Anticancer potential of biologically synthesized silver nanoparticles using Lantana camara leaf extract

Abstract

A Lantana camara leaf (LC) extract was used as a mild reducing agent to produce silver metal nanoparticles (LC-AgNPs) efficiently. The size, shape, and morphology of synthesized silver nanoparticles were verified. LC-AgNPs were found in LC extract by XRD. The optimal concentrations of silver nitrate and LC extract necessary for the production of stable silver nanoparticles were determined. The LC-AgNPs were found spherical in form and monodispersed. Under optimal conditions, the round LC-AgNPs of 50–90 nm were utilized to cure lung cancer (A549 cell line) and breast cancer (MCF7) cell lines. Finally, the produced LC-AgNPs enhanced anti-cancer efficacy against A549 cells, with an IC50 = 49.52 g/mL. Similarly, the effect of LC-AgNPs on MCF7 cell line was assessed using an MTT test and inhibitory concentration (IC50) was determined found that 46.67 g/mL.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40204-023-00219-9.

Introduction

Nanotechnology is a multi-disciplinary field of study that aims to make materials with better properties like supramolecular, atomic, and molecular materials (Vennila et al. 2018; Mufamadi et al. 2019). The metallic nanoparticles like zinc oxide, copper oxide, silver and gold nanoparticles are employed in microelectronics, disease control, heavy detection, RNA/DNA detection and glucose (Sioss et al. 2012; Teengam et al. 2017; Ganachari et al. 2019a; Yaradoddi et al. 2019; Gnanasangeetha and Suresh 2020). In medicinal field, silver nanoparticles (AgNPs) are significantly used in tissue engineering, diagnostic and drug delivery because of their unique surface area modification, characterization, ease of synthesis, chemical stability, low cost, optoelectronic and physicochemical properties (He et al. 2018; Dinparvar et al. 2020; Siddiqui et al. 2020). The phytochemicals present in different parts of the plant species can reduce the Ag⁺ to Ag⁰ during the synthesis of AgNPs without any microbial cell culture (He et al. 2018; Sarli et al. 2020; Siddiqui et al. 2020).

The size, stability, and morphology of silver nanoparticles are primarily determined by the reducing agent strength, reaction mixture, pH, concentration, mixing ratio, nature of solvent, and method of preparation (Banerjee et al. 2017; Mishra and Kannan 2017; Abbasi et al. 2019; Dinparvar et al. 2020). Plants like Hyptissuaveolens, Pedalium murex (Esther Nimshi et al. 2023), Pedalium murex, Mimusopselengi, Hibiscus rosa sinensis, and Jatropha Curcas were effectively screened for the plant extract synthesis of silver nanoparticles (Sen et al. 2022; Kochadai et al. 2022; Prisrin et al. 2022; Anil et al. 2022; Taha et al. 2022; Mbagwu et al. 2023). Green silver nanoparticles showed that robust antimicrobial and anticancer activities of green silver nanoparticles were reported by many researchers (Vennila et al. 2018; Gahlawat and Choudhury 2019; Akintelu and Folorunso 2020; Panja et al. 2020; Singh et al. 2020; Stephen and Thomas 2020). The eco-friendly method synthesis inspired current study. L. camara is a species of flowering plants within the Verbenaceae family. It mainly contained alkaloids, flavonoids, tannins, and polyphenols. In addition to that, it also contained phellandrene, germacrene, gallic acid, catechin, and lantacin. This compound possessed electron-rich elements such as P, N, O and S in their moieties. L. camara can be used in traditional herbal medicines to treat variety of ailments including cancer, asthma, and skin itches. Hence, these compounds expected to show good anti-microbial, and anticancer activity (Jacob et al. 2017; Vivekanandhan et al. 2018; Zada et al. 2018; Sivamaruthi et al. 2019; Acharya et al. 2020; Atwan and Hayder 2020; Deep et al. 2020; Hamida et al. 2020; Hemlata et al. 2020). The silver nanoparticles were prepared using L. camara leaves extract. The L. camara is a low erect or sub-scandent vigorous shrub. Plant taxonomy: belongs to the Planate Kingdom, the Magnoliophyte division, the Magnoliopsida class, the Lamiaceae order, the Verbenaceae family, the Lantana genus, and the L. camara Linn species (Tiwari et al. 2022; Mondal et al. 2022; Seid and Bekele 2023).

