Rosemari Otton led the studies from the Interdisciplinary Graduate Program in Health Sciences at Cruzeiro do Sul University in São Paulo, Brazil. The scientist, who has dedicated more than 15 years to green tea research, explains that her initial motivation came from curiosity about the truth behind the popular belief that the drink aids in weight loss. The results of her most recent study were published in the journal Cell Biochemistry & Function.

To study the effects of green tea on obesity, the research team fed mice a high-calorie diet for four weeks, with both fat and what they call a “cafeteria diet,” which mimics the Western diet. “We give them chocolate, filled cookies, dulce de leche, condensed milk… In other words, the same type of food that many people consume on a daily basis,” says Otton.

After this initial phase, the animals underwent the green tea experiment for another 12 weeks. During this period, they continued on the high-calorie diet, but some of them began receiving standardized green tea extract at a dose of 500 mg per kilogram of body weight, administered intragastrically (via gavage).

“It’s a method that ensures they all receive the exact dose we want to study. If we put it in water, for example, we’d have no way of knowing how much the animal actually ingested,” says the researcher. For humans, this amount would be equivalent to consuming about 3 grams of green tea per day, or three cups.

However, according to the researcher, not all commercial green tea meets the necessary quality standards. “Ready-made tea bags do not always guarantee the quantity or quality of the compounds. The ideal for consumption would be to use standardized green tea extract, like those found in compounding pharmacies. This is a concentrated way of using the plant, with a guarantee of the presence of flavonoids, which are the health-beneficial compounds present in the green tea plant,” Otton points out.

One methodological difference in the study was the controlled room temperature. The animals were kept in a thermoneutral environment (28 °C) throughout the experiment. Animal facilities generally maintain an average temperature of 22 °C, which represents chronic cold for mice.

“Excessive cold activates compensatory regulatory mechanisms in the animals’ bodies, causing them to expend more energy to stay warm. This can mask the real effects of any substance,” explains the researcher. “If the animals are in a colder environment, the effect of the tea is enhanced by the activation of energy expenditure due to the cold. But by maintaining thermoneutrality, we were able to see the effects of green tea in a ‘clean’ way, without environmental interference,” she explains.

A previous study published in August 2022 in the European Journal of Nutrition found that obese mice treated with green tea experienced a reduction of up to 30% in body weight. “If a person loses 5% to 10% of their body weight, that’s already a lot. So this result in animals is very significant,” says the professor.

Muscular effect

Another highlight of the most recent study was the preservation of muscle morphology. Obesity typically causes a reduction in muscle fiber diameter, but green tea prevented this muscle atrophy. “One way to assess muscle function is to look at fiber diameter. If it increases, we have more active muscle components. Green tea managed to maintain this diameter, showing that it protects muscle against the harmful effects of obesity,” Otton explains.

In addition to morphological data, the researchers evaluated the expression of genes related to glucose metabolism. Treatment with green tea increased the expression of Insr, Irs1, Glut4, Hk1, and Pi3k – genes that are important for glucose uptake and use in muscles. The activity of lactate dehydrogenase (LDH), an enzyme that is essential for glucose metabolism, was also restored.

According to Otton, there is evidence indicating that green tea does not affect the weight of lean animals, suggesting that it acts selectively against excess body fat. “It makes obese animals lose weight but keeps lean animals at a balanced weight. This shows that the tea seems to need an environment with excess nutrients to act, which supports the hypothesis that it acts directly on fat cells.”

Another aspect investigated by the team was the action of the compounds in isolation. “Green tea is a complex matrix with dozens of bioactive compounds. We’ve tried to separate these compounds and study their effects individually, but the whole extract is always more effective. There’s a synergy between the compounds that we can’t reproduce when they’re isolated,” she says.

According to the scientist, one hypothesis explaining the mechanism by which green tea affects obesity involves adiponectin, a protein produced by adipocytes that has anti-inflammatory and metabolic regulation functions. “We conducted a study with adiponectin-knockout mice, meaning they don’t produce it. And in these animals, green tea had no effect. This suggests that adiponectin is a key player in the mechanism of action of the tea,” she comments.

