The fact that plant-derived agents are biocompatible and biodegradable is encouraging because it allows them to replace common chemical reagents in the production of nanomaterials (Iravani et al., 2014 [12]). Falconeria insignis Royle is a species that belongs to the Euphorbiaceae family and is native to dry forests and rocky areas in India. It is a shrub or small tree up to 6 meters tall that generates a milky latex which is used to treat skin disorders and also inflammation traditionally.

By taking advantage of the two-fold advantages of medicinal efficacy and environmental sustainability, the incorporation of F. insignis Royle in nanoparticle production systems would help in the evolution of new antimicrobial agents that can be used in clinics and industry.

F. insignis Royle, in this regard, is an unexploited but promising candidate to the green synthesis of silver nanoparticles (AgNPs), particularly since it has a rich arsenal of reducing and capping agents in its naturally occurring leaf and stem extracts. Although the plant has undergone preliminary studies in the area of phytochemical and antimicrobial, its opportunities in nanotechnology usage are still untapped, which gives a new orientation to the research.

A wide variety of bioactive compounds like alkaloids, flavonoids, terpenoids, and phenolics are present in this plant with antimicrobial and anti-inflammatory properties. These phytochemicals assist in reducing and stabilizing silver ions and thus allow the production of silver nanoparticles by the green method. These compounds have been characterized by antioxidant, antimicrobial and anti-inflammatory properties, thus the plant has become a potential candidate in the synthesis of metal nanoparticles using green synthesis. It has been shown that these biologically derived nanoparticles showed increased antimicrobial activity, which is probably explained by a synergistic approach to silver and plant-based bioactives (Patil et al., 2023) [13]. Although the green synthesis of silver nanoparticles using plant extracts is not new, the given work uses Falconeria insignis Royle as a new bioresource in the production of nanoparticles. F. insignis is a medicinal plant which thrives in some ecological niches and contains a large number of diverse phytochemicals, e.g., alkaloids, flavonoids, and latex-associated bioactives (Yadav et al., 2025) [14] Therefore, the use of F. insignis Royle in the synthesis of nanoparticles fits this objective in green chemistry in addition to aiding in the identification of new antimicrobial agents.

Freshly made aqueous solution of 0.1 M silver nitrate (AgNO3) was used in the synthesis of the silver nanoparticles(AgNPs). 5 mL of Falconeria insignis Royle leaf extract was added dropwise into 45 mL of the 0.1 M AgNO3 solution at ambient conditions (Jeeva et al., 2014) [15].

To separate the particles for FTIR measurement, the silver nanoparticles were spun at 10,000 rpm for 30 minutes. Deionised water was added three times to the pellet to get rid of any free proteins and phytochemicals. After the vacuum-dried pellet, FTIR spectroscopy was used to find the functional groups that use the plant extract to reduce and stabilise the nanoparticles (Das et al., 2010) [16].

A colloidal suspension of AgNP was put on a clean glass slide in the form of a drop, and it was left to dry with no obstruction. A sputter coater was then used to cover the dried sample with a thin layer of gold in order to increase conductivity and minimize the effects of charging during imaging. It was followed by the coated sample being viewed under a SEM (Model: JEOL JSM-6390) at accelerating voltage of 10–20 kV. The SEM images will give specific information on the morphology of the surface, size, and shape of the nanoparticles that are synthesized (Das et al.,2010) [16].

X-ray diffraction analysis was conducted to compute the crystallites size of the nanoparticles. The Debye Scherrer equation was used for calculation: D = Kl / (b cos θ) Where: D is the average size of crystallites, K is the shape factor (0.89), l is the wavelength of X-rays, b is the full width at half maximum (FWHM) of the diffraction peak (in radians) and θ is the Bragg angle (Das et al., 2010) [16].

Kirby- Bauer disc diffusion method was used to determine the antimicrobial activity of the synthesized silver nanoparticles as stated by Pal et al. (2007) [17]. The details of the antimicrobial methodology of analyzing the efficacy of silver nanoparticles (AgNPs) by use of the Kirby-Bauer Disk Diffusion method are as follows.

Positive Control: The comparative efficacy was done with the help of the positive control which were Standard antibiotic discs (Azithromycin 15 μg).

This absorption pattern indicates that AgNPs were successfully synthesized because the silver nanoparticles exhibit SPR bands at 300–450 nm. In this region, the absorbance was high and this shows the presence of the colloidal silver nanoparticles. This spectral evidence supports the use of Falconeria insignis Royle extract as reducing and stabilizing agent in the synthesis that the green synthesis process was successful.

The green synthesised nano particles (AgNPs) are non-spherical and heterogeneous in shape and also strong agglomeration is observed, forming clustered structures.

Surface texture appears rough and granular, indicating its possible polycrystalline nature.

The sizes of the particles were determined to be varying and measured were found to be in the range of 18.50 nm to 20.01 nm.

