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Guava (Psidium guajava) Fruit Extract Prepared by Supercritical CO₂ Extraction Inhibits Intestinal Glucose Resorption in a Double-Blind, Randomized Clinical Study

Title data

König, Alice ; Schwarzinger, Bettina ; Stadlbauer, Verena ; Lanzerstorfer, Peter ; Iken, Marcus ; Schwarzinger, Clemens ; Kolb, Peter ; Schwarzinger, Stephan ; Mörwald, Katharina ; Brunner, Susanne ; Höglinger, Otmar ; Weghuber, Daniel ; Weghuber, Julian:
Guava (Psidium guajava) Fruit Extract Prepared by Supercritical CO₂ Extraction Inhibits Intestinal Glucose Resorption in a Double-Blind, Randomized Clinical Study.
In: Nutrients. Vol. 11 (2019) Issue 7 . - No. 1512.
ISSN 2072-6643
DOI: https://doi.org/10.3390/nu11071512

Abstract in another language

Inhibition of intestinal glucose resorption can serve as an effective strategy for the prevention of an increase in blood glucose levels. We have recently shown that various extracts prepared from guava (Psidium guajava) inhibit sodium-dependent glucose cotransporter 1 (SGLT1)- and glucose transporter 2 (GLUT2)-mediated glucose transport in vitro (Caco-2 cells) and in vivo (C57BL/6N mice). However, the efficacy in humans remains to be confirmed. For this purpose, we conducted a parallelized, randomized clinical study with young healthy adults. Thirty-one volunteers performed an oral glucose tolerance test (OGTT) in which the control group received a glucose solution and the intervention group received a glucose solution containing a guava fruit extract prepared by supercritical CO2 extraction. The exact same extract was used for our previous in vitro and in vivo experiments. Blood samples were collected prior to and up to two hours after glucose consumption to quantitate blood glucose and insulin levels. Our results show that, in comparison to the control group, consumption of guava fruit extract resulted in a significantly reduced increase in postprandial glucose response over the basal fasting plasma glucose levels after 30 min (Δ control 2.60 ± 1.09 mmol/L versus Δ intervention 1.96 ± 0.96 mmol/L; p = 0.039) and 90 min (Δ control 0.44 ± 0.74 mmol/L versus Δ intervention −0.18 ± 0.88 mmol/L; p = 0.023). In addition, we observed a slightly reduced, but non-significant insulin secretion (Δ control 353.82 ± 183.31 pmol/L versus Δ intervention 288.43 ± 126.19 pmol/L, p = 0.302). Interestingly, storage time and repeated freeze-thawing operations appeared to negatively influence the efficacy of the applied extract. Several analytical methods (HPLC-MS, GC-MS, and NMR) were applied to identify putative bioactive compounds in the CO2 extract used. We could assign several substances at relevant concentrations including kojic acid (0.33 mg/mL) and 5-hydroxymethylfurfural (2.76 mg/mL). Taken together, this clinical trial and previous in vitro and in vivo experiments confirm the efficacy of our guava fruit extract in inhibiting intestinal glucose resorption, possibly in combination with reduced insulin secretion. Based on these findings, the development of food supplements or functional foods containing this extract appears promising for patients with diabetes and for the prevention of insulin resistance. Trial registration: 415-E/2319/15-2018 (Ethics Commissions of Salzburg).

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Research Institutions
Research Institutions > Research Centres
Research Institutions > Research Centres > Nordbayerisches Zentrum für NMR-Spektroskopie - NMR-Zentrum
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 500 Natural sciences
Date Deposited: 06 Aug 2019 06:40
Last Modified: 10 Feb 2022 09:49
URI: https://eref.uni-bayreuth.de/id/eprint/51775