_____________________________________________________________________________________________________ *Corresponding author: E-mail: anagharanade11@gmail.com; European Journal of Medicinal Plants 19(1): 1-7, 2017; Article no.EJMP.33239 ISSN: 2231-0894, NLM ID: 101583475 Exposition of Role of Diurnal and Seasonal Variation on Latex of Calotropis procera Ait. and Calotropis gigantea L.R.BR. Anagha Ranade 1* , Rabinarayan Acharya 2 , Vinay Shukla 3 and Sudipta Roy 2 1 Regional Ayurved Institute for Fundamental Research, CCRAS, Pune, India. 2 Department of Dravyaguna, IPGT and RA, Gujarat Ayurved University, Jamnagar, India. 3 Pharmaceutical Laboratory, IPGT and RA, Gujarat Ayurved University, Jamnagar, India. Authors’ contributions This work was carried out in collaboration between all authors. Authors AR and RA conceptualized, designed the study and executed it. They also contributed in drafting of the article. Author VS performed the analyses of the study. All authors contributed in logical interpretation. They further read and approved the final manuscript. Article Information DOI: 10.9734/EJMP/2017/33239 Editor(s): (1) Shanfa Lu, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, China. (2) Patrizia Diana, Department of Molecular and Biomolecular Sciences and Technologies,University of Palermo, Palermo, taly. (3) Marcello Iriti, Professor of Plant Biology and Pathology, Department of Agricultural and Environmental Sciences, Milan State University, Italy Reviewers: (1) R. Dhivya, Nirmala College for Women, Tamil Nadu, India. (2) Peter Oluwayinka Akindele, Federal University of Technology, Akure, Nigeria. Complete Peer review History: http://www.sciencedomain.org/review-history/19197 Received 5 th April 2017 Accepted 20 th May 2017 Published 25 th May 2017 ABSTRACT Background: Time (Kala) of collection is an important criterion responsible for the quality of crude drugs of herbal origin. According to their parts used, the guidelines for rutuwise (seasonal) collection of crude plant drugs has been well documented in various treatise of Ayurveda. Among various parts used of medicinal plants, Kshira (latex) of Arka and Shwetarka finds a wide usage in various pharmaceutical processes and formulations in classical literature. The latex has been quoted to be procured in Sharada rutu (September- October) but the scientific reason behind this still remains unexplored. Materials and Methods: The fresh crude latex of both C. gigantean (CG) and C. procera (CP) were collected in clean glass vials regularly in all the six rutu i.e Vasanta (March-April), Grishma (May-June), Varsha (July- August), Sharada (September- October), Hemanta (November- December) and Shishira (January- February). The collection was done for 4 days in each rutu and Original Research Article