SEM micrograph supports the fact that silver nanoparticles are remarkably narrow size distribution for these nanoparticles. shape were biosynthesized successfully, indicating that the presence of certain phytochemicals in Falconeria insignis Royle could be the determinant of nanoparticles during the biosynthesis pathway. It aligns to most of the reports about the green synthesis, most of them usually produce spherical particles (Veerasamy et al., 2011 [21]; Ahmed et al., 2016 [23]. Other few studies have also reported similar non spherical morphologies, including the cases of Aloe vera and Terminalia arjuna extracts, in which directional binding of proteins or flavonoids was the cause of the development of anisotropic growth (Jain and Mehata, 2017) [25] (Fig 4). Although the general size of nano particles in Falconeria insignis Royle (18.50 nm to 20.01 nm) is small, the non-spherical and heterogeneous shapes also vary, which also confirms anisotropic growth. It aligns with earlier studies (Xia & Halas, 2005) [26]. Even small variations in the synthesis conditions or the availability of different directing agents may cause a wide range of anisotropic forms in a population. The textured surface of rough and granular texture, which is suggestive of polycrystalline structure, is also in line with anisotropic growth. Anisotropic growth can be the preferential addition of atoms to specific crystal faces. Growth may occur differently on the different surfaces of the grains in polycrystalline materials, which can add to the rough texture observed, as well as affect the ultimate non-spherical morphology (Jana et al., 2001) [27].

The high order diffraction peaks were found at the values of 35.51deg, 38.50deg, 44.76deg, 64.94deg, 77.92deg, 82.00deg respectively, the characteristic reflections of the (111), (200), (220), (311), (222), and (400) crystallographic planes respectively. Debye-Scherrer equation was applied to estimate the crystallite size. The observed sizes of the crystallites calculated for the observed peaks were between 14.84 nm and 25.55 nm. Mean crystal size was calculated to be around 19.10 nm aligns with the SEM calculated values which implies that the nanoparticles synthesized are in the nanometer range and they are nanocrystalline in nature (Fig 5).

The observed characteristic Bragg reflections at 38.50 deg, 44.76 deg, and 64.94 deg are consistent with the standard face-centered cubic (FCC) structure of silver nanoparticles as it is found in the literature (JCPDS card no. 04-0783) (Zhou et al., 2011 [28]; Tamilvanan et al., 2021 [4]) (Table 1).

The antimicrobial disc has found to be more inhibition 28.33 mm (Fig 6), followed Silver nano particle 21 mm (Fig 6), leaf extract alone 17 mm, Double distilled water 0 mm, Silver Nitrate alone showed 3 mm bacterial inhibition in the case of Staphylococcus aureus (Gram positive) (Table 2).

The findings of the ANOVA showed that there is a statistically significant difference among treatment groups (F = 231.25, p = < 0.0001), which confirms that the antimicrobial activities of the samples differed significantly (Table 3). One-way ANOVA showed that there is a significant difference between the treatment groups (F = 3,8 = 231.25, p = 0.0001), which means that the identified changes are statistically significant at the confidence level of at least 99.99. Of the samples, azithromycin had the higher zone of inhibition of 28.33 mm, whereas the plant leaf extract itself had the least zone (21 mm). The extract prepared by nanoparticles had higher activity compared to the silver nitrate alone and the crude extract implying greater antimicrobial potential owing to nanoparticle additions (Table 4).

Azithromycin (28.33 ± 1.53 mm)> Leaf + AgNP (21 ± 1 mm)> Leaf Extract (17 ± 1 mm)> Silver Nitrate (3 ± 1 mm). No comparison with zero is within the confidence intervals, which proves that there is no overlap between groups. Adding AgNPs to the leaf extract boosts the inhibition zone by 4.0 mm (95% CI 1.0–7.0 mm, p = 0.012). This induces the notion that green-synthesized AgNPs have a greater antimicrobial activity than the crude extract alone- a trend that has been repeatedly observed with plant-mediated AgNPs.

The results obtained in antibacterial activity indicate clearly that the biosynthesized silver nanoparticles (AgNPs) have strong inhibition circles than both Falconeria insignis Royle leaf extract and silver nitrate respectively (Fig 5). AgNPs generated more extensive areas of inhibition (21 mm for Staphylococcus aureus) (Table 2).It is found that leaf extract (17 mm) and green silver nano particles (21 mm), were superior to the negative control (Double distilled water) suggests better antimicrobial activity. It is possible to explain this enhanced activity of AgNPs by the smaller size of the particles, the greater ratio of the surface to the volume, and the capability to infiltrate into the bacterial cell wall and damage its structure and functions (Rai et al., 2012 [6]; Zazo et al., 2016 [29]; Yu et al., 2013 [30]).Tamilvanan et al. 2021 [4] received the same results as AgNPs synthesized using plant extracts were more active in antibacterial than crude extracts and silver salt solutions obtained using plant extracts. Furthermore, these phytochemicals of the Falconeria insignis Royle have probable capping activities that stabilize the nanoparticles and improve their contact with the microbial cells. The similar findings by Li et al. (2011) [31], who reported that the biologically synthesized AgNPs disrupt the bacterial membranes leading to cell lysis. In such way, the enhancing action of phytochemical and nanoscale silver seems to play an important role in the increased antimicrobial action of the study.