Rapid synthesis of copper nanoparticles using Nepeta cataria leaves: An eco-friendly management of disease-causing vectors and bacterial pathogens

Mahendrakumar Mani; Aruna Sharmili Sundararaj; Khalid A. Al-Ghanim; Shiny Punalur John; Kuppusamy Elumalai; Marcello Nicoletti; Marimuthu Govindarajan

doi:10.1515/gps-2023-0022

Article Open Access

Rapid synthesis of copper nanoparticles using Nepeta cataria leaves: An eco-friendly management of disease-causing vectors and bacterial pathogens

Mahendrakumar Mani , Aruna Sharmili Sundararaj , Khalid A. Al-Ghanim , Shiny Punalur John , Kuppusamy Elumalai , Marcello Nicoletti and Marimuthu Govindarajan

Published/Copyright: May 31, 2023

Published by

Become an author with De Gruyter Brill

Submit Manuscript Author Information

From the journal Green Processing and Synthesis Volume 12 Issue 1

Abstract

Insecticides kill mosquitoes but damage other animals including humans. Eco-friendly metal nanoparticles may be a plant-based pesticide for vector control. Here, the copper nanoparticles (Cu NPs) synthesized from Nepeta catarialeaves have been investigated for their antibacterial and larvicidal properties. Fourier transforms infrared spectroscopy demonstrated that biochemicals reduced and stabilized nanoparticles by shifting peaks from 1,049 to 1,492 cm⁻¹, and ultraviolet–visible spectrometry proved that produced Cu NPs had a peak at 550 nm. Transmission electron microscopic and scanning electron microscope showed that the particles are spherical and 23–29 nm in size. X-ray diffraction analysis shows that Cu NPs are crystalline. At a 100 µg·mL⁻¹ concentration, Cu NPs exhibited a higher percentage of inhibition in the order of Escherichia coli ≫ Enterococcus faecalis ≫ Staphylococcus aureus. The lethal concentration (LC₅₀) of the Cu NPs against the larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus was determined to be 60.63, 56.58, and 54.32 µg·mL⁻¹, respectively. This ground-breaking study describes the biological production of Cu NPs utilizing N. cataria leaf extract for the first time. Based on these findings, the bio-synthesized Cu NPs and the aqueous extract of N. cataria may provide a potential alternative method for managing these vector populations.

Graphical abstract

Keywords: biosynthesis; copper nanoparticles; larvicidal efficacy; microbial pathogens; vector control

1 Introduction

Nanotechnology deals with controlling and manipulating matter at the molecular level between 1 and 100 nm. This field leads to the development of discrete properties collated with those related to atoms or molecules or bulk behaviour [1]. In the expanding field of nanotechnology, physical, chemical, and even ecologically friendly biological processes might all be employed to create nanomaterials. Chemical methods of generating nanoparticles (NPs) need the unrestricted use of harmful compounds, polluting the environment [2]. The biologically mediated processes can be conceded using bacteria, fungi, yeast, actinomycetes, and viruses [3,4,5]. Green synthesis based on the extraction of plant extracts has been reported in the literature [6,7,8]. Plant-based approaches are one of the most cost-effective, safe, and environmentally friendly ways to produce NPs [9]. The plant-mediated biosynthesized NPs are also steadier and can be synthesized faster than other synthesis methods [10].

Metallic NPs have been used in drug delivery, cancer treatments, wastewater treatment, DNA analysis, solar energy production, catalysis, and biosensing. Green synthesis can produce metallic NPs cheaply and ecologically. This strategy beats chemical and physical activities. Researchers have studied copper nanoparticles (Cu NPs) for their many health applications. Cu NPs are popular in biological applications due to their antibacterial, optical, catalytic, and electrical capabilities. The small size of Cu NPs also makes them an ideal drug delivery system, allowing for better control and release of anticancer drugs while avoiding toxicity to normal cells. By using Cu NPs as a therapeutic agent, cancer cells can be targeted and eliminated much more efficiently, with minimal toxicity to healthy cells. The NPs can also be conjugated with other molecules, such as antibodies and peptides, to increase their specificity and efficacy against various types of cancer [11].

In recent clinical trials, copper-based NPs have been particularly effective in treating prostate, lung, and various types of breast cancer. Despite the potential benefits of Cu NPs as a therapy for multiple cancer types, much research and development are still needed. There are still unanswered questions surrounding their toxicity, especially in the long term, as well as their effectiveness in targeting a broad range of cancers. However, with ongoing research and innovations in nanotechnology, the potential of Cu NPs in the fight against cancer is undeniable. Nanotechnology has become essential in many industries, including biomedical, consumer products, and biotechnology. NPs are at the core of nanotechnology, and their unique properties offer numerous possibilities for various applications in different fields. Due to their small size, NPs can penetrate biological systems, increasing their potential benefits for human health. One of the significant research areas in NP development is using plant-based materials for their synthesis. The natural abundance of plant materials, their biodegradability, and the sustainable production process make them an attractive choice for NP synthesis. However, despite these advantages, plant-based NPs do have limitations. One critical limitation is the controlled synthesis of NPs. Controlling the particle size and morphology when synthesizing NPs from plants can be challenging. Particle size is crucial in determining the NP’s properties, such as toxicity, absorption, and drug-delivery efficiency. In addition, the particle size distribution of plant-based NPs is less uniform than those synthesized from synthetic materials. The second limitation is the low yield of NPs synthesized from plant extracts. The number of active NPs synthesized can be low, limiting their ability to be used in many applications. This low yield is due to the difficulty in accurately extracting and purifying plant compounds needed to synthesize NPs. The third limitation concerns the biocompatibility of plant-based NPs. The biocompatibility of NPs is the ability of the NPs to interact with biological systems without causing harm [12,13,14].

