Isolation and identification of Three Thio-sildenafil Analogues in Dietary Supplements
KUO-CHIH LAI1, YI-CHU LIU1, YUNG-CHIH LIAO1, YUN-LIAN LIN2, LI-YAO TSAI1,
JER-HUEI LIN3 AND CHI-FANG LO1*
1. Food and Drug Administration, Department of Health, Executive Yuan 161-2, Kuen Yang Street, Nan-kang 115, Taipei, Taiwan, R.O.C.
2. National Research Institute of Chinese Medicine 155-1, Sec. 2, Li Nung Street, Pei-tou 112, Taipei, Taiwan, R.O.C.
3. Graduate Institute of Pharmacognosy, Taipei Medical University 250, Wu Xin Street, Hsin-i 110, Taipei, Taiwan, R.O.C.
(Received: December 23, 2009; Accepted: June 8, 2010)
ABSTRACT
(Received: December 23, 2009; Accepted: June 8, 2010)
Three compounds were found to have been illegally added to dietary supplements marketed for erectile dysfunction. The structures of these compounds were identified with NMR, HRMS, IR, UV and LC/MS/MS, after comparison with the structure of sildenafil, data showed that the oxygen atom of the carbonyl group in the heterocyclic ring had been replaced with a sulfur atom, these thio-sildenafil analogues were identified as thiosildenafil, thiohomosildenafil and hydroxythiohomosildenafil. Since their structures were similar to that of sildenafil, according to structure-activity relationship, the side effects of these analogues might also associate with that of sildenafil. In accordance with this finding, thio-sildenafil analogues have been included in the inspection list of illegal adulterants in Taiwan. From January to October 2009, thiosildenafil was detected in 6 samples, thiohomosildenafil was detected in 4 samples and hydroxythiohomosildenafil was detected in 3 samples.
Key words: thiosildenafil, thiohomosildenafil, hydroxythiohomosildenafil, NMR