_____________________________________________________________________________________________________ *Corresponding author: E-mail: pkagrawal@gmail.com; Journal of Advances in Medical and Pharmaceutical Sciences 9(3): 1-12, 2016, Article no.JAMPS.28152 ISSN: 2394-1111 SCIENCEDOMAIN international www.sciencedomain.org Factors Affecting Radioprotective Efficacy of Ocimum sanctum (Tulsi) Extract in Mice Mrinalini Tiwari 1 , Rajan Murugan 2 , Rajkumar Tulsawani 3 , Vikram Gota 4 , Rajiv K. Sarin 4 , P. Uma Devi 5 , Rajnedra P. Tripathi 1 , Thangaraj Parimelazhagan 2 , Bilikere S. Dwarakanath 1 and Paban K. Agrawala 1* 1 Institute of Nuclear Medicine and Allied Sciences, Brig SK Mazumdar Road, Timarpur, Delhi 110054, India. 2 Department of Botany, Bharathiar University, Tamilnadu 641046, India. 3 Defence Institute of Physiology and Allied Sciences, Brig SK Mazumdar Road, Timarpur, Delhi 110054, India. 4 Advanced Center Treatment Research and Education in Cancer, Kharghar, Navi Mumbai, 410210, India. 5 Plavilakonam, Thachottukavu, Peyad P.O., Trivandrum 695 573, India. Authors’ contributions This work was carried out in collaboration among all authors. Authors PKA and BSD designed the study and wrote the protocol. Authors MT and RT carried out the animal studies while authors TP and RM did extraction and phytochemical analyses. The work is based on initial leads of authors PUD, RKS and VG took part in phytochemical analyses as well as in designing radiation protocol. Author RPT was involved in all administrative issues. All authors read and approved the final manuscript. Article Information DOI: 10.9734/JAMPS/2016/28152 Editor(s): (1) Hamdy A. Sliem, Internal Medicine, Suez Canal University, Egypt And College of Dentistry, Qassim University and EL-Jouf University, Saudi Arabia. Reviewers: (1) Arti Gupta, Uka Tarsadia University, India. (2) Kelvin K. Juma, Kenyatta University, Kenya. Complete Peer review History: http://www.sciencedomain.org/review-history/15953 Received 4 th July 2016 Accepted 14 th August 2016 Published 26 th August 2016 ABSTRACT Background: Oscimum sanctum (Tulsi) is well reported for its medicinal values in Ayurveda. Although several chemical radioprotectors have shown excellent protection under in vitro conditions, lack of acceptable efficacy under in vivo conditions and/or undesirable toxicity has limited their applications in humans. Tulsi leave extract have shown significant normal tissue radioprotection in cell culture and animal models in preclinical studies. Original Research Article