Plant-based NPs may cause cell toxicity, altering cell function and inducing cytotoxicity. The NP’ surface chemistry is significant in their biocompatibility and obtaining the required chemistry for plant-based NPs can be challenging. The fourth limitation is the stability of plant-based NPs in aqueous media. When synthesized, these NPs tend to aggregate, reducing their surface area and interfering with their physicochemical properties. Additionally, the NP’s stability in biological media, such as serum or plasma, is a significant concern due to the potential for particle deposition in tissues or incorrect cell uptake. Finally, plant-based NPs may have limitations in terms of scalability and reproducibility. Several factors influence the NP synthesis process’s reproducibility, including batch-to-batch variations in plant materials, extraction methods, and purification procedures. Also, plant-based NPs have several advantages: sustainability, biodegradability, and low cost. However, the above-mentioned limitations must also be considered when evaluating their use in various applications. Overcoming these limitations may require further research, including new NP synthesis, characterization, and functionalization approaches. Despite these challenges, plant-based NP technology holds significant promise for numerous applications in various fields, including medicine, biotechnology, and sustainable development [15,16,17].

Plants include a wide variety of bioactive chemicals. For this reason, numerous plant components and even whole plants have been used in the ecofriendly synthesis of copper NPs [18]. This kind of manufacturing is sometimes referred to as “green production.” There is evidence to suggest that plant extracts may aid in accomplishing this goal. Extracts from various plant species have successfully synthesized Cu NPs [19,20,21].

The plants in the Lamiaceae family, comprising roughly 250 species, have square stems and fragrant leaves. The glandular leaves are located successively at right angles to one another [22]. People have used Nepeta species from time immemorial for various ailments. Varied biological activities like insect repellent [23] and defense against arthropods [24,25] are accredited to the presence of many bioactive phytochemicals present in Nepeta species [26]. According to reports, Cu NPs are harmless, biocompatible, and devoid of hazardous substances. In this research, the Cu NPs were derived from an aqueous leaf extract of N. cataria, and the antibacterial activity of Cu NPs was tested against Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus. Moreover, the larvicidal efficacy of synthesized Cu NPs was tested using Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus mosquitoes, all of which transmit disease.

2 Materials and methods

2.1 Plant sample collection and processing

Mature N. cataria leaves were gathered from Nandanam (12.9929°N, 80.2219°E), India. The plant identification and authentication were made as N. cataria by Prof. Dr. P. Jayaraman of the PARC Centre, Tambaram, Chennai. Herbarium specimen voucher (GAC/BOT/2017/HERB/24) placed in the Department of Botany herbarium, Government Arts College (Men), Nandanam, Chennai. N. cataria leaves were hand-washed with running tap water and then in double-distilled water to remove any remaining dirt or particles before being air-dried at room temperature (27°C) in the shade. Following final drying, the leaves were crushed into a coarse powder. An aqueous extract was collected and kept at 4℃ for further analysis using the Soxhlet approach.

2.2 Characterization of phytochemical constituents

The preliminary phytochemical analysis of the aqueous extract of N. cataria was carried out to identify the phytochemical constituents per the established protocols [27].

2.3 Nepeta cataria extract-based Cu NP synthesis.

Green synthesis of Cu Nps using N. cataria leaves that had been previously dried. A conical flask containing 100 mL of distilled water and 5 g of dried leaves was heated to 90°C for 10 min. Once clear, the solution was centrifuged and chilled before being added to another conical flask containing 100 mL of 10 mM copper sulfate solution and heated to 100°C for 15 min. After 30 min of heating at 100°C, the pH of the solution was adjusted to 12 using 2 M sodium hydroxide. The light blue to red wine colour change indicates the synthesis of Cu NPs. The formed mixture containing Cu NPs was centrifuged at 10,000 × g for 20 min. It was then washed with deionized water, then twice with 70% ethanol, and again with deionized water, and the obtained pellet was dried at room temperature [28]. The obtained Cu NPs were used for further studies.

2.4 Cu NP characterization

An ultraviolet–visible (UV–Vis) spectrophotometer (ELICO SL-159) was used to study the Cu NPs of N. cataria across the wavelength range of 300–700 nm to determine their optical properties. Utilizing the Panalytical X’pert powder XRD instrument, the nature of the Cu NPs was analyzed. Using a Bruker Fourier transform infrared (FT-IR) spectrometer, we characterized the functional groups of Cu NPs and identified potential phytochemical components responsible for their attenuation and stabilization. The morphology of the synthesized Cu NPs was studied using a TESCAN-VEGA3 SBU-type scanning electron microscope (SEM). Transmission electron microscopy (TEM) was used to quantify the size of the Cu NPs.

2.5 Bacterial cultures

The antibacterial activity was tested on stock cultures of three different harmful bacteria: Escherichia coli (ATCC25922), Enterococcus faecalis (ATCC29212), and Staphylococcus aureus (ATCC25923). The pure bacteria cultures were kept alive and maintained on slants made of nutritional agar. An aliquot of the bacterial culture was used to inoculate the nutrient broth in the test tubes, and the tubes were then placed in an incubator at 37°C for 24 h.