The second paragraph (highlighted with yellow) explains that plant phytochemicals under the optimum conditions of temperature, pH, pressure and electromagnetic radiations act as reducing agents for nano-reduction. Meanwhile, the extraction process and synthesis of silver nanoparticles may also depend on the selection of solvents used for extraction. Many articles show the use of organic solvent for L. camara extracts. We tried polar solvent and carried it out in a short period of time to avoid other synthetic-related complications. During the plant-mediated synthesis of metal nanoparticles, the alcohol, aldehyde, phenol and flavonoids present in the plant extract are oxidized to their respective aldehydes, carboxylic acids, ketones, and flavones and the metal ions are reduced to metal NPs. The formation of silver nanoparticles with L. camara leaves extract was confirmed by UV–Vis, FTIR, XRD and SEM studies. Further, as its application part, their antimicrobial and anticancer activities were also assessed.

Materials and methods

Materials

L. Camara plant leaves were collected from KLE garden, and basic plant identification was done with the support of Botany researchers. Silver nitrite (AgNO₃) and Acetone were indented from Sigma Aldrich (AR grade), Soxhlet apparatus make, double-distilled water, Digital Centrifuge machine, well microtiter plate, MCF-7 cell line, microscope, CO₂ incubator, gyratory shaker.

Preparation and characterization of silver nanoparticles

The preparation of leaf extract was carried out as described in Supplementary data (S1.1). The 0.01 N of AgNO₃ solution was prepared by double-distilled water. The obtained solid leaf extract of L. camara (1 g) was dissolved in 10 mL of distilled water. The standard AgNO₃ solution and extract solution were mixed in a ratio of 1:1 and stirred for 30 min and kept for 24 h. It was then filtered to obtain L. camara leaf extract silver nanoparticles (coded LC-AgNPs).

The preliminary confirmation of Ag⁺ reduction to Ag⁰ was characterized using a Perkin Elmer spectrophotometer UV–Vis spectroscopy in the wavelength of 300–700 nm. The double-distilled water was used as blank. The functional groups present in the phytochemical constituents of AgNPs were screened using the Fourier transform infrared (FTIR) spectrophotometer in the range of 4000–400 cm⁻¹. Morphology and surface integrity of green silver nanoparticles were analyzed by scanning electron microscopy (SEM) technique (Aiswariya and Jose 2021; Rawashdeh et al. 2023; Periakaruppan et al. 2023). The amorphous/crystalline nature of AgNPs was elucidated using powder X-ray diffraction analysis (Rigaku miniflex 600 W) (Prisrin et al. 2022; Keshri and Biswas 2022; Esther Nimshi et al. 2023).

Biological activities: anticancer studies and antibacterial studies

Anticancer studies carried out using “Cell Proliferation Kit I” [MTT – (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide)] is a colorimetric assay which allows cell growth measurement, viability, and cytotoxicity without using radioactive materials. Using procedure, trypsinized cells were aspirated into 15 ml centrifuge tubes. 300 × g centrifugation produced cell pellet. Using DMEM HG media, 200 μl of suspension contained approx.10,000 cells. 200 μl of cell suspension was added to each 96-well microtiter plate and incubated at 37 °C and 5% CO₂ for 24 h. Aspirated spent medium after 24 h, the wells received 200 μl of test drug concentrations (20, 40, 60, 80, and 100 μg/ml from stock). The plate was incubated at 37 ℃ and 5% CO₂ for 24 h. Aspirating drug-containing fluids from the incubator plate. 200 μl of media containing 10% MTT reagent was added to each well to reach 0.5 mg/ml, and the plate was incubated at 37 ℃ and 5% CO₂ for 3 h. The culture media were withdrawn without damaging the crystals. After adding 100 μl of DMSO, the plate was gently agitated in a gyratory shaker to solubilize the formazan. 570 and 630 nm microplate readers assessed absorbance. After subtracting the background and blank, the percentage growth inhibition was computed, and the cell line's dose–response curve was used to calculate the test AgNPs IC50 value.

