INTRODUCTION:

In recent times the research which has been done with the advanced nanoparticles of the various noble metals like silver has gained more interest among the scientists. This is mainly due to its various physiochemical properties such as size, distribution and morphology.^[1]These silver nanoparticles are also been assessed for their catalytic property, various optical property, antibacterial and magnetic properties. It has a large applications in the various fields such as photography, biosensor, biomolecular detection, anti inflammatory agents in cosmetics and particularly antimicrobial activities^.[2]

There are various methods such asreduction in solutions, radiation assisted chemical and photo-reduction in reverse micelles, thermal decomposition of silver compounds used for the synthesis of the silver nanoparticles andrecently green synthesis route have been employed in the synthesis of nanoparticles.^[3]

In this study, natural cumin oil was used for the synthesis of silver nanoparticles. The major components includes arachidonic, eicosadienoic, linoleic, linolenic, oleic, almitoleic and myristic acid as well as sterol esters and sterol glucosides. The cumin oil is very effective in controlling hypertension, diabetes, paralysis, asthma, cough and dyspepsia. It has got a broad spectrum of antimicrobial activity against both gram negative and positive bacteria, virus, parasites and fungi^.[4]In this study, the antimicrobial activity of cumin oil mediated silver nanoparticles were evaluated against oral microbes.

MATERIALS AND METHODS:

Synthesis of silver nanoparticles:

Silver nanoparticles were done with green synthesis method. 10 mL of cumin oil was boiled with 90 mL of water initially.10 mL of this cumin oil extract with 90mL of 1 mM of silver nitrate and kept in magnetic stirrer for nanoparticles synthesis in room temperature and observed for the visible colour change. Formations of gray colour with cumin oil mixture after 60 min indicated formation of silver nanoparticles^[5]. The silver nanoparticles thus obtained was confirmed by UV-Vis spectrophotometer at a wavelength range of 400-700nm.^[6]

Antimicrobial activity:

Agar well diffusion method was used to determine the antimicrobial activity of cumin oil mediated silver nanoparticles. [7,8] Different concentrations of the prepared silver nanoparticles were tested against Staphylococcus aureus, Streptococcus mutans (gram +) and Enterococcus fecalis. The fresh bacterial suspension was dispersed on the surface of Muller Hinton agar plates. 25, 50 and 100 μL of cumin oil mediated silver nanopartcle solution was incorporated into the wells and the plates were incubated at 37°C for 24h. Amoxicillin was used as positive control. To evaluate the antimicrobial activity, the zone of inhibition was measured and recorded in each plate. The experiment was done in triplicate avoid manual error.

RESULTS AND DISCUSSION:

Visual Observation:


Fig 1: Cumin oil mediated silver nanoparticles	Fig 2: Before incubation

UV-Vis spectroscopy:

Figure 3: Graph showing absorbance of cumin oil mediated silver nanoparticles.

Antimicrobial activity:

Figure 4: Antimicrobial activity of Cumin oil mediated silver nanoparticles against S .mutans

Graphical representation:

Figure 5: Antimicrobial activity Cumin oil mediated silver nanoparticles against E.faecalis

Figure 6: Antimicrobial activity Cumin oil mediated silver nanoparticles against S. aureus

Ultraviolet visible spectroscopy:

The cumin oil mediated silver nanoparticles showed a visible colour change to dark brown indicating the formation of AgNPs. The mixture was transparent initially. After 80 minutes there was a significant increase in the brown colour which confirms the growth of the silver nanoparticles as seen in Figure 1, 2. This was confirmed with the help of the UV-vis spectrometer^.[9] It was also known that the silver nanoparticles exhibit yellowish brown colour in water due to surface plasmon vibration concept. The absorbance of the silver nanoparticles at various time intervals was recorded and a graph was plotted [Figure 3] the peak value observed at 352nm, which was been mainly associated with absorbance of AgNPs. The intensity of this absorption peak at 352nm was increasing with time period of the aqueous component of the extract.^[10]

Antimicrobial activity:

Antimicrobial activity refers to the process of killing or inhibiting the disease causing microbes. Various antimicrobial agents are used for this purpose. Antimicrobial may be anti-bacterial, anti-fungal or antiviral. The antimicrobial activity of the cumin oil mediated AgNPs was evaluated in this study by agar well diffusion method^.[11,12]anti microbial activity has been done against the various pathogens such as Steptococcous mutans, Staphylococcus aureus, Enterococcus fecalis. The zone of inhibition was mainly observed against these oral pathogens. Figure 4,5 and 6 showed the antimicrobial effect of the silver nanoparticles against the Streptococcus mutans, Enterococcus fecalis and Staphylococcus aureus respectively. The prepared silver nanoparticles showed a dose dependent antimicrobial activity against all thethree test microorganism. The maximum antimicrobial effect of the cumin oil mediated silver nanoparticles was seen with the maximum concentration used [100 µL] and showed the maximum activity against Enterococcus faecalis. Cumin oil contain Cuminicaldehyde, P-menth-2-en-7-ol, Gamma-Terpene, β-Pinene and all of these compound despite of their little concentration contribute to antibacterial activity. They are known for their bactericidal activity, especially the cumin aldehyde which has a high concentration (13.77%) exhibits a considerable inhibitory effect against different Gram positive and Gram-negative bacteria isolates.^[13]Studies report that AgNPs can be used against bacteria resistant to common antibiotics and even against multi-resistant bacteria.^[14].

CONCLUSION:

The present study concludes that cumin oil mediated silver nanoparticles are good enough to controloral pathogens as it could inhibit various microorganisms such as Steptococcous mutans, Staphylococcus aureus, Enterococcus fecalis in a dose dependant manner. Hence, cumin oil mediated AgNPs may be used a substitute fordrug toprevent the growth ofthese sensitive organism.

ACKNOWLEDGEMENT:

The authors thank Synthite Industries Limited, Kerala for providing cumin oil as gift sample for this research project.

CONFLICT OF INTEREST:

Nil

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Received on 09.03.2019 Modified on 05.04.2019

Research J. Pharm. and Tech 2019; 12(8):3709-3712.

DOI: 10.5958/0974-360X.2019.00634.6