M. N. Nagendra Prasad

Nanoagroparticles emerging trends and future prospect in modern agriculture system

Increment of technical knowledge has remarkably uplifted logical thinking among scientific communities to shape the theoretical concepts into near product-oriented research. The concept of nanotechnology has overwhelmed almost all forms of lives and has traded its applications in myriad fields. Despite rapid expansion of nanotechnology, sustainable competitions still do exist in the field of agriculture. In current scenario, agriculture is a manifestation demand to provide adequate nutrition for relentless growing global population. It is estimated that nearly one-third of the global crop production is destroyed annually. The loss owes to various stresses such as pest infestation, microbial pathogens, weeds, natural calamities, lack of soil fertility and much more. In order to overcome these limitations, various technological strategies are implemented but a majority of these have their own repercussions. Hence there is a scrawling progress on the evaluation of nanoparticles into agriculture sector which can reform the modern agricultural system. Applications of these nanomaterials can add tremendous value in the current scenario of a global food scarcity. Nanotechnology can address the adverse effects posed by the abundant use of chemical agrochemicals which are reported to cause biomagnification in an ecosystem. Based on these facts and consideration, present review envisages on nanoparticles as nanoherbicides, nanopesticides, onsite detection agro-pathogens and nanoparticles in post harvest management. The review also elucidates on the importance of nanoparticles in soil fertility, irrigation management and its influence on improving crop yield. With scanty reports available on nanotechnology in agriculture system, present review attributes toward developing nanoagroparticles as the future prospect which can give new facelift for existing agriculture system.

Investigation of antihyperglycaemic activity of banana (Musa sp. var. Nanjangud rasa bale) pseudostem in normal and diabetic rats

BACKGROUND Postprandial hyperglycaemia in diabetes could be ameliorated by inhibiting intestinal α-glucosidases, responsible for starch hydrolysis and its absorption. Different parts of banana have been in use in conventional medicinal formulations since ancient times. Its role as an antihyperglycaemic agent has also been studied. This study was aimed at explaining the mechanism of hypoglycaemic effect by ethanol extract of banana pseudostem (EE). Additionally, studies on the active components involved in the effect have also been attempted. RESULTS EE significantly inhibited mammalian intestinal α-glucosidases and yeast α-glucosidase (IC50 , 8.11 ± 0.10 µg mL(-1) ). The kinetic studies showed that EE inhibited sucrase, maltase and and p-nitrophenyl-α-d-glucopyranoside hydrolysis by mixed-type inhibition. Further, in vivo studies identified that the oral administration (100-200 mg kg(-1) body weight) of EE significantly suppressed the maltose/glucose-induced postprandial plasma glucose elevation and wielded an antihyperglycaemic effect in normal and alloxan-induced diabetic rats. GC-MS analysis of EE revealed high levels of β-sitosterol (29.62%), stigmasterol (21.91%), campesterol (10.85%) and other compounds. CONCLUSION These findings suggest that EE might exert an anti-diabetic effect by inhibition of α-glucosidases from the intestine, in turn suppressing the carbohydrate absorption into the bloodstream. Hence the results extend a foundation to the future prospects of the food-derived enzyme inhibitors in treatment of diabetes.

Bacteriocins and Their Applications in Food Preservation.

Bacteriocins are ribosomally-synthesized antimicrobial peptides or proteinaceous compounds produced by bacterial strains. They are generally effective in inhibiting the growth of similar or closely related bacterial strains. A high diversity of various bacteriocins is produced by many lactic acid bacteria (LAB) and is found in numerous fermented and non-fermented foods. Several bacteriocins from LAB extend potential applications in food preservation, thus help foods to be naturally preserved and richer in organoleptic and nutritional properties. Though chemical preservatives for the preservation of food are successful to some extent, their quality is not as satisfying as fresh food. Hence, an alternative is required and bacteriocins serve the purpose. Nisin is currently the only bacteriocin widely used as a food preservative. Numerous bacteriocins have been characterized chemically, biochemically, genetically and also at the molecular level to understand their basic mode of action. This article gives an overview of classification of bacteriocins, isolation & characterization, and mode of action. Besides, article highlights the optimized parameters for growth of bacteria in the production of bacteriocins and various bioassays for their determination. Special emphasis has been provided on explaining the beneficial aspects of nisin.

