Vine tea extracts show antimicrobial activity in a range of laboratory tests, with some experimental formulations performing better than the free compound, according to a review. But the findings do not establish that vine tea or its main flavonoid, dihydromyricetin, is an effective or safe treatment for people.
The review brings together reported studies of dihydromyricetin, also known as ampelopsin, against pathogenic bacteria and fungi. It covers laboratory assays, formulation experiments, molecular and pathway analyses, and selected animal models. Because it is a narrative synthesis rather than a pooled analysis, it does not give one overall study count or a combined experimental sample size.
A concentrated flavonoid in the plant
Dihydromyricetin is described as the predominant flavonoid in vine tea. The review reports that it accounts for about 25% to 45% of the plant’s total flavonoids, while total flavonoids have been reported at about 326.8 milligrams per gram of dry weight. Those figures are approximate and can vary with the extraction method and the plant material used.
In one assay involving five foodborne pathogens, three Gram-negative and two Gram-positive, the test reported significant growth inhibition at a concentration of 3.78 milligrams per millilitre. The review says the activity was generally stronger against Gram-positive bacteria, although the species and testing conditions differed across the cited evidence.
The reported results were not limited to bacteria. Dihydromyricetin activity was reported against Aspergillus flavus at 4 milligrams per millilitre. Silver nanoparticles made with dihydromyricetin produced inhibition zones ranging from 17.6 to 22.2 millimetres against several pathogenic fungi, with Penicillium formosus described as the most sensitive.
Delivery systems changed the test results
Several studies summarized in the review found stronger antibacterial responses when dihydromyricetin was delivered in a different form. A dihydromyricetin co-crystal was associated with a 15-millimetre inhibition zone against carbapenem-resistant Acinetobacter baumannii at 128 micrograms per millilitre.
Chitosan-derived nanoparticles showed greater sensitivity against Staphylococcus aureus at 0.51 milligrams per millilitre than against Escherichia coli at 1.02 milligrams per millilitre. In another comparison, nanocapsules were associated with 78.6% inhibition of a Pseudomonas aeruginosa population, compared with a 70.5% reduction for free dihydromyricetin at 1 milligram per millilitre.
An animal wound model involving S. aureus, P. aeruginosa and Candida albicans reported that wound area fell by 66.87%, from 5.15 to 1.71 square centimetres, over 14 days. That result is a preclinical finding from an animal model, not evidence that the treatment heals infected wounds in humans.
Several possible targets, but no settled mechanism
The review describes the antimicrobial effect as potentially involving several processes at once: damage to the bacterial cell wall, changes in membrane permeability, interference with lipid and energy metabolism, disruption of protein production, and suppression of processes linked to virulence. The authors present these as proposed mechanisms, not as a definitive account of what drives the activity.
One cited study reported that three cell-wall-associated proteins increased after treatment: LtaS by ninefold, LytM by 7.22-fold and SceD by 2.68-fold. The review cautions that changes in protein levels do not by themselves show that these proteins are direct molecular targets.
Molecular profiling and docking analyses point to an interconnected network involving metabolism, ribosomes, nucleotide processes, lipids, oxidative stress and cell membranes. Yet the review says direct causal validation remains limited, so the pathway map is better viewed as a set of leads for further testing than as proof of a single mode of action.
What would be needed before practical use
The evidence is difficult to compare because many studies rely on disk-diffusion or inhibition-zone tests, while reports of the lowest growth-blocking concentration, concentration-response patterns, comparator results and effect sizes are often missing. Extraction methods, compound purity, formulations and assay designs also vary, making it hard to identify a standard level of activity.
The review also describes safety evidence as incomplete. In one rat study, total vine-tea flavonoids given for 12 weeks at 0.3 and 1.5 grams per kilogram were reported not to change general appearance, body weight, behavior, relative organ measurements or blood biochemical measures during treatment or after a two-week recovery period. Histopathology showed no apparent lesions and no delayed toxicity was observed, but the review notes that short-term, single-species findings do not establish human safety.
For food, agricultural or pharmaceutical applications, the review identifies further obstacles: variable antimicrobial potency, efficacy that depends on the formulation, limited toxicology beyond dietary exposure and a lack of regulatory guidelines. It recommends standardized testing, direct experiments to verify the proposed mechanisms, better delivery systems, longer-term safety work and validation in real-world settings.
Paper data and sources
Original title: Review of the Composition and Antimicrobial Roles of Extracts of Vine Tea (Ampelopsis grossedentata).
Authors: Lihui Zhang, Rulin Lei, Qiuya Wu et al.
Journal/Repository: Medical science monitor : international medical journal of experimental and clinical research
Status: Peer-reviewed
First online: 2026-08-21
DOI: 10.12659/msm.953688
Original paper