Antibacterial activity was tested by agar diffusion methods, applying a single substance concentration in a reservoir on a seeded nutritional agar medium. The diffusion of the substance into the medium will generate a continuous gradient of decreasing concentrations with increasing distance from the reservoir. The AgNPs substance may be applied to the seeded agar medium. The result is the diameter of the inhibition zone expressed in ‘mm’ and related to the minimal inhibitory concentration of the bacteria.

Results and discussion

The bio-synthesis of metal nanoparticles gained curious attention of researchers towards the growth and development of medical applications. This process is environmentally friendly and cost-effective materials, synthesized by LC extract including one of the medicinal components used for pain relief. The fractionation of LC extract comprises terpenoids, polysaccharides and leads to the reactions such as polyoxypregnanes and glycosides. It was found that L. camara contained tannin and catechin in its leaves and stem as well as phenol and anthroquinone in its roots. It also had plenty of flavonoids, alkaloids, and reducing sugars in its leaves and roots. Leaf and flower extracts made with different solvents had larvicidal properties. The flowers of the plant were able to keep mosquitoes away, which means that flowers could be used to keep mosquitoes away (Ayalew 2020).

Visual observation

Green synthesis of LC-AgNPs using extract of LC was primarily authenticated by visual observation. The extract of LC was exposed to Ag⁺ ions and the LC-AgNPs are formed through reduction process. Initially, the LC extract was in pale yellow color and after 24 h, the reaction mixture (LC extract plus 0.01 AgNO₃) was changed into reddish brown color. This confirms the formation of LC extract silver nanoparticles, as LC-AgNPs, (Fig. 1). This color change indicates the completion of reduction of Ag⁺ to Ag⁰ ion process and it is related to surface plasmon resonance (SPR) (Patil et al. 2021; Abeer Mohammed et al. 2022; Tripathi et al. 2022; Nandhini and Shobana 2022).

Fig. 1.

a Schematic flow of preparation of LC-AgNPs and interaction between Ag2 + ions and LC extract with b Realistic photos

UV–Vis spectrophotometer

UV–Vis spectroscopy is an important tool for determining the optical properties of LC-AgNPs. The UV–Vis spectrum of LC extract and LC-AgNPs was measured between 200 and 600 nm and spectrum shown in Fig. 2. The UV–Vis spectrum of LC-AgNPs shows a surface plasmon resonance (SPR) band centered at 460 nm, which reveals the silver nanoparticle characteristics band (LC-AgNPs) (Fig. 3). It confirms the reduction of silver ions (Ag⁺) to metallic ions (Ag⁰). The SPR band is caused by excitation of LC-AgNPs free electrons, and the single absorption band clearly shows the spherical shape of silver nanoparticles. Furthermore, the broadened band confirms that LC-AgNPs are polydisperse. Similar findings have been reported in the literature (Aiswariya and Jose 2021; Prisrin et al. 2022; Keshri and Biswas 2022; Banthia et al. 2022).

$$AgN{O}_3\left(\mathit{Aq}\right)-\to A{g}_{\left(\mathit{Aq}\right)}^{+}+N{O}_{3\left(\mathit{Aq}\right)}^{-},$$ 1

$$L{C}_{\text{leaf extract phytochemicals}}\left(e^{-}\right)+A{g}_{\left(\mathit{Aq}\right)}^{+}-\to \text{A}{g}_{\left(\mathit{Aq}\right)}^0.$$ 2

Fig. 2.

