The research team set out to answer a question that has long been underexplored for both species: are their chemical constituents safe at the genetic level, and might they even shield living cells from damage? Both plants are prolific invaders. Amorpha fruticosa, a shrub native to North America, and Ailanthus altissima, a tree native to China introduced to Europe and North America at the end of the eighteenth century, tolerate a wide range of habitats and spread aggressively because few herbivores keep them in check. Their unchecked spread is considered a significant driver of biodiversity loss, so any pharmacological use that encourages large-scale harvesting could double as a habitat-protection strategy.

Both species also carry long histories in traditional medicine. Tree of heaven preparations have been applied against asthma, epilepsy, bleeding, dysentery, and eye diseases, while false indigo bush has been used for stomach pain, intestinal worms, eczema, neuralgia, and rheumatism. Chemically, the plants are well stocked with interesting molecules. The fruit of Amorpha fruticosa is rich in isoflavonoids, rotenoids, and prenylated stilbenoids, including the diverse amorfrutin group. The bark of Ailanthus altissima contains more than 221 reported compounds, among them alkaloids, quassinoids, phenylpropanoids, triterpenoids, and volatile oils. Yet despite this pharmacological promise, the authors note that toxicity data for these extracts remain scarce, which is precisely the gap the new study set out to fill.

The researchers prepared three extracts. Fruit of Amorpha fruticosa, collected near Sofia, Bulgaria, was first defatted with chloroform and then extracted with 70 percent methanol to yield the AF extract. Tree of heaven bark was macerated with hexane to produce a lipophilic extract, AAEH, and the remaining defatted material was percolated with 70 percent methanol to give a hydrophilic extract, AAEM. Each extract was then tested at three concentrations, 10, 100, and 1000 micrograms per milliliter, across a suite of assays designed to probe both DNA-damaging and DNA-protective behavior.

The first round of testing measured antioxidant capacity in vitro. In the DPPH radical scavenging assay, which tracks the color change of a stable radical from purple to yellow, the AF extract performed best, with an IC50 value of 63.71 micrograms per milliliter, followed by AAEM at 696.12 and AAEH at 1396.97 micrograms per milliliter. Ascorbic acid, the standard, came in at 15.94 micrograms per milliliter, so even the best plant extract showed only slight to moderate radical scavenging by comparison. A complementary DNA topology assay, which monitors whether supercoiled plasmid DNA stays intact or relaxes into a damaged circular form, produced a consistent ranking, AF greater than AAEM greater than AAEH. Notably, the hexane extract displayed a moderate pro-oxidant potential, meaning it could itself inflict single-strand damage on plasmid DNA under certain conditions.

The heart of the study, however, took place in living cells of the baker’s yeast Saccharomyces cerevisiae, a workhorse model whose major stress-response pathways closely resemble those of human cells. Using yeast also aligns with the European Union’s Directive 2010/63/EU, which enshrines the principle of replacing, reducing, and refining animal experimentation. The team employed two classic yeast systems: Zimmermann’s test on the diploid strain D7ts1, which measures mitotic gene conversion, reverse point mutations, and mitotic crossing-over, and the Ty1 retrotransposition test on haploid strain 551, a proxy for carcinogenic potential. Zeocin, a radiomimetic antibiotic of the bleomycin family that shreds DNA much like ionizing radiation, served as the positive control.

The safety results were unambiguous. When yeast cells were treated with the extracts alone, survival remained comparable to untreated controls at all three concentrations, and the frequencies of convertants, revertants, and total aberrants matched baseline levels. No Ty1 retrotransposition was induced by any extract. According to the authors, this is the first demonstration that Amorpha fruticosa fruit extract and Ailanthus altissima bark extracts are neither genotoxic, mutagenic, nor carcinogenic in this test system, a foundational finding for any future pharmacological development.

The protective results were even more compelling. When cells were pre-treated with an extract before a one-minute exposure to 100 micrograms per milliliter of Zeocin, survival rose roughly twofold compared with Zeocin alone, and the burden of genetic damage fell dramatically. Reverse point mutations dropped to levels comparable with untreated cells after pre-treatment with AF and AAEM, and total aberrants were significantly reduced across the board. The AF extract stood out as the only one capable of reducing Zeocin-induced mitotic gene conversion at every concentration tested, an effect the researchers attribute to its isoflavonoid-rich composition, possibly through activation of homologous recombination repair and modulation of chromatin structure. In the Ty1 assay, pre-treatment with AF and AAEH reduced transposition rates to near-control levels, indicating genuine anticarcinogenic activity, while only the lowest AAEM concentration failed to protect cells.

