Silver nitrate (AgNO3-99.99%) was purchased from Sigma Aldrich chemicals. The Moringa oleifera leaves (southern Indian common name of plant drumstick plant) from Moringaceae family and deionized water. Albino Wistar rats weighing 150 ± 20 g were used in the in-vivo diabetes model. Animals have maintained a 12h light/12 h dark cycle throughout the experiment at a temperature of 22° C. They were supplied with a regular chow pellet diet. And the water was kept ad libitum. The study was started after getting the approval from institutional animal Ethical committee with resolution number 1684/PO/a/13/CPCSEA.
Collection of plant material and preparation of extract:
Fresh leaves of the plant (Moringa oleifera) were collected from the JSS College of Pharmacy, Ooty campus. The collected fresh leaves were washed with deionized water and chopped into pieces by preparing a hot water extract of the leaves, 10g of leaves in 100 mL of distilled water and boiled at 80o C for 15 minutes. The extract solution was obtained by filtration using Whatman filter paper, and the extract was stored at 4oC for further use. The extract solution acts as a reducing and stabilizing agent for the synthesized silver nanoparticles.
Synthesis of Ag nanoparticles:
100 mL (1mM) aqueous solution of silver nitrate was prepared in a conical flask. Then 10 ml of leaf extract was added separately to 50mL aqueous silver nitrate solution kept in separate beakers at room temperature and stirring for 2hrs. The answer was to change the color slowly yellow to dark yellow. Finally, the answer turns yellow to dark brown, indicating the formation of silver nanoparticles [17].
Diabetes induction:
Diabetes was induced in male albino Wistar rats by treating with Streptozotocin 40 mg/kg. Streptozotocin is dissolved in citrate buffer (40 mg/kg in 0.1 M citrate buffer, pH 4.5) and administered to all the animals. After 48 h, blood glucose levels were measured by glucose check (Abbott) for all the induced animals. Animals with more than 250 mg/dL were considered for the diabetic activity, and they were grouped and marked. [18]
Experimental design:
Animals were divided into five groups with six animals each randomly, and they were treated for 28 days.
Group I: Normal (treated with saline)
Group II: Diabetes (Streptozotocin 40 mg/kg i.p)
Group III: Diabetes + Glibenclamide (0.5 mg/kg p.o)
Group IV: Diabetes + AgNP (0.2 mg/kg p.o)
Group V: PMAgNP (0.2 mg/kg p.o)
Acute oral toxicity studies:
Acute oral toxicity studies were carried out by following OECD guidelines 425. From the studies, it was confirmed that 0.2 mg/kg PMAgNPs did not produce any toxicity.
Biochemical parameters: Cholesterol, Triglycerides, SGOT, SGPT
Animals were fasted for 3 hours before administering the test drugs. On the 28th day, animals were sacrificed by the decapitation method. The serum was separated immediately after the blood was collected. Serum was used for the estimation of various biochemical parameters. Few of the major organs were managed and weighed. These organs were stored in 10% buffered formalin for histopathological studies. The serum was used to estimate various biochemical parameters like cholesterol, triglycerides, SGOT, SGPT, Alkaline phosphatase were measured using respective kits from Erba, Germany.
Body weight measurement:
The animal's body weight was monitored on 1, 7, 14, 21 and 28 days during the study in STZ induced diabetic model.
Statistical Analysis:
Whole data were expressed as mean ± SD (n=6). Statistical significance was assessed by one-way ANOVA followed by Bonferroni's multiple comparison test using Graph Pad Prism 5.01.
Histopathology:
After 28 days, animals were sacrificed, and various body organs were collected. The organs were weighed and washed in phosphate buffer. The samples were stored in buffered 10% formalin and further processed for histopathological techniques. All the tissues were embedded in paraffin wax, and sections with 4.5- to 5-μm were processed. The teams were additionally stained with hematoxylin and eosin.
