Plant lectins and their usage in preparing targeted nanovaccines for cancer immunotherapy.

Plant lectins, a natural source of glycans with a therapeutic potential may lead to the discovery of new targeted therapies. Glycans extracted from plant lectins are known to act as ligands for C-type lectin receptors (CLRs) that are primarily present on immune cells. Plant-derived glycosylated lectins offer diversity in their N-linked oligosaccharide structures that can serve as a unique source of homogenous and heterogenous glycans. Among the plant lectins-derived glycan motifs, Man9GlcNAc2Asn exhibits high-affinity interactions with CLRs that may resemble glycan motifs of pathogens. Thus, such glycan domains when presented along with antigens complexed with a nanocarrier of choice may bewilder the immune cells and direct antigen cross-presentation - a cytotoxic T lymphocyte immune response mediated by CD8+ T cells. Glycan structure analysis has attracted considerable interest as glycans are looked upon as better therapeutic alternatives than monoclonal antibodies due to their cost-effectiveness, reduced toxicity and side effects, and high specificity. Furthermore, this approach will be useful to understand whether the multivalent glycan presentation on the surface of nanocarriers can overcome the low-affinity lectin-ligand interaction and thereby modulation of CLR-dependent immune response. Besides this, understanding how the heterogeneity of glycan structure impacts the antigen cross-presentation is pivotal to develop alternative targeted therapies. In the present review, we discuss the findings on structural analysis of glycans from natural lectins performed using GlycanBuilder2 - a software tool based on a thorough literature review of natural lectins. Additionally, we discuss how multiple parameters like the orientation of glycan ligands, ligand density, simultaneous targeting of multiple CLRs and design of antigen delivery nanocarriers may influence the CLR targeting efficacy. Integrating this information will eventually set the ground for new generation immunotherapeutic vaccine design for the treatment of various human malignancies.

Anti-mycobacterial activity of heat and pH stable high molecular weight protein(s) secreted by a bacterial laboratory contaminant.

BACKGROUND: Tuberculosis currently stands as the second leading cause of deaths worldwide due to single  infectious agent after Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The current challenges of drug resistance in tuberculosis highlight an urgent need to develop newer anti-mycobacterial compounds. In the present study, we report the serendipitous discovery of a bacterial laboratory contaminant (LC-1) exhibiting a zone of growth inhibition on an agar plate seeded with Mycobacterium tuberculosis. RESULTS: We utilized microbiological, biochemical and biophysical approaches to characterize LC-1 and anti-mycobacterial compound(s) in its secretome. Based on 16S rRNA sequencing and BIOLOG analysis, LC-1 was identified as Staphylococcus hominis, a human bacterial commensal. Anti-mycobacterial activity was initially found in 30 kDa retentate that was obtained by ultrafiltration of culture filtrate (CF). SDS-PAGE analysis of peak fractions obtained by size exclusion chromatography of 30 kDa retentate confirmed the presence of high molecular weight (≥ 30 kDa) proteins. Peak fraction-1 (F-1) exhibited inhibitory activity against M. bovis BCG, but not against M. smegmatis, E. coli and S. aureus. The active fraction F-1 was inactivated by treatment with Proteinase K and α-chymotrypsin. However, it retained its anti-mycobacterial activity over a wide range of heat and pH treatment. The anti-mycobacterial activity of F-1 was found to be maintained even after a long storage (~12 months) at - 20 °C. Mass spectrometry analysis revealed that the identified peptide masses do not match with any previously known bacteriocins. CONCLUSIONS: The present study highlights the anti-mycobacterial activity of high molecular weight protein(s) present in culture filtrate of LC-1, which may be tested further to target M. tuberculosis. The heat and pH stability of these proteins add to their characteristics as therapeutic proteins and may contribute to their long shelf life. LC-1 being a human commensal can be tested in future for its potential as a probiotic to treat tuberculosis.

Cockroach exposure and its allergy sensitization in asthma patients.

