RESUMEN
AIM: The aim of this study was to purify proanthocyanidins from areca nut seeds (P-AN) and to investigate the bactericidal activity and mechanism of the purified products against Streptococcus mutans. METHODS AND RESULTS: Ultra-performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry, Fourier transform infrared, Matrix-assisted laser desorption/ ionization time of flight mass spectrometry (MADLI-TOF-MS), and thiolysis experiment were used for P-AN chemical analysis. Time-kill analysis and glycolytic pH drop were used to evaluate the activity of S. mutans in vitro. Meanwhile, the investigation of the bacteriostatic mechanism included membrane protein, fluidity, permeability, and integrity tests. The results showed that P-AN was a kind of proanthocyanidin mainly composed of B-type proanthocyanidins and their polymers. Moreover, MADLI-TOF-MS and thiolysis experiments demonstrated that the degree of polymerization of P-AN was 13. The time-kill analysis showed that P-AN had strong bactericidal activity against S. mutans. P-AN at minimum inhibitory concentration (MIC) concentrations was able to induce S. mutans death, while complete lethality occurred at 2 MIC. Glycolysis test showed that P-AN significantly inhibited S. mutans acid production (P < .01). The morphological changes of S. mutans were observed by scanning electron microscopy and transmission electron microscopy experiments, which indicated that P-AN destroyed the cellular structure of S. mutans. At the same time, significant changes were observed in membrane proteins, fluidity, permeability, and integrity. CONCLUSION: P-AN can effectively inhibit the activity of S. mutans. P-AN can reduce the erosion of the tooth surface by the acid of S. mutans. P-AN could break the structure of the cell membrane protein of S. mutans. P-AN could destroy the integrity of membrane, resulting in the death of S. mutans.
Asunto(s)
Antibacterianos , Pruebas de Sensibilidad Microbiana , Proantocianidinas , Semillas , Streptococcus mutans , Proantocianidinas/farmacología , Proantocianidinas/aislamiento & purificación , Proantocianidinas/química , Streptococcus mutans/efectos de los fármacos , Semillas/química , Antibacterianos/farmacología , Antibacterianos/aislamiento & purificación , Nueces/química , Extractos Vegetales/farmacología , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificaciónRESUMEN
<b>Background and Objective:</b> Intensive and commercial development of areca nut requires the provision of high-vigour areca nut. This study aimed to evaluate the effect of scarification and seeds biomatriconditioning using endophytic-rhizobacteria in increasing seedlings vigor of areca nut. <b>Materials and Methods:</b> The research was carried out at the Agronomy Unit of Agrotechnology Laboratory, Agriculture Faculty, Halu Oleo University, from November, 2020-March, 2021. The research design was split-plot in a Completely Randomized Design (CRD). The main plot, seed scarification, consisted of 2 treatments, without scarification and scarification. Sub-plots, seeds biomatriconditioning using endophytic-rhizobacteria, consisted of 6 treatments, control, L1-R, M5-R, LA6-R, LA2-E and RJ6-R. <b>Results:</b> The results showed that the scarification treatment did not affect the seedlings vigor of the areca nut. Seed biomatriconditioning using endophytic-rhizobacteria was able to increase seedling vigor both without scarification and with scarification. There were 3 isolates of endophytic-rhizobacteria which were more able to increase the vigor of areca nut without scarification, namely L1-R, LA6-R and LA2-E, with an increase of 137, 104 and 102%, respectively compared to the control, while in scarified seeds, L1-R isolate was able to increase the seedlings vigor of areca nut by 194% compared to the control. <b>Conclusion:</b> Scarification treatment did not affect the vigor of the areca nut. Seed biomatriconditioning with endophytic-rhizobacteria was able to increase the vigor of areca nut seeds either without scarification or with scarification.