FLAVOUR AND FRAGRANCE JOURNAL Flavour Fragr. J. 2002; 17: 215–217 DOI: 10.1002/ffj.1081 Essential oils from Croton zambesicus Muell. Arg. growing in Cameroon F. Fekam Boyom,1 * F. Keumedjio,1 P. M. Jazet Dongmo,1 B. T. Ngadjui,1 P. H. Amvam Zollo,2 C. Menut3 and J. M. Bessiere3 1 2 3 Faculty of Science, University of Yaounde 1, PO Box 812, Yaounde, Cameroon Faculty of Science, University of Douala, PO Box 2701, Douala, Cameroon Université de Montpellier II, Sciences et Techniques du Languedoc, 34095 Montpellier cedex 5, France Received 4 April 2001 Revised 24 September 2001 Accepted 24 September 2001 ABSTRACT: Three essential oils obtained by hydrodistillation from the leaves, roots and stem barks of Croton zambesicus Muell. Arg. (Euphorbiaceae) were analysed by GC and GC–MS. This West Tropical African species has many uses, especially as a drug source for the cure of many ailments. The three organs were found to contain 0.17–0.34% yield of oil. The qualitative composition of the three types of oil were found to be similar; those from the leaves and stem bark were found to be rich in monoterpenes (69.6% and 75.2% respectively), while the root bark oil contained 57.0% sesquiterpenes. The root and stem barks oils were found to be rich in oxygen-containing compounds, with spathulenol (14.0%) and linalool (33.8%) as the major components, respectively. The leaf oil was found to contain mainly hydrocarbons and only 11.6% of oxygenated compounds. Copyright  2002 John Wiley & Sons, Ltd. KEY WORDS: Croton zambesicus Muell. Arg.; Euphorbiaceae; essential oil; linalool; spathulenol; ˇ-caryophyllene Introduction Croton zambesicus Muell. Arg. (syn. C. amabilis Muell. Arg., Euphorbiaceae) is a shrub or small tree, 9–15 m high and 0.9 m in girth, sometimes with a distinct bole and scaly bark, branchlets grooved, grey and scaly. The leaves are approximately 15 ð 5 cm, oblong-lanceolate or elliptic, acuminate, base rounded, pale green, with whitish and brown scales beneath and have up to 12 pairs of lateral nerves. The flowers (July, November) are greyish-white, inconspicuous, with racemes often crowded at ends of twigs and flowers borne separately, with well-developed petals in male flowers. The fruits are scaly, three-celled, with remains of stigmas at apex. The wood is pale yellow and fine-grained. The stems are used for house posts in parts of West Africa. It is a decorative shrub, sometimes cultivated. The roots are used as an aperient. A leaf decoction is used as a wash for fevers in West Africa, and internally for dysentery, fever or convulsions. The seeds are also used medicinally in the same region.1,2 The stem bark of C. zambesicus has been studied for its antimicrobial *Correspondence to: F. Fekam Boyom, Laboratory of Phytobiochemistry, PO Box 812, Yaounde, Cameroon. E-mail: ffekam@uycdc.uninet.cm Copyright  2002 John Wiley & Sons, Ltd. activities. The extract exhibited wide-spectrum antibacterial effects, comparable to those of ampicillin and gentamycin, and the antifungal effect was comparable to that of tioconazole.3 In a previous work, Menut et al. (1995)10 published the chemical composition of an essential oil from the leaves of Croton zambesicus Muell. Arg. from Tchad, with linalool (9.9%), and ˇcaryophyllene (9.9%) as the major constituents. In this paper, chemical analyses are presented of three essential oils obtained by hydrodistillation from the leaves, stems and root bark of C. zambesicus growing in Cameroon. Experimental Plant Material and Extraction Procedure Leaves, stem bark and roots of