Real-life effects

Despite the encouraging results of the mouse study, Otton points out that it is not yet possible to determine a safe and effective dose of green tea for humans. This is mainly due to the variability of the extracts and the fact that each person behaves differently. “The ideal is chronic consumption, as we see in Asian countries. In Japan, for example, people consume green tea every day, throughout their lives, and obesity rates are low. But this is different from drinking tea for five months and expecting a miraculous weight loss effect,” she ponders.

The researcher argues that natural and accessible treatments should gain ground in the fight against obesity, especially as alternatives to expensive medications that often have side effects. “The idea is to have safe, natural, effective, and high-quality compounds. The Camellia sinensis plant offers this. We’re still studying all the compounds involved, but there’s no doubt that green tea, as a plant matrix rich in flavonoids, has important therapeutic potential.”

The researcher emphasizes that science always seeks to develop practical solutions. “What we see in animals doesn’t always reproduce in humans. But if we want to make this translation to real life, we need to think about all the details, such as ambient temperature. It’s these precautions that increase the validity of our data. We’re far from having all the answers, but we’re getting closer and closer.”

This galaxy has a glowing yellow center and glittering blue outskirts. The colors reflect differences in the average ages, masses and temperatures of the galaxy’s stars. In the heart of the galaxy, the stars tend to be older and smaller. Less massive stars are cooler than more massive stars, and somewhat counterintuitively, cooler stars are redder, while hotter stars are bluer. Farther out along NGC 6000’s spiral arms, brilliant star clusters host young, massive stars that appear distinctly blue.

Hubble collected the data for this image while surveying the sites of recent supernova explosions in nearby galaxies. NGC 6000 has hosted two recent supernovae: SN 2007ch in 2007 and SN 2010as in 2010. Using Hubble’s sensitive detectors, researchers are able to discern the faint glow of supernovae years after the initial explosion. These observations help to constrain the masses of supernova progenitor stars and can indicate if they had any stellar companions.

By zooming in to the right side of the galaxy’s disc in this image, you may see something else yellow and blue: a set of four thin lines. These are an asteroid in our Solar System, which was drifting across Hubble’s field of view as it gazed at NGC 6000. The four streaks are due to different exposures that were recorded one after another with slight pauses in between. These were combined to create this final image. The colors appear this way because each exposure used a filter to collect only very specific wavelengths of light, in this case around red and blue. Having these separate exposures is important to study and compare stars by their colors — but it also makes asteroid interlopers very obvious!

Most people are familiar with the microbes on our skin or in our gut, but recent discoveries have revealed that tumors also host unique communities of bacteria. Scientists are now investigating how these tumor-associated bacteria can affect tumor growth and the response to chemotherapy.

New research, published online in Cell Systems on September 10, 2025, provides a significant breakthrough in this field, identifying a powerful anti-cancer metabolite produced by bacteria associated with colorectal cancer. This finding opens the door to new strategies for treating cancer, including the development of novel drugs that could make existing therapies more potent.

The researchers used a sophisticated large-scale screening approach to test over 1,100 conditions in a type of microscopic worm called C. elegans. Through this, they found that the bacteria E. coli produced a molecule called 2-methylisocitrate (2-MiCit) that could improve the effectiveness of the chemotherapy drug 5-fluorouracil (5-FU).

Using computer modelling, the team demonstrated that the tumor-associated microbiome (bacteria found within and around tumors) from patients was also able to produce 2-MiCit. To confirm the effectiveness of 2-MiCit, the team used two further systems; human cancer cells and a fly model of colorectal cancer. In both cases, they found that 2-MiCit showed potent anti-cancer properties, and for the flies could extend survival.

Professor Filipe Cabreiro, head of the Host-Microbe Co-Metabolism group at the LMS, and group leader at the CECAD Research Cluster in Cologne, explains the significance of the discovery: “We’ve known that bacteria are associated with tumors, and now we’re starting to understand the chemical conversation they’re having with cancer cells. We found that one of these bacterial chemicals can act as a powerful partner for chemotherapy, disrupting the metabolism of cancer cells and making them more vulnerable to the drug.”

