Neem Bark Extract Research Articles

In vitro Study of Neem Bark Extract on Rumen Fermentation and Biohydrogenation of Polyunsaturated Fatty Acids

In vitro Study of Neem Bark Extract on Rumen Fermentation and Biohydrogenation of Polyunsaturated Fatty Acids

Concentration Dependent Effect of Azadirachta indica (Neem) Seed Oil and Neem Bark extract on Planktonic and Established Biofilm Growth of Pseudomonas aeruginosa and Staphylococcus aureus

Azadirachta indica Juss (Neem) is well documented for its antimicrobial activity. The effect of varying concentrations (0.1 to 50% v/v) of Azadirachta indica derived neem seed oil (NSO), neem seed oil with tween 20 and neem bark extract was evaluated on planktonic, biofilm formation and mature biofilms of multiple drug resistant Pseudomonas aeruginosa ATCC 15442 and Staphylococcus aureus ATCC 25923 using the crystal violet assay and scanning electron microscopy. NSO showed antimicrobial activity at 25% v/v for P. aeruginosa but not S. aureus in zone of inhibition assay. Neem bark extract on the contrary showed antimicrobial activity against both the isolates at 50% v/v concentrations. Interestingly, in biofilm formation assay, low concentrations of NSO (3.5 to 0.2% v/v) induced biofilm formation while inhibition of both planktonic and biofilm was seen in concentration dependent manner from 12.5% v/v onwards. Complex of NSO and tween in comparison of NSO alone caused low induction in S.aureus biofilm formation, while inhibiting biofilm formation of P. aeruginosa at all the concentrations. In biofilm eradication assay, NSO induced biofilm of both P. aeruginosa (50 to 0.1%v/v) and S. aureus (50 to 3.13%v/v). Eradication effect of neem bark extract was found on P. aeruginosa biofilm in a dose dependent fashion from 50 to 20% v/v followed by 0.2 to 0.1%v/v concentration respectively. S. aureus biofilm were eradicated at 50 to 25%v/v concentrations. At low concentrations, both the neem derivatives induced biofilm mediated growth of the pathogenic organisms. The data also indicate that neem seed oil was more effective against Gram negative P. aeruginosa while neem bark extract was effective against Gram positive S. aureus. This study highlights the crucial but variable effects of concentration dependent effect of phytochemicals and their composition on biofilm induction as well as eradication, the primary growth form in clinical settings. This challenges the notion that all herbal products are safe as antimicrobial activities differ as per microbial growth modes. Hence, concentration dependent effect of medicinal plant derived products requires thorough investigation prior to their use as antimicrobial agents.

Antibacterial study of carbopol-mastic gum/silver nanoparticle-based topical gels with carvacrol/neem bark extract in vitro.

Resistance to antimicrobial drugs as a result of prolonged use usually results in clinical failure, especially in wound infections. Development of effective antimicrobial therapeutics for the management of infected wounds from a natural source with improved therapeutic effects is a pressing need. In this study, carbopol-mastic gum-based topical gels were loaded with silver nanoparticles in combination with either neem bark extract or carvacrol oil. The effect of combining silver nanoparticles with neem bark extract or the essential oil carvacrol in the prepared gel formulations was investigated on selected bacterial strains. The prepared gels were characterised by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and ultraviolet-visible (UV-vis) spectroscopy, followed by antimicrobial analysis against selected strains of bacteria. There was no interaction between the loaded natural extract or essential oil and the polymer used for the preparation of the formulations, which was visible from the FTIR spectra of the formulations. The gels were selective and effective against selected strains of bacteria. However, the combination of the silver nanoparticles with essential oil or natural extract in some of the gel formulations rendered the formulation ineffective against some of the bacterial strains. The gel formulations were effective against bacterial strains such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis which are the common causes of wound infections. Incorporation of silver nanoparticles into the topical formulations with natural extracts is usually a good approach to overcome antibiotic-resistant infections. However, the combination of antibacterial agents must be managed carefully.

