers with potential in manipulating cellular signaling. Here we report that two ROS generating phytochemicals, hydroxychavicol and curcumin synergize in leukemic cells in inducing enhan...
Hydroxychavicol (HCH), a constituent of Piper betle leaf has been reported to exert anti-leukemic activity through induction of reactive oxygen species (ROS). The aim of the study is to optimize the oxidative stress -induced chronic myeloid leukemic (CML) cell death by combining glutathione synthesis inhibitor, buthionine sulfoximine (BSO) with HCH...
Tetrasubstituted pyrroles (III) are prepared from 1,4-enediones (I) and β-dicarbonyl compounds (II) employing ammonium acetate as a nitrogen source, through a combination of Michael addition and Paal—Knorr cyclization.
This interaction of four novel 9-O-substituted analogs of the plant alkaloid berberine with double stranded poly(A) was studied using a variety of biophysical techniques. Remarkably higher binding of two 9-O-ω-amino alkyl ether analogs compared to the two 9-O-N-aryl/arylalkyl amino carbonyl methyl berberine analogs was observed. Quantum efficiency...
A novel sensitive, specific, reproducible and innovative reverse-phase high-performance liquid chromatographic method was developed for the detection of olmesartan medoxomil. A Hypersil BDS C18, 250x4.6 mm, 5 mm particle size column with a mobile phase composed of acetonitrile and 10 mM KH2PO4 buffer (pH 3.5) in a ratio of 55 : 45 v/v was used at a...
Despite recent advances in medicine, 30–40% of patients with breast cancer show recurrence underscoring the need for improved effective therapy. In this study, by in vitro screening we have selected a novel synthetic indole derivative 2,2'-diphenyl-3,3'-diindolylmethane (DPDIM) as a potential anti- breast cancer agent. DPDIM induces apoptosis both...
Inhibition of phosphorylation of constitutively active EGFR (EGFRvIII) by DPDIM. EGFRvIII (100 ng) was transiently overexpressed in MCF7 cells by transfection using Attractene (Qiagen) according to the manufacturer’s instructions. The transfected cells were then treated with 10 µM DPDIM for 24 hr. Cells expressing vector alone or EGFRvIII, exposed...
Comparison of DPDIM binding with other known EGFR inhibitors. (A) Docked conformation of DPDIM (white stick model) was superimposed with the erlotinib (green stick model) and gefitinib (cyan stick model). PDB IDs 1M17 and 3UG2 were used. EGFR kinase domain was shown in surface representation. (B) Close up view of the binding site. EGFR kinase domai...
Examination of DNA fragmentation in DPDIM treated MCF7 cells. Cells were treated with either DPDIM (1, 10 and 50 µM) or DMSO (vehicle control) for 24 hr before isolation of genomic DNA. DNA was isolated using standard phenol:chloroform:isopropanol (25∶24:1) method followed by ethanol precipitation. DNA ladder formation in DPDIM treated cells shows...
Effect of DPDIM on cell migration. Panels show representative images of DMSO (vehicle control) and DPDIM treated cells. Scratches on monolayer of MCF7 cells treated for 24 and 48 hrs show the increased wound gap at 10 and 50 µM whereas gap remained unchanged in 1 µM. Decreased wound gap was observed in DMSO control. Images were digitally captured b...
Regulation of cell viability by DPDIM in EGFRvIII overexpressed cells. EGFRvIII (100 ng, 200 ng, 300 ng and 400 ng) and vector transfected MCF7 cells treated with or without DPDIM (10 µM) for 24 hr were subjected to cell viability (MTT) assay. Results of three independent experiments were represented in the bar diagram with SD. * indicates P<0.0001...