Composition of pyrolyzate from Japanese green tea

Green tea is a beverage that is produced by hot-water extraction of the leaves of tea (Camellia sinensis L.). As the amount of green tea consumption has increased, the importance of using the residue has grown. To address this problem, chemical compositions of two pyrolyzates obtained with an electric kiln, L and G, which were obtained from the tea leaf product and its hot-water extraction residue, respectively, were examined. Both pyrolyzates were alkaline, in contrast to the acidic pHs that are typical of pyrolyzates from wood materials. The major constituents were nitrogen-containing compounds, which accounted for up to about 70% (based on gas chromatography-mass spectrometry peak area). Caffeine was the main compound in both samples, although it might not be a pyrolysis product but actually sublimates from the samples and then condenses back into the pyrolyzates. Other nitrogen-containing compounds were formed mainly from proteins and amino acids. Acids and phenols, which are typical components in pyrolyzates obtained from wood materials and contribute to acidic pH, were rare in both samples. Other neutral compounds are known as compounds in pyrolyzates from wood materials. The pyrolyzates obtained in this experiment were novel and may have new uses.Contents of this report was presented in the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, 2002     

Composition and antitermite activities of essential oils from <Emphasis Type="Italic">Melaleuca</Emphasis> species

 The composition and antitermite activities of nine essential oils from two Melaleuca species, gelam and cajuputi, were compared using gas chromatography–mass spectrometry analysis and bioassays. Gelam oils were rich in compounds whose boiling points were high, and they were separated into the elemene-rich type and the γ-terpinene- and terpinolene-rich type. Cajuputi oils in this experiment were categorized into three chemotypes according to their 1,8-cineole content: high, low, none. In the termiticidal activity test, gelam oils were stronger than most cajuputi oils in the contact condition. The elemene-rich gelam lost its activity in the noncontact condition, whereas another type of gelam kept its termiticidal activity. The authentic sample of elemene showed the same result as the elemene-rich gelam, indicating that the termiticidal activity of gelam was caused by at least two types of compound: elemene and “others.” 1,8-Cineole exhibited the same tendency as elemene, but it was weak. Hence the 1,8-cineole content of cajuputi was irrelevant to termiticidal activity of samples that exhibited strong activity under both conditions despite their high content. The appearances of gelam and cajuputi leaves are easily confused, a problem that has not yet been solved. Other scientific methods, such as genetic analysis, are required to identify gelam. The difference in the compositions and antitermite activities, however, were charified in this experiment. Received: November 30, 2001 / Accepted: June 5, 2002 Correspondence to:M. Yatagai