Development and Evaluation of Bioconverted Milk with Anti-Microbial Effect against Periodontal Pathogens and α-Glucosidase Inhibitory Activity

Abstract

To decrease periodontal pathogens and increase the number of beneficial bacteria, probiotics and bioactive compounds made via microbial bioconversion are recently used. In addition, the interest regarding probiotics-mediated bioconversion with popular medicinal plants is increasing. Artemisia herba-alba, a type of wormwood, has recently been attention as a medicinal plant due to its various bioactive compounds. Therefore, we developed bioconverted milk containing A. herba-alba that effectively inhibited periodontal pathogens and α-glucosidase. To select the appropriate lactic acid bacteria for the probiotic candidate strain, 74 strains of lactic acid bacteria were screened. Among them, Lactiplantibacillus plantarum SMFM2016-RK was chosen as the probiotic due to its beneficial characteristics such as high acid and bile tolerance, antioxidant activity, and α-glucosidase inhibition. Based on the minimal bactericidal concentration against three periodontal pathogens, the following appropriate concentrations of Artemisia herba-alba extract were added to milk: 5 mg/mL of A. herba-alba ethanol extract and 25 mg/mL of A. herba-alba hot-water extract. Four bioconverted milks (BM), BM1, BM2, BM3, and BM4, were produced by combining L. plantarum SMFM2016-RK alone, L. plantarum SMFM2016-RK and ethanol extract, L. plantarum SMFM2016-RK and hot-water extract, and L. plantarum SMFM2016-RK with both extracts. As a result of antimicrobial activity, BM3 inhibited the growth of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis the most, and BM4 suppressed the growth of Fusobacterium nucleatum the most. In addition, bioconverted milk containing A. herba-alba (BM2, BM3, and BM4) inhibited α-glucosidase more effectively than BM1. The whole genome of L. plantarum SMFM2016-RK was obtained, and 3135 CDS, 67 tRNA, and 16 RNA were predicted. The genome annotation of L. plantarum SMFM2016-RK revealed 11 CDS related to proteolysis and amino acid metabolism and 2 CDS of phenolic acid-metabolizing enzymes. In conclusion, A. herba-alba-added milk bioconverted by L. plantarum SMFM2016-RK displayed both the growth inhibitory effect on periodontal pathogens and the α-glucosidase inhibitory activity; thus, it necessitates to evaluate the effects on the alleviation of periodontal diseases and glycemic control through future animal experiments.