www.elsevier.com/locate/bcdf Available online at www.sciencedirect.com Structural characterization of a biologically active glucan isolated from a hybrid mushroom strain pfle1v of Pleurotus florida and Lentinula edodes Praloy K. Maji a , Ipsita K. Sen a , K. Sanjana P. Devi b , Tapas K. Maiti b , Samir R. Sikdar c , Syed S. Islam a,n a Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore 721102, West Bengal, India b Department of Biotechnology, Indian Institute of Technology (IIT) Kharagpur, Kharagpur 721302, West Bengal, India c Division of Plant Biology, Bose Institute, Centenary Building, P-1/12, C.I.T. Scheme, VII M, Kolkata 700054, West Bengal, India article info Article history: Received 7 May 2013 Received in revised form 5 September 2013 Accepted 6 September 2013 Keywords: Hybrid mushroom Glucan NMR spectroscopy Biological activity abstract A water soluble glucan isolated from hot aqueous extract of the fruit bodies of an edible hybrid mushroom pfle1v of Pleurotus florida and Lentinula edodes, consisting of terminal, (1-3,6)-, two (1-6)- and two (1-3)-linked β-D-glucopyranosyl moieties in a molar ratio of nearly 1:1:2:2 showed macrophages, splenocytes, and thymocytes activation. The structure of the repeating unit of the glucan was established on the basis of chemical analysis (acid hydrolysis, methylation, periodate oxidation study, and Smith degradation) and NMR studies ( 1 H, 13 C, DEPT-135, TOCSY, DQF-COSY, NOESY, ROESY, HSQC, and HMBC). This glucan contained a backbone of β-(1-3)-,(1-6)-glucose residues with branching at O-6 position of one of the (1-3)-linked residues. & 2013 Elsevier Ltd. All rights reserved. 1. Introduction Edible mushrooms are excellent foods which can be incorpo- rated into well balanced diets due to their low content of fat, energy, and high content of dietary fiber and functional com- pounds (Brene, 2010; Manzi, Aquqzzi, & Pizoferrato, 2001). β-glucans are long chain polysaccharides present in the cell wall of fungi, yeasts, certain bacteria, and plants. These are not found in animal; hence, these carbohydrates can be recognized by the inherent immune systems of vertebrates (Brown & Gordon, 2003). They can directly activate leucocytes and phagocytes (Smiderle et al., 2008) and also stimulate the proinflammatory mediators, such as cytokines and che- mokines (Scheperkin & Quinn, 2006), and possess anti-tumor (Mizuno et al., 1990), anti-oxidative (Toklu et al., 2006), anti- inflammatory (Dore et al., 2007) and immunomodulating (Zhang, Cui, Cheung, &Wang, 2007) activities. Various immu- noenhancing polysaccharides from edible mushrooms (Bhunia et al., 2011; Mandal et al., 2010) and hybrid mush- rooms (Maity et al., 2011; Patra et al., 2011) were reported earlier. Four different polysaccharides isolated from Pleurotus florida (Rout, Mondal, Chakraborty, & Islam, 2006, 2008; Rout, Mondal, Chakraborty, Pramanik, & Islam, 2004, 2005) were also reported by our group. A biologically active water insoluble polysaccharide Lentinan, from Lentinula edodes, con- taining (1-3), (1-6)-β-D-glucan (Sasaki & Takasura, 1976), is widely used for cancer therapy. Water soluble polysacchar- ides (Chihara, Hamuro, Maeeda, Arai, & Fukuoka, 1970; 2212-6198/$ - see front matter & 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.bcdf.2013.09.002 n Corresponding author. Tel.: þ91 03222 276558x437; Mobile: þ91 9932629971; fax: þ91 03222 275329. E-mail address: sirajul_1999@yahoo.com (S.S. Islam). Bioactive Carbohydratesand DietaryFibre 2 (2013) 73–83