# Litholytic Activities of Natural Bioactive Compounds and Their Mechanism Insights
## 5 Litholytic Activity of Other Compounds
### In Vivo Investigations
The same restorative effect was observed in the bladder. Additionally, lupeol reduced the level of oxalate supersaturation in tissues. The authors reported that the anti-lithiasis effect of lupeol was involved in different mechanisms, including cytoprotective activity, inhibition of oxalate-induced toxic manifestations, and reduction of free radical production. More interesting, the anti-nephrolithiasis effect of lupeol was evaluated in a rat lithiasis model giving a PDD containing 3% glycolic acid. The oral administration of lupeol (extracted from _Crataeva unrula_) at 35 mg/Kg by [53] showed a significant reduction in oxalate and calcium to normal values (2.74 vs. 2.83 mg/day and 0.30 vs. 0.31 mg/day, respectively) while no significant reduction was observed for uric acid. Simultaneously, lupeol restored the excretion of magnesium and glycosaminoglycans (GAG) to normal (1.05 vs. 1.26 mg/day and 0.56 vs. 0.58 mg/day, respectively) and significantly reduced the excretion of GST and the lysosomal marker enzymes of the kidneys (Glu and NaG) to normal compared to lithiasis rats (2.40 vs. 3.73 units/mg creatinine/h, 0.28 vs. 0.72 units/mg creatinine/h, and 0.29 vs. 0.76 units/mg creatinine/h, respectively). Furthermore, LDH excretion was significantly reduced compared to lithiasis rats (0.40 vs. 0.51 units/mg creatinine/h). In 2008, lupeol at 50 mg/Kg/day for 28 days enhanced the activities of both renal marker enzymes (ALP and \(\gamma\)-GT) and antioxidant enzymes (SOD, CAT, and GPx), reduced the activity of glycolic acid oxidase (GAO), and restricted the oxalate-induced peroxidase changes in kidney tissue [55]. The authors suggested that this effect was achieved by the transmembrane stabilizing effects, due to the increase in the surface area/volume of the cells, and by the antioxidant activity, due to the CH3 group present in the C-17 position of the lupeol structure. Further, few authors evaluated, in vivo, the effect of other terpen on violtitiasis rats [24; 52]. The nephrolithiasis effect of betulin at 35 mg/Kg/day for 15 days was evaluated in violtitiasis induced by the insertion of a piece of zinc (10-12 mg) followed by 2% of ammonium oxalate [52]. In this study, betulin restored the levels of non-enzymatic antioxidants (GSH, NPSH, vitamin C, and vitamin E) and antioxidant enzymes (SOD, GPx, and CAT), and glutathione-related enzymes (GST, GR, and G6 PD) in the kidneys and bladder. In parallel, the level of oxalate supersaturation in the tissues was reduced. Recently, [24] evaluated the effect of the same compound (isolated from _Aerva lunata_) on nephrolithiasis rats induced by EG 0.75%. At 2 mg/kg/day for 28 days, betulin significantly increased urine volume (21.50 mL), excretion of calcium, oxalate, phosphate, and magnesium levels. At the same time, betulin significantly reduced the level of BUN, creatinine, and the size of calculi. The authors suggested that betulin acts through different mechanisms, including the diuretic effect, inhibition of the oxalate oxidase enzyme responsible for stone formation, and reducing the risk of obstructed urine flow. Only one piece of research elaborated by [PERSON] et al. [57] reported the effect of two furanochromes (khellin and visnagin) on EG-induced hyperoxaluria in rats. In this study, khellin and visnagin at 5 and 10 mg/kg/day significantly decreased the incidence of CaOx crystal deposition in animals in the nephrolithiasisic group. Whereas these two compounds did not affect urinary parameters (pH, citrate, calcium, and oxalate), from this study, the authors suggested that khellin and visnagin interfere with calcium blocking activity and not with citrate reabsorption [57]. Carotenoids are proven to play an important role in nutrition and health [63]. However, the effect of carotenoids on kidney stone formation is lacking. One compound, crocin, has been investigated for its nephrolithiasis activity.