Bio-inspired synthesis and bio-activity of ruthenium nanoparticles from Tridax procumbens (Dagadi Pala) leaf extract

Abstract

Herein, ruthenium nanoparticles (RuNPs) were synthesized using Tridax procumbens leaf extract as a reducing and stabilizing agent. The synthesis was optimized by adjusting temperature, leaf extract concentration, and reaction time. The synthesized RuNPs were characterized using UV-visible, XRD, EDAX, FTIR spectroscopy, SEM, and TEM, revealing uniform size and morphology. UV-visible spectroscopy confirmed RuNP formation with an absorption peak at 288 nm. FTIR analysis identified functional groups, with a peak at 600–800 cm^-1 indicating metallic Ru. XRD patterns showed peaks corresponding to RuNPs, with an average crystal size of 12.9 nm. SEM and TEM images revealed spherical RuNPs with an average diameter of 11.30 nm. The biological properties of the RuNPs were evaluated, demonstrating significant antibacterial and antifungal properties, and notable antioxidant activity. Antimicrobial activity was observed against Gram-positive bacteria (B. cereus, S. aureus) and Gram-negative bacteria (P. aeruginosa, E. coli) at concentrations of 50 µg/mL and above. The RuNPs showed antifungal activity against Candida albicans at 75 µg/ml and 100 µg/ml, but no activity against Aspergillus niger. The highest antioxidant activity was 77.13 ± 0.64% at a concentration of 100 µl. This study highlights the feasibility of utilizing Tridax procumbens leaf extract for the environmentally friendly synthesis of ruthenium nanoparticles, demonstrating their potential in biomedical applications and green chemistry.

Graphical abstract

Bio-inspired synthesis and bio-activity of ruthenium nanoparticles from Tridax procumbens leaf extract.

Introduction

An eco-friendly and sustainable approach to producing metal nanoparticles, green synthesis offers a safer alternative to conventional chemical and physical methods that usually depend on harmful chemicals and consume significant energy [1–3]. This approach, which utilizes plant extracts or other biological agents as reducing and stabilizing agents, aligns with the principles of green chemistry and has shown promising outcomes in synthesizing various nanoparticles. Among noble metal nanoparticles, ruthenium nanoparticles (RuNPs) are of particular interest due to their unique physicochemical properties, including high catalytic efficiency, stability, and significant biological activities such as antibacterial, antifungal, and antioxidant effects [3, 4].

Despite these advantages, the synthesis of RuNPs remains limited in the literature, especially through green approaches. Traditional synthesis methods not only pose environmental hazards but also restrict broader biomedical applications due to toxic residues and scalability issues [5, 6]. Furthermore, ruthenium is a relatively expensive metal, making it critical to develop cost-effective, environmentally sustainable synthesis strategies that could increase its feasibility for industrial and biomedical applications. Green synthesis using plant extracts represents a viable route to address these concerns.

Recent literature reports the successful synthesis of RuNPs using a variety of bioresources, including plant extracts such as Gloriosa superba [7], Acalypha indica [8], Nephrolepis exaltata Catharanthus roseus and Ocimum sanctum [9], Catharanthus roseus and Moringa oleifera [10], Gunnera perpensa [11], Iris Kashmiriana [12] and microbial systems like Pseudomonas aeruginosa [13]. These systems are rich in phytochemicals like flavonoids, polyphenols, and alkaloids that facilitate reduction and stabilization during nanoparticle formation [14].

In this context, Tridax procumbens, a widely available and traditionally known medicinal plant, presents an underexplored opportunity. It is rich in bioactive compounds such as flavonoids, alkaloids, and terpenoids, which are known to act as natural reducing and capping agents during nanoparticle synthesis [15]. While T. procumbens has been employed in the green synthesis of other nanoparticles like AgNPs [16] and ZnO NPs [17], its potential in the synthesis of RuNPs remains unexplored in scientific literature.

