97 1. INTRODUCTION Podophyllum belongs to the family of Berberidacea of the order Ranunculales and is globally represented largely by three species, the P. hexandrum, P. peltatum, and P. sikkimensis. Its peculiar growth requirements is of well-drained humus rich soil and temperature of not more than 10-20 ºC, persistent largely in the temperate and sub-alpine regions, has restricted the natural occurrence of this species globally. P. hexandrum grows in the Himalayan region of the Indian subcontinent and is known as The Himalayan or Indian mayapple 1 . P.peltatum is found in North America and known as American Mayapple 2 Podophyllotoxin (PTOX) is the most signifcant and medicinally important secondary metabolite isolated from this species. It is obtained abundantly from the roots and rhizome of Podophyllum species. It is enlisted under the List of Essential Medicines released by the World Health Organisation (WHO) in 2017 3 and is the most active naturally occurring cytotoxic product used for the preparation of anti- cancer drugs Etoposide, Teniposide and their derivatives. It is also reported to have anti-viral activity and protective ability against radioactivity damages 1,4-7 . The precursor to podophyllotoxin biosynthesis is the phenylpropanoid pathway 8 . The scattering of genes that govern this extensive pathway are a major limitation Computational Analysis for Regulation of Podophyllotoxin Biosynthesis Pathway in Podophyllum with Potential Substitute Species Utkarsh Srivastava* and Hemant Sood Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology Himachal Pradesh-173 234, India *Email: utkarsha0587@gmail.com ABSTRACT Podophyllum species, the source of important secondary metabolite, podophyllotoxin, is over-exploited for production of anti-cancer drugs endangering this genus globally. Lack of complete knowledge on podophyllotoxin biosynthesis is a major drawback in its cultivation and identifcation for alternative plants. The current study on secoisolariciresinol dehydrogenase, dirigent protein oxidase and pluviatolide synthase identifes their role in regulating podophyllotoxin biosynthesis. The present computational analysis of podophyllotoxin proposes a correlating interconnected network of pathways for podophyllotoxin biosynthesis besides identifying potential substitute species for the biosynthesis of podophyllotoxin and accounting for possible reason for variation in podophyllotoxin yield from diferent species of this genus. Keywords: Podophyllotoxin; Secoisolariciresinol dehydrogenase; Dirigent protein oxidase; Pluviatolide synthase; Podophyllum; BLAST in understanding it 9 . Coniferyl alcohol is converted to pinoresinol which is further reduced to secoisolariciresinol involving enzymes dirigent protein oxidase and coniferyl alcohol dehydrogenase 10-15 . Secoisolariciresinol is converted to matairesinol by secoisolariciresinol dehydrogenase and further on to podophyllotoxin by a series of multi-step reactions 16 , a brief overview of which is given Fig. 1. The biosynthesis of PTOX involves the production other secondary metabolites as hinokinin and yatein which are considered to be its precursors 17-19. This biochemical pathway is found not only in Podophyllum but also various other plant species 20-23 . Not many natural sources are available for obtaining PTOX, but of those present, the rhizomes of Podophyllum species 24 form the major source for the procurement of this important lignan. Due to extensive demand coupled with the slow growth rate of this important plant 25-26 , this species is now endangered, leading to the exploration of other approaches for the chemical synthesis and in-vitro production of this compound 27-32 . But these methods have been unable to adequately supply to fulfil the demand of PTOX on commercial level due to lack of complete conclusive information on the biosynthetic pathway of this metabolite. Figure 1 A schematic flowchart for showing the biosynthesis of podophyllotoxin and the intermediate pathways involved in the process. The texts in red are our enzymes of interest governing the different steps in the biosynthesis of podophyllotoxin. The present work focuses on the utilisation of computational data for Defence Life Science Journal, Vol. 7, No. 2, April 2022, pp. 97-102 DOI : 10.14429/dlsj.7.17445  2022, DESIDOC Received : 25 August 2021, Revised : 14 February 2022 Accepted : 25 February 2022, Online published : 20 June 2022