IL 6 levels in Periodontitis Induced Rabbits after Treatment with Neem Bark Extract

Background: IL-6 has crucial role in the response to microbial insults. It acts as pro-inflammatory and anti-inflammatory agent. Hence IL 6 is an important inflammatory marker of periodontal disease. Levels of IL6 in Gingival crevicular fluid strongly indicate presence of periodontal disease which ultimately results in many health hazards. Aims: To measure levels of IL 6 in periodontitis induced rabbits after treating animals with neem bark extract and amoxicillin at doses of 500mg/kg and 20mg/kg and to see anti-inflammatory effects of neem bark extract. Methods: Forty eight white New Zealand rabbits were divided in four groups A, B, C and D. Group A was healthy control. Group B was disease group. Group C was neem treated. Group D was amoxicillin treated. Periodontitis was induced and rabbits were given treatment with neem bark extract and amoxicillin for 10 days. Samples were obtained with the help of periopaper absorbent strip and marginal auricular vein and analyzed in laboratory. ELISA test was performed to find levels of IL 6 in all four groups. Practical implication: To gain the evidence that neem can be used in maintenance of oral hygiene and prevention of oral diseases. Results: Treatment with neem bark extract and amoxicillin equally reduced IL 6 levels among group c and D after treatment (0.033±0.003) in gingival crevicular fluid when compared with diseased group B (0.089±0.007).P value was less than 0.001. Conclusion: Neem bark extract has significant effects on reduction of IL 6 levels in gingival crevicular fluid of periodontitis induced rabbits Neem bark extract possess anti-inflammatory and anti-microbial action. Keywords: IL6, Periodontitis, GCF, Inflammation, Neem

Methanolic neem (Azadirachta indica) stem bark extract induces cell cycle arrest, apoptosis and inhibits the migration of cervical cancer cells in vitro

BackgroundCervical cancer remains one of the significant causes of mortality in women due to the limitations of current treatment strategies and their associated side effects. Investigation of alternative medicine, including phytomedicine, has shown effective anti-cancer potential with fewer side effects. Azadirachta indica (commonly known as neem) is known for its medicinal properties. The present study investigated the anti-cancer potential of methanolic neem stem bark extract (MNBE) against cervical cancer using HeLa, SiHa, and ME-180 cell lines.MethodsCytotoxic effect of MNBE on cultured cell lines was evaluated by MTT and clonogenic assay. The growth-inhibiting effect of MNBE was further confirmed by performing cell cycle analysis and apoptosis assay using flow cytometry. The anti-migratory effect of MNBE was evaluated by using wound healing and Boyden chamber assay. Real-time PCR was used to determine the mRNA expression, and western blot and flow cytometry was used to determine the protein levels of growth and migration-related genes.ResultsMNBE significantly suppressed the growth and survival of cervical cancer cells in a dose-dependent manner by inducing cell cycle arrest and apoptosis. In addition, the growth inhibitory effect of MNBE was specific to cervical cancer cells than normal cells. Cell cycle arrest was correlated to transcriptional downregulation of cyclin dependent kinase 1 (CDK1), cyclin A, and cyclin B. Additionally, MNBE treatment resulted in the upregulation of active caspase-3 protein and downregulation of prosurvival genes, Bcl2, and survivin at mRNA level and NFkB-p65 at the protein level. Furthermore, MNBE inhibited the migration of cervical cancer cells accompanied by modulation of migration-related genes, including zona occludens-1 (ZO-1), matrix metalloproteinase 2 (MMP2), focal adhesion kinase (FAK), N-cadherin, snail, and E-cadherin.ConclusionIn summary, the present study provides the first evidence of MNBE in restricting cervical cancer cell growth and migration, which warrants further investigation for developing novel anti-cancer drugs.

