Phosphodiesterase-5 inhibitors and their analogues as adulterants of herbal and food products: analysis of the Malaysian market, 2014–16

<p>Adulteration of herbal health supplements with phosphodiesterase-5 (PDE-5) inhibitors and their analogues is becoming a worldwide problem. The aim of this study was to investigate herbal and food products sold in the Malaysian market for the presence of these adulterants. Sixty-two products that claim to enhance men’s sexual health were sampled between April 2014 and April 2016. These products included unregistered products seized by the Pharmacy Enforcement Division of the Ministry of Health (<i>n</i> = 39), products sent to the National Pharmaceutical Regulatory Agency for pre-registration testing (<i>n</i> = 9) and products investigated under the post-registration market surveillance programme (<i>n</i> = 14). The products were tested against an in-house spectral library consisting of 61 PDE-5 inhibitors and analogues using a validated liquid chromatography-mass spectrometry ion-trap-time-of-flight (LC-MS IT-TOF) method. Thirty-two (82%) of the unregistered products and two (14%) of the registered products were found to be adulterated with at least one PDE-5 inhibitor or analogue, while none of the pre-registration products contained adulterants. A total of 16 different adulterants were detected and 36% of the adulterated products contained a mixture of two or more adulterants. This study has demonstrated that the adulteration of unregistered herbal products in the Malaysian market is an alarming issue that needs to be urgently addressed by the relevant authorities.</p

ARG396-md-10ns

ARG396-md-10ns file to be opened/viewed using Accelrys Discovery Studio or DeepView-Swiss Pdb Viewe

Reverse sequence (c.670_672del)

Chromatogram profile - Reverse sequence (c.670_672del

Reverse sequence (c.1186CT)

FASTA format - Reverse sequence (c.1186CT

wt-lowest-energy-structure

Wild-type pdb file to be opened/viewed using Accelrys Discovery Studio or DeepView-Swiss Pdb Viewe

Forward sequence (c.1186CT)

FASTA format - Forward sequence (c.1186CT

Reverse sequence (c.670_672del)

FASTA sequence format - Reverse sequence (c.670_672del

ASP224-md-10ns

ASP224-md-10ns pdb file to be opened/viewed using Accelrys Discovery Studio or DeepView-Swiss Pdb Viewe

Reverse sequence (c.1186CT)

Chromatogram - Reverse sequence (c.1186CT

Forward sequence (c.670_672del)

FASTA sequence file - Forward sequence (c.670_672del