2.6 Assessment of the antibacterial potential of Cu NPs

The agar well diffusion method determined the synthesized Cu NPs’ antibacterial properties [29]. A sterile cork borer was used to create the wells, and 100 μL of bacterial suspension was seeded onto the plate. The stock solution of 100 μg·mL⁻¹ of Cu NPs was prepared, and from it, 100 μL of Cu NPs was added to the well. Similarly, 100 μL of aqueous extract was added to the well. The positive control employed was Streptomycin. For 24 h, the plates were kept at 37°C. Using green synthesized Cu NPs to measure the width of the inhibitory zone (mm), the antibacterial activity against each test microorganism was evaluated. Triplicates were performed for all the tests.

2.7 Rearing of the mosquitoes

The Ae. aegypti larvae were collected from broken bottles and small watercourses at Velachery, Chennai. An. stephensi and Cx. quinquefasciatus mosquito larvae were collected from the Pallikaranai wetlands and identified by Dr. S. Prabakaran, Zonal Director of the Zonal Scientific Institute in Chennai. Raising the larvae of all mosquito vectors in plastic trays containing water was necessary. Following the methodology established by the WHO [30], the environment was kept in a laboratory setting.

2.8 Larvicidal activity

The mosquito species Ae. aegypti, An. stephensi, and Cx. quinquefasciatus had their third instar larvae tested to determine whether the aqueous leaf extract of N. cataria and Cu NPs efficiently controlled them. The bioassay was conducted in clear cups with a capacity of 250 mL, and five replications were kept. The ten freshly moulted third instar larvae of mosquitoes were introduced in respective concentrations of plant extract (100, 200, 300, and 400 µg·mL⁻¹). The results were observed and recorded after the treatment of 24 and 48 h. The LC₅₀ value was determined by using probit analysis [31]. The LC₅₀ and LC₉₀ values and other statistics, such as χ ² values, were computed using SPSS, and the significance threshold was set at p ≤ 0.05.

(1) Corrected mortality = Observed mortality in treatent − Observed mortality in control 100 − Control mortality × 100

(2) Percentage mortality = Nuber of dead larvae No . of larvae introduced × 100

2.9 Statistical analysis

The one-way analysis of variance (ANOVA) was performed using the statistical programme StatPlus 2009 Professional and Tukey tests to fix the substantial zone differences. MS Excel 2007 was used to analyse the obtained data and presented as mean ± SD of three replicates. The mean was considered statistically significant at p < 0.05.

3 Results and discussion

3.1 Phytochemical characterization

The phytochemical profile of N. cataria is shown in Table 1. Aqueous extract of N. cataria was found to have the majority of the necessary phytochemicals. The aqueous extract of N. cataria includes flavonoids and polyphenols, which are believed to be responsible for N. cataria’s biological activity.

Table 1

Analysis of the phytochemical properties of N. cataria extract

Test for phytochemicals	Results
Alkaloids	++
Flavonoids	++
Steroids	+
Phenol	++
Tannins	++
Phlobatannins	—
Terpenoids	+
Glycosides	+
Coumarins	+
Saponins	—

Strongly present (++), noticeable (+), and absent (−).

3.2 Green-synthesized Cu NPs characterization

3.2.1 UV–Vis spectrophotometric analysis

A color change was observed after the N. cataria leaf extract interacted with the salt solution under specified conditions. The formation of a red wine colour indicated that copper chloride had been reduced to NPs. The surface plasmon resonance shown by the produced NPs may be identified by the sharp peak located at 550 nm (Figure 1).

Figure 1

UV–Vis Spectrum of Cu NPs synthesized with aqueous N. cataria leaf extract.

3.2.2 FT-IR spectroscopic analysis

The organic compounds that mediated the NP reduction and stabilization were studied using FT-IR spectroscopy, as indicated in Figure 2. The peak shifts were observed from 3,419 to 3,425 cm⁻¹ due to the collaboration between OH⁻ groups of the phenolics present in the plant leaf extract with the copper ions. A change in the peaks was observed at 1,451–1,492 and 1,049–1,114 cm⁻¹, implying the interaction between the aromatic stretch (C═C–C) and C–O section of the phytochemicals indicates the pivotal role of the organic compounds in the synthesis. The disappearance of the peaks found in extract A in the fingerprint region, including 875, 772, and 774 cm⁻¹, indicates the biological molecules’ role in reducing and stabilizing the NPs.

Figure 2

FTIR Spectrum: (a) leaf extracts of N. cataria leaves; (b) Cu NPs.

3.2.3 SEM evaluation

The architecture of the synthesized NPs was found to be spherical, as indicated in Figure 3. The well-defined spherical nature of the NPs demonstrates that they are stable.

Figure 3

SEM image of Cu NPs.

3.2.4 TEM analysis

The bioengineered Cu NPs’ TEM examination showed spherical-shaped NPs, as shown in Figure 4. It was discovered that the NPs had a particle size that fell somewhere in the region of 23–29 nm.

Figure 4

TEM image of Cu NPs.

3.2.5 XRD analysis

Figure 5 displays the generated Cu NPs’ XRD pattern. The peaks noticed at 2θ values 43.6°, 50.8°, and 74.5° were indexed as (111), (200), and (220), respectively. The XRD pattern reveals that the Cu NPs were crystalline.

Figure 5

XRD spectrum of synthesized Cu NPs using aqueous leaf extract of N. cataria.