Asthma is a heterogeneous disease with distinct phenotypes. Serum tIgE, SSIgE and SPT are the methods of evaluating allergen sensitization. The present study evaluates the exposure and sensitization to cockroach (Periplaneta americana) antigens in asthma patients in a metropolitan city of India. The study enrolled 200 consecutive bronchial asthma patients, diagnosed as per GINA guidelines. As per history of exposure to cockroaches, the patients are divided in two groups as exposed and non-exposed asthmatic. All the enrolled subjects underwent SPT against common aeroallergens including cockroach, spirometry and estimation of tIgE level and SSIgE against cockroach. Out of 200 asthma patients, a total of 114 (57%) asthmatic were found SPT positive against one of the common aeroallergens, of which 68 (34%) showed SPT sensitivity against cockroach. A total of 103 (51.5%) patients were found exposed to cockroaches. In the cockroach exposed group, the mean serum tIgE was found significantly higher than the non-exposed group (569.31±224.64 vs 479.29±237 IU/ml; p=0.007). The mean SSIgE against cockroach in exposed groups was found not significant than non-expose group (4.87±11.19 vs 4.11±8.39 KUA/L; p=0.589). The mean tIgE was also not significant in atopic compared to non-atopic asthmatic (553.25±218.12 IU/ml vs 489.1±251.16 IU/ml; p=0.056). The mean SSIgE against cockroach was 5.66±10.45 KUA/L for atopic and 2.96±8.98 KUA/L for non-atopic (p=0.054). The airway obstruction was almost the same in both groups.  Asthmatic patients who were exposed to cockroach and atopic had high tIgE, SSIgE levels and SPT positivity against cockroach antigen compared to non-exposed patients.

Transcription factor ZBED6 affects gene expression, proliferation, and cell death in pancreatic beta cells.

We have investigated whether the recently discovered transcription factor, zinc finger BED domain-containing protein 6 (ZBED6), is expressed in insulin-producing cells and, if so, to what extent it affects beta cell function. ZBED6 was translated from a ZC3H11A transcript in which the ZBED6-containing intron was retained. ZBED6 was present in mouse ßTC-6 cells and human islets as a double nuclear band at 115/120 kDa and as a single cytoplasmic band at 95-100 kDa, which lacked N-terminal nuclear localization signals. We propose that ZBED6 supports proliferation and survival of beta cells, possibly at the expense of specialized beta cell function-i.e., insulin production-because (i) the nuclear ZBED6 were the predominant forms in rapidly proliferating ßTC-6 cells, but not in human islet cells; (ii) down-regulation of ZBED6 in ßTC-6 cells resulted in altered morphology, decreased proliferation, a partial S/G2 cell-cycle arrest, increased expression of beta cell-specific genes, and higher rates of apoptosis; (iii) silencing of ZBED6 in the human PANC-1 duct cell line reduced proliferation rates; and (iv) ZBED6 binding was preferentially to genes that control transcription, macromolecule biosynthesis, and apoptosis. Furthermore, it is possible that beta cells, by switching from full length to a truncated form of ZBED6, can decide the subcellular localization of ZBED6, thereby achieving differential ZBED6-mediated transcriptional regulation.

Preparation of glycopeptide-modified pH-sensitive liposomes for promoting antigen cross-presentation and induction of antigen-specific cellular immunity.

Cross-presentation, exogenous antigen presentation onto major histocompatibility complex class I molecules on antigen presenting cells, is crucially important for inducing antigen-specific cellular immune responses for cancer immunotherapy and for the treatment of infectious diseases. One strategy to induce cross-presentation is cytosolic delivery of an exogenous antigen using fusogenic or endosomolytic molecule-introduced nanocarriers. Earlier, we reported liposomes modified with pH-responsive polymers to achieve cytosolic delivery of an antigen. Polyglycidol-based or polysaccharide-based pH-responsive polymers can provide liposomes with delivery performance of antigenic proteins into cytosol via membrane fusion with endosomes responding to acidic pH, leading to induction of cross-presentation. Mannose residue was introduced to pH-responsive polysaccharides to increase uptake selectivity to antigen presenting cells and to improve cross-presentation efficiency. However, direct introduction of mannose residue into pH-responsive polysaccharides suppressed cytoplasmic delivery performance of liposomes. To avoid such interference, for this study, mannose-containing glycans were incorporated separately into pH-responsive polysaccharide-modified liposomes. Soybean agglutinin-derived glycopeptide was used as a ligand for lectins on antigen presenting cells. Incorporation of glycopeptide significantly increased the cellular uptake of liposomes by dendritic cell lines and increased cross-presentation efficiency. Liposomes incorporated both glycopeptide and pH-responsive polysaccharides exhibited strong adjuvant effects in vitro and induced the increase of dendritic cells, M1 macrophages, and effector T cells in the spleen. Subcutaneous administration of these liposomes induced antigen-specific cellular immunity, resulting in strong therapeutic effects in tumor-bearing mice. These results suggest that separate incorporation of glycopeptides and pH-responsive polysaccharides into antigen-loaded liposomes is an effective strategy to produce liposome-based nanovaccines to achieve antigen cross-presentation and induction of cellular immunity towards cancer immunotherapy.