C. zambesicus were collected in the Yaounde area (Cameroon) in July 1998. The plant samples were identified and voucher specimen (820/SRFCAM) deposited at the National Herbarium (Yaounde). Fresh leaves were cut into small pieces and air-dried, stem and root barks were ground using a blender. Batches of 500 g plant material were submitted to hydrodistillation for 12 h using a Clevenger-type 216 F. FEKAM BOYOM ET AL. Table 1. Percentage composition of three essential oils from Croton zambesicus Muell. Arg. Compounds Monoterpenes Monoterpene hydrocarbons ˛-Thujene ˛-Pinene Camphene Sabinene ˇ-Pinene Myrcene ˛-Phellandrene ˛-Terpinene p-Cymene Limonene (Z)-ˇ-Ocimene (E)-ˇ-Ocimene -Terpinene Oxygenated monoterpenes (Z)-Linalool oxide (E)-Linalool oxide Linalool Camphor Borneol Terpinen-4-ol p-Cymen-8-ol ˛-Terpineol Myrtenol Bornyl formate Thymol Bornyl acetate Geranylacetone Sesquiterpenes Sesquiterpene hydrocarbons υ-Elemene ˛-Cubebene ˛-Copaene ˇ-Cubebene ˇ-Elemene Cyperene ˇ-Caryophyllene Bergamotene ˛-Humulene Aromadendrene Germacrene D ˇ-Selinene ˛-Muurolene -Cadinene υ-Cadinene (Z)-Calamenene (E)-Calacorene Germacrene B Oxygenated sesquiterpenes ar-Curcumone Bicyclogermacrone ˛-Nerolidol ˇ-Nerolidol Spathulenol Caryophyllene Oxide Guaiol Humulene oxide Longiborneol 14-HydroxyMuurolene ˛-Cadinol Aliphatic compounds Octan-2-one Dodecan-2-one Undecan-2-one Ł RIŁ 925 934 944 968 974 981 1000 1010 1014 1024 1028 1039 1045 1066 1070 1084 1128 1156 1169 1174 1179 1183 1236 1268 1276 1452 1342 1369 1384 1391 1394 1402 1424 1430 1461 1463 1486 1496 1499 1510 1519 1528 1532 1553 1494 1498 1536 1548 1573 1578 1592 1602 1603 1624 1638 1080 1345 1278 Leaves Rootbark Stem bark 69.6 61.5 1.3 8.7 tr 6.3 18.9 3.7 1.5 tr 1.0 19.2 0.2 0.4 0.2 8.2 — — 5.2 0.5 0.4 0.4 0.6 0.7 0.3 tr — tr — 30.4 27.0 tr 2.5 tr tr 0.2 tr 15.8 tr 2.2 0.6 0.2 — tr 0.4 0.3 tr tr 4.6 3.4 tr 0.2 tr 0.3 2.6 0.3 tr 0.3 — tr — tr tr tr tr 26.6 9.0 0.2 3.7 2.4 0.1 0.5 0.3 0.1 — 0.8 0.7 — — 0.2 17.6 — — 0.3 0.6 10.1 1.3 0.2 0.4 tr 0.2 — 3.3 1.2 57.0 28.9 0.4 0.4 3.6 0.6 0.6 4.7 9.4 0.1 2.0 0.4 1.8 0.4 0.7 0.3 2.0 0.3 0.2 1.0 28.1 1.6 3.6 0.3 — 14.0 2.3 0.5 1.2 0.5 2.2 2.0 1.1 0.1 0.3 0.7 75.2 29.5 0.5 2.3 tr 4.2 7.7 1.7 0.6 tr 0.9 10.8 tr 0.8 — 45.7 0.3 tr 33.8 0.7 0.4 0.4 3.9 3.6 0.7 0.3 0.3 1.2 — 25.7 17.1 — 0.9 tr — tr — 13.9 tr 2.3 — — — tr tr tr — tr — 8.6 — — 1.0 — 4.2 1.0 — 0.6 0.3 1.1 0.4 0.3 0.3 — — Average retention indices on OV-101 column; tr, trace (<0.05%). Copyright  2002 John Wiley & Sons, Ltd. Flavour Fragr. J. 2002; 17: 215–217 ESSENTIAL OILS OF CROTON ZAMBESICUS 217 apparatus.4 The essential oils were dried over anhydrous sodium sulphate and the yields calculated (w/w%). Identification of Components Analysis of the essential oils was carried out by GC and GC–MS.5 The GC analyses were carried out on two fused-silica columns (25 m ð 0.32 mm i.d.), coated with OV-101 (Delsi Instruments) and Carbowax 20 M (Delsi Instruments), respectively, using a Shimadzu GC 14A chromatograph with an ionization flame detector and a Shimadzu C-R3A Chromatopac recorder; the oven temperature was programmed from 50 ° C to 200 ° C at 5 ° C/min. 0.3 µl sample was injected, with respective split ratios of 0.6 ml/s on Carbowax 20 M and 1.2 ml/s on OV 101. The GC–MS analyses were performed on a Hewlett-Packard GC–quadrupole MS system (Model 5970) fitted with a 25 ð 0.32 mm i.d. fused silica column, coated with DB-1, using the same chromatography parameters as described above, and on a Perkin-Elmer GC–MS system (Sigma 3B/VG7070P) fitted with a CPWax 51 column (50 m ð 