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Proanthocyanidin Characterization and Bioactivity of Extracts from Different Parts of Uncaria tomentosa L. (Cat ’ s Claw)

View Article: PubMed Central - PubMed

ABSTRACT

Apart from alkaloids, bioactive properties of Uncaria tomentosa L. have been attributed to its phenolic constituents. Although there are some reports concerning low-molecular-weight polyphenols in U. tomentosa, its polymeric phenolic composition has been scarcely studied. In this study, phenolic-rich extracts from leaves, stems, bark and wood (n = 14) of Uncaria tomentosa plants from several regions of Costa Rica were obtained and analysed in respect to their proanthocyanidin profile determined by a quadrupole-time-of-flight analyser (ESI-QTOF MS). Main structural characteristics found for U. tomentosa proanthocyanidins were: (a) monomer composition, including pure procyanidins (only composed of (epi)catechin units) and propelargonidins (only composed of (epi)afzelechin units) as well as mixed proanthocyanidins; and (b) degree of polymerization, from 3 up to 11 units. In addition, U. tomentosa phenolic extracts were found to exhibit reasonable antioxidant capacity (ORAC (Oxygen Radical Absorbance Capacity) values between 1.5 and 18.8 mmol TE/g) and antimicrobial activity against potential respiratory pathogens (minimum IC50 of 133 µg/mL). There were also found to be particularly cytotoxic to gastric adenocarcinoma AGS and colon adenocarcinoma SW620 cell lines. The results state the particularities of U. tomentosa proanthocyanidins and suggest the potential value of these extracts with prospective use as functional ingredients.

No MeSH data available.


General chemical structure of B-type proanthocyanidins (composed by (epi)catechin units) and propelargonidins (composed by (epi)afzelechin units).
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antioxidants-06-00012-f001: General chemical structure of B-type proanthocyanidins (composed by (epi)catechin units) and propelargonidins (composed by (epi)afzelechin units).

Mentions: Table 2 summarizes the m/z signals corresponding to [M−H]− ions of proanthocyanidins detected in the U. tomentosa extracts following the DI-ESI-QTOF MS analysis described in the methodology. Theoretical m/z data are also included in Table 2. In addition, Figure 1, Figure 2, Figure 3 and Figure 4 show amplifications of mass spectra corresponding to leaves, stems, bark and wood extracts, respectively. For the four types of U. tomentosa extracts, proanthocyanidins resulted to be composed by units of (epi)catechin and/or (epi)afzelechin linked through B-type linkages (Figure 1). However, some differences in molecular composition and degree of polymerization (DP) were found among extracts from the different parts of the plant. Proanthocyanidins in extracts from U. tomentosa leaves included pure procyanidins -only composed by (epi)catechin units- with a DP between 3 and 9 units-, pure propelargonidins -only composed by (epi)afzelechin units- with a DP between 3 and 8 units, and mixtures of both of them -composed by (epi)catechin and (epi)afzelechin units-, with a DP up to 10 units (decamers) (Table 2, Figure 2). For instance, in the case of pentamers (DP = 5) six signals were detected, corresponding to pure procyanidins (5 units of (epi)catechin) (m/z = 1441.308), pure propelargonidins (5 units of (epi)afzelechin units) (m/z =1361,331), and mixed proanthocyanidins containing 4, 3, 2, or 1 units of (epi)catechin and, respectively, 1, 2, 3 or 4 units of (epi)afzelechin (m/z = 1425.311, 1409.316, 1393.321, 1377.326, respectively) (Table 2, Figure 2).


Proanthocyanidin Characterization and Bioactivity of Extracts from Different Parts of Uncaria tomentosa L. (Cat ’ s Claw)
General chemical structure of B-type proanthocyanidins (composed by (epi)catechin units) and propelargonidins (composed by (epi)afzelechin units).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384175&req=5

antioxidants-06-00012-f001: General chemical structure of B-type proanthocyanidins (composed by (epi)catechin units) and propelargonidins (composed by (epi)afzelechin units).
Mentions: Table 2 summarizes the m/z signals corresponding to [M−H]− ions of proanthocyanidins detected in the U. tomentosa extracts following the DI-ESI-QTOF MS analysis described in the methodology. Theoretical m/z data are also included in Table 2. In addition, Figure 1, Figure 2, Figure 3 and Figure 4 show amplifications of mass spectra corresponding to leaves, stems, bark and wood extracts, respectively. For the four types of U. tomentosa extracts, proanthocyanidins resulted to be composed by units of (epi)catechin and/or (epi)afzelechin linked through B-type linkages (Figure 1). However, some differences in molecular composition and degree of polymerization (DP) were found among extracts from the different parts of the plant. Proanthocyanidins in extracts from U. tomentosa leaves included pure procyanidins -only composed by (epi)catechin units- with a DP between 3 and 9 units-, pure propelargonidins -only composed by (epi)afzelechin units- with a DP between 3 and 8 units, and mixtures of both of them -composed by (epi)catechin and (epi)afzelechin units-, with a DP up to 10 units (decamers) (Table 2, Figure 2). For instance, in the case of pentamers (DP = 5) six signals were detected, corresponding to pure procyanidins (5 units of (epi)catechin) (m/z = 1441.308), pure propelargonidins (5 units of (epi)afzelechin units) (m/z =1361,331), and mixed proanthocyanidins containing 4, 3, 2, or 1 units of (epi)catechin and, respectively, 1, 2, 3 or 4 units of (epi)afzelechin (m/z = 1425.311, 1409.316, 1393.321, 1377.326, respectively) (Table 2, Figure 2).

View Article: PubMed Central - PubMed

ABSTRACT

Apart from alkaloids, bioactive properties of Uncaria tomentosa L. have been attributed to its phenolic constituents. Although there are some reports concerning low-molecular-weight polyphenols in U. tomentosa, its polymeric phenolic composition has been scarcely studied. In this study, phenolic-rich extracts from leaves, stems, bark and wood (n = 14) of Uncaria tomentosa plants from several regions of Costa Rica were obtained and analysed in respect to their proanthocyanidin profile determined by a quadrupole-time-of-flight analyser (ESI-QTOF MS). Main structural characteristics found for U. tomentosa proanthocyanidins were: (a) monomer composition, including pure procyanidins (only composed of (epi)catechin units) and propelargonidins (only composed of (epi)afzelechin units) as well as mixed proanthocyanidins; and (b) degree of polymerization, from 3 up to 11 units. In addition, U. tomentosa phenolic extracts were found to exhibit reasonable antioxidant capacity (ORAC (Oxygen Radical Absorbance Capacity) values between 1.5 and 18.8 mmol TE/g) and antimicrobial activity against potential respiratory pathogens (minimum IC50 of 133 µg/mL). There were also found to be particularly cytotoxic to gastric adenocarcinoma AGS and colon adenocarcinoma SW620 cell lines. The results state the particularities of U. tomentosa proanthocyanidins and suggest the potential value of these extracts with prospective use as functional ingredients.

No MeSH data available.