Antifungal Efficacy of Different Extracts of Neem and Turmeric on Candida Species – An in vitro Analysis

Background: Curcumin is an age-old spice, which is known for its anti-inflammatory activity and antibacterial property, and neem is proven to have many medicinal properties, especially known for its antimicrobial properties. Aim: The study aimed at assessing the antifungal activity of different preparations of turmeric and neem over Candida species. Materials and Methods: Using Sabouraud's agar as the medium, Candida species colonies were transferred to the agar plates after preparation of five wells. 75 μl, 50 μl, 25 μl, 10 μl, and 5 μl of neem leaf oil, neem oil, turmeric oil, turmeric extract, and neem seed oil were added and incubated at 37°C for 18–24 h. The diameter of inhibition zone around the wells where the growth was inhibited corresponded to the antifungal activity. Results: Neem bark extract and turmeric extract showed the highest inhibitory range against Candida albicans. Neem leaf extract showed the highest range of inhibition at 75% against Candida krusei and Candida tropicalis. Conclusion: Extracts of turmeric and neem have shown definitive inhibition against different strains of candida in vitro, and hence, these can be used for treating candidiasis as an alternative to regular triazoles.

UTILIZATION OF NEMBA STEM AS AN ANTITUBERCULOSIS COMPARED WITH RIFAMPICIN AND ETAMBUTOL

Indonesia ranks third in the number of tuberculosis, after India and China. Treatment of tuberculosis takes a long time, and the lack of discipline in taking medication has caused the Mycobacterium tuberculosis to be resistant to many synthetic drugs that have been used so far. In contrast, the discovery of new synthetic drugs is very slow. Traditionally, neem bark (Azadirachta indica JUSS.) has been used to treat coughing up blood and phlegm, and the results of previous studies show that ethanol extract of neem bark in vitro can inhibit the growth of Mycobacterium tuberculosis. This study was conducted to determine the toxicity of neem bark extract, formulation of neem bark ethanol extract into tablet preparations, and the potential of this tablet preparation as anti-tuberculosis in vivo in animals. Neem bark extract was made by percolation using an ethanol extractor. Toxicity test was carried out in the form of an acute toxicity test on mice to calculate the LD50 value and histopathological observations of the liver, lungs, and intestines. The tablets were made by wet granulation. The potential test of tablet preparations as anti-tuberculosis was performed in vivo on animals infected with Mycobacterium tuberculosis H37Rv using a nebulizer. The results showed LD 50 = 11.85 ± 0.571, including mild toxic. The ethanolic extract of neem bark can be formulated into tablets using a 6% gelatin binder, Manihot starch and primojel as a binder, and a mixture of starch and lactose as a filler. Neem bark extract tablets can cure tuberculosis of experimental animals that have been infected with Mycobacterium tuberculosis H37RV, which is given a dose of 3 times a day two tablets (50 mg/tablet) for six weeks seen tuberculosis bacteria from +3 to negative, and a dose of 3 times a day once a day. Tablet looks from +3 to +1.

Effectiveness of neem (Azadirachta indica a.juss) bark extract as a gastroprotektor

Background: Gastric ulcer is a digestive problem that has a high prevalence rate, peptic ulcer can cause complications such as bleeding in the gastrointestinal tract, perforation, recurrence, cancer and even death. The neem stem bark extract has a compound that can be a gastroprotective activity so that it can reduce the number of gastric ulcer and gastric acid levels. Gastroprotective effects of neem bark extract in combination have been widely studied can reduce gastric ulcer, but no one has examined the extract of neem bark as a single gastroprotector. Objective: This study aims to determine the dose of extract that can prove the extract of neem stem bark can inhibit the ulcer index by macroscopic observation and microscopic images of in rats Methods: This research is a purely experimental study carried out in July – September 2019. The neem stem bark extract was given to Wistar male white rats with various dosages for seven days orally, after 24 hours of fasting, induced gastric ulcer with ibuprofen 400 mg/kg. Mice were dissected to activate the ulcer index after 8 hours of induction of gastric ulcer. Result: The ulcus index of negative group (ibuprofen), positive group (ranidin), and extracts of mimba rods 250, 500, 1000, and 2000 CMG/kgBB in a row were 7.13, 16.76, 7.41, 2.32, and 2.00 (p= 0.034). Microscopic observations suggest a much better picture of histology after this extract. Conclusion: The extract of a mimba bark has gastroprotective activity at 2,000 mg/kgBB.