This research addresses a significant gap by synthesizing ruthenium nanoparticles (RuNPs) utilizing leaf extract from Tridax procumbens and analyzing their structural, morphological, and biological properties. The characterization of the synthesized nanoparticles was performed using UV-visible spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray analysis (EDAX), along with scanning and transmission electron microscopy (SEM and TEM). Additionally, their antibacterial, antifungal, and antioxidant activities were thoroughly examined to evaluate their potential for biomedical use. This comparison highlights the lack of studies on T. procumbens-mediated RuNPs and emphasizes the novelty and necessity of the present research.

To further justify the novelty and contribution of this work, Table 1 provides a comparative overview of the literature related to green-synthesized RuNPs and previously reported applications of Tridax procumbens in nanoparticle synthesis. This comparison highlights the lack of studies on T. procumbens-mediated RuNPs and emphasizes the novelty and necessity of the present research.

Table 1.

Summary of literature on green synthesis of runps and applications of Tridax procumbens in nanoparticle synthesis

Source	Biological agent	Phytochemicals involved	Key findings	Evaluation
[7]	Gloriosa superba (Plant extract)	Alkaloids, flavonoids, tannins, saponins, phenolics	Successfully synthesized RuNPs with potent antibacterial activity against E. coli and S. aureus; particle size ~ 50 nm	UV-Vis spectroscopy, FTIR, TEM, antibacterial assays (zone of inhibition)
[8]	Acalypha indica (Plant extract)	Alkaloids, flavonoids, terpenoids, saponins	Green synthesized RuNPs showed effective antibacterial and antifungal activity, with variation in efficacy depending on the plant used	UV-Vis, FTIR, SEM, XRD, antimicrobial activity assays (MIC, inhibition zone)
[9]	Nephrolepis exaltata (Fishtail fern), Cycas revoluta (Sago palm), Catharanthus roseus (Rosy periwinkle), Ocimum sanctum (Holy basil)	Alkaloids, flavonoids, terpenoids, saponins	Green synthesized RuNPs showed effective antibacterial and antifungal activity, with variation in efficacy depending on the plant used	UV-Vis, FTIR, SEM, XRD, antimicrobial activity assays (MIC, inhibition zone)
[10]	Catharanthus roseus, Moringa oleifera	Alkaloids, flavonoids, phenolics, saponins, terpenoids	Successfully synthesized ultra-small RuO₂ NPs with average sizes < 5 nm. Particles showed strong antimicrobial activity and effective dye degradation via catalytic/adsorption action.	Characterization via UV-Vis, FTIR, XRD, TEM. High antimicrobial activity; efficient dye removal (MB).
[11]	Gunnera perpensa	Polyphenols, tannins, flavonoids, saponins (presumed)	Successfully synthesized RuO₂ NPs with potent anticancer activity against MCF-7 cells	UV-Vis, XRD, FTIR, SEM, MTT assay
[12]	Iris Kashmiriana (Mazar-Graveyard)	Flavonoids, phenols, saponins, glycosides	RuO2 NPs were successfully synthesized with average size ~ 25 nm; showed broad-spectrum antimicrobial activity	UV-Vis, FTIR, XRD, SEM, antimicrobial assays (disk diffusion, MIC)
[13]	Pseudomonas aeruginosa (Bacteria)	Enzyme-mediated synthesis	Ru–Ag NPs enhanced gentamicin efficacy, showing strong synergistic inhibition of P. aeruginosa	MIC, synergy test (checkerboard), SEM
[14]	Review on Phytochemicals	Flavonoids, alkaloids, tannins, carotenoids, saponins	Comprehensive review highlighting medicinal uses including antimicrobial, anti-inflammatory, and wound-healing properties	Literature survey; compiled ethnomedicinal, phytochemical, and pharmacological evidence
[15]	Review on synthesis of RuNPS	Flavonoids, phenolics, terpenoids	Reviewed synthesis of ruthenium-based nanomaterials; emphasized Tridax as a green reducing and stabilizing agent	Compilation of green methods; compared catalytic and biological properties
[16]	Tridax procumbens	Alkaloids, flavonoids, saponins, terpenoids	Green-synthesized AgNPs showed potent antimicrobial activity against Gram-positive and Gram-negative bacteria	UV-Vis, FTIR, TEM, antibacterial activity via zone of inhibition and MIC
[17]	Tridax procumbens	Flavonoids, polyphenols, terpenoids	ZnO nanoparticles synthesized via green method showed anti-hyperglycemic effects in diabetic rat models	Characterization (UV-Vis, XRD, FTIR), in vivo anti-diabetic assays (glucose levels, biochemical markers)
Present Study	Tridax procumbens (Plant extract)	Flavonoids, phenolics, tannins, alkaloids, terpenoids	Ruthenium nanoparticles were successfully synthesized with average particle size < 50 nm; exhibited significant antimicrobial, Antifungal and antioxidant activity	Characterization: UV-Vis, FTIR, XRD, SEM/TEM; Bioassays: DPPH antioxidant assay, zone of inhibition

