Green Biosynthesis, Antioxidant, Antibacterial, and Anticancer Activities of Silver Nanoparticles of Luffa acutangula Leaf Extract

Studies on green biosynthesis of newly engineered nanoparticles for their prominent medicinal applications are being the torch-bearing concerns of the state-of-the-art research strategies. In this concern, we have engineered the biosynthesized Luffa acutangula silver nanoparticles of flavonoid O-glycosides in the anisotropic form isolated from aqueous leave extracts of Luffa acutangula, a popular traditional and ayurvedic plant in south-east Asian countries. These were structurally confirmed by Ultraviolet-visible (UV-Vis), Fourier transform infrared spectroscopy accessed with attenuated total reflection (FTIR-ATR) spectral analyses followed by the scanning electron microscopic (SEM) and the X-ray diffraction (XRD) crystallographic studies and found them with the face-centered cubic (fcc) structure. Medicinally, we have explored their significant antioxidant (DPPH and ABTS assays), antibacterial (disc diffusion assay on E. coli, S. aureus, B. subtilis, S. fecilis, and S. boydii), and anticancer (MTT assay on MCF-7, MDA-MB-231, U87, and DBTRG cell lines) potentialities which augmented the present investigation. The molecular docking analysis of title compounds against 3NM8 (DPPH) and 1DNU (ABTS) proteins for antioxidant activity; 5FGK (Gram-Positive Bacteria) and 1AB4 (Gram-Negative Bacteria) proteins for antibacterial activity; and 4GBD (MCF-7), 5FI2 (MDA-MB-231), 1D5R (U87), and 5TIJ (DBTRG) proteins for anticancer activity has affirmed the promising ligand-protein binding interactions among the hydroxy groups of the title compounds and aspartic acid of the concerned enzymatic proteins. The binding energy varying from -9.1645 to -7.7955 for Cosmosioside (1, Apigenin-7-glucoside) and from -9.2690 to -7.8306 for Cynaroside (2, Luteolin-7-glucoside) implies the isolated compounds as potential bioactive compounds. In addition, the performed studies like QSAR, ADMET, bioactivity properties, drug scores, and toxicity risks confirmed them as potential drug candidates and aspartic acid receptor antagonists. This research auxiliary augmented the existing array of phytological nanomedicines with new drug candidates that are credible with multiple bioactivities.


Introduction
Phytological origin is the main source for many flavonoids and corresponding flavonoid O-glycosides (FOGs) [1]; these FOGs are proven antioxidant [2], antimicrobial [3], anticancer [4], antiobesity [5], and medicinal agents [6]. The collective advances of FOGs concerning nanotechnology have emerged as a new arena that captivating medicinal researchers to pursue research in it [7,8]. As acclaimed in vivo oxidation being identified as a vital process that spawns the ample energy for the proper execution of biological processes in all organisms, often, it causes the overproduction of free radicals in turn for the cell damage and in turn for the metabolic diseases like diabetes, cardiovascular diseases, cancers, and neurological disorders [9,10]. In its counter administration, antioxidants inhibit the reactive free radicals by neutralizing and arrest the structural disruption of biomolecules in cells [11].
It is profound that excessive usage of antibiotics results in dissemination and emergence of multidrug-resistant strains of several types of microorganisms [31,34]. In this scenario, the needs and demands to discover new medicinal agents are increasing, and nanotechnology paves ways to synthesize NPs to substitute current antibiotics and other synthetic agents. In such, Luffa acutangula (LA), a traditional perennial flowering climber plant, ordinarily stated as ridge gourd regards to Cucurbitaceae family and is enriched with medicinal properties [35] like antioxidant, antidiabetic, antiproliferative, antiangiogenic, anticataleptic, analgesic, antiulcer, and antimicrobial activities [36,37].