Not every interaction was benign. Pre-treatment with the lowest concentration of the hexane extract, 10 micrograms per milliliter, actually potentiated Zeocin’s recombinogenic effect, increasing gene conversion frequencies. The authors point out that AAEH is dominated by phytosterols, and previous work has shown that sterols can enhance the activity of bleomycin, a close relative of Zeocin. This concentration-dependent twist underscores a central lesson of the study: biological effects track phytochemical composition. The protective hierarchy, AF greater than AAEM greater than AAEH, mirrors the flavonoid and stilbenoid content of the extracts, and flavonoids are already well known for antimutagenic properties.

Perhaps the most intriguing mechanistic insight is what the protection does not depend on. Because the extracts showed only mild to moderate antioxidant activity in vitro, the researchers suggest that the reduction of mutations and retrotransposition events is not primarily an antioxidant effect. Instead, they speculate that the extracts may activate protective enzymes independent of the homologous recombination machinery, since reverse mutation frequency is a readout of error-prone recombination. The team, which included Ekaterina Kozuharova, who identified and extracted the plants, emphasizes that further experiments are needed to pin down the mode of action and identify the active constituents. Still, the message is clear: two plants that choke wetlands and crack through pavement may owe their next chapter to the laboratory bench, where their abundant, inexpensive chemistry could be transformed from invasive liability into DNA-protective asset.

Subject of Research: Genotoxicity, mutagenicity, and protective effects of Amorpha fruticosa and Ailanthus altissima extracts in yeast

Article Title: Screening of Amorpha fruticosa and Ailanthus altissima extracts for genotoxicity/antigenotoxicity, mutagenicity/antimutagenicity and carcinogenicity/anticarcinogenicity

Article References: Todorova, T., Boyadzhiev, K., Shkondrov, A., Parvanova, P., Dimitrova, M., Ionkova, I., Krasteva, I., Kozuharova, E., & Chankova, S. (2022). Screening of Amorpha fruticosa and Ailanthus altissima extracts for genotoxicity/antigenotoxicity, mutagenicity/antimutagenicity and carcinogenicity/anticarcinogenicity. BioRisk, 17, 201-212. https://doi.org/10.3897/biorisk.17.77327

Image Credits: AI Generated

DOI: 10.3897/biorisk.17.77327

Keywords: Amorpha fruticosa, Ailanthus altissima, invasive species, genotoxicity, antimutagenicity, Saccharomyces cerevisiae, Zeocin, antioxidant activity, Ty1 retrotransposition, phytochemistry, flavonoids, DNA repair

The researchers prepared extracts from both polished and unpolished Yoom Noon rice and applied them to two well-established colorectal cancer cell lines, HCT116 and HT29. These lines are staples of colon cancer research because they differ in their genetic backgrounds and behavior, giving scientists a way to gauge whether an effect is broad or limited to one tumor type. The team measured cell viability using the MTS assay, a colorimetric technique in which metabolically active cells convert a chemical substrate into a colored product, allowing researchers to quantify how many cells survive after treatment. Trypan blue exclusion, a classic dye-based test that marks dead cells with compromised membranes, provided an independent check on cell survival.

The results revealed a striking difference between the two cancer cell lines. Against HCT116 cells, the polished rice extract achieved a half-maximal inhibitory concentration, or IC50, of 626.74 micrograms per milliliter at 48 hours, while the unpolished extract reached an IC50 of 736.85 micrograms per milliliter. In plain terms, these concentrations were sufficient to cut the viability of HCT116 cells in half within two days. The HT29 line proved more resistant, with both extracts requiring concentrations above 1000 micrograms per milliliter to achieve the same effect. This kind of selectivity between cell lines is common in natural product research and often reflects differences in how tumor cells metabolize compounds or regulate their own survival machinery.

Beyond short-term viability, the investigators probed whether the rice extracts could undermine the long-term proliferative capacity of the cancer cells. They used a clonogenic assay, sometimes called a self-renewal assay, which challenges surviving cells to divide repeatedly and form visible colonies over days to weeks. Cancer cells that retain their ability to seed new colonies are the ones most likely to drive regrowth after treatment. Both polished and unpolished Yoom Noon rice extracts demonstrated a potent anti-proliferative ability against HCT116 and HT29 cells in this assay, indicating that the extracts do not merely slow the cells temporarily but impair their capacity for sustained self-renewal.

