Condensed tannin

Different types of condensed tannins exist, such as the procyanidins, propelargonidins, prodelphinidins, profisetinidins, proteracacinidins, proguibourtinidins or prorobinetidins.

[2] One particular type of condensed tannin, found in grape, are procyanidins, which are polymers of 2 to 50 (or more) catechin units joined by carbon-carbon bonds.

[11] Pycnogenol is a dietary supplement derived from extracts from maritime pine bark, is standardised to contain 70% procyanidin and is marketed with claims it can treat many conditions; however, according to a 2020 Cochrane review, the evidence is insufficient to support its use for the treatment of any chronic disorder.

[15] Their interactions with proteins can be studied by isothermal titration calorimetry[16] and this provides information on the affinity constant, enthalpy and stoichiometry in the tannin-protein complex.

Depolymerisation is an indirect method of analysis allowing to gain information such as average degree of polymerisation, percentage of galloylation, etc.

The depolymerised sample can be injected on a mass spectrometer with an electrospray ionization source, only able to form ions with smaller molecules.

These techniques are generally called depolymerisation and give information such as average degree of polymerisation or percentage of galloylation.

If thiolysis is done directly on plant material (rather than on purified tannins), it is, however, important to subtract naturally occurring free flavanol monomers from the concentration of terminal units that are released during depolymerisation.