Silver nanoparticles from biological extracts and their antimicrobial activities.

Master of Science in Biochemistry. University of KwaZulu-Natal, Durban, 2017.The increasing incidence of multi-drug resistant organisms has led to the resurgence in application of Ag-based compounds. Accordingly, increased efforts have been made in the field of nanotechnology to develop silver nanoparticle (AgNP) synthetic strategies that are inexpensive and environmentally friendly without the use of hazardous chemicals. To this end, sunlight irradiation, a relatively new primary source of energy was used instead of heat to drive the synthesis of AgNPs. Biologically-derived capping substrates were independently extracted fromfresh (F) and freeze-dried (FD) leaf samples of the medicinal tree species, Moringa oleifera. Importantly, the extracted substrates advantageously displayed a dual functionality by reducing Ag+ as well as stabilising the resulting AgNPs. Yield analysis indicated a recovery ranging from 0.81 mg and 0.91 mg AgNPs per gram dry mass F and FD leaf tissue, respectively. AgNPs from both sample types were consistent in terms of their spherical shape with average diameters of 9 nm and 11 nm for F and FD samples, respectively. Fourier transform infrared (FTIR) spectroscopic analysis suggested that flavones; terpenoids and polysaccharides predominate and are primarily responsible for the reduction and subsequent capping of AgNPs. Interestingly, bioactivity screening revealed that AgNPs exhibited broad-spectrum antimicrobial activity against both bacterial and fungal strains. The results suggest that AgNPs derived from M. oleifera leaf extracts exhibit potential for application as broad-spectrum antimicrobial agents

A Review of Biological and Therapeutic Activities of Moringa Oleifera Linn

Moringa oleifera L. family Moringaceae has impressive range of medicinal uses with high nutritional value. Different parts of this plant contain a profile of important phytochemicals, minerals and good source of protein, vitamins, amino acids and various phenolics. In Africa, Moringa oleifera is known as „mother's best friend". It is a relatively fast growing tree with small leaves. The moringa is of economic importance in the production of several commodities and also provides rich and rare combinations of zeatin, quercetin, kaempferom and many other phytochemicals. The leaves of M. oleifera have also been known to contain a number of phytochemicals. Several biological activities have been reported in M. oleifrera which include biological coagulation in drinking water by its seeds. Antimicrobial activities of the plant have been reported so also are the immune-modulatory, anti-asthmatic antipyretic activities of the leaves. Moringa oleifera claimed to treat different ailments in the indigenous system of medicine. This review focuses on the biological activities of Moringa oleifera particularly on relatively little explored area of their microbiological, nutritional and pharmacological applications

Comparative analysis of Silver Nanoparticles prepared from Different Plant extracts (Hibiscus rosa sinensis, Moringa oleifera, Acorus calamus, Cucurbita maxima, Azadirachta indica) through green synthesis method.

Green synthesis of nanoparticle is a novel way to synthesis nanoparticles by using biological sources. It is gaining attention due to its cost effective, ecofriendly and large scale production possibilities. In this present study five plants Hibiscus rosa sinensis, Cucurbita maxima, Moringa oleifera, Azadirachta indica and Acorus calamus were taken to investigate their potential for synthesizing silver nanoparticle. The silver nanoparticles synthesized were confirmed by their change of colour to dark brown due to the phenomenon of surface plasmon resonance. The characterization studied was done by UV-vis spectroscopy, Scanning electron microscopy (SEM), Atomic force microscopy (AFM), Dynamic light scattering (DLS) and zeta potential studies, X-Ray diffraction (XRD), Fourier Transmission infrared spectroscopy (FTIR). All the five plants synthesized silver nanoparticle show good antimicrobial activity against clinically important pathogens Staphylococcus aureus, Klebsiella pneumoniae, Vibrio cholera and Escherichia coli

BIOSYNTHESIZED SILVER NANOPARTICLES USING CATHARANTHUS ROSEUS AND THEIR ANTIBACTERIAL EFFICACY IN SYNERGY WITH ANTIBIOTICS; A FUTURE ADVANCEMENT IN NANOMEDICINE

