2,5‐diketopiperazines mitigate the amount of advanced glycation end products accumulated with age in human dermal fibroblasts

Abstract

OBJECTIVE: Glycation is a common non-enzymatic reaction between proteins and sugars, resulting in the formation of advanced glycation end products (AGEs) in the human body. As can be seen in diabetic patients, the accumulation of AGEs in the skin has aesthetic consequences (wrinkles, brown spots and yellowish complexion). Therefore, the objective of this work was to find compounds isolated from natural sources that could eliminate the final AGEs accumulated in the skin with ageing. METHODS AND RESULTS: A preliminary screening performed on a bank of microbial extracts and pure compounds showed that 2,5-Diketopiperazines (DKPs), as well as the extract of Sphingobacterium sp (SNB-CN13), reduced the presence of AGEs in fibroblasts by À28% and À23%, respectively. In this article, we present the dereplication approach used to reveal the presence of 26 different DKPs in the crude extract of Sphingobacterium sp. Bioguided fractionation has led to the isolation of 12 of them, whose identity has been confirmed by HRMS and NMR. A green synthesis approach has been developed to synthesize 3 symmetrical DKPs. The biological activity of all DKPs was evaluated by the development of an in vitro test using immunocytochemistry to reveal the presence of AGE carboxymethyl-lysine in human dermal fibroblasts. CONCLUSION: Our work shows for the first time that DKPs decrease the amount of carboxymethyl-lysine AGE in elderly human dermal fibroblasts grown in vitro. Therefore, diketopiperazines can be considered as compounds of interest for dermatological and cosmetic applications with an anti-ageing aim. R esum e OBJECTIF: La glycation est une r eaction non enzymatique courante entre les prot eines et les sucres, qui entraîne la formation de produits finaux de glycation avanc ee (AGE) dans le corps humain. Comme on peut le voir chez les patients diab etiques, l'accumulation d'AGE dans la peau a des cons equences esth etiques (rides, taches brunes, teint jaunâtre). Par cons equent, l'objectif de ce travail etait de trouver des compos es isol es de sources naturelles qui pourraient eliminer les AGE finaux accumul es dans la peau avec le vieillissement. M ETHODES & R ESULTATS: Un examen pr eliminaire effectu e sur une banque d'extraits microbiens et de compos es purs a montr e que les 2,5-dic etopip erazines (DKP), ainsi que l'extrait de Sphingobacterium sp. (SNB-CN13), r eduisaient la pr esence d'AGE dans les fibroblastes de-28% et-23% respectivement. Dans cet article, nous pr esentons l'approche de d er eplication utilis ee pour r ev eler la pr esence de 26 DKP diff erentes dans l'extrait brut de Sphingobacterium sp. Le fractionnement bioguid e a conduit a l'isolement de 12 d'entre elles, dont l'identit e a et e confirm ee par HRMS et RMN. Une approche de synth ese verte a et e d evelopp ee pour synth etiser 3 DKP sym etriques. L'activit e biologique de toutes les DKP a et e evalu ee par le d eveloppement d'un test in vitro utilisant l'immunocytochimie pour r ev eler la pr esence de carboxym ethyl-lysine AGE dans les fibroblastes dermiques...

Cyclodipeptides: From Their Green Synthesis to Anti-Age Activity

“…Andrè et al recently reported the ability of DKPs 1–2 to reduce AGEs in fibroblasts by 27 ± 1% and 28 ± 1%, respectively, relative to the controls [ 11 ]. We couldn’t find any further data related to DKP anti-age activity in the literature, and thus we used these two compounds as reference in our experiments.…”

“…Furthermore, they have been recently proposed as anti-age compounds, in light of their established activity to reduce advanced glycation end products (AGEs) that accumulate in fibroblasts during ageing [ 11 ]. AGEs accumulation in the skin is known to have negative effects from an aesthetic point of view, such as the formation of wrinkles, yellowish complexion, and brown spots [ 12 ].…”

“…In particular, 15 CDPs were recently tested in vitro for their anti-age properties, with the most active being cyclo(Leu-Leu), cyclo(Met-Met), and cyclo(Pro-Pro) [ 11 ]. In this work, we thus decided to test two of these as reference compounds, in addition with three more CDPs, i.e., cyclo(His-His), cyclo(His-Pro), and cyclo(His-Met), whose structures are shown in Figure 1 .…”

Use of molecular networking to identify 2,5-diketopiperazines in chocolates as potential markers of bean variety

“…0.4 g of defatted chocolate powder was extracted with 2 mL of ethyl acetate for 2 h at room temperature under constant shaking using an overhead shaker (Hettich Labtechnology, Tuttlingen, Germany) (modified from André et al. [ 29 ]). The mixture was then centrifuged for 15 min at 4400 rpm (Eppendorf model 5702, Schönenbuch, Switzerland) and the supernatant was carefully collected using a glass pipette.…”

Diketopiperazine Gels: New Horizons from the Self-Assembly of Cyclic Dipeptides

“…CDPs are indeed attracting interest as drug carriers, thanks to their demonstrated ability to cross membranes and penetrate cells [ 29 ]. Their aggregates can display fluorescence [ 30 ], and they are widely studied for their diverse biological activities [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ], which make them promising for biomedical applications, as recently reviewed [ 39 ]. Further, they are being investigated also for optoelectronic [ 40 ] and catalytic [ 41 ] applications, as biodegradable and environmentally-friendly substitutes of more traditional options.…”