*Corresponding Author Address: Prof. Wanigasekara Daya Ratnasooriya, Department of Zoology, University of Colombo, Colombo 03, Sri Lanka; E mail: wdr@zoology.cmb.ac.lk World Journal of Pharmaceutical Sciences ISSN (Print): 2321-3310; ISSN (Online): 2321-3086 Published by Atom and Cell Publishers © All Rights Reserved Available online at: http://www.wjpsonline.com/ Research Article In vitro sun screening activity of Sri Lankan orthodox black tea (Camellia Sinensis linn) Wanigasekara Daya Ratnasooriya 1 , Jayakody Ralalage Anusha Chandra Jayakody 1 , Sellapulige Rexy Denzil Rosa 2 , Chatura Dayendra Tissa Ratnasooriya 3 1 Department of Zoology, 2 Department of Physics and 3 Faculty of Medicine, University of Colombo, Sri Lanka Received: 02-12-2013 / Revised: 10-12-2013 / Accepted: 30-01-2014 ABSTRACT Currently, there is demand for the development of herbal sunscreen formulations to suppress harmful effects of UV rays. In this regard, this study, was conducted to investigate the sun screen potential of Sri Lankan Orthodox black tea (made from buds and top most leaves of Camellia sinensis L plant) using three grades (Dust No:1, Broken Orange Pekoe and Orange Pekoe) using UV spectroscopic technique and Mansur equation. Sun Protection Factor (SPF) value was determined using 20% aqueous extracts (Black tea brews). The results revealed that all three tea samples had markedly high absorbance values (1.4 to 4.2) at 290-320 nm range and SPF values above 15 which are considered as the threshold value for good sunscreen. The SPF value of Dust No:1, B.O.P.F and O.P were respectively 36, 23 and 22. This is a novel finding for Sri Lankan black tea. It is concluded that Sri Lankan black tea, especially, Dust No: 1 can function as an efficient sunscreen agent and has great promise to be developed as cheap, safe and effective topical botanical sunscreen acting via multiple mechanisms (considering its other reported bioactivities). Key words: Black tea, Dust No: 1, Broken Orange Pekoe, Orange Pekoe, sunscreen, photo-protection, sun protection factor, Camellia sinensis INTRODUCTION The earth is continuously bombarded with ultraviolet rays (UV-R) from the sun, which are harmful to human skin, the outermost covering of the body, and hair [1]. Human skin and hair are very susceptible target organs to UV radiation [1]. There are three main categories of UVRs depending on their wave length;: UVC (200- 280nm), UVB (280-320 nm) and UVA (320-400 nm)[1,2,3]. Of these, over exposure of UVB is mainly responsible for causing deleterious effects on the skin, such as sunburn, erythrema, inflammation, hyperpigmentation (tanning), rough texture, wrinkling, hyperplasia, local immunosupression , genotoxicity, photoageing, photocarcinogenesis [1,2,4,5,6]. In this context, it is of interest to note that UVB rays are primary cause of skin cancer [1,2,7]; the most common human cancer is skin cancer [8] and more than one million new cases of skin cancer is documented each year in United States of America alone [6]. However, luckily, skin cancer is almost fully curable if treated before it has a chance to spread [7,8]. Dermatologists, strongly recommend using a sunscreen (a photoprotective) with a sun protection factor (SPF) value of 15 or grater preferably year around to protect the skin against harmful UV rays, especially, the UVB [7,8].Currently, in the market several topical sunscreen formulations are available both synthetic and herbal in the form of creams, lotions, oils, gels, sprays to be applied on to the skin [1,2,3,6,9]. The use of synthetic sunscreens appears to be limited as there is a risk of developing contact and/or an irritant dermatitis, hypersensitivity, allergies and even melanomas and skin cancers [6,10,11]. Also, their safety following long term use is not established [10,11]. Further, these are capable of interfering only with certain selected pathways involved in skin carcinogenesis [3,9,10] and often these stain clothings [7]. On the other hand, herbal sunscreens are claimed to be