Aflatoxin B1 Contamination of some Medicinal Herbs Use for the Treatment of Liver Inflammation in Hausaland

Abstract

Aflatoxin B1 (AFB1), is a potent mycotoxin and a common contaminant of food crops and medicinal herbs. In the liver, AFB1 is metabolized by P450 (CYP) to AFB1-8,9-exo-epoxide which binds to DNA to form promutagenic 8,9-dihydro-8-(N7-guanyl)-9-hydroxy-AFB1. In co-infection with hepatitis B virus, 8,9-dihydro-8-(N7-guanyl)-9-hydroxy-AFB1 remained the major cause of liver cancer (hepatocellular carcinoma) worldwide. This research investigated the aflatoxigenic contamination of some common herbs use in Hausaland for the treatment of liver inflammation, and the risk f noor liver cancer in hepatitis B patients, as medicinal herbs are rarely monitored by regulatory institutions. Fungal count and cultural evidence for Aspergillus spp were conducted on roots and leaves of Senna occidentalis (Rai dore), Terminalia macroptera (Kandare), Combretum molle (Gogen damo), Cassia singueana (Runfu), Anogeissus leiocarpus (Marke) and Curcuma domestica (Gangamo) after been identified by experts. Aspergillus spp isolated were probed for aflatoxin producing ability on culture plates by ammonia vapor test and the herbs extracts were developed for Thin Layer Chromatography using Methanol/chloroform mixture as mobile phase on silica gel plates. The AFB1 contents of the herbs were determined using Enzyme-Linked Immunosorbent Assay (ELISA) kits (AgraQuant®) procured from Green Spring Biotech, China and run according to instructions. The Optical Densities were determined on 565nm spectrophotometer, percentage absorbance and the AFB1 content deduced by interpolating with Standards on Excel Spreadsheet. The fungal load in the herbs’ roots and leaves exceeded FAO‘s recommended microbiological limit of 105/g with percentage distribution of 56-87% for Aspergillus spp. Sixty Eight herbs samples were positive on ammonia vapor test and on TLC, AFB1 were detected in the 96 and 87% of the roots and leaves of the herbs respectively with Rf values ranging 0.52-0.53. The roots and the leaves were found contaminated with AFB1 averaged 57.9±SDppbKg-1 and (33.2±SD ppb Kg-1). This research found all the six herbs roots and leaves contaminated with aflatoxin B1 and may pose public health problem including liver cancer.