0.2 mm i.d.); the temperature of the oven was programmed to 5 min at 50 ° C, then 50–220 ° C at 2 ° C/min. Published retention indices, mass spectra and authentic reference compounds were used for the identification of the volatile constituents.6,7 Results and Discussion The essential oils were obtained with the following yields: 0.34% for the leaves, 0.20% for the stem bark and 0.17% for the root bark. The results of the GC and GC–MS analyses of the three essential oils are given in Table 1, where the constituents are listed according to chemical class. It appears from these results that the three essential oils samples are qualitatively similar in composition. From 58 identified components, 55 were terpenes and only three aliphatic compounds, representing on average less than 1.1%. On the other hand, quantitative variations were found between the three oils. The major components of the leaf oil were limonene (19.16%), ˇ-pinene (18.9%), ˇ-caryophyllene (15.8%) and ˛-pinene (8.7%), but spathulenol (14%), borneol (10.1%), and ˇ-caryophyllene (9.4%) for the root bark Copyright  2002 John Wiley & Sons, Ltd. oil. Linalool (33.8%), ˇ-caryophyllene (13.9%), limonene (10.8%) and ˇ-pinene (7.7%) were the main constituents of the stem bark oil. The leaf and stem bark oils were found to contain larger amounts of monoterpenes (69.6% and 75.2%) against 30.4% and 25.7% of sesquiterpenes. Sesquiterpenes were more abundant in the root bark extract (57.0%) which also contained 26.6% of monoterpenes and 1.1% of aliphatic compounds. The bark oils were found to be very rich in oxygen-containing compounds, with 54.6% and 46.8% for the stem and roots, respectively, against only 11.6% for the leaf oil. The major oxygen-containing components were found to be linalool, borneol and spathulenol. These results are slightly different from those obtained by Menut et al. (1995)10 with oil samples from C. aubrevillei and C. zambesicus from the Central African Republic and Tchad, respectively, in that, in addition to linalool (5.2%) and ˇ-caryophyllene (15.8%), our leaf oil contained limonene (19.2%), ˇ-pinene (18.9%) and ˛-pinene (8.7%) as major constituents. This sample is comparable with that from the flowering tops of the Saudi Arabian species, which has limonene as the major constituent (38.0%). References 1. Irvine F. Woody Plants of Ghana. Oxford University Press: London, 1961. 2. Hutchinson J, Dalziels JM. Flora of West Tropical Africa, 2nd edn, vol. 1, part 2, revised by Keay RWJ. Whitefriars: London, 1958. 3. Abo KA, Ogunleye VO, Ashidi JS. Antimicrobial potential of Spondias mombin, Croton zambesicus and Zygotrinia cricea. Phytother. Res. 1999;; 13(6): 494–497. 4. Pharmacopée Française, vol 1. Maisonneuve, Paris, 1985. 5. Fekam Boyom F, Amvam Zollo PH, Menut C et al. Aromatic Plants of Tropical Central Africa, Part XXVII. Comparative study of the volatile constituents of five Annonaceae species growing in Cameroon. Flavour Fragr. J. 1996;; 11(6): 333–338. 6. Stenhagen E, Abrahamsson S, McLafferty FW. Registry of Mass Spectral Data. Wiley: New York, 1974. 7. Jennings W, Shibamoto T. Qualitative Analysis of Flavour and Fragrance Volatiles by Glass Capillary Gas Chromatography. Academic Press: New York, 1980. 8. MacLafferty FW, Staufer DB. Wiley NBS Registry of Mass Spectral Data, vol 2. Wiley: New York, 1989. 9. Von Sydow E, Anjou K, Karlsson G. Arch. Mass Spectral Data 1970;; 1: 392. 10. Menut C, Lamaty G, Bessière JM. J. Essent. Oil Res. 1995;; 7(4): 419–422. Flavour Fragr. 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