Objective: This research work develops an approach to synthesize silver nanoparticles (AgNPs) by reduction of leaf extract of Catharanthus roseus plant. This study produces synthesized nanoparticles that have process-controlled attributes which make their antibiotic action highly efficient. These attributes include smaller size, proper morphology, uniform dispersion, metal ion content, and formation of functional groups. By optimizing the reduction process parameters, AgNPs gain the desired properties.  Methods: The biosynthesis of AgNPs process was performed using reaction of 10% (w/v) C. roseus leaf extract with AgNO3. The optimum conditions and concentration used for synthesis of nanoparticles were: 1 mM AgNO3, pH 5, and temperature 80°C with an incubation time of 72 h. All the above parameters were analyzed by ultraviolet-visible spectrophotometer with the surface plasmon resonance peak obtained at 440 nm. Results: Various characterization techniques were performed, namely, scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, photoluminescence study, X-ray diffraction spectroscopy, Fourier transform infrared, dynamic light scattering, and atomic force microscopy. The results obtained from characterization confirmed the spherical morphology of the nanoparticles with size between 50 and 87 nm. In the current investigation, the antimicrobial activity of biosynthesized AgNPs was also determined using minimum inhibitory concentration and zone of inhibition methods against six different bacteria at different doses of AgNPs (100, 150, and 200 μg/ml) alone and also in combination with antibiotic-streptomycin. Conclusion: The results revealed that high concentration of AgNPs inhibits the bacterial growth. Furthermore, AgNPs revealed much stronger antibacterial action in synergy with streptomycin against antibiotic-resistant bacteria

Bactericidal properties of plants-derived metal and metal oxide nanoparticles (NPs)

Nanoparticles (NPs) are nano-sized particles (generally 1–100 nm) that can be synthesized through various methods. The wide range of physicochemical characteristics of NPs permit them to have diverse biological functions. These particles are versatile and can be adopted into various applications, particularly in biomedical field. In the past five years, NPs’ roles in biomedical applications have drawn considerable attentions, and novel NPs with improved functions and reduced toxicity are continuously increasing. Extensive studies have been carried out in evaluating antibacterial potentials of NPs. The promising antibacterial effects exhibited by NPs highlight the potential of developing them into future generation of antimicrobial agents. There are various methods to synthesize NPs, and each of the method has significant implication on the biological action of NPs. Among all synthetic methods, green technology is the least toxic biological route, which is particularly suitable for biomedical applications. This mini-review provides current update on the antibacterial effects of NPs synthesized by green technology using plants. Underlying challenges in developing NPs into future antibacterials in clinics are also discussed at the present review

STANDARDIZATION OF DRIED FLOWERS OF MORINGAOLEIFERA (LAMK.) AND JASMINUMSAMBAC (L.) AITACCORDING TO WHO GUIDELINES

Objective: The aim of the present study is to evaluate various pharmacognostic standards like macroscopy, microscopy, fluorescence analysis, preliminary phytochemical screening and thin layer chromatography of Moringa oleifera (Lamk.) and Jasminum sambac (L.) Ait.Methods: Cellular arrangement of the flower of M. oleifera and J. sambac were examined under electronic microscope. Fine powder of both flowers was used for powder microscopy. The phytochemical screening of the aqueous and ethyl acetate extracts of flowers of M. oleifera andJ. sambac was performed for carbohydrates, terpenoids, alkaloids, flavonoids, saponins, tannins, steroids, lignin and fixed oil. The color intensity or the precipitate formation was used as analytical responses to these tests. The aqueous and ethyl acetate extracts of both plants were gone through TLC monitoring by reconstituting each extracts with 5 ml solvent respectively. Results: Under microscopic observation the dried powder of M. oleifera revealed abundant calcium oxalate crystals, small spherical oil globules, starch grains, irregular fragments and tannin content. While powder microscopy of flower of J. sambac showed tannin, oil globules and simple fibers. Preliminary phytochemical analysis of aqueous and ethyl acetate extracts of both flowers revealed that the strength of active agents i. e, carbohydrate, tannins, fixed oil, terpenes in variable percentage.Conclusion: The findings could be helpful in identification and authentication of Moringa oleifera andJasminum sambac in future for further research and utilization.Â

The antiproliferative and apoptosis inducing effects of Moringa oleifera aqueous leaf extract and its synthesised gold nanoparticles - modulation of oncogenes and tumour suppressor genes in human cancer cell lines.

