ABSTRACT
Fructans are categorized as fructose-based metabolites with no more than one glucose in their structure. Agave species possess a mixture of linear and ramified fructans with different degrees of polymerization. Among them, fructooligosaccharides are fructans with low degree of polymerization which might be approachable by high performance thin layer chromatography (HPTLC). Thus, this study used two emblematic Agave species collected at different ages as models to explore the feasibility of HPTLC-based fingerprinting to characterize fructooligosaccharides (FOS) production, accumulation, and behavior through time. To do so, high performance anion exchange was also used as analytical reference to determine the goodness and robustness of HPTLC data. The multivariate data analysis showed separation of samples dictated by species and age effects detected by both techniques. Moreover, linear correlations between the increase of the age in agave and their carbohydrate fraction was established in both species by both techniques. Oligosaccharides found to be correlated to species and age factors, these suggest changes in specific carbohydrate metabolism enzymes. Thus, HPTLC was proven as a complementary or stand-alone fingerprinting platform for fructooligosaccharides characterization in biological mixtures. However, the type of derivatizing reagent and the extraction color channel determined the goodness of the model used to scrutinize agavin fructooligosaccharides (aFOS).
ABSTRACT
Despite the recognition of Agave tequilana Weber var. Azul as raw material for producing tequila and obtaining prebiotics, there are other highly relevant Agave species in Mexico. Oaxaca contains a startlingly diverse range of Agave species; Agave angustifolia Haw. and Agave potatorum Zucc. are two classic specimens with great commercial potential. In this study, we examined the fructan fluctuation in these two species during their lifetime in the field (from 1 to 6 years old). First, we analyzed their morphological diversity based on vegetative characteristics. Subsequently, fructan extracts were analyzed by TLC, FT-IR, and HPAEC-PAD to identify carbohydrates. Multivariate analyses of the morphological parameters indicated a morphological divergence between the two species. Furthermore, we found that the concentration of simple carbohydrates and fructans, as well as the fructan DP, changed during plant development. Glucose, fructose, and fructooligosaccharides (FOS) were more abundant in A. potatorum, while A. angustifolia showed a greater amount of sucrose and fructans with a high DP. Fructan DP heatmaps were constructed using HPAEC-PAD profiles-the heatmaps were very helpful for establishing an easy correlation between age and the carbohydrate types present in the fructan extracts. This study is an important contribution to the agave fructan knowledge of the Mexican agave diversity.
ABSTRACT
MAIN CONCLUSION: The relationship of fructan to plant growth regulators is clearly more complicated than it looks and is likely related to differences between fructan molecules in size and structure as well as localization. Fructans are a complex group of carbohydrates composed mainly of fructose units linked to a sucrose molecule. Fructans are present in plants as heterogeneous mixtures with diverse molecular structures and mass, different polymerization degrees, and linkage types between fructosyl residues. Like sucrose, they are frequently stored in leaves and other organs, acting as carbohydrate reserves. Fructans are synthesized in the cell vacuole by fructosyltransferase enzymes and catabolized by fructan exohydrolase enzymes. Several publications have shown that fructan metabolism varies with the stage of plant development and in response to the environment. Recent studies have shown a correlation between plant growth regulators (PGR), fructan metabolism, and tolerance to drought and cold. PGR are compounds that profoundly influence the growth and differentiation of plant cells, tissues, and organs. They play a fundamental role in regulating plant responses to developmental and environmental signals. In this review, we summarize the most up-to-date knowledge on the metabolism of fructans and their crosstalk with PGR signaling pathways. We identify areas that require more research to complete our understanding of the role of fructans in plants.
Subject(s)
Hexosyltransferases , Plant Growth Regulators , Carbohydrate Metabolism , Fructans , Hexosyltransferases/metabolism , Plant Leaves/metabolism , SucroseABSTRACT
Agavins act as a fermentable dietary fiber and have attracted attention due to their potential for reducing the risk of disease. Therefore, we evaluated the effect of supplementation using 10% agavins with a short-degree of polymerization (SDP) from Agave angustifolia Haw. (AASDP) or Agave potatorum Zucc. (APSDP) along with chicory fructans (RSE) as a reference for 5 weeks, on the energy intake, body weight gain, satiety-related hormones from the gut and blood (GLP-1 and ghrelin), blood glucose and lipids, and short-chain fatty acids (SCFAs) from the gut of ad libitum-fed mice. We evaluated the energy intake daily and weight gain every week. At the end of the experiment, portal vein blood samples as well as intestinal segments and the stomach were collected to measure glucagon-like peptide-1 (GLP-1) and ghrelin using RIA and ELISA kits, respectively. Colon SCFAs were measured using gas chromatography. The energy intake, body weight gain, and triglycerides were lower in the fructan-fed mice than in the STD-fed mice. The AASDP, APSDP, and RSE diets increased the serum levels of GLP-1 (40, 93, and 16%, respectively vs. STD) (P ≤ 0.05), whereas ghrelin was decreased (16, 38, and 42%, respectively) (P ≤ 0.05). Butyric acid increased significantly in the APSDP-fed mice (26.59 mmol g(-1), P ≤ 0.001) compared with that in the AASDP- and RSE-fed mice. We concluded that AASDP and APSDP are able to promote the secretion of the peptides involved in appetite regulation, which might help to control obesity and its associated metabolic disorder.