Materials and Methods
2.1. Chemistry. Silver nitrate (AgNO 3 ) and 2, 2-diphenyl-1picrylhydrazyl (DPPH) were procured from Sigma (St. Louis, Missouri MO, United States). All the other chemicals were of analytical grade. Human glioma cells (DBTRG and U87) and human breast adenocarcinoma cells (MCF-7 and MDA-MB-231) were procured from the American Type Cell Culture (ATCC). The media, serum, and antibiotics were procured from Gibco™ (Melbourne, Australia).

Collection of Plant Materials.
Fresh leaves of LA were collected from the botanical garden, Department of Botany, Universiti Malaysia Kelantan, Campus Jeli, Malaysia. The collected plant material was rinsed under running tap water to remove all attached materials. The plants and its components have been collected according to the guidelines.

Preparation of Plant Extract and Synthesis of LAAgNPs.
The leaves were shade dried and powdered. Three different concentrations of leaf extracts were prepared (1.0, 2.5, and 5.0%). The mixture was boiled in water bath continuously for 30 min at 100°C and filtered through Whatman No. 1 filter paper, and the same filtrate was used as reducing agent during the nanoparticle synthesis. A stock solution of 1 mM AgNO 3 was prepared. LA leaf extracts (25 mL) were added to 25 mL of AgNO 3 solution in 1 : 1 ratio in the dark conditions. The colour changes and was observed from light colour to dark colour, and the synthesis of nanoparticle was confirmed by using UV-Vis spectroscopy. The solution was centrifuged at 8000 rpm for 10 min. The pellets of formed silver nanoparticles were dried and powdered for further use.

Characterization of LAAgNPs.
The solution that contained colloidal silver nanoparticles was diluted 10 fold using into distilled water. The reduction of pure silver ions was monitored in the range of 200-700 nm in the visible region by measuring the UV-Vis spectrum of the colloidal solution obtained at different functional time. The crystallization nature of the silver nanoparticles was analysed by using XRD crystallography. The functional groups associated with silver nanoparticles analysis were done by FTIR-ATR spectroscopy. The FTIR spectrum was measured at the adsorption range of 500-4000 cm -1 . The particle size was determined by using scanning electron microscope (SEM). The thin layer of synthesised silver nanoparticles was mounted on a copper grid coated with carbon. The extra solution was removed by using blotting paper. Lastly, the  3 BioMed Research International against LAAgNPs concentrations were determined in the form of IC 50 , tamoxifen (5) was used as reference standard for activity against DBTRG and U87cell lines, and gefitinib (6) was used as reference standard for activity against MCF-7 and MDA-MB-231 cell lines.
2.8. Molecular Docking Studies. The potential bioactivity of the two FOG ligands (Cosmosioside and Cynaroside) has been mechanistically investigated from the molecular docking studies by predicting effective interactions against selected proteins. In execution, the protein crystal structures are obtained in PDB form from protein data bank repository and removed the unnecessary bound ligands, cofactors, and water molecules from their vicinity. The .mol2 and .pdb files of the corresponding FOG ligands were generated from ChemBioOffice 14.0 (Chem3D Pro) software and performed docking on SwissDock software [39]. The best outfit interactions optimized with energy minima at a gradient of 0.100 of root mean standard deviation were captured on UCSF Chimera by envisaging the best binding modes [40]. The binding energies of two FOG ligands interacted with the corresponding target protein receptors in chain A of 3NM8 (oxidoreductase, tyrosinase complex) for DPPH antioxidant activity, chain A of 1DNU (oxidoreductase, myeloperoxidase-thiocyanate complex) for ABTS antioxidant activity, chain A of 5FGK (transferase, cyclindependent kinase 8 associated with cyclin C) for gram positive bacteria (B. subtilis, S. aureus, and S. felicis in the current study), chain A of 1AB4 (topoisomerase, the N-terminal 59 kDa fragment of Gyrase A) from gram negative bacteria (E. coli and S. boydii in the current study), chain A of 4GBD (lyase, adenosine deaminase complex) for MCF-7 anticancer activity, chain C of 5FI2 (hydrolase, kidney glutaminase isoform C complex of UPGL 00009 inhibitor) for MDA-MB-231 anticancer activity, chain A of 1D5R (hydrolase, PTEN tumor suppressor) for U87