Schematic illustration of the synthesis, characterization, and biological applications of ruthenium nanoparticles.

Materials and methods

Plant material and extraction

Fresh leaves of Tridax procumbens were collected from the sub-campus in Devrukh, Sangameshwar, Ratnagiri, India. The identity of the plant material was confirmed by Dr. Ranjit Bansode and a voucher specimen was deposited at the Department of Botany ASP College, Devrukh, Sangameshwar, Ratnagiri, India. This ensures reproducibility and allows for future reference. The leaves were thoroughly cleaned to remove any surface contaminants. The cleaning process involved multiple rinses with running tap water, followed by a final rinse with double-distilled water. This meticulous washing procedure was crucial to eliminate any unwanted debris or microorganisms that could interfere with the subsequent experiments. After cleaning, the leaves were dried under shaded conditions at room temperature to minimize the degradation of thermolabile bioactive compounds. The dried leaves were then ground into a fine powder using a laboratory grinder. This powdering process increased the surface area of the plant material, facilitating efficient extraction of the desired phytochemicals. A 5.0-gram of dried leaf powder was boiled in 100 mL of double-distilled water at a temperature of 50–60 °C for 20 min. The resulting mixture was filtered through Whatman filter paper No. 1 to remove any particulate matter. The filtrate, containing the extracted plant compounds, was collected and stored in a well-sealed bottle at 5 °C to preserve its integrity and stability for subsequent use in the synthesis of ruthenium nanoparticles.

Green synthesis of ruthenium nanoparticles

The leaf extract of Tridax procumbens was mixed with 100 mL of a 2 mM Ruthenium Chloride solution is heated between 60 and 70 °C with constant stirring for about 60 min. Within 30 min, the reduction of Ru nanoparticles (RuNPs) became visibly evident. The initial brown colour slowly converted to a light blackish-yellow, indicates the formation of RuNPs (Fig. 1).

Fig. 1.

Synthesis of Ru NPs

Characterization of runps

The synthesized nanoparticles were analyzed for their UV-visible spectra using a Jasco V-770 spectrophotometer. X-ray diffraction pattern of the ruthenium nanoparticles was recorded on a BRUKER AXS D8 powder diffractometer by Cu Kα radiation (λ = 0.15425 nm), scanning from 20° to 80° (2θ). FTIR analysis was conducted with a JASCO FTIR-410 instrument (USA). To examine the chemical constituents, 1% KBr plates were prepared using the powdered samples and lyophilized plant extract.

A comprehensive analysis of the samples’ surface morphology and elemental composition was conducted by SEM coupled with EDX on a JEOL JSM IT 200 tool. For interpretation of SEM, the dried leaf samples were gold-coated and kept on carbon tape. The morphological characteristics of the prepared nanoparticles were analyzed by TEM using a Tecnai 120 G2 microscope with an operational voltage of 120 kV.