Susceptibility Screening of Thymol, Quercetin, Neem, Cinnamaldehyde and Eugenol against Pseudomonas aeruginosa

Pseudomonas aeruginosa exhibits intrinsic and acquired resistance to antibiotics. An under‐utilized source of antimicrobic activity is phytochemicals. Their use against P. aeruginosa may serve as an alternative to conventional antibiotics in this age of ever‐increasing resistance. The purpose of this study was to investigate susceptibility patterns of P. aeruginosa in the presence of phytochemicals selected from literature citations reporting antibacterial activity. The hypothesis was that phytochemicals thymol, quercetin, neem bark extract, cinnamaldehyde and eugenol inhibit growth of P. aeruginosa. Susceptibility testing of phytochemicals was performed by the Kirby Bauer disk diffusion method and phytochemicals were tested at different concentrations (0–100%) after 2‐fold serial dilutions of the agents into tryptic soy broth. Results showed zones of growth inhibition of P. aeruginosa (ATCC strain 27853) around cinnamaldehyde‐ and eugenol‐impregnated disks when the phytochemicals were presented singly or in combination with each other. Specific results indicated that significant zones of inhibition were evident at 100%, 50% and 25% concentrations of cinnamaldehyde. Zones of inhibition were evident at 100% and 50% eugenol. A combination study of cinnamaldehyde and eugenol, each at 12.5% concentration, produced a notable zone of inhibition (measured at 16 mm diameter): neither cinnamaldehyde nor eugenol displayed zones of inhibition independently at that concentration (of 12.5%). Thymol, quercetin and neem bark extract did not yield visible zones of inhibition at any concentration tested. To conclude, cinnamaldehyde and eugenol each individually possess antimicrobial activity against P. aeruginosa (strain ATCC 27853) as indicated by disk diffusion susceptibility testing. Additionally, the two phytochemicals act synergistically in combination to effectively inhibit bacterial growth. Evidence of synergistic activity at low concentrations not effective individually by either cinnamaldehyde or eugenol offers potential therapeutic value. Other phytochemicals (thymol, quercetin, neem bark extract) failed to inhibit P. aeruginosa growth at any concentration tested. Future studies aim to screen more phytochemicals independently and in combination against other strains of P. aeruginosa to allow for statistical analysis and determination of susceptibility patterns.Support or Funding InformationFinancial support for JK was received from the DeNardo Education and Research Foundation.

Influence of ultrasonic radiation on extraction and green dyeing of mordanted cotton using neem bark extract

The current research presents the exploration of coloring potential of neem bark under the influence of ultrasonic treatment. It is found that good color strength is obtained when tannin from bark is extracted in acidified methanol medium and is used to dye irradiated cotton fabric. New shades and good ratings of fastness were obtained when optimal fabric was mordanted with herbal biomolecules where excellent rating has been obtained after bio-mordanting the fabrics under optimal conditions. It is concluded that US treatment being green tool in natural dyeing has a great potential to isolate colorants from plant sources under mild conditions.

Effects of Crude Extract of Neem Bark on the Pancreas of Streptozotocin Induced Diabetic Wistar Rats