BioMed Research International
is <4 is poor permeable, value in the range of 4-70 is moderately permeable, and value >70 is extremely permeable and is certainly transported to cellular cite in the biochemical processes. Furthermore, the degree of plasma protein binding (PPB) influences the level of distribution of compound unbound in body tissues and infers about unbound quantity of the compound that has been distributed in the active cellular sites and then stimulated further to metabolize and then excreted from the system. The in vitro PPB percentage > 90% classifies the compounds under study as strongly bound and in vitro PPB percentage < 90% classifies the compounds under study as weakly bound and eventually replicates its action as well as proficiency. In addition, the MDCK cell system is considered as a sensible tool to predict the prompt permeable compounds and determine their capability as greater the life span of Caco-2 cells than the cellular life span consequences for its high correspondence.
Here, the compounds with in vitro MDCK permeability value < 25 are poor permeable, and compounds with in vitro MDCK permeability value in the range of 25-500 are good permeable. In addition, the percentage of HIA is considered as the percentage of an orally administered compound with significant bioavailability into the hepatic portal vein by absorption in relation to total content that excreted through bile, urine, and feces. Compounds with the percentage of HIA in the range of 0-20 are of identified with poor absorbance, 20-70 are of identified with moderate absorbance, and 70-100 are of identified with good absorbance. The consideration of toxicology properties of a compound with its structure greatly helps to design them with bioactivity. The negative toxicology value of a compound affords it as a safer drug works against mutagenicity, carcinogenicity,    2.12. Statistical Analysis. The results were expressed as the mean ± standard deviation of triplicates. Statistical analysis was performed using one-way analysis of variance (ANOVA) followed by Tukey's test. P < 0:05 was considered statistically significant.

Results and Discussion
3.1. Chemistry 3.1.1. Observation of Colour Changes of Silver Nanoparticles. The colour of LA leaf extract was changed from light colour to brown colour ( Figure 2), indicating the synthesis of silver nanoparticles. The noticeable colour change in LA leaf extract was mainly due to the reduction of Ag + ions to Ag 0 atoms (Equation (2)). Bounteous biomolecules present in the leaf extracts act as natural reducing agents and the reduction reaction can be summarised as follows.
In this connection, previous studies showed similar colour changes to form dark brown colour [21,46,47]. It was confirmed that concentrations of plant extracts are one of the significant aspects that influence the rate of synthesis of silver nanoparticles. Higher intensity of colour was spotted as the concentrations increased from 1.0, 2.5, and 5.0%. This could be a result of higher content of the biomolecules that reacted as reducing agents in silver reduction process. Uniform results had also been noticed in the leaves of Luffa acutangula in synthesising silver nanoparticles [22].