The study revealed that 2-MiCit works by inhibiting a key enzyme in the mitochondria (structures inside cells that generate energy for cellular functions) of cancer cells. This leads to DNA damage and activates pathways known to reduce the progression of cancer. This multi-pronged attack weakens the cancer cells and works in synergy with 5-FU. The combination was significantly more effective at killing cancer cells than either compound alone.

Dr Daniel Martinez-Martinez, postdoctoral researcher at the LMS and first author of the paper, says: “Microbes are an essential part of us. That a single molecule can exert such a profound impact on cancer progression is truly remarkable, and another piece of evidence on how complex biology can be when considering it from a holistic point of view. It is really exciting because we are only scratching the surface of what is really happening.”

In collaboration with medicinal chemists, the researchers also modified the 2-MiCit compound to enhance its effectiveness. This synthetic version proved even more powerful at killing cancer cells, demonstrating the potential to develop new drugs based on natural microbial products. Filipe adds: “Using the natural microbial product as a starting point, we were able to design a more potent molecule, effectively improving on mother nature.”

These exciting discoveries highlight how the cancer-associated microbiome can impact tumor progression, and how metabolites produced by these bacteria could be harnessed to improve cancer treatments. These findings are also important in the context of personalized medicine, emphasizing the importance of considering not only the patient, but also their microbes.

This study was primarily funded by the Leverhulme Trust, the Wellcome Trust/Royal Society, the DFG German Research Foundation, and the Medical Research Council.

You could call it a ‘quantum lie detector’: Bell’s test designed by famous physicist John Bell. This test shows whether a machine, like a quantum computer, is truly using quantum effects or just mimics them.

As quantum technologies become more mature, ever more stringent tests of quantumness become necessary. In this new study, the researchers took things to the next level, testing Bell correlations in systems with up to 73 qubits — the basic building blocks of a quantum computer.

The study involved a global team: theoretical physicists Jordi Tura, Patrick Emonts, PhD candidate Mengyao Hu from Leiden University, together with colleagues from Tsinghua University (Beijing) and experimental physicists from Zhejiang University (Hangzhou).

The world of quantum physics

Quantum mechanics is the science that explains how the tiniest particles in the universe — like atoms and electrons — behave. It’s a world full of strange and counterintuitive ideas.

One of those is quantum nonlocality, where particles appear to instantly affect each other, even when far apart. Although it sounds strange, it’s a real effect, and it won the Nobel Prize in Physics in 2022. This research is focused on proving the occurrence of nonlocal correlation, also known as Bell correlations.

Clever experimenting

It was an extremely ambitious plan, but the team’s well-optimized strategy made all the difference. Instead of trying to directly measure the complex Bell correlations, they focused on something quantum devices are already good at: minimizing energy.

And it paid off. The team created a special quantum state using 73 qubits in a superconducting quantum processor and measured energies far below what would be possible in a classical system. The difference was striking — 48 standard deviations — making it almost impossible that the result was due to chance.

But the team didn’t stop there. They went on to certify a rare and more demanding type of nonlocality – known as genuine multipartite Bell correlations. In this kind of quantum correlation, all qubits in the system must be involved, making it much harder to generate — and even harder to verify. Remarkably, the researchers succeeded in preparing a whole series of low-energy states that passed this test up to 24 qubits, confirming these special correlations efficiently.

This result shows that quantum computers are not just getting bigger — they are also becoming better at displaying and proving truly quantum behaviour.

Why this matters

This study proves that it’s possible to certify deep quantum behaviour in large, complex systems — something never done at this scale before. It’s a big step toward making sure quantum computers are truly quantum.

These insights are more than just theoretical. Understanding and controlling Bell correlations could improve quantum communication, make cryptography more secure, and help develop new quantum algorithms.

A solution from nature in the spotlight

DMT is also present in the human brain, and it is currently undergoing clinical trials to aid recovery of brain function after stroke. However, its exact mechanism of action had not been fully understood until now. “It is amazing how we can always turn to Nature to find ingenious solutions for health problems” says co-lead author Mária Deli from the HUN-REN BRC.

