Grases Felix, Rodriguez Adrian, Costa-Bauza Antonia
Laboratory of Renal Lithiasis Research, University Institute of Health Sciences Research (IUNICS-IdISPa) and Faculty of Science of the University of the Balearic Islands, Palma, Spain.
PLoS One. 2014 Oct 21;9(10):e111184. doi: 10.1371/journal.pone.0111184. eCollection 2014.
To assess the capacity of methylxanthines (caffeine, theophylline, theobromine and paraxanthine) to inhibit uric acid crystallization, and to evaluate their potential application in the treatment of uric acid nephrolithiasis.
The ability of methylxathines to inhibit uric acid nucleation was assayed turbidimetrically. Crystal morphology and its modification due to the effect of theobromine were evaluated by scanning electron microscopy (SEM). The ability of theobromine to inhibit uric acid crystal growth on calculi fragments resulting from extracorporeal shock wave lithotripsy (ESWL) was evaluated using a flow system.
The turbidimetric assay showed that among the studied methylxanthines, theobromine could markedly inhibit uric acid nucleation. SEM images showed that the presence of theobromine resulted in thinner uric acid crystals. Furthermore, in a flow system theobromine blocked the regrowth of post-ESWL uric acid calculi fragments.
Theobromine, a natural dimethylxanthine present in high amounts in cocoa, acts as an inhibitor of nucleation and crystal growth of uric acid. Therefore, theobromine may be clinically useful in the treatment of uric acid nephrolithiasis.
评估甲基黄嘌呤（咖啡因、茶碱、可可碱和副黄嘌呤）抑制尿酸结晶的能力，并评估它们在治疗尿酸肾结石中的潜在应用。
采用比浊法测定甲基黄嘌呤抑制尿酸成核的能力。通过扫描电子显微镜（SEM）评估可可碱作用下的晶体形态及其变化。使用流动系统评估可可碱抑制体外冲击波碎石术（ESWL）产生的结石碎片上尿酸晶体生长的能力。
比浊法测定表明，在所研究的甲基黄嘌呤中，可可碱能显著抑制尿酸成核。扫描电子显微镜图像显示，可可碱的存在导致尿酸晶体更薄。此外，在流动系统中，可可碱可阻止ESWL后尿酸结石碎片的再生长。
可可碱是可可中大量存在的一种天然二甲基黄嘌呤，可作为尿酸成核和晶体生长的抑制剂。因此，可可碱在治疗尿酸肾结石方面可能具有临床应用价值。