Tumor-specific migration routes of xenotransplanted human glioblastoma cells in mouse brain.

The migration of neural progenitor cells (NPCs) to their final destination during development follows well-defined pathways, such as along blood vessels. Cells originating from the highly malignant tumor glioblastoma (GBM) seem to exploit similar routes for infiltrating the brain parenchyma. In this report, we have examined the migration of GBM cells using three-dimensional high-resolution confocal microscopy in brain tumors derived from eight different human GBM cell lines xenografted into immunodeficient mice. The primary invasion routes identified were long-distance migration along white matter tracts and local migration along blood vessels. We found that GBM cells in the majority of tumors (6 out of 8) did not exhibit association with blood vessels. These tumors, derived from low lamin A/C expressing GBM cells, were comparatively highly diffusive and invasive. Conversely, in 2 out of 8 tumors, we noted perivascular invasion and displacement of astrocyte end-feet. These tumors exhibited less diffusive migration, grew as solid tumors, and were distinguished by elevated expression of lamin A/C. We conclude that the migration pattern of glioblastoma is distinctly tumor cell-specific. Furthermore, the ability to invade the confined spaces within white matter tracts may necessitate low expression of lamin A/C, contributing to increased nuclear plasticity. This study highlights the role of GBM heterogeneity in driving the aggressive growth of glioblastoma.

ß1 integrins restrict the growth of foci and spheroids.

Extracellular matrices (ECM) have important roles for tissue architecture, both as structural and signaling components. Members of the integrin family are the main regulators of ECM assembly and transmitters of signals from the ECM to cells. In this study, we have analyzed the role of integrin subunit ß1 in two-dimensional (2D) and three-dimensional (3D) cell cultures using integrin ß1 null cells (MEFß1(-/-) and GD25) and their ß1 integrin-expressing counterparts. GD25 and GD25ß1 cells proliferated with similar kinetics in sub-confluent 2D cultures, whereas GD25 cells attained higher cell numbers in confluent culture and formed foci with fivefold higher frequency than GD25ß1 cells. Fibronectin fibrils were abundantly deposited throughout the GD25ß1 colonies but strictly limited to the central multilayered area (focus) of GD25 colonies. During 3D growth as spheroids, GD25 continuously increased in size for >21 days while the growth of GD25ß1 spheroids ceased after 14 days. Similarly, MEFß1(-/-) cells formed foci and grew as spheroids, while the ß1 integrin-expressing MEF did not. Expression levels of the cell cycle markers Ki67, PCNA, and histone H3-pSer10 were similar between GD25ß1 and GD25 spheroids. Apoptotic cells accumulated earlier in GD25 spheroids; however, cell death increased with spheroid volumes in both spheroid types. In both cell systems, the presence of ß1 integrins resulted in higher levels of active myosin light chain and inactive myosin light chain phosphatase, and a more compact spheroid structure. In conclusion, our results reveal that regulation of 3D growth in spheroids and foci is dependent on the ß1 subfamily of integrins, and suggest that myosin-based spheroid contraction in combination with cell death limits the growth of ß1-expressing spheroids.

Allergic bronchopulmonary aspergillosis--a clinical review.

Allergic Bronchopulmonary Aspergillosis (ABPA) was first described by Hinson and colleagues in 1952. ABPA is a hypersensitivity disorder induced by a fungus Aspergillus and affects non-immunocompromised patients. The diagnosis is based on the presence of a combination of clinical, biological and radiological criteria. The treatment is based on oral corticosteroids for 6-8 weeks at acute phase or exacerbation and Itraconazole is now recommended and validated at a dose of 200 mg/day for 16 weeks.

Sensing the interactions between carbohydrate-binding agents and N-linked glycans of SARS-CoV-2 spike glycoprotein using molecular docking and simulation studies.