Biological activities

Antimicrobial assay

The antimicrobial activities of the Ru nanoparticles were assessed against some Gram-negative bacterium such as E.coli [NCIM 2832] and P. aeruginosa [NCIM 9027] and Gram-positive bacterium like S. aureus [NCIM 5345] and B. cereus [NCIM 2703] to the test sample was assessed using the agar well diffusion assay [10, 18–21, 27–29]. Fresh bacterial cultures (24 h old) were spread evenly on the surface of nutrient agar plates (Hi-Media) using a sterilized glass spreader to ensure uniform growth. Meanwhile, nanoparticle solutions were prepared by dissolving them in sterilized distilled water. Wells were formed on the nutrient agar plates using a sterilized stopper tool under aseptic conditions. Each well was then filled with 100 µL of the nanoparticle solution at 25–100 µg/mL concentrations. The plates were left in the refrigerator to allow proper diffusion of the nanoparticles within the agar. After incubating the plates at 37 °C for 24 h, they were visually examined to determine the presence and extent of antimicrobial activity. Streptomycin served as a positive control as well as sterile distilled water acted as a negative control.

Antifungal assay

Antifungal activities of Ru Nanoparticles were done by using the above procedure against Aspergillus niger [NCIM 1265] and candida albicance [NCIM 3471] fungal pathogens. Malt extract, Glucose, Yeast extract, and Peptone [MGYP] agar plates were used for this Ketoconazole was used as the positive control, while sterile distilled water acted as the negative control [22–24, 27].

Antioxidant assay

The antioxidant properties of the synthesized nanoparticles were assessed by evaluating their capacity to neutralize the DPPH free radical using a scavenging activity assay. The reaction was carried out using 1 mL of the nanoparticle sample by varying concentrations of 2 mL of a 1.0 mmol/L solution DPPH radical in methanol ranging from 25 to 100 µg [10, 21, 25–29]. The mixture was kept in the dark at 37 °C for 30 min, after which the absorbance was determined at a wavelength of 570 nm using a Shimadzu UV-1800 spectrophotometer (Japan). The DPPH radical scavenging activity was measured using the following formula:

The results are presented graphically, with ascorbic acid (concentration: 1000 µg/mL) as a reference standard (Figs. 12 and 13).

Fig. 12.

Antioxidant activity of nanoparticles here different concentrations of nanoparticles compared with the ascorbic acid as a standard

Fig. 13.

DPPH radical scavenging activity of ruthenium nanoparticles (RuNPs) at various concentrations. Values are expressed as mean ± SD (n = 3). Asterisks (*) indicate statistically significant differences compared to the control group (p < 0.05)

Pictorial representation of biological activities using RuNPS.

Statistical analysis

All experiments were performed in triplicate, and the results are expressed as the mean ± standard deviation (SD). Statistical analysis was carried out using one-way ANOVA, followed by Tukey’s post-hoc test to determine significance. Differences were considered significant at p < 0.05. Statistical analysis was performed using GraphPad Prism version 9 and all other graphs were drawn using Origin software.

Results and discussion

Characterization of nanoparticle

UV-visible spectroscopic analysis of nanoparticle

The formation of RuNPs was indicated through UV-visible spectroscopy. Measurements are verified over the wavelength range of 200–800 nm using a Jasco Spectrophotometer V-770, with a resolution set to 1 nm. The UV-visible spectrum as shown in Fig. 2 exhibits a distinct absorption peak at approximately 288 nm. This peak is characteristic of ruthenium nanoparticles (RuNPs). The presence of this peak confirms the formation of RuNPs. The peak arises due to the surface plasmon resonance (SPR) of the RuNPs. SPR is a phenomenon where conduction electrons in the nanoparticles collectively oscillate in response to incident light. The intensity and sharpness of the peak can be influenced by the size, shape, and concentration of the nanoparticles. The spectrum indicates that the synthesized RuNPs are relatively uniform in size.

Fig. 2.