UV-Vis Spectral Studies of LA Silver Nanoparticles.
Time interval to measure the absorption peak was 30-     There are no qualms that silver nanoparticles achieved the highest peak as cause of Surface Plasmon Resonance (SPR) adsorption band. Free electrons of biologically synthesised silver nanoparticles promote the generation of SPR band through coalescing the vibrations of electrons in resonance with the light wave [48]. The aspects like size and shape of the nanoparticles, type of biomolecules existing in the plant extracts, silver nitrate concentration, and amount of extracts have influenced the SPR banding patterns.
3.1.3. XRD Analysis. X-ray diffraction analysis is an advanced method to figure out the crystalline nature of metallic nanoparticles. As shown in Figure 4, the peaks at 2θ values of 38°, 44°, 64°, and 77°are reflecting (111), (200), (220), and (311) lattice plans for silver, respectively. The present result clearly illustrates that the biologically synthesised silver nanoparticles are in crystalline nature and face-centered cubic (fcc) shape. The studies on carob and olive leaf extract confirmed the shape of the synthesised nanoparticles as fcc [49,50]. Debye Scherrer's equation (Equation (3)) was used to calculate the average particular size of the silver nanoparticles synthesised by present biological method, where β is the full width at half maximum of the diffraction peak, t is the mean crystalline size, θ is the centre angle of the peak, and λ is the wavelength of X-ray source. The recognized crystalline size of LAAgNPs is 44 nm. This clearly illustrates that LAAgNPs is nanocrystalline shape. Similar results have been reported on the biologically synthesised AgNPs using Pulicaria glutinosa plant extract showed average crystalline size of 42 nm [13].       The interaction between biologically synthesised nanoparticles and biological molecules of aqueous leaf extracts of LA can be understood from the FTIR-ATR spectrum. In Figure 5, the absorption peaks at 3030.73 and 2970.97 cm -1 represent the O-H groups in alcohols, phenols, and C-H stretching of alkenes amide I or proteins [26]. Band appearing at 2383.51 and 2349.20 cm -1 denotes C-O groups. Further, the adsorption peaks at 2298.3 and 1508.31 cm -1 reflect the functional groups of -C=C-group and C=C of amide II groups, respectively 12 . Specific IR bands at 1366.08, 1152.67, 1229.28, and 1217.29 cm -1 attribute to C-H alkenes and C-N stretching vibration of aliphatic amines, respectively [26]. Absorption peaks at 1016.18 and 672.32 cm -1 assign the presence of ether linkage and aromatic hydrocarbon [51,52]. A similar result was reported for phenols, flavonoids, alkaloids, and proteins in plant extracts lead to stabilization and synthesis of AgNPs [50]. In the present study, the stretching vibrations of silver nanoparticles of LA indicated different proteins and terpenoids in aqueous extracts and enhanced the bioreduction of Ag ions. A previous study reported that LA leaves possess numerous molecules such as alkaloids, flavonoids, saponins, and glycosides [53]. These functional groups in aqueous leaf extracts of LA facilitate capping and reduction process of Ag ions. In the present study, the stretching vibrations of green mediated synthesised silver nanoparticles using LA indicated different proteins and terpenoids in aqueous extracts and enhanced the bioreduction of Ag ions. A previous study reported that LA leaves possess numerous molecules such as alkaloids, flavonoids, saponins, and glycosides [53]. These functional groups in aqueous leaf extracts of LA facilitate capping and reduction process of Ag ions.
3.1.5. SEM Analysis. The biosynthesised LAAgNPs were morphologically visualized on scanning electron microscopy (SEM) and identified as uniform and spherical in shape with 10 μm size under 7000× magnification ( Figure 6). However, the structure of all the AgNPs could be observed more clearly at higher magnification. Further, the overall SEM image is attributed due to electrostatic interaction between bioorganic capping molecules attached on the AgNPs surface. Several factors such as aggregation of the smaller ones and SEM measurements could influence the formation of larger AgNPs [11].  Figure 7). A similar result was reported for the biosynthesised AgNPs from Syzygium cumini (L.) seed extract exhibited high DPPH free radical scavenging activity [11] compared to Argemone mexicana and Turnera ulmifolia seed extracts [55]. The present data is in accordance with the result reported for the biosynthesised AgNPs from aqueous leaf extracts of Terminalia mellueri, Terminalia catappa, Terminalia bellerica, and Terminalia bentazoe showed high DPPH free radical scavenging activity (more than 80%) compared to leaf extracts in the range of 60%-70% [56]. The values represented are the mean ± S:D of triplicate sample significant level at (P < 0:05). The IC 50 values of LA and LAAgNPs were 126.29 μg/mL and 96.89 μg/mL. The lower IC 50 values indicate the greater tendency for antioxidant activity of the extracts. Similar activity was reported for the lower IC 50 value of Psidium guajava extract and AgNPs from Psidium guajava was 110 μg/mL and 80 μg/mL, respectively [57].

