Table of Contents
Original Excerpt: Evaluating Nanoparticle Performance
Investigating the Antibacterial Activity of Nanoparticles
This study focused on the investigation of the antimicrobial potential of different solvent extracts along with synthesized gold (AuNPs) and silver (AgNPs) nanoparticles from different parts of A. jacquemontii, H. nepalensis, and V. jatamansi. During the study, six different bacterial and four different fungal strains were used to assess the antimicrobial activities of the samples.
The antimicrobial activities of all the plant extracts, along with the AuNPs, were tested at three different concentrations of 1mg, 2mg, and 3mg. While the antimicrobial potential of AgNPs was evaluated at 0.5mg, 1mg, and 1.5mg concentration. The antibacterial activity of nanoparticles and anti-Candidal activities were determined by disc diffusion method, while the rest of the antifungal activity was evaluated by well diffusion assay.
Antimicrobial Testing Protocol
- Media Preparation: Nutrient agar media and nutrient broth media were prepared in required amounts. After autoclaving, the nutrient agar media was poured into sterile petri plates inside a laminar flow hood (LFH).
- Activity Test: Bacterial strains were sub-cultured to obtain fresh cultures. After standardization, 50µl of the culture was spread on basal media plates. Whatman filter paper discs (6mm diameter) were placed on the plates.
- Application: Plant extract and nanoparticle solutions were applied to the discs at varying concentrations. DMSO and a standard antibiotic (Azithromycin) were used as negative and positive controls.
- Incubation & Measurement: The antibacterial assay plates were incubated for 24 hours at 37°C. After 24 hours, the zone of inhibition in millimeters was measured for each sample to determine the antibacterial activity of nanoparticles.
Results: The Antibacterial Activity of Gold Nanoparticles (AuNPs)
AuNPs Against E. coli
E. coli reported sensitivity towards the AuNPs synthesized from methanolic crude extracts of all three different plants. It is clear from the data that all three tested concentrations of all the synthesized AuNPs inhibited the growth of the microbe to some level.
AuNPs synthesized from the extract of H. nepalensis stem reported the largest zone of inhibition (56.77%) at a 3mg concentration, while AuNPs from the leaves of the same plant revealed the smallest zone of inhibition (30%) at a 1mg concentration. A relatively moderate activity was recorded for AuNPs synthesized from A. jacquemontii tuber extract.
AuNPs Against P. aeruginosa
The data regarding growth inhibition activity of different AuNPs synthesized from methanolic crude extracts of different parts of the three test plants against P. aeruginosa showed that the subject microbe was susceptible to all the tested concentrations of all the AuNPs samples. AuNPs synthesized from A. jacquemontii tuber extract reported the most remarkable activity by exhibiting the largest zone of inhibition (85.83%) at a 3mg concentration. The smallest zone of inhibition was measured for AuNPs of H. nepalensis leaves extract (35.83%) at a 1mg concentration.
AuNPs Against S. aureus
The data indicated that all the AuNPs samples were effective in inhibiting the growth of the microbe at all the tested concentrations. When compared with other samples and control, the maximum antibacterial activity of nanoparticles was contributed by AuNPs synthesized from A. jacquemontii tubers extract (67.67%) at a 3mg concentration. Minimum activity was carried out by AuNPs synthesized from H. nepalensis stem extract (27.33%) at a 1mg concentration.
Results: The Antibacterial Activity of Silver Nanoparticles (AgNPs)
AgNPs Against E. coli
AgNPs synthesized from methanolic crude extracts of the three different plant species were active in controlling the growth of E. coli. Depending on the activity measured for the highest concentration of AgNPs used, different levels of effectiveness of the samples against the microbe were observed.
Among all the tested samples, the highest effectiveness was characterized by a maximum zone of inhibition for AgNPs synthesized from V. jatamansi shoot extract (65.97%) at a 1.5 mg concentration. The minimum zone of inhibition was noted for AgNPs synthesized from H. nepalensis leaves extract (28.39%) at 0.5 mg.
AgNPs Against K. pneumonia
The effect of AgNPs synthesized from methanolic crude extracts of different parts of the three test plants on the growth of K. pneumonia showed that all the tested samples actively restricted the growth of the pathogen. Among all the samples, the largest zone of inhibition was measured for AgNPs synthesized from V. jatamansi root extract (51.18%) at 1.5 mg. The smallest zone of inhibition was recorded for AgNPs synthesized from H. nepalensis stem extract (24.08%) when applied at 0.5 mg.
AgNPs Against P. aeruginosa
The data represents the potent antibacterial activity of nanoparticles. Although all the AgNPs samples were productive in suppressing the growth of the microbe up to significant levels, the most remarkable growth reduction was contributed by the AgNPs synthesized from H. nepalensis leaves extract (75.62%) when applied at the highest tested concentration of 1.5 mg. The lowest growth reduction was recorded for AgNPs synthesized from A. jacquemontii tubers extract (33.96%) at 0.5 mg.
Overall, among all the tested microbes, P. aeruginosa was the most sensitive microbe (62-88% growth inhibition) followed by C. albicans (59-82% growth inhibition). The most resistant bacterium was K. pneumonia (35-47% growth inhibition). V. jatamansi showed better antimicrobial activities than the other two tested plant species. AgNPs reported greater antimicrobial activity than AuNPs.
Conclusion
This comprehensive study confirms the significant antibacterial activity of nanoparticles synthesized through green, plant-based methods. Both gold and silver nanoparticles demonstrated a remarkable ability to inhibit the growth of a wide range of harmful bacteria, including resistant strains like P. aeruginosa. These findings highlight the immense potential of nanobiotechnology to provide novel solutions in the ongoing battle against microbial infections and antibiotic resistance.
Source Citation
- Researcher: Madiha Iqbal
- Thesis Title: BIOGENIC SYNTHESIS, CHARACTERIZATION AND PHARMACOLOGICAL EVALUATION OF NANO-PARTICLES PREPARED BY USING THE EXTRACTS OF Arisaema jacquemontii, Hedera nepalensis AND Valeriana jatamansi
- Guide: Prof. Dr. Jehan Bakht (Chairman, Supervisory Committee)
- University: The University of Agriculture, Peshawar, Pakistan
- Completion Date: August, 2017
- Excerpt Source Pages: 18, 24, 91, 93, 95-96, 99-101.
Disclaimer
Disclaimer: Some sentences have been lightly edited for SEO and readability. For the complete and original research, please refer to the full thesis PDF above.
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