XRD ANALYSIS OF SILVER NANO PARTILCES:
The X-ray diffraction patterns of silver nanoparticles (Ag NPs) are shown in Fig 2. Careful analysis of X-ray diffraction of Ag Nanoparticles from fig. 2 (A) suggests that it has crystalline nature. The characteristics peaks appear at 2θ = 38.22°, 44.41°, 64.57° and 77.46° corresponding to the planes (111), (200), (220) and (311) respectively. The obtained lattice planes are in good agreement with the JCPDS card No. 04-0783 and can be indexed as a face-centred cubic phase with lattice parameters a = b = c =0.40862 nm. Debye determined the crystalline size–Scherrer's formula and Williamson Hall Plot method (fig.2(B)) D = 0.9*λ/(βCosθ and 𝛽cos𝜃 = + 4𝜖sin𝜃, Where β is full width at half maximum in radians, and λ is the wavelength of X-rays, and θ is the Bragg's angle. The average crystalline size Ag NPS was calculated to be 13.49 nm and 12.61nm. The Ag NPs through green synthesized can reduce the dislocations.
Fig. 2 (C) shows the FT-IR spectra of Moringa olifera plant silver nanoparticles. The broadband between peak at 3500–3800 cm—1 was assigned to OH stretching vibrations of free alcohol, at 3400-3500 cm—1 was an indication of the phenols and hydrogen-bonded alcohols, a weak peak at 2924 cm—1 was an indication of the C–H stretching vibrations of poly- saccharide. The band at 1000–1200 cm—1 was attributed to the C–O antisymmetric trying in the C–O–H and C–O–C groups of polysaccharides. It can be observed that the characteristic absorption peak of OH for the Moringa olifera plant silver nanoparticles was at 3450 cm—1, and 1500-500 cm-1 represents the nitro compounds. Hydroxyl and carboxyl present in Moringa olifera silver nanoparticles act as reducing agents and conclude it worked good in diabetic activity. UV -VIS absorption spectra of Moringa olifera synthesized silver nanoparticles as in fig. 2 (D) showed that the absorbance and peak bordering at around 412 nm indicated that silver nanoparticles were monodispersed and showed (SPR) surface Plasmon resonance with UV visible light. The size of the particles has a strong influence on this absorption.
The present study XPs technique was done to detect the composition of Moringa olifera plant silver nanoparticles (Ag NPS). The binding energy of C1s was referenced to the original is at 284.85 eV, as shown in fig.3(C). The XPS survey wide scan identifies the elementals found at a depth of 10nm from the surface materials. It will give you different binding energies for different elements. The high-resolution XPS gives information about the chemical state of the elements. Fig.3(D) shows the wide XPS survey scan spectra of silver nanoparticles that conformed to detecting C, O, N and Ag nanoparticles. No other absorbed peaks were found that showed the high purity of the Silver nanoparticles. The binding energies of C 1s and O 1s were resolved in two peaks at arose at 284.25 eV (fig3.(B)) and 525.9eV(fig.3(C)), respectively. The N peak at 401.04eV scan suggested the presence of charged nitrogen atoms, which showed the electrostatic interaction with the silver surface. High resolution can be performed on Ag 3d core levels, which gave information about the nature of silver element and spectra, as shown in figure 3. The binding energies for Ag 3d5/2 and Ag 3d3/2 were found at 366.6eV and 37.45eV (fig .3(A)) respectively. Moreover, the obtained narrow peaks showed that only a single -element was present in the system. Fig.3 (A-D) represents the formation of Ag NPs with negligible impurities, which showed good diabetic activity.
Moreover, Ag NPs absorbed 412nm (fig. 2(B)), which corresponds to the surface Plasmon resonance, and this is confirmed that the Ag NPS synthesized with the ignorable amount of impurity. It showed the weight percentage of Ag. Furthermore, the particle size and shape as indicated by HRTEM, which conformed spherical in fig 4(A), confirmed the size of silver nanoparticles in the range of diameter 5-10 nm in fig 4(B). The d spacing of Ag NPs d=1.229, hkl (311) obtained from Moringa Olifera in fig.5(C) is matched with JCPDF card no of silver 04-0783. From Fig 4 (D), the SEAD pattern shows the brighter spots in the ring pattern indicating Ag of (111), (200), (220) and (310) surfaces.