Microbial Biotechnology

Electronic Journal of Biotechnology ISSN: 0717-3458 Vol. 11 No. 3, Issue of July 15, 2008
© 2008 by Pontificia Universidad Católica de Valparaíso -- Chile Received June 7, 2007 / Accepted May 22, 2008
DOI: 10.2225/vol11-issue3-fulltext-10
RESEARCH ARTICLE

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

 Aminul Islam
Research and Development Centre
Natreon Inc.
Cl-18A, Sector -ІІ, Salt Lake City
Kolkata 700091, India
Tel: 033 23216459
Fax: 033 23371910
E-mail: natr1910@dataone.in

Runa Ghosh*
Research and Development Centre
Natreon Inc.
Cl-18A, Sector -ІІ, Salt Lake City
Kolkata 700091, India
Tel: 033 23216459
Fax: 033 23371910
E-mail: natr1910@dataone.in 

Dipankar Banerjee
Research and Development Centre
Natreon Inc.
Cl-18A, Sector –ІІ, Salt Lake City
Kolkata 700091, India
Tel: 033 23216459
Fax: 033 23371910
E-mail: natr1910@dataone.in

Piali Nath
Research and Development Centre
Natreon Inc.
Cl-18A, Sector –ІІ, Salt Lake City
Kolkata 700091, India
Tel: 033 23216459
Fax: 033 23371910
E-mail: natr1910@dataone.in

Upal Kanti Mazumder
Department of Pharmaceutical Technology
Jadvapur University
Kolkata-700032, India
Tel: 033 23216459
Fax: 033 23371910
E-mail: mazumderu@yahoo.co.in 

Shibnath Ghosal#
Research and Development Centre
Natreon Inc.
Cl-18A, Sector -ІІ, Salt Lake City
Kolkata 700091, India
Tel: 033 23216459
Fax: 033 23371910
E-mail: natr1910@dataone.in; vishnu20024@rediffmail.com

*Corresponding author

Financial support: Natreon Inc, USA.

Keywords: Coenzyme Q10 reduction, electron transport chain humification, paleohumus.

#Present address: Research Adviser, R&D Centre, Indian Herbs Ltd. Saharanpur-247001 (U.P), India.

Abbreviations:

3,8(OH)2-DBP: 3,8 Dihydroxydibenzo-α-pyrone
3-OH-DBP: 3-Hydroxydibenzo-α-pyrone
AUC: area under the curve
BSFTA: N, O-bis (Trimehylysislyl)-triflouro-acetamide
CD: Czapek Dox
DBPs: dibenzo-α-pyrones
FM: fermentation medium
GC-MS: gas chromatography-mass spectrometry
HPFC: high performance flash chromatography
HPLC: high performance liquid chromatography
TMS: trimethylsilyl

Abstract   Full Text

“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.

Supported by UNESCO / MIRCEN network