Doctor of Philosophy in Medical Microbiology. University of KwaZulu-Natal, Medical School 2015.Cancer is one of the leading causes of global mortality. In South Africa (SA), the burden of cancer (lung and oesophageal) continues to increase. Moringa oleifera (MO), indigenous to India, is found widely in SA and used in traditional treatments of cancer. Gold nanoparticles (AuNP’s) are showing potential in cancer therapies and can be synthesised using plants extracts such as MO leaf extract (MOE). This study investigated the antiproliferative effect of MOE and AuNP’s synthesised from MOE (MLAuNP) in A549 lung and SNO oesophageal cancer cells. MO crude aqueous leaf extract was prepared and cytotoxicity (MTT assay) was assessed in A549, SNO cells and normal peripheral blood mononuclear cells (PBMCs) (24h). Oxidative stress, DNA fragmentation and apoptotic markers were determined. A one-pot green synthesis technique using MOE to synthesise MLAuNP was then conducted. A549, SNO cells and PBMCs were also exposed to MLAuNP and CAuNP to evaluate cytotoxicity and apoptotic markers. MOE was cytotoxic to A549 cells. MOE (IC50: 166.7μg/ml, 24h) significantly increased lipid peroxidation, decreased glutathione (GSH) and Nrf2 levels leading to DNA fragmentation. MOE induced apoptosis by significantly increasing p53, caspase-9, enhancing caspase-3/7 activities and Smac/DIABLO expression. MOE significantly cleaved PARP-1 into 89kDa and 24kDa fragments. MOE was not cytotoxic to PBMCs but in SNO cells (IC50: 389.2μg/ml, 24h), it significantly increased lipid peroxidation, DNA fragmentation, decreased GSH, catalase and Nrf2 levels. Apoptosis was confirmed by the significant increase in phosphatidylserine (PS) externalisation, caspase-9, enhanced caspase-3/7 activities and significant decrease in ATP levels. MOE significantly increased p53, Smac/DIABLO and cleavage of PARP-1, resulting in an increase in the 24kDa fragment. MLAuNP was successfully synthesised. MLAuNP and CAuNP were not cytotoxic to PBMCs, whilst its pro-apoptotic properties were confirmed in A549 (IC50: MLAuNP - 98.46μg/ml; CAuNP - 121.4μg/ml) and SNO (IC50: MLAuNP - 92.01μg/ml; CAuNP - 410.4μg/ml) cells. MLAuNP significantly increased caspase activity in SNO cells while MLAuNP significantly increased PS externalisation, mitochondrial depolarisation, caspase-9, caspase-3/7 activities and decreased ATP levels. Also, MLAuNP significantly increased p53, Bax, Smac/DIABLO, PARP-1 24kDa fragment and enhanced SRp30a levels. Conversely, MLAuNP significantly decreased Bcl-2, Hsp70, Skp2, Fbw7α, c-myc levels and activated alternate splicing with caspase-9a splice variant being increased. These findings indicate that MOE exerts antiproliferative effects in cancerous A549 and SNO cells by increasing oxidative stress, DNA fragmentation and inducing apoptosis. MLAuNP also possessed antiproliferative properties in SNO cells and induced apoptosis in A549 cells by modulating oncogenes, tumour suppressor genes and activating alternate splicing of caspase-9. MOE and MLAuNP showed potential use as a complementary and alternative treatment for lung and oesophageal cancer. MOE fractionation studies are further recommended to identify the bioactive compounds responsible for the antiproliferative effect seen in A549 and SNO cells. In addition, membrane transport proteins as well as cell cycle analysis will provide further insight into MOE and MLAuNP antiproliferative effect

Synthesis of Silver Nanoparticles

Nanoparticles of noble metals, especially the silver nanoparticles, have been widely used in different fields of science. Their unique properties, which can be incorporated into biosensor materials, composite fibers, cosmetic products, antimicrobial applications, conducting materials and electronic components, make them a very important subject to be studied by chemistry, biology, healthcare, electronic and other related branches. These unique properties depend upon size and shape of the silver nanoparticles. Different preparation methods have been reported for the synthesis of the silver nanoparticles, such as electron irradiation, laser ablation, chemical reduction, biological artificial methods, photochemical methods and microwave processing. This chapter aims to inform the synthesis methods of the silver nanoparticles