ABTS Antioxidant Assay.
In the present study, ABTS free scavenging test was analysed on AgNPs and leaf extract of LA. ABTS +· is considered as protonated radical which could readily accept electron from antioxidant compound and transfer its colour from blue to pink which was detected at 734 nm [58]. The leaf extract of LA showed the potential to scavenge the free radicals was found to be 43.8-82.9% at concentrations from 50-300 μg/mL, respectively, whereas biologically synthesised AgNPs showed the activity as 47.9-85.2% at different concentrations from 50-300 μg/mL, respectively (Figure 8). The values represented are the     [57]. Similar ABTS radical scavenging action of biologically synthesised AgNPs was found in previous studies [59,60].

Antibacterial Activity.
There are no qualms that silver and silver-based compounds are the potential antibacterial or antimicrobial agents [61]. It has become compulsory to produce the safer substitutes for the currently available antimicrobial agents and also the antibiotics due to the high multidrug resistance problems [62]. The synthesis of metallic nanoparticles from the biological sources with potential antibacterial or antimicrobial properties has opened up a new avenue against multidrug resistance bacteria.
In the current study, human pathogenic microorganisms such as B. subtilis, S. aureus, S. faecilis, E. coli, and S. boydii were chosen to study the antibacterial efficacy of biologically synthesised silver nanoparticles. LA leaf aqueous extracts expressed potential antibacterial effect against both Grampositive and Gram-negative bacterium. LA leaf extract expressed the highest inhibition which was seen in S. faecilis with 7.9 mm diameter, followed by S. boydii (7.6 mm), S. aureus (7.6 mm), E. coli (7.4 mm), and B. subtilis (7.2 mm). Moreover, biologically synthesised AgNPs revealed that the antibacterial efficacy of LA leaf extract was enhanced by inducing a higher zone of inhibition against the tested microorganisms. The silver nanoparticles from LA showed the highest inhibition against E. coli, Gram-negative bacteria. The zone of inhibition was recorded as 11.5 mm. Similarly, LA leaf-mediated silver nanoparticles did express high anticidal property by suppressing the growth of other microorganisms, B. subtilis (10.9 mm), S. aurus (10.8 mm), S. boydii (10.7 mm), and S. faecilis (10.5 mm) (Figure 9). Ampicillin was chosen as standard and positive control in this study. Ampicillin performed the highest inhibitory effect against all tested microorganisms compared to LA leaf extract and synthesised AgNPs.
The present study proved that gram-negative bacteria, E. coli, were more sensitive to the action of biologically synthesised silver nanoparticles compared to gram-positive bacteria. This is in accordance with the result stated by Kim and the coworkers [63]. Literature denoted the inhibitory effects of silver nanoparticles could be associated with characteristics of specific bacterial species. Naturally, gram-positive and gram-positive grouped bacteria have dissimilar membrane structure, especially the difference in thickness of peptidoglycan layer. The mild antibacterial features of synthesised silver nanoparticles in contradiction of grampositive bacteria could be due to membrane structure [63]. The antibacterial mechanism of action of metallic nanoparticles is still not exactly explained and being unverified. However, several theories and possible mechanism(s) of actions of biologically and chemically synthesised silver nanoparticles have been reported with basic information [64]. The graphic representation ( Figure 10) depicts the penetration of silver nanoparticles (AgNPs) into the cell and their different mode of antibacterial mechanisms. The reactivity begins with synthesis of silver nanoparticles using silver nitrate and selected plant extracts.
3.4. Anticancer Activity. Plants contain several types of bioactive compounds that are ideally favorable for the drug development in anticancer therapy. Nowadays, researchers found that the plant-based medicines or drugs are safer and cost-effective when compared to the synthetic drugs [65]. LA is one of the herbal plants which belongs to a family of Cucurbitaceae and widely cultivated in Asia, India, Brazil, and USA [66]. Previously, itself isolated five major components of LA, a bioactive component among them named 1,8 dihydroxy-4-methylanthracene 9,10-dione (DHMA) was reported as potential antiproliferative agent against nonsmall cell lung cancer cells (NCI-H460). DHMA showed promising anticancer activities through inhibition of cell growth, generation of reactive oxygen species (ROS), and induction of p53-mediated apoptotic pathway against human nonsmall cell lung cancer cell line (NCI-H460) [67,68]. Another study reported on the potential anticancer effect of LA on human colon cancer cell line HT29 cells [69]. LA seeds consist of ribosome inactivating proteins which were reported, and the study revealed the potential   BioMed Research International anticancer activity of luffaculin 1 and luffaculinin in human leukemia K562 cells [70]. Anticancer effects of AgNPs have been demonstrated in various cell models. It observed a dose-dependent cytotoxic effect of biosynthesized AgNPs from Piper longum extract in MCF-7 breast cancer cells [71]. Cytotoxic effects of AgNPs from other plant extracts such as Iresine herbstii and Vitex negundo Linn were demonstrated in HeLa (cervical) and HCT15 (colorectal) cancer cells, respectively [9,25]. In the present study, LAAgNPs were tested against four human cancer cell lines, MCF-7, MDA-MB-231, DBTRG, and U87. The synthesised