3.3 Antibacterial activity

Figure 6 displays the bactericidal effectiveness of the synthesized Cu NPs. When evaluated at a 100 µg·mL⁻¹ concentration, the NPs demonstrated the highest percentage of inhibition against Escherichia coli, followed by Enterococcus faecalis, and finally, Staphylococcus aureus. The zone of inhibition for E. coli was measured at 30 mm, whereas for En. faecalis was 21 mm, and that for S. aureus was 11 mm.

Figure 6

Synthesized Cu NPs with aqueous leaf extract of N. cataria have antibacterial activity against selected microorganisms.

3.4 Larvicidal activity

The extract of N. cataria displayed maximum larvicidal efficacy at the concentration of 400 ppm against Ae. aegypti (96.33%), An. stephensi (97.33%), and Cx. quinquefasciatus (95.77%), as mentioned in Table 2. It was noted that the LC₅₀ was found at 216.029 ppm against Ae. aegypti with the LC₉₀ of 372.136 µg·mL⁻¹. In the same way, the LC₅₀ value was found at 211.226 µg·mL⁻¹ against An. stephensi with the LC₉₀ value of 359.03 µg·mL⁻¹. Similarly, the LC₅₀ value was found at 215.640 µg·mL⁻¹ against Cx. quinquefasciatus with the LC₉₀ value of 377.548 µg·mL⁻¹.

Table 2

The larvicidal activity of aqueous extract of N. cataria against third-instar vector mosquito larvae

Mosquito species	Concentration (µg·mL⁻¹)	Mortality*	LC₅₀ (LCL–UCL)	LC₉₀ (LCL–UCL)	χ ²
Aedes aegypti	100	22.33	216.029 (from 112.91 to 296.54)	372.136 (from 292.95 to 690.04)	6.108
	200	36.66
	300	73.99
	400	96.33
Anopheles stephensi	100	21.66	211.226 (from 193.62 to 227.95)	359.03 (from 333.89 to 392.40)	5.437
	200	38.33
	300	76.99
	400	97.33
Culex quinquefasciatus	100	24.99	215.640 (from 31.124 to 361.946)	377.548 (from 279.18 to 1,527.05)	10.124
	200	33.66
	300	74.33
	400	95.99

* Five replications’ mean ± S.D.

The Ae. aegypti larvae, when treated with Cu NPs, exhibited an LC₅₀ value of 60.63 µg·mL⁻¹ and LC₉₀ value of 100.48 µg·mL⁻¹ against Ae. aegypti; similarly, LC₅₀ of 56.58 µg·mL⁻¹ and LC₉₀ value of 97.76 µg·mL⁻¹ were found to be against An. stephensi. When tested against Cx. quinquefasciatus, they showed an LC₅₀ value of 54.32 µg·mL⁻¹ and LC₉₀ 91.63 µg·mL⁻¹ as mentioned in Table 3.

Table 3

Percent corrected mortality of Cu NPs of N. cataria on the third instar larvae mosquitoes

Test organism	LC₅₀ (LCL–UCL)	LC₉₀ (LCL–UCL)	χ ² value
Aedes aegypti	60.63 (32.59–88.43)	100.48 (77.87–221.66)	7.53
Anopheles stephensi	56.58 (24.8–82.38)	97.76 (75.27–220.71)	7.26
Culex quinquefasciatus	54.32 (35.67–70.02)	91.63 (74.56–142.36)	4.56

The use of plant-based products with insecticidal efficacy has fascinated the significant attention of scientists worldwide. Their biodegradability and safety for humans and non-target creatures are the key reasons. An exhaustive flora analysis was performed to find plant extracts or substances that might be utilized to control important human vector mosquitoes. Furthermore, studies on the insecticidal properties of the extracts of the plants have gained significant impulse because of the imposed constraints on chemical pesticides for vector control programs. Various authors have already reported a similar type of activity.

In this investigation, the mosquito-killing potential of an aqueous extract of N. cataria leaf was examined using three mosquito vectors, including Ae. aegypti, An. stephensi, and Cx. quinquefasciatus. All three of these mosquito species were investigated. The cumulative death rate was the greatest at a concentration of 250 µg·mL⁻¹. The obtained results corroborate with earlier reports. The inquiry of the larvicidal activity of the leaf extract of T. procumbens was tested against Cx. tritaeniorhynchus and showed good larvicidal activity [32]. The larvicidal ability of several solvent extracts of Melia azedarach was evaluated against the 3rd instar of Cx. quinquefasciatus and Ae. aegypti. Results showed that all of the extracts were effective. According to the data, the ethyl acetate extract of M. azedarach showed a very promising larvicidal potential [33]. The ethyl acetate extract of Phyllanthus emblica at 250 ppm showed more than 90% larval mortality against Cx. quinquefasciatus [34]. Furthermore, the synthesized NPs could be interplayed with the larval respiratory process. The larvae can respire through its spiracles, a minute opening found laterally on either side into which the CuNPs make blockings, thereby preventing the further exchange of gases through spiracles and respiratory siphon of the mosquito larvae. Another possible reason is that the CuNPs interfered with the moulting process of the larvae while passing its stage from one instar to another. While experimenting, all the larvae found dead in the experimental group showed that the attachment of old skin and the larvae were in intermediate form between the third and fourth instars. Besides, the CuNPs could enter easily through the bacterial walls and make the bacterial cells more susceptible to the toxic nature of the CuNPs. The exact mechanism of the above-said actions must be studied in detail and pave the way for the new area of research.