Synthesis of silver nanoparticles by endosymbiont Pseudomonas fluorescens CA 417 and their bactericidal activity

The present study emphasizes on biogenic synthesis of silver nanoparticles and their bactericidal activity against human and phytopathogens. Nanoparticle synthesis was performed using endosymbiont Pseudomonas fluorescens CA 417 inhabiting Coffea arabica L. Synthesized nanoparticles were characterized using hyphenated spectroscopic techniques such as UV-vis spectroscopy which revealed maximum absorption 425nm. Fourier transform infrared spectroscopy (FTIR) analysis revealed the possible functional groups mediating and stabilizing silver nanoparticles with predominant peaks occurring at 3346 corresponding to hydroxyl group, 1635 corresponding carbonyl group and 680 to aromatic group. X-ray diffraction (XRD) analysis revealed the Braggs diffraction pattern with distinct peaks at 38° 44°, 64° and 78° revealing the face-centered cubic (fcc) metallic crystal corresponding to the (111), (200), (220) and (311) facets of the crystal planes at 2θ angle. The energy dispersive X-ray spectroscopy (EDS) analysis revealed presence of high intense absorption peak at 3keV is a typical characteristic of nano-crystalline silver which confirmed the presence of elemental silver. TEM analysis revealed the size of the nanoparticles to be in the range 5-50nm with polydisperse nature of synthesized nanoparticles bearing myriad shapes. The particle size determined by Dynamic light scattering (DLS) method revealed average size to be 20.66nm. The synthesized silver nanoparticles exhibited significant antibacterial activity against panel of test pathogens. The results showed Klebsiella pneumoniae (MTCC 7407) and Xanthomonas campestris to be more sensitive among the test human pathogen and phyto-pathogen respectively. The study also reports synergistic effect of silver nanoparticles in combination with kanamycin which displayed increased fold activity up to 58.3% against Klebsiella pneumoniae (MTCC 7407). The results of the present investigation are promising enough and attribute towards growing scientific knowledge on development of new antimicrobial agents to combat drug resistant microorganisms. The study provides insight on emerging role of endophytes towards reduction of metal salts to synthesize nanoparticles.

Assessment of In Vivo Antidiabetic Properties of Umbelliferone and Lupeol Constituents of Banana (Musa sp. var. Nanjangud Rasa Bale) Flower in Hyperglycaemic Rodent Model

Banana is an extensively cultivated plant worldwide, mainly for its fruit, while its ancillary product, the banana flower is consumed as a vegetable and is highly recommended for diabetics in the traditional Indian medicine system. This study is based on an investigation of the in vivo antihyperglycaemic activity of Umbelliferone (C1) and Lupeol (C2) isolated from the ethanol extract of banana flower (EF) in alloxan induced diabetic rat model. Diabetic rats which were administered with C1, C2 and EF (100 and 200 mg/kg b. wt.) for 4 weeks showed deterioration in fasting hyperglycaemia and reversal of abnormalities in serum/urine protein, urea and creatinine, when compared to the diabetic control group of rats. The diabetic group of rats fed with EF, C1 and C2 (100 mg/kg b. wt.) once daily, for a period of 28 days resulted in a significant reduction of diabetic symptoms viz., polyphagia, polydipsia, polyuria and urine sugar together with an improved body weight. HbA1c extent was reduced whereas levels of insulin and Hb were increased. Both the extract and compounds wielded positive impacts in diabetic rats by reversal of altered activities of hepatic marker enzymes viz., aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP); glycolytic enzyme (hexokinase); shunt enzyme (glucose-6-phosphate dehydrogenase); gluconeogenic enzymes (glucose-6-phosphatase, fructose-1,6-bisphosphatase, lactate dehydrogenase) and pyruvate kinase. The characteristic diabetic complications such as hypercholesterolemia and hypertriacylglycerolemia also significantly reverted to normal in the serum/liver of diabetic rats. Besides these, the treatment increased the activities of enzymatic and non-enzymatic antioxidants in the serum and liver. The histological observations revealed a marked regeneration of the β-cells in the drug treated diabetic rats. In conclusion, the present study illustrates that EF, C1 and C2 enhances the glycolytic activities, besides increasing the hepatic glucose utilization in diabetic rats by stimulating insulin secretion from the remnant β-cells along with potential enzymatic and non-enzymatic antioxidant activities.

