Ugwuoke Chidera Linus

Over the years, nanomaterials have become popular in science, technology, and agriculture. Their use has advanced due to the numerous advantages of their modified sizes and dimensions. In medicine, the versatility of nanomaterials is striking, as they serve as drug carriers in drug delivery systems, enhance the biological activities of various drugs, and increase drug solubility and permeability across biological membranes. Their applications extend to diagnosis and other aspects of medicine, making them a versatile and impactful tool in healthcare.

Silver nanoparticles are known to improve encapsulated drugs’ characteristics, solubility, and activities. They have also been reported to possess antimicrobial properties and efficiently penetrate different human body areas. There are several ways of synthesizing nanoparticles, each with its own set of challenges. Physical methods, for instance, often require high energy and are costly. On the other hand, chemical methods can lead to contamination due to using toxic solvents. Understanding these challenges is crucial in choosing the most suitable synthesis method for the Green Synthesis of silver nanoparticles.

The method applied in the synthesis can follow one of two well-established approaches: bottom-up or top-down. The bottom-up approach is a building process that gradually synthesizes nanomaterials, starting with atoms and advancing through clusters to form nanoparticles. This method generally includes processes such as sol-gel, spinning, and biosynthesis.  Other examples include sedimentation, reduction, green synthesis, centrifugation, biochemical synthesis, atomic layer deposition, and molecular self-assembly (Burlec et al., 2023). Conversely, the top-down approach reduces raw, unprocessed material to nanometric dimensions by breaking down the initial structures using various physical forces to synthesize nanoparticles. Techniques such as mechanical milling, nanolithography, laser ablation, sputtering, and thermal decomposition are some of the most recognized methods within this approach.

The biological method of synthesizing nanoparticles is an eco-friendly way of producing nanoparticles using biological raw materials such as bacteria, fungi, and plant extracts. These biological raw materials serve as reducing and stabilizing agents, and when medicinal plants are used, they also serve as active ingredients. One of the most cost-effective and eco-friendly methods for synthesizing nanoparticles involves using plants as bio-generators for nanoparticle production, known as “green synthesis.” The potential for large-scale production of nanoparticles through plant-based methods is significant due to the abundance of plants, their easy accessibility, and their ability to thrive in diverse environmental conditions. Additionally, this approach avoids using expensive and hazardous chemicals typical of conventional methods, making it a safer and more sustainable option. However, there are some challenges with using plants for nanoparticle synthesis, such as variations in the size and shape of the nanoparticles, which can arise from differences in plant species, geographical area or growth condition, and harvesting season.

Anogeissus leiocarpus, also known as African Birch, belongs to the Combretaceae family and is extensively used in African traditional medicine and veterinary practices. Traditional healers and livestock farmers have employed it to treat various ailments, including “African trypanosomiasis, animal diarrhea, asthma, cancer, cough, diabetes, dysentery, erectile dysfunction, fever, giardiasis, helminthiasis, meningitis, menstrual disorders, monkeypox, oral infections, poliomyelitis, sickle cell anemia, snake bites, toothache,  schistosomiasis, and yellow fever (Adekunle et al., 2024).

The medicinal properties of A. leiocarpus are largely attributed to its high content of polyphenolic compounds, such as ellagic acid derivatives, flavonoids, stilbenes, tannins, and triterpenes. Notably, ellagitannins, ellagic acid derivatives, flavonoids, and triterpenes are recognized as the primary active constituents. These compounds have been associated with various pharmacological effects, including antibacterial, antifungal, antihyperglycemic, antihypertensive, antimalarial, antioxidative, antiparasitic, antitumor, and anti-ulcer activities.

Research has primarily concentrated on the stem bark of A. leiocarpus, the most frequently used part in traditional medicine. Studies conducted in vitro and in vivo have demonstrated its effectiveness against various parasites that cause diseases such as helminthiasis, leishmaniasis, malaria, and trypanosomiasis. Given its significant role in traditional medicine and its wide spectrum of pharmacological effects, A. leiocarpus has attracted substantial interest from researchers.

The silver nanoparticles produced in this study will be characterized using scanning electron microscopy (SEM), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). The Nanoparticles will also be analyzed for antibacterial activities using standard clinical pathogenic isolates from the University College Hospital (UCH) Ibadan. Owing to the numerous phytochemicals, biological activities, and uses of A. leicarpus, using it as a reducing and stabilizing agent in the formulation of silver nanoparticles will help combat the rising burden of multidrug-resistant organisms that have been of great public health concern.

References

Adekunle Y.A, Babatunde B. S, Lutfun N, Fatokun A.A, Satyajit D.S. 2024. Anogeissus leiocarpus: A review of the traditional uses, phytochemistry and pharmacology of African birch. Fitoterapia 176  105979.

Burlec, A.F.; Corciova, A.; Boev, M.; Batir-Marin, D.; Mircea, C. Cioanca, O.; Danila, G.; Bucur, A.F.; Hancianu, M. Current Overview of Metal Nanoparticles’ Synthesis, Characterization, and Biomedical Applications, with a Focus on Silver and Gold Nanoparticles. Pharmaceuticals 2023, 16, 1410. https://doi.org/10.3390/ ph16101410