A recent surge in finding new candidate vaccines and potential antivirals to tackle atypical pneumonia triggered by the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) needs new and unexplored approaches in solving this global pandemic. The homotrimeric transmembrane spike (S) glycoprotein of coronaviruses which facilitates virus entry into the host cells is covered with N-linked glycans having oligomannose and complex sugars. These glycans provide a unique opportunity for their targeting via carbohydrate-binding agents (CBAs) which have shown their antiviral potential against coronaviruses and enveloped viruses. However, CBA-ligand interaction is not fully explored in developing novel carbohydrate-binding-based antivirals due to associated unfavorable responses with CBAs. CBAs possess unique carbohydrate-binding specificity, therefore, CBAs like mannose-specific plant lectins/lectin-like mimic Pradimicin-A (PRM-A) can be used for targeting N-linked glycans of S glycoproteins. Here, we report studies on the binding and stability of lectins (NPA, UDA, GRFT, CV-N and wild-type and mutant BanLec) and PRM-A with the S glycoprotein glycans via docking and MD simulation. MM/GBSA calculations were also performed for docked complexes. Interestingly, stable BanLec mutant (H84T) also showed similar docking affinity and interactions as compared to wild-type BanLec, thus, confirming that uncoupling the mitogenic activity did not alter the lectin binding activity of BanLec. The stability of the docked complexes, i.e. PRM-A and lectins with SARS-CoV-2 S glycoprotein showed favorable intermolecular hydrogen-bond formation during the 100 ns MD simulation. Taking these together, our predicted in silico results will be helpful in the design and development of novel CBA-based antivirals for the SARS-CoV-2 neutralization.Communicated by Ramaswamy H. Sarma.

Canvassing Prospects of Glyco-Nanovaccines for Developing Cross-Presentation Mediated Anti-Tumor Immunotherapy.

In view of the severe downsides of conventional cancer therapies, the quest of developing alternative strategies still remains of critical importance. In this regard, antigen cross-presentation, usually employed by dendritic cells (DCs), has been recognized as a potential solution to overcome the present impasse in anti-cancer therapeutic strategies. It has been established that an elevated cytotoxic T lymphocyte (CTL) response against cancer cells can be achieved by targeting receptors expressed on DCs with specific ligands. Glycans are known to serve as ligands for C-type lectin receptors (CLRs) expressed on DCs, and are also known to act as a tumor-associated antigen (TAA), and, thus, can be harnessed as a potential immunotherapeutic target. In this scenario, integrating the knowledge of cross-presentation and glycan-conjugated nanovaccines can help us to develop so called 'glyco-nanovaccines' (GNVs) for targeting DCs. Here, we briefly review and analyze the potential of GNVs as the next-generation anti-tumor immunotherapy. We have compared different antigen-presenting cells (APCs) for their ability to cross-present antigens and described the potential nanocarriers for tumor antigen cross-presentation. Further, we discuss the role of glycans in targeting of DCs, the immune response due to pathogens, and imitative approaches, along with parameters, strategies, and challenges involved in cross-presentation-based GNVs for cancer immunotherapy. It is known that the effectiveness of GNVs in eradicating tumors by inducing strong CTL response in the tumor microenvironment (TME) has been largely hindered by tumor glycosylation and the expression of different lectin receptors (such as galectins) by cancer cells. Tumor glycan signatures can be sensed by a variety of lectins expressed on immune cells and mediate the immune suppression which, in turn, facilitates immune evasion. Therefore, a sound understanding of the glycan language of cancer cells, and glycan-lectin interaction between the cancer cells and immune cells, would help in strategically designing the next-generation GNVs for anti-tumor immunotherapy.

Mannose-binding dietary lectins induce adipogenic differentiation of the marrow-derived mesenchymal cells via an active insulin-like signaling mechanism.