UV Spectra of silver nanoparticles and synthesis constituents

Fig. 3.

FTIR spectra of L. camara extract: a pure extract and b LC-AgNPs

The scattering, absorption cross section, extinction, and quadrupolar coupling of various silver nanoparticles investigated show that the optical properties vary with nanoparticle size (Acharya et al. 2021; Sattari et al. 2021; Bhat et al. 2023). This suggests that absorption varies with the encapsulation of phyto-mediated synthesis of silver nanoparticles and their various phases of application (Uddin et al. 2022; Tripathi et al. 2022; Nandhini and Shobana 2022; Ameen 2022).

FTIR spectroscopy

FTIR spectroscopy is used to investigate the formation of LC-AgNPs with modifications and stretching vibrations of organic species present. FTIR technique shows the functional groups of phytochemical constituents in the LC extract responsible for the reduction of Ag⁺ ions into metallic silver nanoparticles. FTIR results are shown in Fig. 4. The result shows that both LC extract and LC-AgNPs contain similar bands with modification in the wavenumber. Three new bands were observed in LC-AgNPs and one small band disappeared in the LC extract. LC extract exhibited broad band at 3400 cm⁻¹ which was shifted into 3500 cm⁻¹ in LC-AgNPs and could be assigned to hydroxyl groups. The two new bands appeared at 2900 cm⁻¹ and 2800 cm⁻¹ in silver nanoparticles may be assigned to stretching C–H groups. It is observed a slight variation in the broad band at 1600 cm⁻¹ in LC-AgNPs. Likewise, only major changes observed in the wavenumber in both LC extract and LC-AgNPs confirmed the presence of hydroxyl and carbonyl groups. This functional moiety plays a vital role in stabilizing and reducing agent in silver nanoparticles (Abeer Mohammed et al. 2022; Mbagwu et al. 2023; Lakhera et al. 2023).

Fig. 4.

XRD pattern of LC-AgNPs

X-ray diffraction (XRD) studies

The XRD pattern of LC-AgNPs shows the diffraction peaks at 2Ɵ angles of 37. 35˚, 43.76˚, 63.68˚ and 78.58˚ and this confirms the pure crystalline nature of LC-AgNPs (Fig. 4). The XRD different parameters such as inter-crystalline separation (R), quality factor (Q), interplanar spacing (d), and crystalline size (p) are depicted in the Table 1. Scherrer’s equation (Eqs. 3 and 4) is used to find out crystalline size (p), interplanar spacing (d) (Sen et al. 2022; Kochadai et al. 2022; Abdel-Rahman et al. 2022), inter-crystalline separation (R) and quality factor (Q).

$$\frac{K\lambda }{\left(\beta Cos\theta \right)}=P,$$ 3

where

Table 1.

Antimicrobial activity of LC-AgNPs

Escherichia coli (Gram -ve)
Sample name	Drug vol	Control	10 µL	20 µL	30 µL
Sample 1 LC-AgNPs		20 mm	–	–	–

Bacillus cereus (Gram + ve)
Sample name	Drug vol	Control	10 µL	20 µL	30 µL
Sample 1 LC-AgNPs		50 mm	11 mm	–	–

$\lambda =$ 1.5405 A,k = 0.9, $\beta =\text{width at half maximum intensity}$,

Average intercrystalline separation (R) was obtained from the below equation;

$$\left(\frac{5\lambda }{8sin\theta }\right)=R.$$ 4

Prominent peaks are observed at the XRD analysis of silver nanoparticles corresponding to (1 1 1), (2 0 0) and (2 2 0), confirming the formation of a crystalline face-centered cube (FCC) structure of AgNPs. The XRD patterns obtained matched the JCPDS standard reference JCPDS Silver: 04–0783.