Perhaps the most clinically relevant findings concerned metastasis, the process by which cancer cells spread from the original tumor to distant organs and which accounts for the majority of colorectal cancer deaths. The team used wound healing assays, in which a scratch is made across a confluent cell layer and researchers track how quickly cells migrate to close the gap, along with transwell migration assays, in which cells are challenged to move through a porous membrane toward a chemical attractant. At doses that were not cytotoxic, meaning they did not kill the cells outright, the Yoom Noon rice extracts significantly suppressed both the migration and the invasion of HCT116 cells. This distinction matters because it suggests the rice compounds may interfere with the motility machinery of cancer cells at concentrations that would be safer for normal tissue.

To understand the cellular mechanisms driving the suppression of proliferation, the researchers turned to flow cytometry, a technique that passes thousands of individual cells through a laser and quantifies their characteristics one by one. Using Annexin V and propidium iodide staining, they found that treatment with the rice extracts increased apoptotic cell death in both HCT116 and HT29 cells in a dose-dependent manner. Apoptosis is the body’s programmed cell death pathway, a controlled form of cellular suicide that, unlike necrosis, avoids triggering inflammation. Many chemotherapy drugs work by pushing cancer cells into apoptosis, so a food-derived extract that promotes this pathway is of considerable interest for chemoprevention research.

Flow cytometric cell cycle analysis added a second mechanistic layer. The extracts arrested HCT116 cells at the S phase, the stage of the cell cycle during which DNA is replicated. Blocking cells at this checkpoint prevents them from progressing to mitosis and dividing, effectively putting the brakes on tumor growth. The combination of apoptosis induction and S phase arrest suggests the rice extracts act through multiple complementary routes, a pattern often seen with complex botanical mixtures that contain many bioactive compounds working in concert rather than a single isolated molecule.

Just as important as what the extracts did to cancer cells is what they did not do to healthy ones. Using a cytokinesis-blocked micronucleus assay on V79 lung fibroblast cells, the team evaluated genotoxicity, the potential to damage DNA. Micronuclei are small fragments of genetic material that break away from the main nucleus when chromosomes are damaged or missegregated during cell division, and their frequency is a sensitive indicator of DNA harm. The Yoom Noon rice extracts at concentrations of 250 to 750 micrograms per milliliter did not increase the number of micronuclei compared with untreated controls after 24 hours of exposure, indicating the extracts themselves are not genotoxic under these conditions.

The anti-genotoxic results may prove to be the study’s most provocative contribution. When the researchers co-treated the fibroblast cells with the rice extracts and Mitomycin C, a well-known mutagen, they observed a significant reduction in the frequency of micronucleated cells compared with cells exposed to the mutagen alone. In other words, the rice extracts appeared to shield DNA from a known damaging agent. This antimutagenic effect, if it holds up in further studies, would position Yoom Noon rice not only as a possible source of anti-cancer compounds but also as a candidate for chemoprevention, the strategy of using dietary or medicinal agents to stop cancer before it starts.

The authors are careful to frame this as an in vitro study, and the usual caveats apply. Extract concentrations in the hundreds of micrograms per milliliter cannot be directly translated into dietary recommendations, and compounds that survive the digestive system, cross the intestinal barrier, and reach tumor tissue in sufficient quantities remain an open question. Clinical effects would require animal studies and eventually human trials. Nevertheless, the research, supported by the Office of the Royal Development Projects Board of Thailand, establishes a credible first link between a locally significant rice strain and a suite of desirable biological activities: selective inhibition of colorectal cancer cell growth, suppression of migration and invasion, induction of apoptosis, cell cycle arrest, and protection of DNA from mutagenic damage. For a grain developed through a royal agricultural initiative in southern Thailand, Yoom Noon rice has now earned a place in the growing catalogue of natural products under scrutiny for cancer prevention and therapy.

Subject of Research: Anti-cancer and anti-genotoxic effects of Yoom Noon rice extracts on colorectal cancer cells in vitro

Article Title: Anti-cancer and anti- genotoxic potential of Yoom Noon rice: induction of apoptosis, cell cycle arrest, and inhibiting migration and invasion in vitro

Article References: Praphasawat, R., Payuhakrit, W., Surachaijarin, C., Yana, B., & Palipoch, S. (2026). Anti-cancer and anti- genotoxic potential of Yoom Noon rice: induction of apoptosis, cell cycle arrest, and inhibiting migration and invasion in vitro. BMC Complementary Medicine and Therapies. https://doi.org/10.1186/s12906-026-05613-x

Image Credits: AI Generated

DOI: 10.1186/s12906-026-05613-x

Keywords: Yoom Noon rice, colorectal cancer, apoptosis, cell cycle arrest, S phase, micronucleus assay, genotoxicity, antimutagenicity, flavonoids, rice extract, chemoprevention, in vitro