698 Original article doi: 10.12980/jclm.4.2016J6-176 ©2016 by the Journal of Coastal Life Medicine. All rights reserved. Screening of marine algae (Padina sp.) from the Lengeh Port, Persian Gulf for antibacterial and antifungal activities Azadeh Taherpour, Bita Archangi * , Sadraddin Ghaemmaghami, Hossein Zolgharnein, Kamal Ghanemi Department of Marine Science and Oceanography, Faculty of Marine Biology, Khorramshahr University of Marine Science and Technology, Khorramshahr, Iran Journal of Coastal Life Medicine 2016; 4(9): 698-702 Journal of Coastal Life Medicine *Corresponding author: Bita Archangi, Department of Marine Science and Oceanography, Faculty of Marine Biology, Khorramshahr University of Marine Science and Technology, Khorramshahr, Iran. E-mail: bita.archangi@gmail.com The journal implements double-blind peer review practiced by specially invited international editorial board members. 1. Introduction To date, infectious diseases are one of the main causes of high mortality in global human societies. Synthetic drugs and medicines ultimately are led to increase antibiotic resistance. Infectious diseases caused by bacteria and fungi have raised awareness to improve public health and protect global economies. Drug resistant infections especially with bacterial involvement are still a major challenge. Therefore, it is essential to discover new antibiotic compounds from alternative sources including oceans and marine organisms. Marine natural sources such as seaweeds and marine algae can be excellent alternative to remedy the situation by screening, developing and manufacturing antibacterial and antifungal compounds from novel bioactive substances. There is an increasing demand for therapeutic drugs from natural products. Recently, the high potential to contribute marine organisms, especially algae to the discovery of new bioactive substances is being increased[1]. The new therapeutic agents should be effective and have a novel mechanism of action regarding resistance behavior[2]. Marine algae are potential renewable resources in the world. Algae are considered as diverse source of secondary metabolites having a broad spectrum of biological activities such as antimicrobial[3], antiviral[4], antifungal[5], anti-allergic[6], anti- cancer[7], anti-fouling[8] and antioxidant[9] that have been used to develop the pharmaceutical industries. Despite the importance of medicinal properties and pharmaceutical applications of marine algae, few pharmacological researches undertaken to detect novel therapeutic agents for infectious diseases treatments[10]. There are many scientific records with reference ARTICLE INFO ABSTRACT Objective: To evaluate the antibacterial efficacy of different solvent extracts of Padina sp. against selected human pathogenic bacteria and fungi species such as Escherichia coli, Shigella sp., Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa, Aspergillus flavus and Candida albicans. Methods: Various solvents including methanol, ethyl acetate, chloroform and hexane were used to acquire crude extracts from marine algae Padina sp. After crude preparation, antibacterial and antifungal activities were screened against clinically important human pathogenic bacteria using disc and well diffusion methods. For all the bacterial species used in this research, minimum inhibitory concentration was undertaken considering various solvent extracts of Padina sp. To ensure the accuracy of experiments, a positive control was also included. Results: Confirmed that hexane is the best solvent to extract antimicrobial agents from Padina sp. Among selected bacteria, S. aureus was the most sensitive test microorganism. While, all other microorganisms showed resistance against methanol, ethyl acetate, chloroform extracts. In fact, by increasing concentration of hexane extract, inhibition of S. aureus growth or antimicrobial activity was increased. Growth inhibition zone in well method showed better results compared to disc diffusion method. The minimum inhibitory concentration and minimum bactericidal concentration of hexane extract were 15 and 30 mg/mL against S. aureus, respectively. All Padina sp. extracts did not reveal any antifungal activities against fungi species in this study. Conclusions: Brown algae extracts showed sufficient antibacterial properties against S. aureus. Therefore, Padina sp. in this research can be a good candidate to design and manufacture novel antibacterial agents used in pharmaceutical industries. Article history: Received 5 Sep 2016 Accepted 12 Sep 2016 Available online Keywords: Padina sp. Antibacterial Antifungal Lengeh Port Persian Gulf journal homepage: www.jclmm.com