To investigate the antidiabetic property of Merremia emarginata (M. emarginata) Burm. F. plant in streptozotocin induced diabetic rats. The dose dependent effects of 28 days oral treatment with methanol extract (100, 200 and 400 mg/kg) from the plant of M. emarginata on blood glucose level, body weight, insulin, total hemoglobin, glycosylated haemoglobin (HbA1C), total protein, serum urea, serum creatinine and carbohydrate metabolizing enzymes were evaluated in streptozotocin induced diabetic rats. Histology of pancreas was also studied. A significant decrease in blood glucose, serum urea and serum creatinine and significant increase in body weight, insulin and protein level were observed in diabetic rats treated with M. emarginata. Treatment with M. emarginata resulted in a significant reduction of HbA1C and an increase in total hemoglobin level. The activities of carbohydrate metabolizing enzymes such as hexokinase were significantly increased whereas glucose-6-phosphatase, fructose-1, 6-bisphosphatase were significantly decreased by the administration of M. emarginata in diabetic rats. Histology of diabetic rats treated with M. emarginata showed the pancreatic β-cells regeneration. These findings suggest that M. emarginata has potent antidiabetic activity in streptozotocin induced diabetic rats.

Lactic acid bacteria (LAB) have the potential to degrade intestinal oxalate and this is increasingly being studied as a promising probiotic solution to manage kidney stone disease. In this study, oxalate degrading LAB were isolated from human faeces and south Indian fermented foods, subsequently assessed for potential probiotic propertyin vitroandin vivo. Based on preliminary characteristics, 251 out of 673 bacterial isolates were identified as LAB. A total of 17 strains were found to degrade oxalate significantly between 40.38% and 62.90% and were subjected to acid and bile tolerance test. Among them, nine strains exhibited considerable tolerance up to pH 3.0 and at 0.3% bile. These were identified asLactobacillus fermentumandLactobacillus salivariususing 16S rDNA sequencing. Three strains,Lactobacillus fermentumTY5,Lactobacillus fermentumAB1, andLactobacillus salivariusAB11, exhibited good adhesion to HT-29 cells and strong antimicrobial activity. They also conferred resistance to kanamycin, rifampicin, and ampicillin, but were sensitive to chloramphenicol and erythromycin. The faecal recovery rate of these strains was observed as 15.16% (TY5), 6.71% (AB1), and 9.3% (AB11) which indicates the colonization ability. In conclusion, three efficient oxalate degrading LAB were identified and their safety assessments suggest that they may serve as good probiotic candidates for preventing hyperoxaluria.

Calcium oxalate (CaOx) is the major constituent of about 75% of all urinary stone and the secondary hyperoxaluria is a primary risk factor. Current treatment options for the patients with hyperoxaluria and CaOx stone diseases are limited. Oxalate degrading bacteria might have beneficial effects on urinary oxalate excretion resulting from decreased intestinal oxalate concentration and absorption. Thus, the aim of the present study is to examine the in vivo oxalate degrading ability of genetically engineered Lactobacillus plantarum (L. plantarum) that constitutively expressing and secreting heterologous oxalate decarboxylase (OxdC) for prevention of CaOx stone formation in rats. The recombinants strain of L. plantarum that constitutively secreting (WCFS1OxdC) and non-secreting (NC8OxdC) OxdC has been developed by using expression vector pSIP401. The in vivo oxalate degradation ability for this recombinants strain was carried out in a male wistar albino rats. The group I control; groups II, III, IV and V rats were fed with 5% potassium oxalate diet and 14th day onwards group II, III, IV and V were received esophageal gavage of L. plantarum WCFS1, WCFS1OxdC and NC8OxdC respectively for 2-week period. The urinary and serum biochemistry and histopathology of the kidney were carried out. The experimental data were analyzed using one-way ANOVA followed by Duncan’s multiple-range test. Recombinants L. plantarum constitutively express and secretes the functional OxdC and could degrade the oxalate up to 70–77% under in vitro. The recombinant bacterial treated rats in groups IV and V showed significant reduction of urinary oxalate, calcium, uric acid, creatinine and serum uric acid, BUN/creatinine ratio compared to group II and III rats (P < 0.05). Oxalate levels in kidney homogenate of groups IV and V were showed significant reduction than group II and III rats (P < 0.05). Microscopic observations revealed a high score (4+) of CaOx crystal in kidneys of groups II and III, whereas no crystal in group IV and a lower score (1+) in group V. The present results indicate that artificial colonization of recombinant strain, WCFS1OxdC and NC8OxdC, capable of reduce urinary oxalate excretion and CaOx crystal deposition by increased intestinal oxalate degradation.

Aim The aim of the present study is to constitutively express heterologous oxalate decarboxylase (OxdC) in Lactobacillus plantarum and to examine its ability to degrade oxalate in vitro for their future therapy against enteric hyperoxaluria. Method and Results In this study, we generated a recombinant strain of Lb. plantarum to constitutively overexpress B. subtilis oxalate decarboxylase (oxdC) using a host lactate dehydrogenase promoter (P_ldhL). The recombinant Lb. plantarum was able to degrade more than 90% oxalate compared to 15% by the wild type. In addition, the recombinant strain also had higher tolerance up to 500 mmol l⁻¹ oxalate. Conclusion We developed a recombinant Lb. plantarum NC8 that constitutively expressed heterologous oxalate decarboxylase and degraded oxalate efficiently under in vitro conditions. Significance and impact of study The long-term aim is to develop an efficient strain for future therapy against oxalosis.