This study investigated the histological and serum enzymatic activities of Azadirachta indica, an Indian medicinal plant, on the pancreas in streptozotocin induced diabetic adult wstar rats.
 Forty six adult wistar rats weighing 100 g to 220 g were randomly separated into four groups; Group A was regarded as the control , while group B was the diabetic group, C and diabetic – extract treated group. The control group received distilled water throughout the experiment; the remaining three groups were induced with streptozotocin intra-peritoneally to induced diabetes in the wistar rats. After some days, the animals were confirmed diabetic with the help of a measuring glucometer. Thereafter, group B diabetic rats remained untreated while Group C and D were treated with a low dose (250 mg/kg) of the crude neem bark extract and a high dose (500 mg/kg) of the extract respectively for 42 days. The aqueous neem bark extract was suspended in the drinking water of the treated animals for the period of 42 days. The body weights of the animals were weighed weekly and likewise the measurement of the blood glucose level was taken. The animals were sacrificed at the end of 42 days by cervical dislocation and the pancreas was removed and weighed immediately using sensitive weighing balance. The blood samples were collected from the sacrificed animals into EDTA bottle for serum enzymatic analysis. The organ pancreas was fixed in a 10% formol saline, processed and stained with Heamatoxylin and Eosin for general histological study.
 The microscopic examination of diabetic group showed some degenerative and necrotic cells which made the pancreatic tissue distorted compared with the control that appeared normal. The diabetic group C and D rats treated with the extract showed ameliorative potentials of the extract with improvement in histo-architecture of the pancreatic tissue following recovery from damage. Analysis of the blood serum level showed that the aqueous neem bark extract has ameliorative effect on the enzymatic activities in serum of the treated rats. The alanine amino transferase, aspartate amino transferase and alkaline phosphatase levels were significantly reduced (P<0.05) in the crude extract- treated animals compared with the untreated group B and control group A with significantly increased ( P<0.05 ) enzymatic activities in wistar rats in these groups. The antioxidant status was compromised in diabetic group B with significantly increased (P<0.05) LPO, reduced SOD and GSH compared with significantly reduced (P<0.05) LPO, increased (P<0.05) SOD and GSH in group A- control and Group C and D diabetic-extract treated Wistar rats.
 Similarly, the blood glucose level increased significantly (P<0.05) in group B diabetic group compared with significantly reduced (P<0.05) blood glucose level in group A control as well as C and D extract-treated rats. The study concluded that crude extract of neem has ameliorative potentials on streptozotocin-induced diabetic wistar rats characterized by oxidative damage which reveals improvement in tissue morphology.

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Biogenic silica nanoparticles loaded with neem bark extract as green, slow-release biocide

Biogenic silica derived from Equisetum arvense was used as a carrier of an eco-friendly biocide consisting of a neem bark extract cross-linked with polycarboxylic acids. Infrared spectroscopy indicated the presence of ester bonds between the silica support and the loaded bark extract. Surface area analysis, porosimetry and microscopy confirmed a high level of biocide loading in the silica support. Furthermore, compared with the unloaded biogenic silica nanoparticles, a better thermal stability was determined for the system carrying the extracted compounds. Experiments consisting of three sequential release profiles showed full mass release after 20 days of unloaded neem while the extract loaded in the solid support reached only 60–75% released after 30 days. A four-fold improvement in the neem extract stability was observed in aqueous media if loaded in the silica support. The neem compounds released from silica showed a satisfactory scavenging activity over 50% of DPPH free radical, and could cause the mortality of the major workers of Acromyrmex crassispinus ant specie.

SCREENING STUDY ON THE EFFECT OF NEEM BARK EXTRACT ON PREGNANT RATS AND THEIR FETUSES

The aim of the present study was to conduct a preliminary screen of neem, a valuable plant source commonly used in traditional medicine and in modern drug development, to determine its potential for reproductive toxicity. Neem bark extract at dose 50, 100 and 300 mg/kg bodyweight was administered by gavage to pregnant rats daily from gestational day 1 to 20. Implantation rate, fetal mortality, fetal body weight and length, external and skeletal abnormalities, micronucleus assay in fetal liver cells, as well as histological and ultrastructural examination of fetal liver, were studied. On the other hand, maternal body weight, absolute and relative organs weight, micronucleus assay in bone marrow, histological and cytological examination of liver, and certain parameters related to liver function (serum alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase activities, as well as total protein, albumin and globulin content) were determined in mothers. No effects were observed on reproductive outcomes or dams received dose of 50 or 100 mg/kg body weight, except some histological and cytological liver defects were observed at 100 mg/kg body weight. Neem bark extract administered at dose 300 mg/kg body weight was associated with reduced fetal body weight, minor skeletal variations, and moderate histological and ultrastructural alterations in the liver. However, no considerable adverse effect on implantation, mortality rate, external malformation, or in frequency of micronucleated polychromatic erythrocytes in fetal liver cells was observed. In dams exposed to the high dose, significant physiological, histological and cytological alterations in liver were observed without affecting body weight, organs weight, or bone marrow micronuclei rate. In conclusion, neem bark extract was not teratogenic or genotoxic in rats. It has a low potential to adversely affect prenatal development only at maternally toxic dose.

