A high molecular weight complex lipid, aliphatic polyaldehyde tetraterpenediol polyacetal from Botryococcus braunii (L race)
Bertheas, O; Metzger, P; Largeau, C
| HERO ID | 2832197 |
|---|---|
| In Press | No |
| Year | 1999 |
| Title | A high molecular weight complex lipid, aliphatic polyaldehyde tetraterpenediol polyacetal from Botryococcus braunii (L race) |
| Authors | Bertheas, O; Metzger, P; Largeau, C |
| Journal | Phytochemistry |
| Volume | 50 |
| Issue | 1 |
| Page Numbers | 85-96 |
| Abstract | An aliphatic polyaldehyde tetraterpenediol polyacetal (APTP) has been isolated from the heptane extract of an Ivorian strain of the L chemical race of the green microalga, Botryococcus brauniil Size exclusion HPLC showed an unimodal distribution from M-r 5000 to 4000000, with a peak at 237000. The chemical structure of this soluble high M-r polymer was determined by spectroscopic methods and chemical degradation. The aliphatic polyaldehyde moiety is probably derived from the condensation-polymerization of a n-C-32 diunsaturated alpha,omega-dialdehyde, involving an aldolization-dehydration mechanism. The acyclic tetraterpenediol is a 14,15-dihydroxy lycopa-18-ene, closely related to lycopadiene, the characteristic hydrocarbon produced by the L race of B. braunii. Acetalation of the polyaldehyde with the tetraterpenediol occurs for ca. seven aldehyde functions out of ten. Further extraction of the biomass with chloroform allowed isolation of an additional amount of polymer exhibiting by HPLC analysis a higher M-peak (400000), but with similar spectroscopic features. The polymers were isolated from the heptane and chloroform extracts in a yield of 13.2 and 2% of the dry biomass, respectively Moreover, the algaenan, i.e. the non-hydrolyzable highly aliphatic insoluble biomacromolecular material, present in the outer walls, has been isolated in a yield of 12.3% of the biomass, using a new isolation process which avoids the formation of artifactual materials and allows for a more efficient hydrolysis of some sterically hindered oxygenated functions. FTIR analysis and 400 degrees C pyrolysis of this algaenan, and comparisons with APTP clearly indicated that the molecular structure of the algaenan of the L race is based on an aliphatic polyaldehyde network. Moreover, the results suggested that the algaenan is likely to be formed from the hydrolysis of a highly condensed or reticulated form of APTP, which cannot be extracted with solvents. (C) 1998 Elsevier Science Ltd. All rights reserved. |
| Wosid | WOS:000077888100014 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Keyword | Botryococcus braunii; Chlorophyceae; alga; L race; aliphatic polyaldehyde; tetraterpenediols; 14,15-dihydroxy lycopa-18-ene; acetal; absolute configuration; algaenan |