The Cx. quinquefasciatus larvae were used in an experiment to investigate the toxicity of leaf extracts from various Vitex species [35]. According to Cetin et al. [36], the ethanolic extracts of T. divaricatum, M. longifolia, M. officinalis, S. sclarea, and M. pulegium were tested for larvicidal activity, and the LC₅₀ values were 18.6, 26.8, 39.1, 62.7, and 81 ppm, respectively. Rathy et al. [37] have stated that the aqueous extracts of O. gratissimum, P. emblica, T. chebula, A. marmelos Lantana camara demonstrated more than 90% larval mortality at 1.08 to 9.12 mg·mL⁻¹ on Ae. aegypti. Kamaraj et al. [38] discovered that methanol extracts from some plants killed all larvae of An. subpictus and Cx. tritaeniorhynchus at doses from 4.69 to 1,000 mg·L⁻¹. J. curcas, P. tithymaloides, P. amarus, E. hirta, and E. tirucalli solvent extracts were tested against Ae. aegypti larvae by Rodrigues et al. [39]. Chaithong et al. [40] found that ethanol extracts from P. longum, P. ribesoides, and P. sarmentosum killed Ae. aegypti 4th instar larvae with LC₅₀ between 2.23 and 8.13 ppm.

The Cu NPs synthesized using Fusarium proliferatum (YNS2) Whole Cell Biomass exhibited good larvicidal activity against these tested species. This study reports the LC₅₀ of Cu NPs to be 39.25 µg·mL⁻¹ against Ae. aegypti, 81.34 µg·mL⁻¹ against An. stephensi, and 21.84 µg·mL⁻¹ against Cx. quinquefasciatus [41]. Other NPs, like Ag NPs, showed similar larvicidal potential against Ae. aegypti [42]. In concordance with all these results, it is evident that the Cu NPs synthesized using the extract of N. cataria is a potent larvicidal and antibacterial agent. The role of bioencapsulated NPs has tremendous applications in various biological arenas [43]. The CuO-NPs synthesized from the endophytic bacterium Brevibacillus brevis showed potential agents that can greatly control the Fusarium oxysporum, Alternaria alternate, and Aspergillus niger fungi. Further, the test material also showed remarkable mosquitocidal activity against the larvae of Culex antennatus [44]. NP synthesized from corn silk fabricated with silver also exhibited the potential to control the larvae of Ae. aegypti [45]. In recent years, the NPs and their exact action upon the target species have proven their imminent role in vector control [46,47]. Furthermore, Barsola and Kumari [48] reviewed the applications of nanoencapsulated materials in genera and silver and selenium-mediated NPs to control bacterial and fungal infections. Silver NPs synthesized from the Marsilea quadrifolia were found to have highly toxic to the Ae aegypti and certain selected bacteria such as B. subtilis, E. faecalis, P. aeruginosa, and P. vulgaris [49]. Alshehri et al. [50] reported that the chitosan encapsulated with silver showed significant larvicidal and adulticidal activities against important medical vectors such as Ae. aegypti, An. stephensi, and Cx. quinquefasciatus. In addition to that, the Cs-AgNPs also showed antibacterial activity against B. subtilis, K. pneumoniae, and S. typhi. Off late, various nanofilms were prepared using cellulose, citric acid, glycerol, and zinc oxide nanoparticles, and all of them showed excellent antimicrobial activity and their biodegradability was also remarkable [51]. NPs synthesized using N. sativa seeds showed remarkable cytotoxic activity against Vero cell lines and antibacterial activity against E. coli and S. aureus [52]. Barsola et al. [53] biosynthesized nanopropolis and reported its role in treating COVID patients during the pandemic period.

4 Conclusion

Because of this broad pesticide resistance, future outbreaks of vector-borne diseases are more probable. Metal NPs are being researched as a possible mosquito repellent since they are hazardous to mosquitoes throughout their life cycle. However, metal NPs have been mostly examined for their larvicidal efficiency, with just a few publications focusing on their antibacterial capabilities. In the present investigation, the leaves of N. cataria were used to synthesize Cu NPs for this study. The phytochemical profile of the aqueous leaf extracts of N. cataria indicated the presence of several active substances, such as polyphenols and flavonoids, which have the potential to bind metallic ions and contribute to the biological reduction of Cu NPs. To confirm the formation of Cu NPs, UV–Vis spectrophotometry, FTIR, scanning electron microscopy, and X-ray diffraction were used. Modern technology is required for efficient mosquito vector control. A green and cheap way to make CuO NPs is disclosed, and it involves using N. cataria leaf extract. Research on the effectiveness of CuO NPs against Aedes aegypti and Anopheles stephensi was performed. The synthesized Cu NPs exhibited remarkable specific toxicity against the three mosquito vectors and may thus be used as an efficient larvicidal agent to control disease-transmitting vectors and suppress bacterial infections.

Acknowledgments

The authors sincerely thank the Researchers Supporting Project Number (RSP2023R48), King Saud University, Riyadh, Saudi Arabia. The authors would like to thank the Principal of Government Arts College for Men (Autonomous), Nandanam, Chennai, and the General Secretary and Correspondent of Guru Nanak College (Autonomous), Velachery, Chennai, for providing the essential facility for this study.

Funding information: The research was funded by the Researchers Supporting Project Number (RSP2023R48), King Saud University, Riyadh, Saudi Arabia.
Author contributions: Mahendrakumar Mani: conceptualization, methodology, software; Aruna Sharmili Sundararaj: conceptualization, software; Khalid A. Al-Ghanim: funding acquisition, resources, validation; Shiny Punalur John: formal analysis; Kuppusamy Elumalai: writing – original draft; Marcello Nicoletti: writing – review and editing; Marimuthu Govindarajan: writing – review and editing.
Conflict of interest: The authors state no conflict of interest.