Study of die back disease incidence of neem in Karnataka, India and PCR based identification of the isolates

A disease survey of die back of neem was done in different agroclimatic regions of Karnataka, India using Global Positioning System (GARMIN 12). Twigs of Azadirachta indica (Neem) infected with die back were collected from different regions of Karnataka, India and they were further analysed to determine the pathogen. Phomopsis azadirachtae the causal organism was isolated on malt extract agar from die back infected neem twigs. They were identified by conventional and molecular methods. Phomopsis genus specific primers (5.8S r-DNA) were then used for the detection of P. azadirachtae, the causative agent of die back of neem by polymerase chain reaction (PCR). Studies revealed the amplification of expected 141 bp DNA in P. azadirachtae isolated from the diseased trees of different regions of Karnataka indicating the causal organism of die back disease on neem. Studies revealed a very high incidence of die back in most of the places of Karnataka. This is the first report on disease incidence of die back of neem. Hand held GPS was used in the study which helps in continuous monitoring of the diseased trees.

Endo-symbiont mediated synthesis of gold nanobactericides and their activity against human pathogenic bacteria

Synthesis of gold nanobactericides (AuNBs) were achieved by treating 1mM chloroaurate with cell free supernatant of Aneurinibacillus migulanus. Formation of AuNBs was initially was monitored with change in colour to ruby red. Further confirmation was assessed with UV-visible spectra with maximum absorption occurring at 510nm. Transmission electron microscopy (TEM) analysis revealed the polydispersity of AuNBs with size distribution ranging from 10 to 60nm with an average size of 30nm. Crystalline nature was studied using X-ray diffraction which exhibited characteristic peaks indexed to Braggs reflection at 2θ angle which confers (111), (200), (220), and (311) planes suggesting AuNBs were face-centred cubic. Fourier transform infrared spectroscopy (FTIR) analysis revealed absorption peaks occurring at 3341cm-1, 1635cm-1 and 670cm-1 which corresponds to functional groups attributing to synthesis. The antibacterial efficacy of AuNBs was tested against selective human pathogenic bacteria and activity was measured as zone of inhibition by using disc and well diffusion. Bactericidal activity was interpreted with standard antibiotics gentamicin and kanamycin. Micro broth dilution assay expressed the minimal concentration of AuNBs to inhibit the growth of test pathogens. Highest activity was observed against Pseudomonas aeruginosa (MTCC 7903) with 21.00±0.57mm compared to other pathogens. The possible mode of action of AuNBs on DNA was carried out with in vitro assay as preliminary test against pathogenic DNA isolated from P. aeruginosa. Further studies will be interesting enough to reveal the exact interactive mechanism of AuNBs with DNA. Overall study contributes towards biogenic synthesis of AuNBs as one of the alternative in combating drug resistant pathogens.

Evaluating the inhibitory potential of Withania somnifera on platelet aggregation and inflammation enzymes: An in vitro and in silico study

