A review of mulberry leaves and fruit finds that their compounds may change the makeup of gut bacteria, which could then affect how the body handles energy. Researchers from Wroclaw Medical University led the study into whether the plant’s active ingredients can alter the gut microbiome.
A larger study of how mulberry compounds affect gut microorganisms included a review of both white mulberry (Morus alba) and black mulberry (Morus nigra). The findings from that review showed that black mulberry fruit produced the most noticeable results.
The Mulberry Plant
For a very long time, people have eaten mulberry as food and employed it within traditional medicine. The plant holds many bioactive compounds, among them polyphenols and polysaccharides, which may affect the bacteria living inside the human body, according to Anna Prescha, PhD, DSc, a professor at Wroclaw Medical University, who works in the Department of Dietetics and Bromatology.
Different mulberry species contain different compounds. Mulberry leaves contain 1-deoxynojirimycin (DNJ), which affects carbohydrate metabolism, along with polyphenols and polysaccharides. Black mulberry fruit contains high levels of anthocyanins and other phenolic compounds, as well as polysaccharides.
Processing Matters
The way plant material gets treated makes a real difference. Methods like drying, fermentation, and extraction change how much of each compound is present and what proportion they occur in. That means two preparations made from the very same starting material can end up quite different in their composition and how they work inside the body.
The review found that mulberry leaf and fruit preparations may change the composition and activity of the gut microbiota. Several studies reported shifts in beneficial bacteria alongside increased production of short-chain fatty acids, including acetate, propionate, and butyrate.
Short-Chain Fatty Acids
When gut microbes break down food, they produce these substances, which play a key role in keeping the intestines working normally. Some studies have found that shifts in the makeup of the microbiota were tied to better readings on measures connected to glucose and lipid metabolism.
Not every preparation produced the same results. The material being studied, along with how it was processed, seemed to shape the outcome.
Polysaccharides From Fruit
One example comes from black mulberry fruit polysaccharides. Scientists used a variety of extraction methods to produce fractions with distinct structures, which led to varying degrees of utilization by gut microbes. The fractions made through water extraction and those processed with pectate lyase showed the strongest prebiotic potential.
Research on mulberry leaf polysaccharides points to the importance of structural features. The molecular weight and monosaccharide composition of these compounds may decide which bacteria can break them down and which short-chain fatty acids are eventually formed.
Combined Preparations Work Best
In several trials, researchers joined parts of mulberry fruit for use in animals eating a high-fat diet. One particular piece of work put together a portion rich in polyphenols with a portion rich in polysaccharides from white mulberry fruit. When both were given together to the animals, the mixture caused more beneficial changes in their gut microbes than either portion did by itself.
Some measures tied to metabolic syndrome and intestinal health improved alongside shifts in the gut’s microbial population. A separate experiment involving transplantation of the gut microbiota was carried out with the same model. Microbiota from animals that had received the combined mulberry fraction were transferred to other creatures. These recipients also showed gains in some metabolic irregularities, lending support to the idea that alterations in the microbiota may help bring about the effects of the mulberry treatment.
“These findings suggest that what matters is not only the presence of an individual compound, but also the complex composition of the preparation, the proportions of its compounds, and their interactions,” emphasizes Prof. Prescha.
The Nutri-Sfera Origin Story
The idea behind the project came from the Nutri-Sfera Student Research Group at the Department of Dietetics and Bromatology at Wroclaw Medical University. Two students who have since finished their studies suggested the subject matter. Marta Miszczak, from the Dietetics program, and Karolina Kłosowska-Buryło, from the Pharmacy program, both contributed to proposing the topic.
The collaboration united nutritional and pharmaceutical approaches to studying mulberry and the gut microbiota, according to “This fitted very well with the interdisciplinary nature of the study. It combined a perspective on mulberry as a plant material with a specific composition with an analysis of its potential effects on the microbiota and metabolism,” who adds Prof. Prescha’s name to the account.
Human Studies Are Missing
While the experimental results look promising, a key issue has yet to be settled. There is still no research involving humans that looks at how mulberry preparations affect the gut microbiota.
Animal models and in vitro experiments supply most of the current evidence on this topic. The remaining challenge is to compare their findings with what happens in humans.
Key Findings
Gut bacteria and metabolic pathways may be influenced by compounds found in mulberry leaves and fruit, according to the review. Two species, white mulberry (Morus alba) and black mulberry (Morus nigra), yield distinct outcomes. Drying, fermentation, and extraction alter the composition of bioactive compounds present. Preparations derived from both leaves and fruit appear capable of changing gut microbiota composition and activity. Some studies reported shifts favoring beneficial bacteria alongside increased short-chain fatty acid production. Combined polyphenol and polysaccharide fractions demonstrated stronger effects in mice compared to single fractions. Microbiota transplantation experiments further supported the idea that microbiota changes underlie mulberry’s effects.
The Limits of Current Research
What the review sets forth as its findings is a record of what the research has revealed thus far, alongside what remains to be examined through human trials. The case made is encouraging, though the advantages it points to have yet to be proven in people.
The guidance from Prof. Prescha is useful: “rather than searching for a single universal product, it is worth determining which combination of species, plant part, composition, and processing method produces a specific biological effect.”
The review’s conclusions represent a current picture of what the science says about the plant. It has served as both food and medicine for a very long time, and the latest evidence points to its chemical makeup having effects that go beyond simple nutrition — these compounds may actually alter the community of microorganisms living within the human body.
The results so far look promising, though many questions remain unanswered, and work at Wroclaw Medical University continues.
Key Facts Box
- Plant species: White mulberry (Morus alba), black mulberry (Morus nigra)
- Key compound: 1-deoxynojirimycin (DNJ)
- Fatty acids: Acetate, propionate, butyrate
- Extraction technique: Water extraction, pectate lyase
- Study model: Mice fed a high-fat diet
Timeline
| Date | Event |
|---|---|
| Not specified | Nutri-Sfera Student Research Group formed at Wroclaw Medical University |
| Not specified | Topic proposed by Marta Miszczak (Dietetics) and Karolina Kłosowska-Buryło (Pharmacy) |
| Not specified | Review published as part of broader examination of mulberry compounds |
A review offers a look at what the science says now about the plant. It has served as both food and medicine for a long time. New data suggest its compounds do more than feed the body — they appear to shape the ecosystem within it.
Source material: “Mulberry may reshape gut bacteria and influence metabolism,” ScienceDaily.
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