JournalandProceedings,RoyalSocietyofNewSouthWales,Vol.118,pp.101-104,1985 ISSN0035-9173/85/020101—04$4.00/1 The Volatile Leaf Oils of Two Cultivars of Callistemon viminalis J.J. BRopHy, E. V. LASSAK AND R. F. TOIA ABSTRACT. A sum total of 52 components were detected by gas chromatographic/mass spectrometric analyses of the steam volatile leaf oils from two cultivars of Calltstemon viminalits. Both oils were rich in monoterpenes (95%) with cineole as the major component (>50%) in each case. The key difference between the oils lies in the relative quantities of a-pinene, linalool and a-terpineol. Cultivar I contains a substantial amount of linalool (16%) with small quantities (v1%) of qg-pinene and a-terpineol whilst cultivar II contains significant amounts of the latter two components (18% and 12%, respectively) and only a trace amount (0.5%) of linalool. ENTRODUCTION Many species of the Australian genus Calltstemon(Myrtaceae), the so-called "bottlebrushes," are noted for their attractive red flowers and are thus in great demand as ornamental shrubs. Given the commercial importance of this family, it is perhaps surprising that the leaf oils have only received scantattention. In an early report on the composition of the volatile oils from C. viminalts, detected d-a-pinene, limonene, dipentene, terpineol, phenols and sesquiterpenoids were detected along with major amounts of 1,8-cineole (Penfold, 1923). Similarly, the oil from C. lanceolatus was found to contain dipentene, limonene, a-terpineol, 1,8-cineole, phenols and sesquiterpenes (Penfold, 1923). In a later investigation on this latter species, the leaf oil was recognized to have fungistatic activity (Pandey et al., 1982). C. rtqtdus has also received some attention, with 1,8-cineole being identified as the major component (Takemoto and Yahagi, 1955) whilst C. spectosus has been found to yield an oil, again with major amounts of 1,8-cineole (81.5%) but with a-pinene, limonene, myrcene, a-terpinene, a-terpineol and caryophyllene also being identified (Wasicky and Saito, 1972). In this paper we present the results from a detailed examination of the steam-volatile leaf oils of two cultivars of C. viminalis. EXPERIMENTAL Collection of Plant Material and Isolation of Volatile Oils Fresh foliage from two cultivars of C. viminalts (Sol.) Cheel growing at Randwick, N.S.W. was steam-distilled as previously described (Lassak, 1979) to yield pale yellow mobile oils. For cultivar I, the 011 was obtained in 1.8% yield (n,“¥= 1.4648;0,°* = + 0.894°) whilst for cultivar II "James Cook" a 1% yield Gr = 1.4665; age! = e+ 1029352) was obtained. Botanical voucher specimens have been lodged at the National Herbarium, Royal Botanic Gardens, Sydney. Identification of Oil Components Analytical GLC was conducted on a) a Perkin Elmer Sigma 2B chromatograph using a 50m x 0.2mm i.d. FFAP coated fused silica column and b) a Shimadzu GC 6 AMP chromatograph using a 70m x 0.5mm i.d. FFAP coated SCOT column with He as carrier gas in both cases. Individual runs were programmed a) from 80°C to 170°C at 6°/min following an initial holding period of 9 min at 80°C and b) from 80°C to 230°C at 3°/min. Individual components were tentatively identified by their retention times and by co-injection with authentic compounds. A Perkin Elmer Sigma 10B Chromatography Data Station was used to determine percentage compositions. GLC-MS were determined using a Shimadzu chromatograph as described under b) above interfaced to an AEI MS12 mass spectrometer through an all-glass straight split with He as carrier gas. The gas chromatograph was programmed from 70 C to 230 C at 3 /min while the mass spectrometer was operated at 70 eV with the 1on source at 180 C. Spectra were acquired every 6 seconds and processed by a VG Digispec Display data system which produced standard bar graphs for direct comparison with published spectra (Heller and Milne, 1978, 1980; Stenhagen et al., 1974).