SEM analysis

To understand the morphological changes, SEM analysis of the synthesized LC-AgNPs was carried out (Fig. 5a,b). Topography property and size details of synthesized LC-AgNPs were provided by screened by SEM images. The particle size of the AgNPs was observed from the SEM topography between the ranges of 40 and 70 nm (Fig. 5b). Similar observations are reported in the literature (Ganachari et al. 2019b; Hublikar et al. 2021; Abdel-Rahman et al. 2022; Bhat et al. 2023). The variation in the size of LC-AgNPs is due to the presence of phytochemical constituents in the plant extract which exhibited spherical shape of synthesized LC-AgNPs. On the surface, green moiety silver particles are highly charged with the shining appearance of Ag nanoparticles with uniform distribution over them. Further, the synthesized LC-AgNPs are separated well, exhibiting no agglomeration. Dispersion of AgNPs in water was used for the green synthesis in quantitative yields as a green catalytic system under mild reaction conditions. The biological synthesis of AgNPs using leaf extract was shown as a rapid synthesis and produced particles of a fairly uniform size and shape. The rate of synthesis depended on the quality of leaf as well as the concentration of leaf extract; as concentration increased, the rate of reduction that reduced the particle size also increased it as well as their agglomeration. SEM results are well supported by UV–Vis, FTIR and XRD results.

Fig. 5.

a, b SEM topography of LC-AgNPs (the AgNPs charged in organic moiety separated using dual tone image enhancer)

HRTEM analysis

The transmission electron microscopy image of LC-AgNPs as represented in Fig. 6 and indicates that particles are dispersed in more or less spherical shape.

Fig. 6.

HRTEM image of LC-AgNPs

This revealed that the particle size of silver particles ranged from 10 to 50 nm. The average size of silver nanoparticles approximately 60 nm showed significantly large spherical silver nanoparticles through HRTEM micrographs.

Biological applications of LC-AgNPs

Anticancer activity

The efficiency of AgNPs for targeted cancer cells, i.e., human breast cancer cells MCF-7 and A549 lung cancer cells. AgNPs damage the polymer components of the cell membrane and concentration of AgNPs, and it has a remarkable effect on the rupture of cell wall. As the concentration of AgNPs increases, the permeability of the membrane would be high.

An electron-coupling reagent breaks down the tetrazolium salt MTT in the presence of reagent. The water-insoluble formazan salt must be dissolved in the next step. It takes about 4 h for cells grown in a 96-well tissue culture plate to be incubated with the MTT solution that is mixed with them. Formazan dye is made after this time of incubation. Scanning of multi-well spectrophotometers measure the formazan dye after it has been solubilized in water (ELISA reader). The number of viable cells is related to the amount of light detected.

Cell proliferation and viability tests are very important for everyday cell biology applications. Tetrazolium salts (such as: MTT, XTT, and WST-1) are very useful for this kind of study. This is the succinate-tetrazolium reductase system (EC 1.3.99.1). It is part of the mitochondria respiratory chain and it is only active in healthy cells. It breaks down tetrazolium salts into formazan. It is not only the cells energy factories that mitochondria are in charge of, but they are also in charge of signaling that the cell is going to expire.

During the data analysis of cell proliferation, average readings of each sample are taken, and the subtracted culture medium readings result from assay readings to obtain corrected absorbance. This is directly proportional to the cell number, which gives the standard curve. Percentage cytotoxicity can be calculated with the Eq. (5).

$$\frac{\text{Absorbance}}{\text{Toxicity}\left(\%\right)}=\left[100\times \left(\text{control}-\text{sample}\right)\right].$$ 5

