Details of the in vitro experiment

On this page you will find detailed charts summarizing the results obtained during the experiment conducted by the Department of Pharmacological and Biomolecular Sciences of the University of Milan. The purpose of the experiment was to determine whether the tannins present in vegetable tanned leather have antibacterial properties.

The experiment was conducted in vitro and involved samples of leather with different types of vegetable tannins (Chestnut, Quebracho and Tara), samples of chrome tanned leather and one sample of synthetic material.  The results confirmed that the tannin contained in the vegetable tanned leather exhibited a powerful antibacterial activity.

%

is the minimum percentage of bacteria that must be eliminated for a substance to be considered an antibacterial.

The study was conducted entirely in a laboratory and involved 6 different materials

3 samples of vegetable tanned leather with different types of vegetable tannins (Chestnut, Quebracho, Tara).

1 sample of chrome tanned leather.

1 sample of chrome tanned leather, then retanned with vegetable tannins.

1 sample of synthetic lining.

2 species of bacteria:

Escherichia coli

Gram negative

Staphylococcus aureus

Gram positive

Results of the Experiment

Vegetable Tanning with Tannin

󬓰

Time Zero

Gram +

%

Antibacterial

Gram –

%

Non-antibacterial

󬓰

After 6 hours

Gram +

%

Antibacterial

Gram –

%

Antibacterial

Chrome Tanning

󬓰

Time Zero

Gram +

%

Non-antibacterial

Gram –

%

Non-antibacterial

󬓰

After 6 hours

Gram +

%

Antibacterial

Gram –

%

Non-antibacterial

Chrome Tanning, Vegetable Retanning

󬓰

Time Zero

Gram +

%

Antibacterial

Gram –

%

Non-antibacterial

󬓰

After 6 hours

Gram +

%

Antibacterial

Gram –

%

Antibacterial

Synthetic Material

󬓰

Time Zero

Gram +

%

Non-antibacterial

Gram –

%

Non-antibacterial

󬓰

After 6 hours

Gram +

%

Non-antibacterial

Gram –

%

Non-antibacterial

A Natural Antibacterial

The experiments conducted prove that the presence of tannin imparts antibacterial properties to vegetable tanned leather. As result, all articles created from leather containing tannins boast a particular characteristic that ensures their durability over time. Go to the page “Tannin, a Natural Antibacterial” for more details.

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