Investigation of prebiotic activity of various Salvia L. species growing in Türkiye

Probiotics are evaluated as an economical and safe option for treating numerous chronic diseases and improving human health. They are recognized to modulate host immunity and protect against various infectious and non-infectious diseases. colonization, elimination of pathogens and stimulation of host cells are a few of the significant probiotic properties that influence various functions of the host. Furthermore, prebiotics and non-digestible food substances selectively promote the growth of probiotics and human health through nutrient enrichment and modulation of the gut microbiota and immune system. Medicinal and aromatic plants constitute important plant groups that have been used in public health for centuries. Salvia L. genus is one of the important medicinal and aromatic plant genera. In this study, the prebiotic effects of water and ethanol extracts of Salvia fruticosa L., Salvia huberi Hedge, Salvia sclarea L. and Salvia aethiopis L., which are grown in our country, on Lactobacillus fermentum and Lactobacillus plantarum strains were investigated. Prebiotic activity scores (PAS) of plant extracts, protective effects on probiotic bacteria in simulated gastrointestinal tract, effects on antioxidant activity of probiotic bacteria, effects on cell surface hydrophobicity of probiotic bacteria, phenolic compound use by probiotic bacteria, DPPH free radical scavenging effect of extracts, iron chelating effect, determination of phenolic and flavonoid compounds and HPLC content analysis of plant phenolic compounds were determined. According to the data obtained at the end of the study, the highest PAS value in both bacterial strains was determined in S. huberi ethanol plant extract. In simulated gastric acid L. plantarum 120. and 240. min. results, S. fruticosa water extract (58.76-97.51, respectively) had a % viability reduction value. According to L. fermentum 120. and 240. min. results, S. huberi water extract (31,54-90,06, respectively) showed a decrease in % viability. According to the bile solution results, L. plantarum was detected in S. sclarae ethanol extract at 30, 90 and 180 min. In L. fermentum, % viability decrease was determined in S. fruticosa ethanol extract. According to the results of antioxidant activities of probiotic bacteria after incubation, S. huberi water showed the highest antioxidant activity in both L. fermentum and L. plantarum. According to L. fermentum hydrophobic index results, S. sclarae ethanol extract (45,98) and S. huberi water extract (45,83) gave the highest results. In L. plantarum hydrophobic index results, S. aethiopis ethanol extract (45,38) and S. huberi water extract (44,77) gave the highest hydrophobicity values. In the utilization of phenolic substances after fermentation, it was determined that L. plantarum and L. fermentum bacterial strains used S. sclarae water and ethanol extracts the most. The antioxidant properties of the extracts were determined by DPPH free radical scavenging effect, iron chelating effect, phenolic compounds and flavonoid compounds. According to these results, it was determined that the extract with the best DPPH free radical scavenging effect was S. huberi ethanol extract (0.25). In iron chelating effect, S. huberi ethanol extract (3,07) gave the best result. According to the results of phenolic compounds determination, the highest result was found in the ethanol extract of S. sclarae (812,30). According to the results of flavonoid compounds determination, S. huberi water extract (702,22) showed the highest activity. According to HPLC results, quinic acid, protocatechuic acid, caffeic acid, protocatechuic aldehyde, chlorogenic acid, salicylic acid, naringenin, acacetin, rosmarinic acid, quercetin, luteolin, quercitrin, rutin, hesperidin, chrysin phenolic compounds were determined. Of all the extracts, S. huberi plant species contained the highest content of different phenolic substances (for both extracts). When all the results obtained were evaluated, it was determined that the lactic acid bacteria used in the study metabolized the extracts obtained from different Salvia species were metabolized differently. In this respect, it was determined that Salvia species, a medicinal and aromatic plant used in the study, showed prebiotic activity and could be evaluated to generate synbiotic forms.