LC-AgNPs were shown to have the potential to treat various cancer cell lines. In this study, we glanced at the cytotoxicity of bio-synthesized silver nanoparticles on MCF-7 breast cancer cells and A549 lung cancer cells. As a control, a medium without any drug formulation was used. The in vitro studies of cytotoxic effect of silver nanoparticles on cell lines MCF-7 (Fig. 8a–f) and A549 (Fig. 8a–f) were carried out, and percentage of cell inhibition was obtained by MTT assay which are then compared with cisplatin, standard anticancer drug which is commercially available. Its cytotoxicity values revealed similar mortality rates at concentrations of 20, 40, 60, 80 and 100 μg/mL from stock 200 μL (Fig. 7 a–d). This increased cytotoxicity is due to the nanoparticles which improved cellular absorption and retention. This internal effect explained that the smaller size of nanoparticles allows them to enter cells more easily through endocytosis. Not only do they enter cells, but they also interfere with the functioning of cellular proteins, causing changes in cellular structure and chemistry. However, because these are small and non-aggregated particles, they are also capable of producing reactive oxygen species (ROS) in cells. Furthermore, ROS can cause oxidative stress by damaging DNA and causing morphological changes in cell lines, eventually leads to apoptotic cell death (Alvur et al. 2022; Farshori et al. 2022; Çınar Ayan et al. 2022; Kim et al. 2022; Ko et al. 2022).

Fig. 8.

a Untreated and b–f influence of AgNPs on cancer cells with addition of LC-AgNPs (20, 40, 60, 80, and 100 µg, respectively) to MCF7 cell line

Fig. 7.

a–d Linearity curve of anticancer activity and barographs

Overall, LC-AgNPs are effective current method of non-toxic, cost-effective, and effective towards antibacterial and anticancer activity.

After following the above-mentioned procedure 50% of the cell growth inhibition factor (IC- 50) of the synthesized AgNPs against MCF-7 and A549 cell lines was found to be 46.67 µg/mL and 49.52 µg/mL respectively at the incubation period of 24 h and 5% CO₂ (Fig. 7a–d). Lung cancer > breast cancer is the order of potency of synthesized silver nanoparticles on in vitro cytotoxicity effect of cell lines. From the results, we can acknowledge that cancer cell death rate in both cases of MCF-7 and A549 cell lines directly varies with the increasing concentration of LC-AgNPs. These silver nanoparticles aimed at speedily separating cancer cells, are expected to have unexpected effects on normal cells that divide at the similar rate.

As in earlier reported articles, leaf extract of Mentha pulegium was used to synthesize AgNPs and was found cytotoxic to MCF-7 cancer cells, showing abrupt morphological changes in the affected cell lines. Cell clustering and cytoplasmic shrinkage were also observed in the cancerous cells (Kelkawi et al. 2017). From Coriandrum sativum extract which is used to synthesize AgNPs. Resulting AgNPs showed efficient anticancer activity against MCF-7 cancer cells. The dose-dependent anticancer activity is shown by these nanoparticles. Along with this, anti-acne and anti-dandruff efficacy is also shown by green synthesized AgNPs using Coriandrum sativum leaf extract.

Similar results were also observed in green synthesized of multifunctional silver nanoparticles from the Siberian ginseng, the herbal adaptogen. Efficiency of Sg-AgNPs conferred to 40% cytotoxicity in the MCF7 cell lines at 10 µg⋅mL⁻¹ concentration (Abbai et al. 2016). Potential anticancer activity is also shown in triggering cell death process through necrosis and apoptosis both by silver nanoparticles synthesized using leaf extract of Andrographis echioides, and its bio-cytotoxicity is observed by transfer of electron from molecular oxygen (Elangovan et al. 2015). The fetter of anticancer activities on MCF-7 cancer cells of AgNPs are assessed by bioactive compounds present in extract of Gymnemasylvestre 18 and Plumeria alba (frangipani) flower extract (Mata et al. 2015). Ethanolic extract of Rosa indica petals as bio-reductants for AgNPs synthesis and its anticancer activity on MCF-7 cancer cells and anti-inflammatory activities. Silver nanoparticles synthesis using mangrove plant Excoecariaagallocha, Chinese herbal Cornus officinalis and Glycyrrhizauralensis have also shown their efficient cytotoxic effects on MCF-7 cancer cell lines (Bhuvaneswari et al. 2017).