References

[1] Balalakshmi C, Alharbi N, Kadaikunnan S, Khaled J, Alanzi K, Gopinath K, et al. Development of chitosan/agar-silver nanoparticles-coated paper for antibacterial application. Green Process Synth. 2020;9(1):751–9.10.1515/gps-2020-0070Search in Google Scholar

[2] Gangula A, Podila R, Karanam L, Janardhana C, Rao AM. Catalytic reduction of 4-nitrophenol using biogenic gold and silver nanoparticles derived from Breynia rhamnoides. Langmuir. 2011;27:15268–74.10.1021/la2034559Search in Google Scholar PubMed

[3] Prema P, Iniya PA, Immanuel G. Microbial mediated synthesis, characterization, antibacterial and synergistic effect of gold nanoparticles using Klebsiella pneumonia (MTCC-4030). RSC Adv. 2006;6:4601–7.10.1039/C5RA23982FSearch in Google Scholar

[4] Kowshik M, Ashtaputre S, Kharrazi S, Vogel W, Urban J, Kulkarni SK, et al. Extracellular synthesis of silver nanoparticles by a silver-tolerant yeast strain MKY3. Nanotechnol. 2002;14:95.10.1088/0957-4484/14/1/321Search in Google Scholar

[5] Wen AM, Steinmetz NF. Design of virus-based nanomaterials for medicine, biotechnology, and energy. Chem Soc Rev. 2016;45:4074–126.10.1039/C5CS00287GSearch in Google Scholar PubMed PubMed Central

[6] Alam MN, Das S, Batuta S, Roy N, Chatterjee A, Mandal D, et al. Murraya koenegii Spreng, Leaf extract: an efficient green multifunctional agent for the controlled synthesis of Au nanoparticles. ACS Sustain. Chem Eng. 2014;2:652–64.10.1021/sc400562wSearch in Google Scholar

[7] Rajeshkumar S, Tharani M, Rajeswari V, Alharbi N, Kadaikunnan S, Khaled J, et al. Synthesis of greener silver nanoparticle-based chitosan nanocomposites and their potential antimicrobial activity against oral pathogens. Green Process Synth. 2021;10:658–65.10.1515/gps-2021-0060Search in Google Scholar

[8] Kartha B, Thanikachalam K, Vijayakumar N, Alharbi N, Kadaikunnan S, Khaled J, et al. Synthesis and characterization of Ce-doped TiO2 nanoparticles and their enhanced anticancer activity in Y79 retinoblastoma cancer cells. Green Process Synth. 2022;11:143–9.10.1515/gps-2022-0011Search in Google Scholar

[9] Iravani S. Green synthesis of metal nanoparticles using plants. Green Chem. 2011;13:2638–50.10.1039/c1gc15386bSearch in Google Scholar

[10] Ramesh P, Rajendran A, Meenakshisundaram M. Green Synthesis of Zinc Oxide Nanoparticles Using Flower Extract. Cassia auriculata. J Nanosci Nanotechnol. 2014;2:41–5.Search in Google Scholar

[11] Argueta-Figueroa L, Morales-Luckie RA, Scougall-Vilchis RJ, Olea-Mejía OF. Synthesis, characterization and antibacterial activity of copper, nickel and bimetallic Cu–Ni nanoparticles for potential use in dental materials. Prog Nat Sci. 2014;24:321–8.10.1016/j.pnsc.2014.07.002Search in Google Scholar

[12] Kasana RC, Panwar NR, Kaul RK, Kumar P. Biosynthesis and effects of copper nanoparticles on plants. Environ Chem Lett. 2017;15:233–40.10.1007/s10311-017-0615-5Search in Google Scholar

[13] Din MI, Rehan R. Synthesis, characterization, and applications of copper nanoparticles. Anal Lett. 2017;50:50–62.10.1080/00032719.2016.1172081Search in Google Scholar

[14] Shobha G, Moses V, Ananda S. Biological synthesis of copper nanoparticles and its impact. Int J Pharm Sci Invent. 2014;3:6–28.Search in Google Scholar

[15] Lee HJ, Lee G, Jang NR, Yun JH, Song JY, Kim BS. Biological synthesis of copper nanoparticles using plant extract. Nanotechnoly. 2011;1:371–4.Search in Google Scholar

[16] Ishwarya R, Vaseeharan B, Anuradha R, Rekha R, Govindarajan M, Alharbi NS, et al. Eco-friendly fabrication of ag nanostructures using the seed extract of Pedalium murex, an ancient indian medicinal plant: Histopathological effects on the zika virus vector Aedes aegypti and inhibition of biofilm-forming pathogenic bacteria. J Photochem Photobiol B Biol. 2017;174:33–43.10.1016/j.jphotobiol.2017.07.026Search in Google Scholar PubMed

[17] Banumathi B, Vaseeharan B, Ishwarya R, Govindarajan M, Alharbi NS, Kadaikunnan S, et al. Toxicity of herbal extracts used in ethno-veterinary medicine and green-encapsulated ZnO nanoparticles against Aedes aegypti and microbial pathogens. Parasitol Res. 2017;116:1637–51.10.1007/s00436-017-5438-6Search in Google Scholar PubMed

