CHENNAI: Can the leaves grown in the cool hills of Ooty one day help combat breast cancer and life-threatening infections? These researchers believe so.
In a promising convergence of nature and nanoscience, researchers have demonstrated that tea tree leaves from the Nilgiris can be used to create powerful, eco-friendly silver nanoparticles with wide-ranging healthcare potential.
A team of Indian and international researchers has successfully synthesised silver nanoparticles using leaf extracts of Melaleuca alternifolia, popularly known as the tea tree, collected from Ooty. The research, published in Nature (Scientific Reports), shows that these plant-based nanoparticles exhibit strong antibacterial, antifungal, antioxidant, and anticancer properties under laboratory conditions.
The work was led by B Mary Dayana and Dr Raja Venkatesan, under senior supervision by Dr J Thomas Joseph Prakash and Seong-Cheol Kim, and contributions from researchers, including P Saravanan, M Sherlin Nivetha, Adhigan Murali, Alexandre A Vetcher and Munusamy Settu.
"This study demonstrates how green nanotechnology can offer a safer and more sustainable alternative to conventional chemical synthesis," said Dr Raja Venkatesan, one of the corresponding authors. "By using tea tree leaf extract, we eliminated toxic reagents while achieving nanoparticles with excellent biological activity," he explained.
Using an eco-friendly green synthesis method, the researchers converted silver ions into stable nanoparticles with an average core size of about 10 nanometres, a scale considered ideal for biomedical applications. Advanced imaging and spectroscopic analyses confirmed that the particles were uniform, crystalline, and biologically stable.
In antimicrobial tests, the nanoparticles showed strong effectiveness against harmful bacteria such as Pseudomonas aeruginosa and Streptococcus pyogenes, pathogens commonly associated with hospital-acquired infections. They also displayed antifungal activity, particularly against Aspergillus fumigatus, a serious threat to patients with weakened immune systems.
"The antimicrobial performance was notable even at low concentrations," said Dr J Thomas Joseph Prakash, adding that such properties could be valuable in infection control, wound care, and medical coatings.
Beyond infection management, the study reported meaningful antioxidant activity, indicating the nanoparticles' ability to neutralise harmful free radicals. Most strikingly, laboratory experiments on MCF-7 breast cancer cells revealed a strong dose-dependent cytotoxic effect. The nanoparticles reduced cancer cell viability by 50 per cent at a relatively low concentration, accompanied by clear morphological damage to tumour cells.
"This is an early but encouraging signal. While these are in-vitro results, they open the door for further investigation into plant-based nanomaterials for cancer research," said B Mary Dayana, the study's lead author.
The researchers emphasised that the findings do not represent a clinical cure and that extensive animal studies and human trials will be required.