Therefore, apoptosis instructed as this is also called as “programmed cell death”. This may arise when cells are experiencing the stress, which may be due to any infections, DNA damage or deficiency in growth factors (scheme in Fig. 10). This cell death is rooted mainly in the sequence of intrinsic processes involving the cytoplasm, and mitochondria (Figs. 7, 8 and 9).

Fig. 10.

Apoptosis of AgNPs

Fig. 9.

a Untreated and b–f influence of AgNPs on cancer cells with addition of LC-AgNPs (20, 40, 60, 80, and 100 µg, respectively) to A549 cell line

In detained way, apoptosis can be attained by either structural or biochemical changes leading to cell inactivity, by shrinkage, membrane rupture or DNA fragmentation (Fig. 10). As cancer cells show greater permeability and also retention ability the AgNPs are more preferentially interact with them because of their nano-size. When AgNPs are entering the target cells continuously, there appears a hinderance for their uncontrolled cell divisions leading to target cell death. In addition, target tumor cells experience apoptosis to the earliest by controlling the physiological up- and down-regulating factor, which will check the rapid cell divisions. ROS is one of the known basic pathways for the apoptosis. This causes weakening of membrane permeability causing cytochrome c, and procaspases-2,-3, to release. By the activation of caspases through combination of cytotoxic and genotoxic agents, it would lead to mitochondrial destabilization. LCLE-AgNP’s responses to intracellular signaling are through ROS activation. The AgNPs-induced p53-mediated apoptosis is possible because, p53, signaling molecule shows most amazing effect in treatment with p53-LCLE-AgNPs-induced apoptosis process (Wang et al. 2012).

Continuing the study, complete cell apoptosis after destroying DNA further needs to understand the importance of mitochondrial death. Because mitochondria is the energy packet of the cell, it is a singular cell organelle in which chemical energy is stored in the form of adenosine triphosphate (ATP). These provide through the respiratory chain to perform maximum biochemical reactions of the cell. The main persistence of the mitochondria is to oxidize food, to generate energy, to accomplish respiration to the cell and to make available adenosine triphosphate (ATP) (Kumari and Subramanya 2020; Nibret et al. 2021; Acharya et al. 2021; Sattari et al. 2021; Patil et al. 2021; Takagi et al. 2022; Salman et al. 2022; Narasimha et al. 2022).

Further, mitochondrial damage is resulted by cytotoxicity of AgNPs in cells. The damage in mitochondrial disturbance in the variability of regulatory mechanisms comprises as autophagy, oxidative damage, and energy imbalance. The toxic effects of AgNPs on mitochondria are analyzed and it is found that NPs contact interrupts mitochondrial dynamics and biogenesis in A549 and MCF7 cells. As shown in Fig. 11a–f, fluorescence-stained biomarkers are promoting the apoptosis of cells (He et al. 2018; Rashid et al. 2021; Çınar Ayan et al. 2022; Ameen 2022).

Fig. 11.

a, b, c shows the A549 cancer cell death and Figure d, e, f shows MCF-7 cancer cell death d, e, f

The proteins of LC extract exhibited the enhanced results in dose-dependent manner. When the concentration of LC-AgNPs was increased over time, the percentage of protein expression level increased. Caspase-3 expression was found to be up-regulated in A549 and MCF7 cells treated with biogenic AgNPs. It will happen because p53 causes Bax membrane translocation and the release of cytosolic cytochrome-C. This may make the apoptotic signal even stronger by activating caspase-9 and other downstream caspases, like caspases 3, 6, and 7. It is important for these targeted cells to make ATP, but it also plays a role in apoptosis. Cytochrome-C, which is needed to make the ATP, causes further changes in the nucleus, DNA fragmentation, and the appearance of cells. The main way AgNPs ceased to kill A549 and MCF7 cells through an apoptosis process that happened inside these cells (Fig. 12).

Fig. 12.

