Available online www.jocpr.com Journal of Chemical and Pharmaceutical Research, 2013, 5(12):1512-1520 Research Article ISSN : 0975-7384 CODEN(USA) : JCPRC5 1512 Photoprotective properties of Zanthoxylum rhetsa: An in vitro analysis Ramesh Kumar Santhanam 1 , Syahida Ahmad 2 , Faridah Abas 1 , Intan Safinar Ismail 1 , Yaya Rukayadi 1 and Khozirah Shaari 1* 1 Laboratory of Natural Products, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia 2 Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia _____________________________________________________________________________________________ ABSTRACT This research highlights the photoprotective potential of a traditional medicinal plant, Zanthoxylum rhetsa. The photoprotective effect was measured based on the sunscreen protection factor (SPF value) and UV absorption spectrum of various solvent fractions of the plant. The ethyl acetate fraction had the highest SPF value (13.36±0.12) followed by butanol (8.6±0.08), at a test concentration of 100μg/ml. All of the fractions exhibited broad UV spectrum absorption covering both the UVB and UVA regions. The free radical scavenging properties were assessed using the selected antioxidant assays, namely, diphenylpicrylhydrazyl (DPPH) and nitric oxide (NO) free radical scavenging assays. In both assays, the ethyl acetate exhibited the highest activity followed by the butanol fraction. The DPPH and NO free radical scavenging activity were highly expressed in the ethyl acetate fraction with IC 50 values of140±1.20 μg/ml and 50 ± 0.35μg/ml, respectively. The total phenolic and flavonoid content were also determined for all the fractions. These results indicate that the bark extract of Z. rhetsa has great potential for use as a natural active ingredient in broad spectrum sunscreen and anti-ageing cosmetic preparations. Keywords: Zanthoxylum rhetsa; Photoprotective; Sunscreen protection factor(SPF); Broad spectrum ;Antioxidant. _____________________________________________________________________________________________ INTRODUCTION Photo ageing generally occurs due to continuous exposure to UV radiation which stimulates the discharge of free radicals in the skin. The free radicals activate the NF-kB and AP-1 pathways and in reverse inhibit the TGF-B pathway, finally promoting the expression of matrix metalloproteinases (MMPs) and inflammatory cytokines [1]. About 95% of the sun’s UV-radiation reaching the earth’s surface is long wave UV radiation (UVA, 320-400 nm). UVA radiation is able to penetrate the deeper layers of the epidermis and dermis skin, resulting in wrinkle formation and premature ageing [2]. A lower percentage of UV radiation (UVB, 280-320 nm) reaches the earth surface but the radiation is more intense, enough to cause skin reddening and sunburns. Preventing or reducing exposure to UVA and UVB radiation will reduce signs of ageing, deep wrinkles, solar elastosis, coarse textures, telangiectasias and skin cancer [1, 2]. Numerous synthetic organic compounds that absorb UV radiation have been developed to protect skin from the damaging effects of sunlight. These synthetic compounds are either UVA- or UVB-absorbing compounds and hence are used in combination to provide a broad-spectrum UV screen. The necessity to provide high sun protection factor (SPF) and blocking efficiency against both UVA and UVB wavelengths has led to the development of sunscreen formulations with multiple added sunscreen chemicals [3]. Most chemical compounds used in sunscreen products are active in the UVB region while only a few chemicals block the UVA region. It is also a point of growing concern that the safety of many of these compounds has not been established, especially for long- term human use. For example, although broad-spectrum protection is achievable using titanium dioxide, zinc oxides or iron oxides, these are promoted on the basis that they may be less harmful than organic sunscreen absorbers. It should be noted that microfine (nanoparticles) titanium dioxide as a sunscreen product also has no long-term safety data [4]. Hence, there is a need to search for alternative source of effective and safer photoprotective agents that can be utilized in sunscreen products as well as in cosmetic preparations. In general, whole plant extracts have shown