Biofabrication of Silver Nanoparticles from Withania Somnifera Root Extract and Its Investigation of Anti-Inflammatory and Anti-Bacterial Activity

This study represents, green synthesis is a safe, inexpensive, and sustainable method for the synthesis of nanoparticles. The green synthesis of metal and metal oxide nanoparticles is extremely appealing in the present and future eras. Various kinds of natural extracts like bacteria, fungi, yeast, and plant extracts have been used as effective supplies for the fabrication of materials. Among them, the plant extracts made by biological methods, have proven to possess chiefly stable products that do not cause any adverse reactions, and the waste disposal is toxic-free and effortless. The synthesized silver nanoparticles by green synthesis are having a wide range of applications that are applied extensively both in the field of environmental remediation and in other important areas like pharmaceutical, food, cosmetic industries, and many more. In the study, the biological synthesis of Withania Somnifera silver nanoparticles was successfully prepared. The method was found to be simple and does not need any specialized equipment or isolation techniques. Different characterization methods prove the formation of silver nanoparticles. The synthesized silver nanoparticles were of an estimated size, the first indication was visual observation and further characterization using the UV-Visible spectroscopy showed a peak at 431nm for F4 formulation, which confirmed the synthesis of silver nanoparticles. The FTIR result of formulated silver nanoparticles showed no interaction between silver nitrate and the extract. The particle size of the nanoparticles is homogeneous in size and the size distribution is compared with that of the extract. All the formulations showed lower particle sizes. Among these, the F4 formulation showed the lowest particle size range of (64.14 d.nm). Zeta potential is an indication of the stability of the formulations which should be around ±20 mV. The Zeta potential of F4 (-14.9 mV)indicated good quality and showed the best formulation. The image of the SEM result showed agood surface morphologyin small rectangular needle-shaped structure for F4 formulation when compared with that of Withania Somnifera root extract. The XRD technique for F4 formulation showed reduced diffraction peaks when compared with that of Withania Somniferaroot extract and the XRD technique showed the faced centered cubic in nature of the nanoparticles. The formulated F4silver nanoparticle was investigated for its Anti-Bacterial and Anti-inflammatory activity. The Anti-Bacterial activity against Gram-positive and Gram-negative bacteria was carried out by the agar diffusion method. The biosynthesized silver nanoparticles exhibited more excellent antibacterial activity against S. aureus and B. substilis than E. coli and K. Pneumonia. The formulated silver nanoparticle, F4 formulation also showed Anti-inflammatory activity, which was investigated by using in -vitro method of denaturation of protein albumin. Through this study, we summarized that the formulated silver nanoparticles showed good anti-inflammatory activity when compared to the extract. The present study showed the potential of Withania Somnifera root extract to reduce the silver ions to synthesize silver nanoparticles that can be used for different applications like Anti-bacterial and Anti-inflammatory activity. In the future, it can be further formulated for various clinical applications as well. From the Scientific view, there is more scope for the synthesis of silver nanoparticles because of their simple method for manufacture and various applications, like eco-friendly, low cost, and used for large scale synthesis

Role of Moringa oleifera in regulation of diabetes-induced oxidative stress

AbstractObjectiveTo evaluate the antioxidant activity of aqueous extract ofMoringa oleifera (M. oleifera) young leaves by in vivo as well as in vitro assays.MethodsIn vitro study included estimation of total phenolic, total flavonol, total flavonoid and total antioxidant power (FRAP assay). In addition, in vivo study was done with the identified most effective dose of 200 mg/kg of its lyophilized powder on normal and diabetic rats. Its effect on different oxidative free radical scavenging enzymes,viz, superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), lipid peroxide (LPO) contents were measured.ResultsSignificant increase in activities of SOD, CAT, GST while, a decrease in LPO content was observed. Whereas, total phenolic, flavonoid and flavonol contents in the extract were found to be 120 mg/g of GAE, 40.5 mg/g of QE and 12.12 mg/g of QE, respectively. On the other hand, FRAP assay results ofM. oleifera leaves was (85.00±5.00)μM/g of extract powder.ConclusionsThe significant antioxidant activities ofM. oleifera leaves from both in vivo as well as in vitro studies suggests that the regular intake of its leaves through diet can protect normal as well as diabetic patients against oxidative damage