In order to determine whether green tea tannin ameliorates abnormal arginine metabolism as the result of excessive arginine, we have assessed the effects of the administration of green tea tannin mixture in rats treated 30 days with 2% arginine. In the arginine-treated group, the level of guanidino compounds such as arginine (Arg), guanidinoacetic acid (GAA), creatinine (Cr), methylguanidine (MG) and guanidinosuccinic acid (GSA), nitric oxide, urea, protein and glucose increased significantly in the serum, urine and kidney, whereas the oxygen species-scavenging enzymes of kidney were reduced as compared with the non-argmme-treated group. By way of contrast, the administration of green tea tannin reduced blood urea nitrogen and serum creatinine, and reduced the urinary excretion of guanidinoacetic acid, creatinine, and NO2-+NO3-. The increased levels of urinary urea, protein and glucose in the arginine-treated group were also lowered by the administration of green tea tannin. In these groups, the activities of superoxide dismutase and catalase in the kidneywere increased, thereby suggesting the involvement of radicals in the normalizing of kidney function. These results show that the abnormal renal function induced by the adminstration of excessive arginine in rats may be restored by treatment with green tea tannin.

적채시기별 녹차의 침출조건에 따른 유리당, 총질소 및 탄닌함량은 침출온도(55~95℃)가 높을수록 침출시간(30초~10분)이 길수록 증가하였다. 침출조건에 따른 녹차의 관능검사 결과 유리당 및 총 질소는 유의성 있는 상관관계가 나타나지 않았으나 탄닌함량과는 15~30mg/g의 농도에서 변곡점을 형성하는 유의성 있는 상관관계(r=-0.9061)을 나타내었다. 탄닌함량과 관능검사에 의한 녹차의 최적 침출조건은 상급차의 경우 낮은 온도(55~75℃)에서 단시간 (0.5~1분)이었고 중급차는 85℃ 이하에서 2분 이내가 최적 조건이었다.