UV–vis spectrum of plant extract and synthesized RuNPs

Infrared spectroscopic characterization using FT-IR

The FTIR spectra of the Tridax procumbens extract and synthesized RuNPs (Fig. 3) reveal significant shifts and changes in functional group vibrations, indicating the involvement of phytochemicals in nanoparticle synthesis. The broad peak around ~ 3400 cm^-1 observed in both the plant extract and RuNPs corresponds to O–H stretching vibrations, indicative of alcohols and phenols, suggesting the involvement of hydroxyl groups in hydrogen bonding and stabilization of nanoparticles. Peaks near ~ 2920 cm^-1 are attributed to C–H stretching of alkanes, confirming the presence of aliphatic chains in both samples. A distinct band around ~ 1630 cm^-1, associated with C=O or C=C stretching, appears in both spectra, with a slight shift in the RuNPs, implying the participation of carbonyl or alkene groups in the reduction of Ru²⁺ ions. The signal at ~ 1380 cm^-1 can be assigned to C–N stretching or C–H bending, which suggests the presence of amine groups or methyl moieties. Peaks in the region of ~ 1100–1050 cm^-1 correspond to C–O–C or C–O stretching, indicating alcohols, esters, or ethers that may act as capping agents, stabilizing the nanoparticles. Notably, a new absorption band in the range of ~ 800–600 cm^-1 appears only in the RuNPs spectrum, which is likely due to aromatic C–H bending or metal–O vibrations, supporting the formation of Ru–O or Ru–ligand bonds. This comparative analysis highlights the significant role of phytochemicals in the bioreduction and stabilization process during the green synthesis of RuNPs. It is shown in Table 2.

Fig. 3.

FT-IR spectra of plant extract and synthesized RuNPs

Table 2.

FTIR comparison and interpretation

Wavenumber (cm-1)	Peak value	Plant extract (Fig. 4)	RuNPs (Fig. 5)	Functional group/interpretation
~ 3400	O–H stretching	✔	✔	Alcohols, phenols– hydrogen bonding
~ 2920	C–H stretching (alkanes)	✔	✔	Aliphatic C–H stretch
~ 1630	C=O or C=C stretching	✔	✔ (slightly shifted)	Carbonyl or alkene group– possible involvement in reduction
~ 1380	C–N stretching or C–H bending	✔	✔	Amine group or methyl bending
~ 1100–1050	C–O–C or C–O stretching	✔	✔	Alcohols, esters, ethers– likely capping agents
~ 800–600	Aromatic C–H bending or metal–O vibration	✖	✔	Suggests Ru–O or Ru–ligand bond formation in NPs

X-ray diffraction (XRD) analysis

The XRD pattern of the samples showed peaks at 20.68°, 30.00°, 41.51°, 46.84°, 58.43°, 66.97°, and 74.44°, corresponding to the (100), (002), (101), (102), (110), (220), and (311) planes, respectively, confirming the presence of RuNPs. The XRD patterns also exhibited characteristic peaks for RuO. The major diffraction peak observed at 41.52° (2θ) corresponds to the (101) plane, indicating the formation of spherical-shaped RuNPs with a hexagonal crystal structure and is in agreement with the JCPDS card No. 06-0663 card for Ru metal. The results are shown in Fig. 4.

Fig. 4.

X-ray diffraction pattern of the synthesized Ru nanoparticles

To determine the average particle size of the RuNPs, the Debye–Scherrer equation was used:

In this equation, the variables are defined as follows: D is the particle diameter in nanometers, K is the dimensionless Scherrer constant (approximately 0.94), λ denotes the X-ray wavelength, measured as 0.1541 nm; β represents the full width at half maximum (FWHM) of the diffraction peak, it is expressed in radians, and θ signifies the Bragg angle of diffraction. The calculated crystal sizes ranged from 10 to 20 nm, with an average size of 12.9 nm. The Miller indices values and d-spacing values as shown in Table 3.

Table 3.

Miller indices values and d-spacing values

2θ (°)					Miller indices (hkl)	d-spacing (Å)
20.68					(100)	4.29
30.00					(002)	2.98
41.51					(101)	2.18
46.84					(102)	1.94
58.43					(110)	1.57
66.97					(220)	1.39
74.44					(311)	1.27

Morphological and elemental characterization using SEM and EDX

The morphological features and size distribution of the synthesized ruthenium nanoparticles were employed to investigate using SEM. Figure 5 display the scanning electron microscopy (SEM) images, revealing that the Ru nanoparticles predominantly exhibit a spherical morphology. Magnifications of 5000× (Fig. 5) highlight the narrow size distribution and the formation of spherical shapes.

Fig. 5.

