Investigating the Powerful Antioxidant Activity of Nanoparticles

Investigating the Powerful Antioxidant Activity of Nanoparticles

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Introduction

Free radicals are unstable molecules that cause cellular damage, leading to aging and disease. Antioxidants are our body’s defense against this damage. While we often think of vitamins and plant compounds as antioxidants, cutting-edge science is exploring a new frontier: nanotechnology.

This research excerpt investigates the powerful antioxidant activity of nanoparticles synthesized from medicinal plants. It reveals how these tiny gold and silver particles can neutralize harmful free radicals, opening up exciting new possibilities for health and medicine.

Original Excerpt: Nanoparticles as Free Radical Scavengers

How the Antioxidant Activity of Nanoparticles is Measured

The antioxidant potential of gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), and the tested plant extracts was determined by the DPPH free radical scavenging assay. This test measures the ability of a substance to neutralize the stable DPPH (1,1-diphenyl-2-picrylhydrazyl) radical.

The study used different nanoparticle and extract concentrations, including 250, 125, 50, and 25 µg/ml. Gallic acid, a well-known antioxidant, was used as a positive control for comparison. The percent of antioxidant activity was calculated based on the absorbance of the sample recorded by a UV-vis spectrophotometer.

Revealing the Antioxidant Activity of Gold Nanoparticles (AuNPs)

The data regarding the antioxidant activity of nanoparticles, specifically gold nanoparticles, revealed that the AuNPs showed activity at all tested concentrations.

Generally, an increase in AuNPs concentration yielded higher activity, while a decrease in concentration resulted in lower antioxidant activity.

Upon comparison with the positive control (gallic acid) and the other samples, the key findings were:

• Maximum Activity: The highest activity was recorded for AuNPs synthesized from H. nepalensis leaves methanolic extract (92.84%) at 250µg/ml. This was followed closely by the AuNPs from the same extract (91.03%) at 125µg/ml.
• High Performance: H. nepalensis stem methanolic extract AuNPs also performed well, showing 86.81% activity at 250µg/ml.
• Minimum Activity: The lowest activity was reported by AuNPs from the H. nepalensis stem extract (57.14%) at the lowest concentration of 25µg/ml.

Assessing the Antioxidant Activity of Silver Nanoparticles (AgNPs)

The results of the DPPH radical scavenging activity of silver nanoparticles synthesized from the methanolic extracts of all three test plants were equally promising.

All AgNPs synthesized from A. jacquemontii tubers, H. nepalensis stem and leaves, and V. jatamansi shoot and root showed antioxidant activity of nanoparticles at all tested concentrations.

When compared with gallic acid, the AgNPs demonstrated significant potential:

• Maximum Activity: AgNPs synthesized from V. jatamansi root extract reported the highest antioxidant activity (93.93%) at 250µg/ml.
• Strong Performers: This was followed by V. jatamansi shoot extract AgNPs (91.82%) and H. nepalensis stem methanolic extract AgNPs (91.78%), both at the 250µg/ml concentration.
• Minimum Potential: The lowest antioxidant potential was noted for A. jacquemontii tubers extract AgNPs (61.54%) at the 25µg/ml concentration.

Generally, higher tested concentrations of AgNPs revealed higher antioxidant activity, while a decrease in AgNPs concentrations resulted in decreased antioxidant potential.

The Source of Power: Phytochemicals and Their Role

The impressive antioxidant activity of nanoparticles is directly linked to the bioactive compounds present in the plant extracts used for their synthesis. Phytochemical screening of the different extracts revealed the presence of tannins, sterols, flavonoids, proteins, lipids, alkaloids, and saponins.

These compounds, especially flavonoids and tannins, are known for their potent antioxidant properties.

• A. jacquemontii Tubers: The methanolic crude extract contained a high concentration of tannins, sterols, and flavonoids. The ethyl acetate and n-butanol fractions, which showed the highest antioxidant activity, were rich in flavonoids, saponins, and tannins.
• H. nepalensis Leaves & Stem: The n-butanol and ethyl acetate fractions of the leaves and stem, which demonstrated maximum antioxidant activity, were rich in proteins, tannins, alkaloids, and flavonoids.
• V. jatamansi Shoot & Roots: The ethyl acetate and n-butanol fractions, which showed the highest antioxidant potential, contained high concentrations of sterols, flavonoids, saponins, and tannins.

These bioactive compounds are not only responsible for reducing the metal salts into nanoparticles but also coat the surface of the nanoparticles, conferring their powerful antioxidant properties to the final product. The data clearly shows that extracts rich in these phytochemicals produced nanoparticles with superior free radical scavenging capabilities.

Conclusion

The evidence is clear: the antioxidant activity of nanoparticles synthesized via green methods is significant and robust. By harnessing the natural power of phytochemicals from medicinal plants, we can create nanomaterials capable of effectively neutralizing harmful free radicals.

This dual functionality—acting as both antimicrobial and antioxidant agents—positions these bio-inspired nanoparticles as highly promising candidates for advanced biomedical applications, from targeted drug delivery to novel therapeutic treatments.

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: 162, 164, 166, 168, 169-173.

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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