silver nanoparticles by LA leaf extract triggered a dose-dependent reduction in the cell proliferation with IC 50 values ranging from 35-42 μg/ml ( Figure 11). There are several anticancer mechanisms that have been suggested based on previous studies. AgNPs tend to generate reactive oxidative species (ROS) intracellularly that results excess oxidative stress [72]. High oxidative stress inhibits chromosome inhibition and eventually damage cell cycle of tumor cells [73,74]. Size independent property of AgNPs enhances cytotoxic effect against drug-resistant cancer cells [75]. In addition, cytotoxic effect can be as the result of poor angiogenesis and programmed cell death by AgNPs [76]. Further studies are needed to interpret the anticancer mechanism(s) of the biosynthesized AgNPs. In view of antioxidant activity, the hydroxy groups (-OH) of FOGs bound with carbonyl groups (O=C) of aspartic acid and amino groups (-NH) of arginine in 3NM8 (Chain A) are responsible for DPPH radical scav-enging activity; and binding of -OH of FOGs bound with O=C of aspartic acid and alanine, -NH of arginine, and -OH of tyrosine in 1DNU (Chain A) is responsible for ABTS radical scavenging activity. Concerning the antibacterial activity, the -OH of FOGs bound with C=O of aspartic acid, valine and glutamic acid, and -NH of aspartic acid and lysine in 5FGK (Chain A) is responsible for gram-positive bacterial activity; and binding of -OH in FOGs with C=O of aspartic acid, glutamine, histidine and phenyl alanine, and -NH of glutamine and lysine in 1AB4 (Chain A) is responsible for gram-negative bacterial activity. In relation to MCF-7 anticancer inhibition, the -OH of FOGs bound with C=O of aspartic acid and lysine, and -NH of arginine and isoleucine in 4GBD (Chain A) were identified as responsible. Coming to MDA-MB-231 anticancer inhibition, the -OH of FOGs bound with C=O of aspartic acid, cysteine and serine, -OH of tyrosine and glutamic acid, and -NH of asparagine in 5FI2 (Chain C) was identified as responsible.
Concerning the U87 anticancer inhibition, the -OH of FOGs bound with C=O of aspartic acid, and -NH of lysine, and tyrosine and arginine in 1D5R (chain A was identified as responsible). In aspects of DBTRG anticancer inhibition, the -OH of FOGs bound with C=O of aspartic acid and glutamic acid, -OH of glutamic acid and serine, and -NH of aspartic acid and serine in 5TIJ (chain B) was identified as responsible. The binding specificity studies have affirmed the promising ligand-protein binding interactions in between the hydroxy groups of the FOGs and aspartic acid of the concerned enzymatic proteins with a binding energy in the range of -9.2690 to -7.7955 KCal/mol. 3.6. ADMET Properties. The study of ADMET properties of the interested analytes under investigation helps to realize their physicochemical interactions [77]. The potentiality of a drug depends on its degree of absorption and in turn on its inherent bioavailability properties. Once a potential drug be absorbed and self-distributed in to muscles and organs by circulation through extracellular sites and hence lowers its plasma concentration individually, therefore, metabolizes in vivo, then, such metabolites will be distributed by the action of reduction and oxidation reactions by the enzymatic action and work potentially on cellular systems, and    3.8. Bioactivity and Toxicity Risk Studies. The bioactivity and toxicity risk exploration studies of the FOGs have shown their bioactivity properties viz., GPCR ligand property, ion channel modulator, kinase inhibitor, nuclear receptor ligand interactions, protease inhibitor, and enzyme inhibitor interactions; and the drug properties like drug-likeness and drug score and established as potential nontoxic drugs (Table 15). This molinspiration exploration comprehensively assists us to explore the cheminformatics of the molecules under investigation by correlating with the in vitro and in vivo results database of the recognized drugs basing on the functional group similarities in mutual. The drug property exploration of the two FOGs has evidenced for their safer drug properties as they are with no risks of tumorigenicity, irritant effects, mutagenicity, and shown no effect on reproductive system. The positive magnitude of the drug-likeness value represents that the scrutinized molecule comprises the significant fragments that are present in the established commercial drugs [45]. Drug-likeness is an significant factor which helps in understanding the kinesis of a molecule from the site of administration to the bloodstream, hence, its good solubility accounts for good absorption and assures the drug-likeness [80]. Similarly, drug score is also a complementary parameter of the drug-likeness and helps to assure to decide molecule's drug potentiality. Hence, the present investigation reveals that all the properties of the bioactivity    Blood − brain barrier ðBBBÞ penetration = ½brain/½blood; b Caco-2 cells are derived from human colon adenocarcinoma and possess multiple drug transport pathways through intestinal epithelium; c % of drug binds to plasma protein; d MDCK cell system used as tool for rapid permeability screening; e human intestinal absorption is the sum of bioavailability and absorption evaluated from ratio of excretion or cumulative excretion in urine, bile, and feces; f in vitro Ames test by metabolic and nonmetabolic activated TA100 and TA1535 strains collected from rat liver homogenate.  density (gm/cc). 24 BioMed Research International and toxicity risk studies are up to the potential limits of the safe drugs and ascertains the FOGs as the drug-like compounds.