<i>In vitro</i> investigation of anticholinesterase activity of four biochemical pesticides: spinosad, pyrethrum, neem bark extract and veratrine

The anticholinesterase activity of four biochemical pesticides: spinosad, pyrethrum, neem bark extract and veratrine was tested against one acetylcholinesterase extracted from Electrophorus electricus and two from Drosophila melanogaster. Pyrethrum, neem bark extract, and veratrine induced a dose-related inhibition of a variable type. Electric eel cholinesterase was inhibited uncompetitively by neem bark extract, the inhibition of the wilde-type fruit fly enzyme by pyrethrum was competitive, and the other enzyme-biochemical pesticide inhibitions were non-competitive. The sensitivity of each enzyme toward biochemical pesticides was variable.

Antidiabetic activity of alcoholic extract of Neem (Azadirachta Indica) root bark

Background: Most of the parts of neem tree were studied in details by many researchers but neem root bark was not screened for antidiabetic effect. To evaluate antidiabetic effect of neem root bark this study was conducted. Aims & Objective: The present study was undertaken to evaluate the 70% alcoholic neem root bark extract (NRE) in diabetes. Materials and Methods: Basal blood sugar levels were estimated in overnight fasted wistar albino rats of either sex. To evaluate antihyperglycemic action of Neem root bark extract (NRE) OGTT was done by giving glucose orally 60 minutes after giving standard drug (Glibenclamide),Test drug (NRE) in the dose of 200,400 and 800 mg/kg and blood sugar levels were estimated every half hourly up to 4 hours. To evaluate hypoglycemic activity in alloxan induced diabetic rats similar doses once daily for 15 days. Blood sugar levels were estimated by using glucometer. Results: For glucose tolerance test Glibenclamide significant (p< 0.01) reduction in blood sugar levels. The NRE showed statistically significant results in only 800 mg/kg dose. In comparison to glibenclamide it did not show. In alloxan induced diabetes Glibenclamide showed significant (p

Selective colorimetric sensing of toxic metal cations by green synthesized silver nanoparticles over a wide pH range

Selective colorimetric sensing of potentially health and environmentally hazardous heavy metal ions in aqueous solution was demonstrated using green synthesized silver nanoparticles (AgNPs) from plant extracts, by taking advantage of metal coordinating organic functional groups present in the extracts. AgNPs synthesized using fresh neem leaf extracts (NF-AgNPs) selectively detected Hg2+ whereas sun-dried neem leaf extract based AgNPs (ND-AgNPs) were observed to selectively sense Hg2+ and Pb2+ at micromolar concentrations. Neem bark extract based AgNPs exhibited selective colorimetric sensing of Hg2+ and Zn2+. Similarly, AgNPs synthesized from mango leaf (fresh, MF-AgNPs; sun-dried, MD-AgNPs) and green tea extracts (GT-AgNPs) showed selective colorimetric sensing of Hg2+ and Pb2+ ions. AgNPs obtained using pepper seed extracts exhibited Hg2+, Pb2+ and Zn2+ selective colorimetric sensor properties. Importantly these green synthesized AgNPs selectively detected the presence of hazardous metal ions in aqueous solutions across a wide range of pH values (2.0–11), which is a highly desirable attribute from the perspective of different sources of water pollution. The selective colorimetric sensing of Hg2+, Pb2+ and Zn2+ ions by green synthesized AgNPs over a wide pH range demonstrates the multi-functional utility of plant extracts in green nanotechnology and environmental sensor applications.