Abstract Context Withania somnifera (L.) Dunal is traditionally used for treating various ailments, but lacks scientific evaluation. Objective This study evaluates Withania somnifera (WS) for its effect on platelet activity and inflammatory enzymes. Materials and methods Aqueous and ethanolic (1:1) leaf extracts were subjected to in vitro indirect haemolytic activity using Naja naja venom, human platelet aggregation was quantified for lipid peroxidation using arachidonic acid (AA) as agonist and 5-lipoxygenase (5-LOX) levels were determined using standard spectrometric assays. Further, molecular docking was performed by the ligand fit method using molegro software package (Molegro ApS, Aarhus, Denmark). Results The study found that aqueous and ethanol extracts have very negligible effect (15%) with an IC50 value of 13.8 mg/mL on PLA2 from Naja naja venom. Further, extracts of WS also had very little effect (18%) with an IC50 value of 16.6 mg/mL on malondialdehyde (MDA) formation. However, a 65% inhibition of 5-LOX with an IC50 value of 0.92 mg/mL was observed in 1:1 ethanol extracts. The same was evident from SAR model with the active ingredient withaferin A binding predominantly on Phe 77, Tyr 98, Arg 99, Asp 164, Leu 168, Ser 382, Arg 395, Tyr 396 and Tyr 614 with an atomic contact energy value of −128.96 compared to standard phenidone (−103.61). Thus, the current study validates the application of WS for inflammatory diseases. Conclusion This study reveals the inhibitory potential of W. somnifera on inflammatory enzymes and platelet aggregation. Thus, WS can serve as a newer, safer and affordable medicine for inflammatory diseases.

A survey of die-back disease of neem in Tamil Nadu, India and PCR-based confirmation of the isolates

A survey of die-back disease of neem was done in different agro climatic regions of Tamil Nadu, India using Global Positioning System (GARMIN 12). Twigs of Azadirachta indica (Neem) infected with die-back were collected from different regions of Tamil Nadu, India and they were further analyzed to determine the pathogen. Phomopsis azadirachtae the causal organism was isolated on malt extract agar from die-back infected neem twigs. They were identified by conventional and molecular methods. Phomopsis genus specific primers (5.8S r-DNA) were then used for the confirmation of P. azadirachtae – the causative agent of die-back of neem by Polymerase chain reaction (PCR). Studies revealed the amplification of expected 141bp DNA in P. azadirachtae isolated from the diseased trees of different regions of Tamil Nadu confirming the causal organism of die-back of neem. Studies revealed a very high incidence of die-back in most of the places of Tamil Nadu. Hand held GPS was used in the study which would help in continuous monitoring of the diseased trees.

Inhibition of group IIA secretory phospholipase A2and its inflammatory reactions in mice by ethanolic extract of Andrographis paniculata, a well-known medicinal food

Andrographis paniculata Nees is an important medicinal plant found in the tropical regions of the world, which has been traditionally used in Indian and Chinese medicinal systems. It is also used as medicinal food. A. paniculata is found to exhibit anti-inflammatory activities; however, its inhibitory potential on inflammatory Group IIA phospholipases A2(PLA2) and its associated inflammatory reactions are not clearly understood. The aim of the present study is to evaluate the inhibitory/neutralizing potential of ethanolic extract of A. paniculata on the isolated inflammatory PLA2(VRV-PL-VIIIa) from Daboii rusellii pulchella (belonging to Group IIA inflammatory secretory PLA2[sPLA2]) and its associated edema-induced activities in Swiss albino mice. A. paniculata extract dose dependently inhibited the Group IIA sPLA2enzymatic activity with an IC50value of 10.3 ± 0.5 μg/ml. Further, the extract dose dependently inhibited the edema formation, when co-injected with enzyme indicating that a strong correlation exists between lipolytic and pro-inflammatory activities of the enzyme. In conclusion, results of this study shows that the ethanolic extract of A. paniculata effectively inhibits Group IIA sPLA2and its associated inflammatory activities, which substantiate its anti-inflammatory properties. The results of the present study warranted further studies to develop bioactive compound (s) in ethanolic extract of A. paniculata as potent therapeutic agent (s) for inflammatory diseases. SUMMARY This study emphasis the anti-inflammatory effect of A. paniculata by inhibiting the inflammatory Group IIA sPLA2 and its associated inflammatory activities such as edema. It was found that there is a strong correlation between lipolytic activity and pro-inflammatory activity inhibition. Therefore, the study suggests that the extract processes potent anti-inflammatory agents, which could be developed as a potential therapeutic agent against inflammatory and related diseases.