Bioactivities and Compositions of Betula nigra Essential Oils

Abstract

The essential oils of Betula nigra (river birch, Betulaceae) buds, leaves, and inner bark were extracted by hydrodistillation and analyzed by GCMS. The bud essential oils were dominated by eugenol and paraffin hydrocarbons, the leaf oils were rich in (2E)-hexenal, linalool, and eugenol, and the bark essential oils were composed largely of fatty acids, paraffin hydrocarbons, and benzenoid aromatics. A screening of the oils for biological activity, including phytotoxic activity against Lactuca sativa (lettuce) and Lolium perenne (perennial ryegrass), nematocical activity against Caenorhabditis elegans, brine shrimp lethality against Artemia salina, insecticidal activity using Solenopsis invicta × richteri (red imported fire ant), and antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Aspergillus niger. The leaf oil demonstrated notable biological activity in all bioassays. INTRODUCTION Birch preparations, such as teas and infusions, have been important as traditional medicines in several cultures worldwide. The oil from B. alba bark (birch tar) has been used to preserve leather in northern Europe and has demonstrated insect repellent activity, while a tea prepared from B. alba leaves has been used for treatment of gout, rheumatism, and dropsy (Grieve, 1971). In Ayurveda, the essential oil of B. alba is used in treating eczema and psoriasis and to combat hair loss (Vinod et al., 2012). A decoction of the inner bark of B. occidentalis was used by western Native Americans to treat colds, coughs, and other pulmonary ailments (Lewis and ElvinLewis, 1977). The Makandwewininiwag band of the Ojibwe people used a tea prepared from B. pumila buds as a postparturition tonic, while B. pumila buds were heated to make an incense to treat respiratory disorders (Lewis and Elvin-Lewis, 1977). Teas made from the bark of B. lenta were used by Native Americans to treat stomachaches and lung ailments, and teas made from bark and from twigs were used for treating fevers. The essential oil from B. lenta has been used for treatment of rheumatism, gout, scrofula, bladder infections, and neuralgia, and also as an anti-inflammatory analgesic (Foster and Duke, 1990). Betula nigra L., river birch, is a tree native to the southeastern United States (Grelen, 1990). This woody plant, which has reddish-brown shredding bark and simple, alternate, double-toothed leaves, and which can grow over 20 m in height, was used by Southeastern Native Americans in traditional medicines. The Catawba people boiled B. nigra buds to make syrup that was mixed with sulfur for treatment of ringworm and sores (Speck, 1944). The Cherokee chewed leaves to treat dysentery and used a tea made from the bark to treat colds, stomachaches, and urination difficulties (Casey and Wynia, 2010). Creek Indians used B. nigra to treat tuberculosis (Hutton, 2010). European-Americans that settled in the Ozark and Ouachita Mountains discovered B. nigra was useful in treating wounds and urinary pains (Nolan, 1998). Woods et al.: Bioactivities and Compositions of Betula nigra Essential Oils