Molecular fingerprint of bioactive plant extracts through hyphenated techniques and their dentin biomodifying activities

One of the major problems related to the longevity of restorations in dentistry is due to the degradation of collagen present at the dentin/restorative interface. Once exposed during adhesive procedures, due to the inability of resinous monomers to infiltrate and “protect” collagen fibrils, degradation occurs due to hydrolysis or protease action [1]. Thus, dentin biomodification, a biomimetic approach mediated by bioactive agents, has been proposed to improve and strengthen dentin, inducing the formation of crosslinking of collagen fibrils [2]. Currently there is a tendency to use bioactive agents extracted from plant drugs for the development of biomaterials in dentistry, as they act as dentin biomodifiers. Thus, plant drug extracts containing bioactive agents have been applied as dentin primers prior to the application of an adhesive system. In an earlier study [3], extracts of the plant drugs Mastruz (Dysphania ambrosioides), Cat's claw (Uncaria tomentosa), Guaraná (Paullinia cupana), Galla chinensis (Rhus chinensis), and Tannic acid (obtained from Acacia decurrens) used as Primers positively influenced dentin / restorative bond strength when compared to chlorhexidine (positive control). These results were maintained after 6 months of treatment, unlike controls. Due to the complex chemical composition of these extracts, it was proposed to define the phytochemical profile (Fingerprint) of these extracts through hyphenated techniques, such as, UPLC/DAD-ESI/HRMS/MS, in order to better understand the reported activities. Gallic acid ions - m/z 169.0139 [M - H] - were observed in the extracts of Galla chinensis, Guaraná and Mastruz, and in the last two extracts could be attributed as fragments of hydrolysable tannins - m/z> 1000. At Mastruz, citric acid (m/z 191.0197) and malic acid (m/z 133.0142) ions were observed; nonioside A (m/z 409.1704), as well as ions for three kaempferol glycoside derivatives (m/z 417.0841; 431.0995 and 577.1554). Finally, in cat's claw species ions were observed for quinic acid - m/z 191.0562 [M-H] - , which were attributed to the compound itself, and to fragments of chlorogenic acid derivatives - m/z 353.0878 [M-H] - , confirmed by the joint presence of caffeic acid fragments m/z 179.0488 [M-H] - . Ions were also found for quercetin and kaempferol glycosides, as they contain characteristic fragments of these flavonoids, 301.0363 and 284.0317 [M-H] - , respectively. Due to the compounds identified in the medicinal plants addressed in this study, it can be suggested that the dentin biomodifying activities of Guaraná and Galla chinensis species can be attributed to gallic acid and tannins, while Mastruz contains in addition to tannins, flavonoid derivatives, known for the inhibitory action of protease activity [4]. Due to this property, the activity found in the Cat's claw species, seems to be related to flavonoids and possibly chlorogenic acids.

References
[1] PASHLEY, D. H. et al. Journal of Dental Research, v. 83, n. 3, p. 216-21, 2004
[2] BEDRAN-RUSSO, A.K. et al. Dental Materials, v. 30, n. 1, p. 62-76, 2014.
[3] POLASSI et al. Proceedings of the 36º Meeting of SBPqO. Brazilian Oral Research, 2019
[4] CRASCI, L. et al. Crit Rev Food Sci Nutr, v. 58, n. 6, p. 893-904, 2018.