[18] Banik S, Pérez-de-Luque A. In vitro effects of copper nanoparticles on plant pathogens, beneficial microbes and crop plants. Span J Agric Res. 2017;15:e1005.10.5424/sjar/2017152-10305Search in Google Scholar

[19] Govindarajan M. Evaluation of Andrographis paniculata Burm.F. (Family:Acanthaceae) extracts against Culex quinquefasciatus (say.) and Aedes aegypti (Linn.) (Diptera:Culicidae). Asian Pac J Trop Med. 2011;4:176–81.10.1016/S1995-7645(11)60064-3Search in Google Scholar PubMed

[20] Govindarajan M. Evaluation of indigenous plant extracts against the malarial vector, Anopheles stephensi (Liston) (Diptera: Culicidae). Parasitol Res. 2011;109:93–103.10.1007/s00436-010-2224-0Search in Google Scholar PubMed

[21] Govindarajan M, Rajeswary M, Benelli G. δ-Cadinene, calarene and δ-4-carene from Kadsura heteroclita essential oil as novel larvicides against malaria, dengue and filariasis mosquitoes. Comb Chem High Throughput Screen. 2016;19:565–71.10.2174/1386207319666160506123520Search in Google Scholar PubMed

[22] Chopra RN, Nayar SL, Chopra IC. Glossary of indian medicinal plants. CSIR: New Delhi, India; 1956. p. 1747.Search in Google Scholar

[23] Schultz G, Simbro E, Belden J, Zhu J, Coats J. Catnip, Nepeta cataria (Lamiales: Lamiaceae) - A closer look: Seasonal occurrence of nepetalactone isomers and comparative repellency of three terpenoids to insects. Environ Entomol. 2004;33:1562–9.10.1603/0046-225X-33.6.1562Search in Google Scholar

[24] Smith RM, Brophy JJ, Cavill GWK. Davies NWIridodials and nepetalactone in the defensive secretion of the coconut stick insects, Graeffea crouani. J Chem Ecol. 1979;5:727–35.10.1007/BF00986557Search in Google Scholar

[25] Blum MS, Severson RF, Arrendale RF, Whitman DW, Escoubas P, Adeyeye O, et al. A generalist herbivore in a specialist mode: Metabolic, sesquestrative, and defensive consequences. J Chem Ecol. 1990;16:223–44.10.1007/BF01021281Search in Google Scholar PubMed

[26] Asgarpanah J, Sarabian S, Ziarati P. Essential oil of Nepeta genus (Lamiaceae) from Iran: A review. J Essent Oil Res. 2014;26:1–12.10.1080/10412905.2013.851040Search in Google Scholar

[27] Harborne JB. Phytochemical methods. London: Chapman & Hall; 1998. p. 60–6.Search in Google Scholar

[28] Cheirmadurai K, Biswas S, Murali R, Thanikaivelan P. Green synthesis of copper nanoparticles and conducting nanobiocomposites using plant and animal sources. RSC Adv. 2014;4:19507.10.1039/c4ra01414fSearch in Google Scholar

[29] Cheesbrough M. District laboratory practice in tropical countries, part 2. Cambridge, UK: Cambridge University Press; 2000. p. 434.Search in Google Scholar

[30] World Health Organization. Guidelines for laboratory and field testing of mosquito larvicides. World Health Organization; 2005.Search in Google Scholar

[31] Finney DJ. Probit analysis. 3rd edn. Cambridge: Cambridge University Press; 1971.Search in Google Scholar

[32] Kamaraj C, Bagavan A, Elango G, Abduz Zahir A, Rajakumar G, Marimuthu S, et al. Larvicidal activity of medicinal plant extracts against Anopheles subpictus & Culex tritaeniorhynchus. Indian J Med Res. 2011;134:101–6.10.1007/s00436-010-1816-zSearch in Google Scholar PubMed

[33] Ravichandran R, Kanayairam V. Larvicidal efficacy of medicinal plant extracts for the control of mosquitoe vectors. Int J Pharma Bio Sci. 2014;5:707–15.Search in Google Scholar

[34] Jeyasankar A, Premalatha S, Elumalai K. Larvicidal activity of Phyllanthus Emblica Linn. (Euphorbiaceae) leaf extracts against important human vector mosquitoes (Diptera: Culicidae). Asian Pac J Trop Dis. 2012;S399–S403.10.1016/S2222-1808(12)60190-XSearch in Google Scholar

[35] Kannathasan K, Senthilkumar A, Chandrasekaran M, Venkatesalu V. Differential larvicidal efficacy of four species of Vitex against Culex quinquefasciatus larvae. Parasitol Res. 2007;101:1721–3.10.1007/s00436-007-0714-5Search in Google Scholar PubMed

[36] Cetin H, Cinbilgel I, Yanikoglu A, Gokceoglu M. Larvicidal activity of some Labiatae (Lamiaceae) plant extracts from Turkey. Phytother Res. 2006;20(12):1088–90.10.1002/ptr.2004Search in Google Scholar PubMed

[37] Rathy MC, Sajith U, Harilal CC. Larvicidal efficacy of medicinal plant extracts against the vector mosquito Aedes albopictus. Int J Mosq Res. 2015;2:80–2.Search in Google Scholar

[38] Kamaraj C, Abdul Rahuman A, Bagavan A, Abduz Zahir A, Elango G, Kandan P, et al. Larvicidal efficacy of medicinal plant extracts against Anopheles stephensi and Culex quinquefasciatus (Diptera: Culicidae). Trop Biomed. 2010;27:211–9.Search in Google Scholar