We have recently demonstrated that the mannose-binding lectins, namely banana lectin (BL) and garlic lectin (GL), interacted with the insulin receptors on M210B4 cells--an established mesenchymal cell line of murine marrow origin--and initiate mitogen-activated protein kinase kinase (MEK)-dependent extracellular signal-regulated kinase (ERK) signaling in them. In this study, we show that this lectin-mediated active ERK signaling culminates into an adipogenic differentiation of these cells. Gene expression studies indicate that the effect takes place at the transcriptional level. Experiments carried out with pharmacological inhibitors show that MEK-dependent ERK and phosphatidylinositol 3-kinase-dependent AKT pathways are positive regulators of the lectin- and insulin-mediated adipogenic differentiation, while stress-activated kinase/c-jun N-terminal kinase pathway acts as a negative one. Since both lectins could efficiently substitute for insulin in the standard adipogenic induction medium, they may perhaps serve as molecular tools to study the mechanistic aspects of the adipogenic process that are independent of cell proliferation. Our study clearly demonstrates the ability of BL and GL to activate insulin-like signaling in the mesenchymal cells in vitro leading to their adipocytic differentiation. The dietary origin of these lectins underscores an urgent need to examine their in vivo effects on tissue homeostasis.

Carbohydrate-Binding Agents: Potential of Repurposing for COVID-19 Therapy.

With the emergence of the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the whole world is suffering from atypical pneumonia, which resulted in more than 559,047 deaths worldwide. In this time of crisis and urgency, the only hope comes from new candidate vaccines and potential antivirals. However, formulating new vaccines and synthesizing new antivirals are a laborious task. Therefore, considering the high infection rate and mortality due to COVID-19, utilization of previous information, and repurposing of existing drugs against valid viral targets have emerged as a novel drug discovery approach in this challenging time. The transmembrane spike (S) glycoprotein of coronaviruses (CoVs), which facilitates the virus's entry into the host cells, exists in a homotrimeric form and is covered with N-linked glycans. S glycoprotein is known as the main target of antibodies having neutralizing potency and is also considered as an attractive target for therapeutic or vaccine development. Similarly, targeting of N-linked glycans of S glycoprotein envelope of CoV via carbohydrate-binding agents (CBAs) could serve as an attractive therapeutic approach for developing novel antivirals. CBAs from natural sources like lectins from plants, marine algae and prokaryotes and lectin mimics like Pradimicin-A (PRM-A) have shown antiviral activities against CoV and other enveloped viruses. However, the potential use of CBAs specifically lectins was limited due to unfavorable responses like immunogenicity, mitogenicity, hemagglutination, inflammatory activity, cellular toxicity, etc. Here, we reviewed the current scenario of CBAs as antivirals against CoVs, presented strategies to improve the efficacy of CBAs against CoVs; and studied the molecular interactions between CBAs (lectins and PRM-A) with Man9 by molecular docking for potential repurposing against CoVs in general, and SARSCoV- 2, in particular.

Effect of laser application in the healing of intrabony defects treated with bioactive glass.

AIMS: Presence of bacteria within the environment of infrabony pockets affects healing during their treatment. Present investigation utilized a diode laser for pocket sanitization before the placement of bone biomaterial with the aim of enhancing the healing. MATERIALS AND METHODS: Twelve patients with bilateral intrabony defects participated in a split-mouth study design. Control group received biomaterial application only after surgical debridement. Infrabony pockets in the test group were irradiated with 810-nm diode laser at 0.8 W, continuous wave for 20 s before surgical debridement and biomaterial application. Healing was assessed using clinical and radiologic parameters. RESULTS: Control group showed mean probing depth (PD) reduction of 3.25 ± 0.62 at 3, 4.08 ± 0.90 mm at 6 months. 3.00 ± 0.73 at 3, 3.91 ± 0.66 mm at 6 months reduction in mean PD was seen in the test group (P < 0.001). No statistically significant differences between the groups were observed. A gain of 2.50 ± 0.67 at 3, 3.25 ± 0.62 mm at 6 months in relative clinical attachment level was seen in the control and of 2.33 ± 0.77 at 3, 3.16 ± 0.57 mm at 6 months in the test group (P < 0.001) without significant differences between groups. 1.33 ± 0.57 and 0.95 ± 0.68 mm hard-tissue fill (difference in the radiographic distance between cementoenamel junction and base of the intrabony defect pre- and post-operative) at 6 months was observed in the control and test groups, respectively (P < 0.001). Between groups differences (0.22 ± 0.24 mm) were not significant. CONCLUSIONS: Similar reduction in soft- and hard-tissue parameters in both groups indicates that adjunctive pocket sanitization with diode laser did not improve the healing of intrabony defects treated with bioactive glass.

Engineering anti-cancer nanovaccine based on antigen cross-presentation.

