Holzforschung, Vol. 63, pp. 551–558, 2009 • Copyright  by Walter de Gruyter • Berlin • New York. DOI 10.1515/HF.2009.095 Article in press - uncorrected proof Extractives in bark of different conifer species growing in Pakistan Stefan Willfo ¨r 1, *, Mumtaz Ali 2 , Maarit Karonen 3 , Markku Reunanen 1 , Mohammad Arfan 2 and Reija Harlamow 1 1 A ˚ bo Akademi Process Chemistry Centre, Laboratory of Wood and Paper Chemistry, A ˚ bo Akademi University, Turku, Finland 2 Phytopharmaceutical and Nutraceutical Research Labs, Institute of Chemical Sciences, University of Peshawar, Peshawar, Pakistan 3 Department of Chemistry, Laboratory of Organic Chemistry and Chemical Biology, University of Turku, Turku, Finland *Corresponding author. Laboratory of Wood and Paper Chemistry, A ˚ bo Akademi University, Porthansgatan 3, FI-20500, Turku, Finland Phone: q358-2-215-4729 Fax: q358-2-215-4868 E-mail: swillfor@abo.fi Abstract The amount and composition of lipophilic and hydrophilic extractives, including proanthocyanidins, has been ana- lysed as a first screening in the bark of six Pakistani coniferous tree species, namely Pinus wallichiana, Pinus roxburghii, Pinus gerardiana, Abies pindrow, Taxus fuana and Cedrus deodara. The predominant lipophilic extrac- tives were common fatty and resin acids, fatty alcohols and sterols. In all bark samples, short-chain fatty acids were more abundant than long-chain fatty acids. Gen- erally, the amount of free fatty acids was also larger than the amount of triglycerides. Oleic acid was the most common fatty acid, except in C. deodara, where ligno- ceric acid dominated. The largest amounts of fatty acids and fatty alcohols were found in P. wallichiana and P. gerardiana. P. gerardiana contained an exceptionally large amount of resin acids, approximately 3% of the bark weight, compared to the other species. The amount of free sterols was approximately at the same level or larger than the amount of steryl esters in most samples. In addition to proanthocyanidins, different known lignans, stilbenes, ferulates and flavonoids were generally pre- dominant amongst the hydrophilic extractives. Resvera- trol glycoside was abundant in P. wallichiana, while C. deodara and P. gerardiana contained large amounts of lignans and lignan derivatives. All bark extracts contained large amounts of proanthocyanidin-related catechin and its derivatives. Furthermore, C. deodara and P. roxburghii contained quite large amounts of taxifolin. In particular, P. wallichiana and A. pindrow are potential rich sources of proanthocyanidins, representing approximately 16% and 5% of the bark weight, respectively. Keywords: bark; extractives; lignans; proanthocyanidins; stilbenes; tannins. Introduction Extracts from various species from the conifers family Pinaceae contain a number of compounds with biological activities. The amount and composition of lipophilic and hydrophilic extractives obtained from various parts of the tree render possible their industrial usage as bioactive substances. For example, recent research revealed that softwood knots, i.e., branch bases inside tree stems, commonly contain large amounts of lignans (e.g., Willfo ¨r et al. 2004a,b, 2007). Lignans and other polyphenols are known to have remarkable biological activities being antibacterial, antifungal, antiviral, antioxidant, anticancer, anti-inflammatory and analgesic (Tiwari et al. 2001; Will- fo ¨ r et al. 2003; Pietarinen et al. 2006; Cosentino et al. 2007; Va ¨ limaa et al. 2007). Another potential source of bioactive compounds is the stem bark. The barks of pines are used since more than 20 centuries, e.g., for wound healing (Packer et al. 1999). Essential oils derived through steam distillation of needles and bark of Pinus and Picea species are widely applied as ointments, bathing oils, or inhaling drugs for curing a wide range of diseases (Grassmann et al. 2003). In the New World, the bark of pines is utilised as bever- age, food, and also remedy for various conditions, such as inflamed wounds or ulcers, now recognised to have free radical involvement (Chandler et al. 1979; Packer et al. 1999). Various plant products, such as wood tar and resins, exhibit antimicrobial effects against bacteria, and might therefore become tools to treat infections. Conifers have recently been the focus of much atten- tion as a source of pharmacologically active procyani- dins, one subclass of proanthocyanidins (Zhang et al. 1990; Escribano-Bailo ´ n et al. 1992; Jerez et al. 2007). The procyanidins extracted from the bark of Pinus pinas- ter have been utilised as nutritional supplement through- out the world and as a remedy for cardiovascular diseases (Jerez et al. 2007). The analysis of bark tannins and proanthocyanidins has also been cited in the litera- ture (Malik and Khan 1967; Karchesy and Hemingway 1980; Ahmad et al. 1989; Karonen et al. 2004a). Some bark extracts have been shown to be strong antioxidants and radical scavengers (Pietarinen et al. 2006). To the best of our knowledge, there is only limited information on the chemical composition of bark extrac- tives for the pine and fir species included in the present study. Sugars and some specific compounds have been studied from Pinus roxburghii (Beri 1970; Ahmad et al. 1990; Rawat et al. 2006) and the bark has also been eval- uated for removal of toxic metals from industrial waste water (Ahmad et al. 2005). Abies pindrow bark was crudely examined by Beri and Sharma (1972), while, for example, Joshi et al. (1998) isolated some specific compounds. Brought to you by | Dalhousie University Authenticated Download Date | 5/19/15 3:21 AM