In vitro antiviral activity of neem (Azardirachta indica L.) bark extract against herpes simplex virus type‐1 infection

Herpes simplex virus type 1 (HSV-1) causes significant health problems from periodical skin and corneal lesions to encephalitis. We report here that an aqueous extract preparation from the barks of neem plant Azardirachta indica acts as a potent entry inhibitor against HSV-1 infection into natural target cells. The neem bark extract (NBE) significantly blocked HSV-1 entry into cells at concentrations ranging from 50 to 100 microg/ml. The blocking activity of NBE was observed when the extract was pre-incubated with the virus but not with the target cells, suggesting a direct antiHSV-1 property of the neem bark. Further, virions treated with NBE failed to bind the cells which implicate a role of NBE as an attachment step blocker. Cells treated with NBE also inhibited HSV-1 glycoprotein-mediated cell-cell fusion and polykaryocytes formation suggesting an additional role of NBE at the viral fusion step. These findings open a potential new avenue for the development of NBE as a novel antiherpetic microbicide.

The use of neem for controlling gastric hyperacidity and ulcer

H(2)-receptor blockers and proton pump inhibitors are now used extensively to control gastric and duodenal ulcer, inflammation and pain, but these drugs have limitations and are not always affordable. The development of novel nontoxic antiulcer drugs, including from medicinal plants, is therefore desirable, and Azadirachta indica A. Juss, commonly known as Neem, is known to have potent gastroprotective and antiulcer effects. This review deals with the pharmacological and biochemical studies carried out regarding the antiulcer activities of Neem extracts and their mechanism of action, including the inhibition of acid secretion. A comparison with ranitidine and omeprazole in some animal models has been included and clinical studies, where available, have also been incorporated, along with a safety evaluation. Neem bark extract has the potential for the development of novel medicines for the therapeutic control of gastric hyperacidity and ulcer.

ASSESMENT OF BIOACTIVITY OF A FISCHERELLA SPECIES COLONIZING AZADIRACHTA INDICA (NEEM) BARK

In order to investigate whether a. Fischerella sp. colonizing Azadirachta indica (neem) bark is able to show, like neem derived extracts/products, bioactivity with respect to glucose metabolizing potential in animal models, laboratory cultivated neem colonized cyanobacterial biomass was fed to mice and its effects on liver lactate dehydrogenase (LDH: a key enzyme of glucose metabolism) vis a vis blood glucose level was monitored. Neem bark extract and purified azadirachtin (a bioactive neem product) were also tested simultaneously for comparison. As compared to the control, none of the samples could produce much variation in blood glucose levels except a transitory decline, 34% and 26% at 2 nd & 12 th h, in azadirachtin and Fischerella (isolated from neem) fed mice respectively. However, all the test samples showed significant increase in liver LDH activity after 2nd h of treatment (p< 0.01) followed by a decline at 6th h. Thereafter, the enzyme activity increased progressively up to 24 th h in mice fed with azadirachtin and neem colonized Fischerella only (p < 0.001 at 24 th h). Expression pattern of the enzyme was also studied using polyacrylamide gel electrophoresis. Liver specific M4-LDH (homo-tetramer of M sub-unit) was detected in all the cases and time-dependent changes in expression of the enzyme paralleled the alterations observed in its activities. To ascertain whether such a bioactivity is common with Fischerella sp. colonizing other trees also, liver LDH profile was compared between mice fed with Fischerella isolated from neem and jamun (Eugenia jambolana) barks separately. Though Fischerella from jamun did not alter liver LDH profile, Fischerella isolated from neem could produce significant increase in the enzyme activity (p < 0.001) and corresponding changes in the expression of LDH isozymes. The results suggest that Fischerella sp. inhabiting neem bark, like bioactivity of its host plant products, modulates activity and expression of liver LDH in mice.