Biotransformation of 3-hydroxydibenzo-α-pyrone into 3,8 dihydroxydibenzo-α-pyrone and aminoacyl conjugates by Aspergillus niger isolated from native“shilajit”

“shilajit” is a panacea in ayurveda, the indian traditional system of medicine. the major bioactives of “shilajit” have been identified as dibenzo-α-pyrones (dbps), its oligomers and aminoacyl conjugated derivatives. these bioactive compounds play a crucial role in energy metabolism in all animal cells including those of man. 3-hydroxydibenzo-α-pyrone (3-oh-dbp), a key dbp component of “shilajit” is converted, among other products, to another active dbp derivative, viz. 3,8-hydroxydibenzo-α-pyrone, 3,8(oh)2-dbp, in vivo, when its precursor is ingested. 3,8(oh)2-dbp is then involved in energy synthesis in the mitochondria in the reduction and stabilization of coenzyme q10 in the electron transport chain. as the chemical synthesis of 3,8(oh)2-dbp is a complex, multi-step process and economically not readily viable, we envisioned the development of a process using microorganisms for bioconversion of 3-oh-dbp to 3,8(oh)2-dbp. in this study, the biotransformation of 3-oh-dbp is achieved using aspergillus niger, which was involved in the humification process on sedimentary rocks leading to “shilajit” formation. a 60% bioconversion of 3-oh-dbp to 3,8(oh)2-dbp and to its aminoacyl derivatives was achieved. the products were characterized and estimated by high performance liquid chromatography (hplc), high performance flash chromatography (hpfc) and gas chromatography-mass spectrometry (gc-ms) analyses. among the aspergillus species isolated and identified from native “shilajit”, a. niger was found to be the most efficient for this bioconversion.