Dendritic cells (DCs) present exogenous antigens on major histocompatibility complex (MHC) class I molecules, thereby activating CD8+ T cells, contributing to tumor elimination through a mechanism known as antigen cross-presentation. A variety of factors such as maturation state of DCs, co-stimulatory signals, T-cell microenvironment, antigen internalization routes and adjuvants regulate the process of DC-mediated antigen cross-presentation. Recently, the development of successful cancer immunotherapies may be attributed to the ability of DCs to cross-present tumor antigens. In this review article, we focus on the underlying mechanism of antigen cross-presentation and ways to improve antigen cross-presentation in different DC subsets. We have critically summarized the recent developments in the generation of novel nanovaccines for robust CD8+ T-cell response in cancer. In this context, we have reviewed nanocarriers that have been used for cancer immunotherapeutics based on antigen cross-presentation mechanism. Additionally, we have also expressed our views on the future applications of this mechanism in curing cancer.

Transcriptome data of cultivated tetraploid and hexaploid wheat variety during grain development.

Wheat is a major food crop and an important component of human diet throughout the world. There are two major types of cultivated wheat; one is tetraploid durum (pasta) wheat and another one is hexaploid bread wheat. Wheat grain is the reservoir of two major dietary components - carbohydrate and protein, which get accumulated during seed maturation and directly affects yield and quality. Hexaploid, having 6 copies of each chromosome differs to a great extent from tetraploid having 4 copies of each chromosome. Studying the gene expression pattern in developing grain would help in understanding the difference in metabolic process as well as involvement of the genes in these two types of wheat. A transcriptional comparison of developing grains was carried out between the two wheat genotypes; tetraploid (AABB:PDW233) and hexaploid (AABBDD:PBW343) using RNA-seq. Approximately 194 million raw reads were obtained from both libraries. After removal of contaminations, a huge proportion (>99%), of high quality reads were obtained, were aligned to reference genome. A total of 2324 up-regulated and 522 down-regulated genes were identified as differentially expressed between PDW233 vs PBW343. Gene ontology annotation and enrichment analysis gave further information about differentially expressed genes between durum and bread wheat. This information will help in understanding process grain reserve in tetraploid and hexaploid wheat in relation to their nutritional quality.

The guanine nucleotide exchange factor, C3G regulates differentiation and survival of human neuroblastoma cells.

Neuronal differentiation involving neurite growth is dependent on environmental cues which are relayed by signalling pathways to actin cytoskeletal remodelling. C3G, the exchange factor for Rap1, functions in pathways leading to actin reorganization and filopodia formation, processes required during neurite growth. In the present study, we have analyzed the function of C3G, in regulating neuronal cell survival and plasticity. Human neuroblastoma cells, IMR-32 induced to differentiate by serum starvation or by treatment with nerve growth factor (NGF) or forskolin showed enhanced C3G protein levels. Transient over-expression of C3G stimulated neurite growth and also increased responsiveness to NGF and serum deprivation induced differentiation. C3G-induced neurite growth was dependent on both its catalytic and N-terminal regulatory domains, and on the functions of Cdc42 and Rap1. Knockdown of C3G using small hairpin RNA inhibited forskolin and NGF-induced morphological differentiation of IMR-32 cells. Forskolin-induced differentiation was dependent on catalytic activity of C3G. Forskolin and NGF treatment resulted in phosphorylation of C3G at Tyr504 predominantly in the Golgi. C3G expression induced the cell cycle inhibitor p21 and C3G knockdown enhanced cell death in response to serum starvation. These findings demonstrate a novel function for C3G in regulating survival and differentiation of human neuroblastoma cells.

In vivo evaluation of anti-oxidant and anti-lipidimic potential of Annona squamosa aqueous extract in Type 2 diabetic models.