Schematic representation of mitochondrial apoptosis

However, LC-AgNPs are evidence of drug efficiency for chemotherapeutic treatment. Further, this could be a promising therapeutic agent for cancer treatment. The safety and mechanism of action of method of synthesis of silver nanoparticles, in various cancer cell lines, is acceptable in future, which facilitates their survival in A549 and MCF7 tumors.

Antibacterial activity

The supportive study of biological and biomedical applications is important because inappropriate usage of antibiotics induced the spreading of resistance of microorganisms. Agar diffusion methods were used to test antibacterial activity, with a single substance concentration in a reservoir on a seeded nutritional agar medium that had been mixed with seeds and water. This helps bacterial enhancement in the growth and spreading through the medium. As one moves away from the reservoir, the concentration of the substance drops. The AgNPs substance can be added to agar that has been seeded. Micrometers are used to measure the diameter of the “inhibition zone”. It is based on the bacterial “minimum inhibitory concentration”. A diffusion assay is a way to see how well a substance spreads through a medium. The most important factors are the density of the inoculum, the depth of agar, the concentration of the substance, the diameter of the reservoir, and when it is applied and when the incubation begins. These variables must be controlled to acquire the same results again and again. It does not apply to the media that do not spread well or the bacteria that grow slowly in the conditions that were being made. When bacteria and nanoparticles come into contact with each other for a specific time, how many bacteria are still alive. After incubation of the bacteria, the number of bacteria that are still alive in an antimicrobial-free agar nutrient is compared to the number of bacteria still alive in a control without the substance (Prasad and Swamy 2013; Hussain et al. 2019). They could also come into contact on top of the agar. After incubation, the colonies are counted and compared to the number of colonies present in an area without exposure to the AgNPs (Loo et al. 2018; Prasher et al. 2018; Aiswariya and Jose 2021; Abdel-Rahman et al. 2022; Motshekga 2023). This procedure was employed in the current work produced miscellaneous results. Following that, there was no zone of inhibition observed in Escherichia coli, while Std. ciprofloxacin and B.cereus (+ ve) exhibited an inhibition zone (Fig. 13), as shown in Table 1.

Fig. 13.

Zone of inhibitions for gram + ve (a and b) of Bacillus cereus and gram -ve (c and d) of Escherichia coli antimicrobials

Overall, the observed results indicated that they are effective against the bacterial diseases.

From these observed results, it may be concluded that there is a low antigenicity mechanism. Membrane disturbance occurs through diverse means. It can make holes penetrate throughout the membrane, shrink the membrane, or make lipid–peptide domains that end the membrane (Raghunandan et al. 2011; Loo et al. 2018; Wypij et al. 2018; Kalaivani et al. 2018). The LC-AgNPs have shown efficient anti-cancer and antimicrobial activities; however, lacking this proficiency in Bacillus cereus might be due to the lack of antimicrobial peptides in the plant extract.

Conclusion

Present work of silver nanoparticles (LC-AgNPs) was synthesized using L. Camara and further characterized for phase purity and morphology employing various characterization methods. A detailed synthesis of LC-AgNPs is explained with the necessary conditions. Spherical-shaped silver nanoparticles of 40–70 nm dimensional range were obtained. The phytochemicals present in plant extract have significantly stimulated the rate of synthesis, with stabilized and enhanced bioactivity. This method of synthesis can be a promising way and used for large-scale production. These nanoparticles are employed as effective anticancer and antibacterial agents. They show the efficiency of LC-AgNPs as anticancer agents higher than their antimicrobial activity. The cytotoxic effects on MCF-7 and A549 cell lines were found to be 46.67 g/mL and 49.52 g/mL, respectively, after a 24-h incubation period with 5% CO₂. It was demonstrated that the potency of LC-AgNPs on in vitro cytotoxicity effect on cell lines is lungs > breast cancer in that order. In which, it is proposed that silver nanoparticles could be investigated as therapeutic agents for anticancer agents in the future for the treatment of various cancer types.

Supplementary Information

Below is the link to the electronic supplementary material.

Funding

No funding available for this work.

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.

Declarations

Conflict of interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.