SEM images show the synthesized RuNPs’ morphology

The chemical composition of the RuNPs was characterized by EDX, and the corresponding results are presented in Fig. 6, which were produced using the leaf extract of Tridax procumbens. The EDX spectrum showed a peak at 2.6 keV, corresponding to ruthenium (Ru), along with smaller peaks associated with oxygen (O) and Carben (C). A peak observed at 2.6 keV confirms the formation of metallic ruthenium through the reduction of ruthenium ions.

Fig. 6.

The energy-dispersive X-ray spectroscopy (EDX) of the synthesized Ru nanoparticles

Characterization of nanoparticles using TEM

The size distribution and shape of the synthesized ruthenium nanoparticles were characterized using TEM. As shown in the TEM image (Fig. 7), the synthesized Ru NPs displayed a relatively narrow size distribution, with an average diameter of 11.30 nm and individual particle sizes ranging from 2.00 to 22 nm. TEM analysis reveals that the synthesized Ru NPs generally have a spherical shape.

Fig. 7.

TEM analysis of synthesized Ru NPs

Biological activity analysis

Antimicrobial activity

The antimicrobial properties of the ruthenium nanoparticles synthesized in this study were assessed using a modified agar healthy diffusion technique. The zones of inhibition against various bacterial pathogens are summarized in Table 4. The antimicrobial activity of the Ru nanoparticles was tested at concentrations varying from 25 to 100 µg/mL. No antimicrobial activity was observed at a concentration of 25 µg/mL. However, at 50 µg/mL and above concentrations, a distinct inhibition zone was observed against both Gram-positive and Gram-negative bacteria. This study concludes that the synthesized nanoparticles exhibit significant antimicrobial properties of the sample and were assessed against a selection of clinically relevant bacterial pathogens, comprising B. cereus, S. aureus, E. coli, and P. aeruginosa. These findings suggest that these nanocomposites could effectively combat future bacterial infections. The results are tabulated in Figs. 8 and 9.

Table 4.

Antimicrobial activity of Ru NPs against different test pathogens

Sr. No.	Tested pathogens	Zone of inhibition in millimetres (mm)
		1 (25 µg/mL)	2 50 µg/mL	3 75 µg/mL	4 100 µg/mL	Streptomycin	Water	Significance
a	P. aeruginosa	00	21	25	29	31	00	Significant (↑)
b	E. coli	00	20	21	00	27	00	Moderate
c	S. aureus	00	22	24	27	29	00	Significant (↑)
d	B. cereus	00	24	26	29	30	00	Significant (↑)

Fig. 8.

Antimicrobial activity of Ru NPs against gram positive (B. cereus and S. aureus) and gram negative (E. coli, and P. aeruginosa) pathogens

Fig. 9.

Comparative statistical analysis of antibacterial activity of ruthenium nanoparticles against P. aeruginosa, E. coli, S. aureus, and B. cereus

Antifungal activity

As per this study, Ru nanoparticles didn’t show any antifungal activity [No zone of inhibition] against Aspergillus niger, but they showed antifungal activity from 75 µg/ml to 100 µg/ml against candida alliance shown in Table 5. The results are tabulated in Figs. 10 and 11.

Table 5.

Antifungal activity of Ru NPs against different test fungus

Sr. No	Tested pathogens	Zone of inhibition in millimetres (mm)
		1 (25 µg/mL)	2 (50 µg/mL)	3 (75 µg/mL)	4 (100 µg/mL)	Ketoconazole	Water	Significance
A	Aspergillus niger	00	00	00	00	28	00	Not Significant
b	Candida albicance	00	00	24	26	29	00	Significant (↑)

Fig. 10.

Antifungal activity of Ru NPs against A. niger and C. albicans

Fig. 11.

