**4. Role of plant-based nanoparticles in leishmaniasis treatment**

Infectious illness control methods have revolutionized translational sciences, allowing for the development of a better infectious disease control approach. Nanomedicine has showed tremendous promise in the development of very sensitive diagnostic tools with outstanding medication delivery properties. Nanoparticleconjugated medications have recently been examined as a cost-effective, alternative therapy with improved efficacy. Toxicity, on the other hand, is a significant impediment that must be overcome. Several studies have demonstrated that several metal/ metal oxide nanoparticles, as well as the *Leishmania* causative organism, have effective antibacterial effects due to their large surface area and unique characteristics. Nanoparticles made from crude and various solvent-fractionated extracts of medically significant plants are thought to be effective delivery for specific phytoconstituents into cells. Keeping in view the effective antimicrobial activities of silver metal, silver/silver oxide NPs synthesized using a variety of medicinally important plant species, including *Mentha arvensis* L., *Ficus benghalensis*, *Cuminum cyminum*, *Moringa oleifera*, *Silybum marianum*, and *Sechium edule*, at a dosage of 10, 300, 0.5, 246, and 51.88 μg/ml tested against *L. tropica*, *L. donovani*, *L. major*, and *L. donovani*, respectively [23–27]. This condition has also been reported to be prevented utilizing gold and silver bimetallic NPs produced from therapeutically significant plants [28]. However, Au-NPs derived from *Cannabis sativa* had excellent antileishmanial activity against amastigote forms (IC50: 171•00± 2•28 μg/ml) [25]. The flavonoid 7,8-dihydroxyflavone, which is common in plants used to make

gold nanoparticles, has also been shown to prevent leishmaniasis [29]. The cytotoxicity of ZnO-NPs against *L. tropica* was likewise observed to be dose-dependent (IC50: 8.30 μg/ml). With an IC50 value of 0.001 mg ml, rod-shaped zinc oxide NPs made from *Lilium ledebourii* tuber extract suppressed the growth of *L. major* [29]. Saleh [30] also found that green TiO2 nanoparticles were efficient in reducing *L. tropica* toxicity in male rats. Hematite (Fe2O3) NPs made from *Rhus punjabensis* extract were found to be effective in the treatment of leishmaniasis [31]. Khalil et al. [32] used aqueous leaf extracts of *Sageretia thea* to make lead oxide NPs (PbO-NPs). PbO-NPs were found to be significantly active in stopping the growth of promastigote and amastigotes forms of *L. tropica*, with IC50 values of 14.7 and 11.95 g/ml, respectively. Plant-mediated iron oxide nanoparticles (*Trigonella foenum-graecum*) have been shown to have considerable inhibitory effects on *L. tropica* [33]. Abbasi et al. [34] also indicated that NiO-NPs made from *Geranium wallichianum* has antileishmanial activity against *L. tropica*.

In addition, the nanostructured drug delivery method has been shown to help with NTDs like leishmaniasis. Furthermore, crude plant extracts and specific phytoconstituents produced from plants that are involved in the preventative mechanism were loaded into the nanostructured drug delivery system and used as a therapeutic source to cure leishmaniasis, as shown below:


According to the literature review, plant-based nanoparticles play an effective function in the treatment of leishmaniasis when compared to other treatments. At a far lower concentration than the required dose of Amp B to cure this condition, phytosynthesized NPs had the same effect on parasite growth suppression. Furthermore, green bimetallic nanoparticles such as Au-Ag, Zn-Ag, and Ti-Ag were produced and successfully used as a medicinal source to treat leishmaniasis [28]. Because of its nontoxic, safe, and efficient vaccine delivery technique, NPs are recommended above other medicinal options to treat this dreadful disease. With the progress of nanosciences, a new way of producing vaccines employing NPs as antigen carriers is now available. Solid lipid nanoparticles may be useful in the

development of a leishmanial vaccine [41]. However, no NP-based vaccination is currently available, and further research is required.