[39] Rodrigues AMS, de Paula JE, Roblot F, Fournet A, Espindola L. Larvicidal activity of Cybistax antisyphilitica against Aedes aegypti larvae. Fitoterapia. 2005;76:755–7.10.1016/j.fitote.2005.08.015Search in Google Scholar PubMed

[40] Chaithong U, Choochote W, Kamsuk K, Jitpakdi A, Tippawangkosol P, Chaiyasit D, et al. Larvicidal effect of pepper plants on Aedes aegypti (L.) (Diptera: Culicidae). J Vector Ecol. 2006;31(1):38144.10.3376/1081-1710(2006)31[138:LEOPPO]2.0.CO;2Search in Google Scholar

[41] Kalaimurugan D, Sivasankar P, Lavanya K, Shivakumar MS, Venkatesan S. Antibacterial and larvicidal activity of Fusarium proliferatum (YNS2) whole cell biomass mediated copper nanoparticles. J Clust Sci. 2019;30:1071–80.10.1007/s10876-019-01568-xSearch in Google Scholar

[42] Gopu M, Kumar P, Selvankumar T, Senthilkumar B, Sudhakar C, Govarthanan M, et al. Green biomimetic silver nanoparticles utilizing the red algae Amphiroa rigida and its potent antibacterial, cytotoxicity and larvicidal efficiency. Bioprocess Biosyst Eng. 2021;44:217–23.10.1007/s00449-020-02426-1Search in Google Scholar PubMed

[43] Shafey A. Green synthesis of metal and metal oxide nanoparticles from plant leaf extracts and their applications: A review. Green Process Synth. 2020;9:304–39.10.1515/gps-2020-0031Search in Google Scholar

[44] Fouda A, Hassan S, Eid A, Awad M, Althumayri K, Badr N, et al. Endophytic bacterial strain, Brevibacillus brevis-mediated green synthesis of copper oxide nanoparticles, characterization, antifungal, in vitro cytotoxicity, and larvicidal activity. Green Process Synth. 2022;11:931–50.10.1515/gps-2022-0080Search in Google Scholar

[45] Sujitha V, Murugan K, Panneerselvam C, Aziz A, Alatawi F, Trivedi S, et al. Fabrication of green nanoinsecticides from agri-waste of corn silk and its larvicidal and antibiofilm properties. Green Process Synth. 2022;11:810–22.10.1515/gps-2022-0062Search in Google Scholar

[46] Ramkumar G, Shivakumar M, Alshehri M, Panneerselvam C, Sayed S. Larvicidal potential of Cipadessa baccifera leaf extract-synthesized zinc nanoparticles against three major mosquito vectors. Green Process Synth. 2022;11:757–65.10.1515/gps-2022-0071Search in Google Scholar

[47] Elumalai K, Kavipriya M, Lakshmi Prabha A, Krishnappa K, Pandiyan J, Nicoletti M, et al. Green synthesis of silver nanoparticles using Atalantia monophylla: A potential eco-friendly agent for controlling blood-sucking vectors. Green Process Synth. 2022;11:915–30.10.1515/gps-2022-0078Search in Google Scholar

[48] Barsola B, Kumari P. Green synthesis of nano-propolis and nanoparticles (Se and Ag) from ethanolic extract of propolis, their biochemical characterization: A review. Green Process Synth. 2022;11:659–73.10.1515/gps-2022-0059Search in Google Scholar

[49] Ishwarya R, Saravanan K, Selvaraj D, Govindarajan M, Alharbi N, Kadaikunnan S, et al. Antibacterial greener silver nanoparticles synthesized using Marsilea quadrifolia extract and their eco-friendly evaluation against Zika virus vector, Aedes aegypti. Green Process Synth. 2021;10:742–55.10.1515/gps-2021-0070Search in Google Scholar

[50] Alshehri M, Aziz A, Trivedi S, Panneerselvam C. Efficacy of chitosan silver nanoparticles from shrimp-shell wastes against major mosquito vectors of public health importance. Green Process Synth. 2020;9:675–84.10.1515/gps-2020-0062Search in Google Scholar

[51] Alzain H, Hussein K, Jabr I, Alsubaie A. Biodegradation of synthetic PVP biofilms using natural materials and nanoparticles. Green Process Synth. 2023;12:20230011.10.1515/gps-2023-0011Search in Google Scholar

[52] Al-Karagoly H, Rhyaf A, Naji H, Albukhaty S, AlMalki F, Alyamani A, et al. Green synthesis, characterization, cytotoxicity, and antimicrobial activity of iron oxide nanoparticles using Nigella sativa seed extract. Green Process Synth. 2022;11:254–65.10.1515/gps-2022-0026Search in Google Scholar

[53] Barsola B, Saklani S, Kumari P, Sidhu A, Dhar A. Role and the importance of green approach in biosynthesis of nanopropolis and effectiveness of propolis in the treatment of COVID-19 pandemic. Green Process Synth. 2023;12:20228106.10.1515/gps-2022-8106Search in Google Scholar

Received: 2023-02-06

Revised: 2023-04-07

Accepted: 2023-05-07

Published Online: 2023-05-31

This work is licensed under the Creative Commons Attribution 4.0 International License.

Articles in the same Issue

https://doi.org/10.1515/gps-2023-0022

Keywords for this article

biosynthesis; copper nanoparticles; larvicidal efficacy; microbial pathogens; vector control

Creative Commons

BY 4.0