Statistical analysis of antifungal activity of ruthenium nanoparticles against Aspergillus niger and Candida albicans

Antioxidant activity

Antioxidant activity of biosynthesized ruthenium nanoparticles assessed by DPPH free radical scavenging assay. The scavenging activity was measured at different concentrations of nanoparticles: 25 µg/mL, 50 µg/mL, 75 µg/mL, and 100 µg/mL. The percentage of scavenging activity increased with concentration, peaking at 77.13 ± 0.64% at 100 µg/mL. Ascorbic acid was used as the positive control, and distilled water served as the negative control. The results are shown in Fig. 10 and the DPPH radical scavenging activity of ruthenium nanoparticles (RuNPs) at various concentrations as show in Figs. 12 and 13.

Correlation between nanoparticle topography and biological activity

The synthesized ruthenium nanoparticles (RuNPs), prepared using Tridax procumbens leaf extract, exhibit a spherical morphology and a narrow size distribution with an average particle size of approximately 11.30 nm, as confirmed by SEM and TEM analyses. This nanoscale dimension and consistent shape significantly influence the nanoparticles’ biological functionality.

The high surface-area-to-volume ratio of these nanoparticles is a critical factor enhancing their antimicrobial and antioxidant activities. This extensive surface area provides numerous reactive sites for interaction with microbial cell walls. Specifically, the spherical geometry facilitates close and uniform contact with bacterial membranes, leading to disruption of cell integrity, leakage of intracellular contents, and generation of reactive oxygen species (ROS), all of which contribute to microbial cell death.

Antimicrobial studies showed pronounced activity against both Gram-positive (Bacillus cereus, Staphylococcus aureus) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria, particularly at concentrations of 50 µg/mL and above. These findings underscore the efficacy of the nanoparticle surface in mediating antibacterial interactions. Similarly, antifungal activity was observed against Candida albicans, but not against Aspergillus niger, suggesting that the effectiveness of RuNPs can be limited by the structural characteristics of different fungal pathogens.

Moreover, FTIR spectra revealed the presence of functional groups such as hydroxyl, carbonyl, and amine groups on the nanoparticle surface, which are likely derived from the bioactive phytochemicals in Tridax procumbens. These groups not only stabilize the nanoparticles but also contribute to their bioactivity by enhancing interaction with biological membranes and supporting ROS generation.

In the antioxidant assays, the RuNPs demonstrated a strong DPPH radical scavenging effect, with maximum efficiency reaching 77.13% at 100 µg/mL concentration. This activity can be attributed to the synergistic effect of the small particle size, high surface reactivity, and phytochemical functionalization.

The topographical features of RuNPs, particularly their small size and spherical shape, along with phytochemical surface modifications, are crucial in defining their antimicrobial and antioxidant effectiveness. These findings justify the critical role of nanoparticle surface and size in enhancing biological applications, emphasizing their potential in nanomedicine and therapeutic interventions.

Conclusion

This research presents an environmentally friendly approach for synthesizing Ru nanoparticles (NPs) using leaf extract from Tridax procumbens. X-ray diffraction (XRD) analysis indicated that the Ru NPs exhibited high crystallinity, with an average crystalline size of 12.9 nm. Transmission electron microscopy (TEM) analysis showed that the nanoparticles were spherical, with an average size of approximately 11.30 nm. UV-visible spectroscopy, spanning the range of 200–800 nm, confirmed the successful formation of Ru NPs. The synthesized RuNPs exhibited stronger antibacterial activity against Gram-positive bacteria compared to Gram-negative bacteria. Moreover, the synthesized Ru NPs showed antifungal activity against Candida albicans. Furthermore, the RuNPs also exhibited enhanced antioxidant activity, supporting their applicability in biomedical and therapeutic domains. This green synthesis method is rapid, simple, cost-effective, time-efficient, and environmentally safe. This technique can be extended to synthesizing metal and metal oxide nanoparticles.

Author contributions

Neeraj Prasad and Ajit Devale conceived and designed the experiments; Ajit Devale performed the experiments; Ajit Devale and Amit Varale analysed the data; Samadhan Nikalaje prepared the draft; and Amit Varale supervised for the present investigation. All authors reviewed and approved the final manuscript.

Funding

This work was carried out without financial support from any governmental, commercial, or non-profit funding agencies.

Availability of data and materials

Data availability “Data is provided within the manuscript”.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

All authors are aware of this submission.

Competing interests

The authors declare no competing interests.