Conclusions
Luffa acutangula is one of the regularly used plants with various secondary metabolites such as polyphenols and flavonoids, which possesses biological and pharmacological activities. Here in this study, the aim is to test the biogenically synthesised nanoparticles for their biological activities including antibacterial, antioxidant, and anticancer activities. The results revealed that the silver nanoparticles of Luffa acutangula leaf extract enriched with its inherent flavonoid O-glycosides (FOGs, viz., Cosmosioside (1, Apigenin-7-glucoside) and from -9.2690 to -7.8306 for Cynaroside (2, Luteolin-7-glucoside)) prepared by green biosynthetic approach. The biogenically synthesised silver nanoparticles found to be significant against bacteria and cancer cell lines which clearly show antibacterial and anticancer activities. Antioxidants play an important in reducing the oxidative stress and diminishing the growth of the cancerous cell. The results showed that AgNPs showed potential antioxidant activity. The profound studies performed based on the molecular docking analysis have revealed that the FOGs are identified as antagonists of aspartic acid receptor of enzymatic proteins referenced based on the microorganisms, cell lines, and oxidizing agents considered for the in vitro studies. Furthermore, QSAR, ADMET properties showed them as prospective drugs. The results validated that AgNPs could be potential agents to treat various types of cancers and boosting the immune system functions. Never-theless, future studies with in vivo toxicological studies with clear mechanism of action and the pharmacodynamics studies of LAAgNPs would shed the light more thoroughly to show the possible mechanisms for anticancer activities.

Data Availability
The data has been included in the manuscript.

Conflicts of Interest
The authors declare that there are no conflicts of interest.