It is well accepted that frequent and heavy intake of purine-rich foods causes elevation of serum uric acid levels, which is a risk factor of hyperuricemia. Reducing intestinal absorption of dietary purines may attenuate the elevation of serum uric acid levels and exacerbation of hyperuricemia. This reduction may be achieved by the ingestion of lactic acid bacteria that take up purines in the intestine. In this study, we investigated the degree of uptake and utilization of purines of three lactobacilli strains. Among them, Lactobacillus gasseri PA-3 (PA-3) showed the greatest incorporation of ¹⁴C-adenine. PA-3 also incorporated ¹⁴C-adenosine and ¹⁴C-AMP. Additionally, using defined growth medium, PA-3 demonstrated greater proliferation in the presence of these purines than in their absence. Although further investigation is required, ingestion of PA-3 may lower serum uric acid levels by reducing intestinal absorption of purines in humans.

Excessive intake of purine-rich foods elevates serum levels of uric acid. Animal and fish meats contain high amounts of inosine and its related purines, and the reduction of taking those purines is crucial for the improvement of serum uric acid levels. We previously showed that Lactobacillus gasseri PA-3 (PA-3) incorporates adenosine and its related purines and that oral treatment with PA-3 reduced adenosine absorption in rats. This study investigated whether PA-3 also incorporates IMP (inosine 5′-monophosphate), inosine, and hypoxanthine, and whether it reduces their absorption in rats. PA-3 was incubated in vitro with radioisotope (RI)-labeled IMP, inosine, and hypoxanthine, and the incorporation of these compounds by PA-3 was evaluated. In addition, rats were orally administered PA-3 along with RI-labeled inosine 5′-monophosphate, inosine, or hypoxanthine, and the ability of PA-3 to attenuate the absorption of these purines was determined. PA-3 incorporated all three purines and displayed greater proliferation in the presence than in the absence of these purines. Oral administration of PA-3 to rats reduced the absorption of IMP, inosine, and hypoxanthine. These results indicate that PA-3 reduces the absorption of purines contained in foods and it is expected that PA-3 contributes attenuation of the excessive intake of dietary purines.

Excessive intake of purine-rich foods elevates serum uric acid levels, making it a risk factor for hyperuricemia. We hypothesized that lactic acid bacteria ingested with food might utilize purines and contribute to their decreased absorption in the intestines, thereby preventing hyperuricemia. We previously reported that Lactobacillus gasseri PA-3 (PA-3) incorporates adenosine/inosine and related purines and that oral ingestion of PA-3 reduced the absorption of these purines in rats. However, it is unclear whether PA-3 also decreases the absorption of other purines, such as guanosine 5′-monophosphate (GMP) and guanosine. This study investigated whether PA-3 incorporates GMP and guanosine and reduces their absorption in rats. PA-3 incorporated both purines, with ¹⁴C-GMP uptake being greater than that of ¹⁴C-guanosine. Radioactivity in rat blood was significantly lower 30, 45, and 60 minutes after administration of ¹⁴C-GMP plus PA-3 than after administration of ¹⁴C-GMP alone and was significantly lower 15 minutes after administration of ¹⁴C-guanosine plus PA-3 than after administration of ¹⁴C-guanosine alone. PA-3 incorporates GMP and guanosine in vitro. Oral administration of PA-3 with GMP and guanosine reduces the intestinal absorption of these purines in vivo. These findings, together with those of previous studies, indicate that PA-3 reduces the absorption of major purines contained in foods. PA-3 may also attenuate the excessive absorption of dietary purines in humans, protecting these individuals against hyperuricemia.

Lactococcus lactis has been reported unable to directly incorporate mononucleotides but instead requires their external dephosphorylation by nucleotidases to the corresponding nucleosides prior to their incorporation. Although Lactobacillus gasseri PA-3 (PA-3), a strain of lactic acid bacteria, has been found to incorporate purine mononucleotides such as adenosine 5’-monophosphate (AMP), it remains unclear whether these bacteria directly incorporate these mononucleotides or incorporate them after dephosphorylation to the corresponding nucleosides. This study evaluated whether PA-3 incorporated radioactively-labeled mononucleotides in the presence or absence of the 5’-nucleotidase inhibitor α,β-methylene ADP (APCP). PA-3 took up ¹⁴C-AMP in the presence of APCP, as well as incorporating ³²P-AMP. Furthermore, radioactivity was detected in the RNA/DNA of bacterial cells cultured in the presence of ³²P-AMP. Taken together, these findings indicated that PA-3 incorporated purine mononucleotides directly rather than after their dephosphorylation to purine nucleosides and that PA-3 utilizes these purine mononucleotides in the synthesis of RNA and DNA. Although additional studies are required to identify purine mononucleotide transporters in PA-3, this study is the first to show that some lactic acid bacteria directly incorporate purine mononucleotides and use them for growth.

We investigated the effects of Lactobacillus paragasseri OLL2716 on gastrointestinal symptoms in healthy adults with gastric complaints. In this randomized, double-blind, placebo-controlled trial, 174 healthy Japanese adults were randomly assigned to an OLL2716 or placebo group, and each group consumed 85 g of yogurt containing L. paragasseri OLL2716 or placebo yogurt daily for 12 weeks. The primary endpoint was the change in gastric symptoms from baseline as per the participants’ questionnaires at 6 and 12 weeks. The secondary endpoints were changes from baseline in the short-form Nepean Dyspepsia Index (SF-NDI), the Gastrointestinal Symptom Rating Scale (GSRS), and the Council on Nutrition Appetite Questionnaire-Japanese (CNAQ-J) scores at 6 and 12 weeks. The primary endpoint data showed that the changes in “epigastric pain” at 6 and 12 weeks were significantly decreased in the OLL2716 group compared with those in the placebo group. Additionally, the changes in “epigastric pain syndrome-like symptoms” were significantly decreased in the OLL2716 group compared with those in the placebo group at 6 weeks. The SF-NDI items that improved at 6 weeks were “irritable, tense, or frustrated”, “enjoyment of eating or drinking”, and “tension”, which are sub-scales related to mental stress. The items “Over-all” in the GSRS and “feeling hungry” in the CNAQ-J significantly improved in the OLL2716 group compared with the placebo group at 12 weeks. The results suggest that regular intake of L. paragasseri OLL2716 may improve both gastric discomfort and mental stress in healthy adults with gastric complaints, such as postprandial fullness or early satiety.