286 Structural composition and protein precipitation capacity of condensed tannins from purple prairie clover (Dalea purpurea Vent.)
Bibliographic record
Abstract
Condensed tannins (CT) from purple prairie clover (PPC; Dalea purpurea Vent.) have shown anti-Escherichia coli O157:H7 activity in vitro and in vivo, but the composition and structure of these CT are unknown. The objectives of this study were to determine the concentration and composition of CT in different tissues of PPC at differing maturities and to determine their protein-precipitating capacity. Condensed tannins were extracted from leaf, stem, and flower tissues of PPC harvested at vegetative, early flowering (EF), and late flowering (LF) stages. The structural compositions of CT were elucidated by in situ thiolytic degradation and HPLC–mass spectrometry. The general composition of the CT in PPC obtained from thiolytic degradation was corroborated by 1H-13C heteronuclear single quantum coherence nuclear magnetic resonance spectroscopy. The protein-precipitating capacity of isolated CT was determined by their ability to precipitate BSA and ribulose 1,5-disphosphate carboxylase (RuBisCO). Flowers contained the highest CT concentration followed by leaf and stem tissues. As the plant matured, CT concentration decreased in stem tissue but remained relatively constant in leaf and flower tissues. Regardless of plant tissue or maturity, PPC CT consisted mostly of epicatechin (EC; 70–80%) and epigallocatechin (EGC; 20–30%), with minor amounts of catechin and gallocatechin. Leaf CT consisted of more EC (P < 0.01) but less EGC units (P < 0.01) than CT from stem and flowers at both EF and LF stages. The procyanidin:prodelphinidin (PC:PD) ratio was greater (P < 0.05) for leaf CT than for stem and flower CT. The mean degree of polymerization (mDP) was highest for stem CT and lowest for leaf CT. The PC:PD ratio of stem CT decreased and the mDP increased as the plant matured. Leaf CT had higher BSA-precipitating capacity than stem and flower CT (P < 0.001), with EF leaf CT exhibiting the highest capacity (P < 0.001). Leaf and flower CT had a greater ability to precipitate RuBisCO protein than stem CT (P < 0.05). These results demonstrated that PPC CT were predominantly of the procyanidin type and that the concentration and chemical structure varied with different plant tissues and growth periods. Condensed tannins in PPC at the early flower stage exhibited the greatest protein-precipitation capacity.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".