AIM OF THE STUDY: Diabetes is known to involve oxidative stress and changes in lipid metabolism. Many secondary plant metabolites have been shown to possess antioxidant activities, improving the effects of oxidative stress due to diabetes. The present study was aimed to evaluate the effect of water extract of Annona squamosa leaves on antioxidant enzymes and lipid profile of animal models of type 2, non-insulin dependent diabetes mellitus (NIDDM). MATERIAL AND METHODS: The plant material was extracted with boiling water for 2 h. Albino Wistar rats (n=24) were divided into four groups. Diabetes was induced by streptozotocin injection (ip) at a dose of 50 mg/kg. Animals of treated groups were given the dose of 350 mg/kg of the extract. The excised rat tissues were rinsed in ice-cold saline, blotted dry and weighed. RESULTS AND CONCLUSIONS: The results clearly suggest that the water extract of Annona squamosa leaves possessed antioxidant activity as shown by increased activities of scavenging enzymes, catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione reductase (GR) and glutathione-s-transferase (GST) and decrease in malondialdehyde levels present in various tissues. Administration of the extract also improved the lipid profile of the treated groups indicating thereby that the high levels of triglyceride and total cholesterol associated with diabetes can also be significantly managed with the extract.

Studies on the glycemic and lipidemic effect of Murraya koenigii in experimental animals.

Diabetes is often accompanied by lipid abnormalities, which contribute significantly to cardiovascular morbidity and mortality in diabetic patients. Previously, we have demonstrated potent hypoglycemic activity of lyophilized aqueous extract of Murraya koenigii leaves in normal and alloxan induced diabetic rabbits for short duration of 6 h. In this study, we examined the effect of 1 month oral administration of Murraya koenigii aqueous leaves extract in normal and STZ induced severe diabetic rats, at the dose of 300 mg/kg bw, on various biochemical parameters, viz., fasting blood glucose (FBG), total cholesterol (TC), HDL-cholesterol (HDL), triglyceride (TG), alkaline phosphatase (ALKP), serum glutamate oxaloacetate and pyruvate transaminases (SGOT and SGPT) and serum creatinine. In case of diabetic animals fasting blood glucose (FBG) levels of treated animals reduced by 48.2% after 30 days treatment with the aqueous leaves extract. A fall of 19.2 and 30.8% in TC and 22.97 and 37.1% in TG levels were also observed in the case of treated normal as well as diabetic rats, respectively. Feeding the extract increased the HDL-cholesterol level by 16 and 29.4% in normal and diabetic rats, respectively, as compared with their initial values. In the normal rats after 1 month of oral administration of the extract SGOT and SGPT levels were decreased by 21.7 and 25.0%. Serum alkaline phosphatase values of the treated normal animals were also reduced by 33% while negligible change was observed in the normal control animals. In the case of diabetic rats, SGOT and SGPT levels were reduced by 36.7 and 32.2%, respectively, whereas ALKP levels decreased by 39.7% after 1 month oral administration of the extract. The serum creatinine levels decrease in normal as well as in the diabetic animals by 17.75 and 18.2%, respectively, as compared to initial values. In the diabetic control animals the urinary sugar remains at +4 level but there was a decrease of 75% in urine sugar in the case of treated diabetic rats. This indicates that the aqueous extract of Murraya koenigii has favorable effect in bringing down the severity of diabetes.

Assessment of antidiabetic potential of Cynodon dactylon extract in streptozotocin diabetic rats.

This study was undertaken to investigate the hypoglycemic and antidiabetic effect of single and repeated oral administration of the aqueous extract of Cynodon dactylon (Family: Poaceae) in normal and streptozotocin induced diabetic rats, respectively. The effect of repeated oral administration of aqueous extract on serum lipid profile in diabetic rats was also examined. A range of doses, viz. 250, 500 and 1000mg/kg bw of aqueous extract of Cynodon dactylon were evaluated and the dose of 500mg/kg was identified as the most effective dose. It lowers blood glucose level around 31% after 4h of administration in normal rats. The same dose of 500mg/kg produced a fall of 23% in blood glucose level within 1h during glucose tolerance test (GTT) of mild diabetic rats. This dose has almost similar effect as that of standard drug tolbutamide (250mg/kg bw). Severely diabetic rats were also treated daily with 500mg/kg bw for 14 days and a significant reduction of 59% was observed in fasting blood glucose level. A reduction in the urine sugar level and increase in body weight of severe diabetic rats were additional corroborating factors for its antidiabetic potential. Total cholesterol (TC), low density lipoprotein (LDL) and triglyceride (TG) levels were decreased by 35, 77 and 29%, respectively, in severely diabetic rats whereas, cardioprotective, high density lipoprotein (HDL) was increased by 18%. These results clearly indicate that aqueous extract of Cynodon dactylon has high antidiabetic potential along with significant hypoglycemic and hypolipidemic effects.