The researchers prepared the nanoparticles, designated TA-AgNPs, by adding 1 mL of aqueous Trachyspermum ammi seed extract to 10 mL of 1.5 mM silver nitrate and stirring the mixture for five minutes at 25 °C. The solution changed from pale yellow to dark brown, a visible change the team treated as confirmation of reduction. UV-visible spectroscopy showed a prominent absorption peak at 420 nm. Dynamic light scattering and zeta analysis indicated a mean hydrodynamic diameter of 34.27 nm, an average zeta potential of −28 mV and a polydispersity index of 0.255. The particles were also characterized by scanning electron microscopy and Fourier-transform infrared spectroscopy, and the authors described them as spherical and nanoscale.

The seed extract was prepared by shaking 10 g of powdered T. ammi seeds in 100 mL of double-deionized water for approximately four hours at 37 °C before filtering the mixture. The researchers proposed that constituents associated with the plant’s essential oil, including thymol, p-cymene and gamma-terpinene, could serve as reducing agents during silver nanoparticle formation. Plant-mediated synthesis may also leave biologically active plant compounds associated with the silver surface, potentially influencing how the particles interact with cells. The experiment therefore tested TA-AgNPs as a combined product of silver and plant-derived material, but it did not isolate the effect of individual seed constituents or establish which chemical features were responsible for the observed activity.

In the cell-culture experiment, A431 human epidermal skin-cancer cells were exposed for 24 hours to TA-AgNPs at concentrations of 2.5, 5, 10, 20 and 25 micrograms per milliliter. Cell viability was assessed with the Alamar Blue assay, which detects the metabolic reduction of resazurin to fluorescent resorufin. Viability declined as nanoparticle concentration increased. At 20 micrograms per milliliter, viability averaged 20.2% for TA-AgNPs compared with 86.8% for the corresponding seed extract alone; at 25 micrograms per milliliter, the respective values were 11.9% and 87%. These differences were significant at p less than 0.01, whereas differences at 2.5, 5 and 10 micrograms per milliliter were reported as non-significant. The result supports a concentration-dependent cytotoxic effect in one human cancer cell line, but the supplied results include no non-cancer cell comparator, benchmark anticancer treatment or reported half-maximal inhibitory concentration.

For the animal experiment, 25 male Swiss albino mice aged six to seven weeks and weighing 28–35 g were divided into five groups of five. Skin carcinogenesis was induced by topical application of 7,12-dimethylbenz[a]anthracene, or DMBA, at 50 mg/kg, followed by 12-O-tetradecanoylphorbol-13-acetate, or TPA, at 0.01 micrograms per microliter three times weekly for 14 weeks. One group received only the carcinogens. Three intervention groups also received 0.1 mg/mL TA-AgNPs in carbopol gel, corresponding to 25 micrograms per kilogram per day: treatment began after DMBA, began after TPA, or continued throughout the full carcinogenesis protocol. A fifth group received TA-AgNPs without either carcinogen. The investigators measured tumor incidence, yield, burden, dimensions, weight, height and latency, along with liver superoxide dismutase activity, serum interleukin-6 and skin histopathology.

Continuous treatment produced the clearest change in tumor outcomes. All five mice in the carcinogen-only group developed tumors, with a reported tumor yield of 100%, an average tumor burden of five and tumors first appearing in week four. Their average latent period was five weeks. Starting TA-AgNPs after DMBA did not reduce incidence or yield, although tumor burden fell to 4.32 and the average latent period increased to six weeks. Starting treatment after TPA likewise left incidence and yield at 100%, while burden declined to 3.96 and latency increased to seven weeks. With TA-AgNPs administered throughout, tumor incidence and yield were each reported as 20%, average tumor burden fell to 1.71 and the average latent period reached nine weeks. The average tumor diameter changed little among carcinogen-exposed groups, remaining between 4.22 and 4.55 mm, indicating that the clearest measured effects involved the occurrence, number and timing of tumors rather than the size of tumors that did develop.

Oxidative-stress measurements suggested that the protective pattern depended on treatment duration. Liver superoxide dismutase activity fell to 25.52 ± 0.032 units per 50 microliters in the carcinogen-only group, compared with 34.90 ± 0.60 units per 50 microliters in untreated mice, a difference reported at p less than 0.01. TA-AgNPs introduced after DMBA or after TPA produced values of 45.22 ± 0.008 and 43.34 ± 0.005 units per 50 microliters, respectively, but neither differed significantly from the carcinogen control. Continuous TA-AgNP treatment raised activity to 55.41 ± 0.006 units per 50 microliters, a significant increase relative to the carcinogen group. The nanoparticle-only group measured 26.20 ± 0.049 units per 50 microliters and did not differ significantly from the carcinogen control. This pattern is consistent with an association among sustained administration, higher antioxidant-enzyme activity and reduced tumor burden, but the experiment does not establish that SOD upregulation caused the protective effect.

Serum interleukin-6 measurements showed that the anti-inflammatory interpretation was more limited. The cytokine rose to 181.60 ± 0.75 picograms per milligram of protein in the carcinogen-only group, compared with 63.30 ± 0.30 picograms per milligram in untreated mice. Beginning TA-AgNPs after DMBA failed to lower IL-6 and instead yielded 198.50 ± 0.85 picograms per milligram. Treatment after TPA reduced IL-6 to 163.20 ± 0.60 picograms per milligram, and continuous treatment produced a similar value of 162.80 ± 0.65 picograms per milligram; both were significantly lower than the carcinogen control at p less than 0.01, yet both remained well above the untreated baseline. Mice receiving TA-AgNPs without carcinogens had 65.20 ± 1.00 picograms per milligram, close to baseline. The data therefore indicate a partial, schedule-dependent reduction in IL-6 rather than elimination of the carcinogen-associated inflammatory environment.

Histopathological findings broadly supported the tumor measurements but also showed why the findings should not be described as a cure. Hematoxylin-and-eosin-stained skin sections contained squamous-cell-carcinoma features and keratin pearls in the carcinogen-only group and in each group that received TA-AgNPs alongside carcinogens, although the extent differed among treatment schedules. In the nanoparticle-only group, no tumors appeared, no keratin pearls were observed and epithelial architecture remained preserved. Quantitative results were summarized as means with standard deviations and compared through one-way analysis of variance followed by Tukey’s post hoc honestly significant difference test; the cell assay used three replicates. The small animal number, use of only one sex and one chemically induced mouse model, absence of a clinical comparator, and lack of long-term toxicity or pharmacokinetic analysis limit translation. The study identifies plant-mediated nanosilver as an experimental chemopreventive candidate, but it does not establish efficacy, safety or dosing for people with cancer.

Subject of Research: Experimental evaluation of Trachyspermum ammi-mediated silver nanoparticles for skin-cancer chemoprevention

Article Title: Trachyspermum ammi seed extract modulated nanosilver as a transformative agent for anticancer activity

Article References: Saxena, N., Jain, S., Yadav, N., Sharma, B., Kasodekar, S. A., Gupta, N., & Chatterjee, S. (2026). Trachyspermum ammi seed extract modulated nanosilver as a transformative agent for anticancer activity. Frontiers in Biomaterials Science, 5, Article 1942456. https://doi.org/10.3389/fbiom.2026.1942456

Image Credits: AI Generated

DOI: 10.3389/fbiom.2026.1942456

Keywords: Trachyspermum ammi, silver nanoparticles, green synthesis, skin cancer, A431 cells, DMBA-TPA model, tumor incidence, antioxidant defense, interleukin-6, mouse model, Trachyspermum, ammi