The blood-brain barrier as a therapeutic target

“We found that DMT significantly reduced infarct volume and edema formation in a rat stroke model,” explains co-first author Marcell László. In both animal experiments and cell culture models, the authors showed that DMT treatment restored the structure and function of the damaged blood-brain barrier and improved the function of astroglial cells. This psychoactive compound also inhibited the production of inflammatory cytokines in brain endothelial cells and peripheral immune cells, while reduced the activation of brain microglia cells through Sigma-1 receptors.

DMT could serve as therapeutic adjuvant to existing stroke treatments

“The therapeutic options currently available for stroke are very limited. The dual action of DMT, protecting the blood-brain barrier while reducing brain inflammation, offers a novel, complex approach that could complement existing treatments,” says Judit Vigh, co-first author of the work.

Since current stroke therapies do not always result in full recovery, a DMT-based treatment may represent a promising new alternative, mainly in combination with existing methods. The recent findings from researchers in Szeged and Budapest, Hungary, support the development of a therapy that goes beyond the limitations of conventional stroke treatment. Clinical trials on the use of DMT and investigation on its long-term effects are currently ongoing.

Unfortunately, despite its prevalence, the underlying causes of Long COVID and brain fog remain poorly understood. Previous imaging studies have shown some structural changes in the brain, but they could not pinpoint the molecular dysfunctions responsible for the cognitive symptoms. Since it’s difficult to observe the molecules that govern communication between brain cells directly, researchers are left without objective biomarkers to confirm a Long COVID diagnosis or develop therapies.

To address this challenge, a research team led by Professor Takuya Takahashi from the Graduate School of Medicine at Yokohama City University, Japan, has made a significant breakthrough in understanding the cause of Long COVID brain fog. As explained in their paper, published in Brain Communications on October 1, 2025, the team hypothesized that patients with brain fog might exhibit disrupted expression of AMPA receptors (AMPARs) — key molecules for memory and learning — based on prior research into psychiatric and neurological disorders such as depression, bipolar disorder, schizophrenia, and dementia. Thus, they used a novel method called [¹¹C]K-2 AMPAR PET imaging to directly visualize and quantify the density of AMPARs in the living human brain.

By comparing imaging data from 30 patients with Long COVID to 80 healthy individuals, the researchers found a notable and widespread increase in the density of AMPARs across the brains of patients. This elevated receptor density was directly correlated with the severity of their cognitive impairment, suggesting a clear link between these molecular changes and the symptoms. Additionally, the concentrations of various inflammatory markers were also correlated with AMPAR levels, indicating a possible interaction between inflammation and receptor expression.

Taken together, the study’s findings represent a crucial step forward in addressing many unresolved issues regarding Long COVID. The systemic increase in AMPARs provides a direct biological explanation for the cognitive symptoms, highlighting a target for potential treatments. For example, drugs that suppress AMPAR activity could be a viable approach to mitigate brain fog. Interestingly, the team’s analysis also demonstrated that imaging data can be used to distinguish patients from healthy controls with 100% sensitivity and 91% specificity. “By applying our newly developed AMPA receptor PET imaging technology, we aim to provide a novel perspective and innovative solutions to the pressing medical challenge that is Long COVID,” remarks Prof. Takahashi.

While further efforts will be needed to find a definitive solution for Long COVID, this work is a promising step in the right direction. “Our findings clearly demonstrate that Long COVID brain fog should be recognized as a legitimate clinical condition. This could encourage the healthcare industry to accelerate the development of diagnostic and therapeutic approaches for this disorder,” concludes Prof. Takahashi.

In summary, the team’s findings resolve key uncertainties about the biological basis of Long COVID brain fog and may pave the way for novel diagnostic tools and effective therapies for patients suffering from this condition.

Funding information

This clinical trial project was supported by donations from the READYFOR crowdfunding platform. This project was partially supported by Takeda Science Foundation (T.T.), the Japan Agency for Medical Research and Development (AMED) under grant numbers JP24wm0625304 (T.T.), and JST through the Establishment of University Fellowships Towards the Creation of Science Technology Innovation program, under grant JPMJFS2140 (Y.F.).