Determination of the volatile constituents of liverwort porella densifolia (Hepaticae) by using gas chromatography/mass spectrometry (GC/MS)

JOURNAL OF SCIENCE OF HNUE Natural Sci., 2010, Vol. 55, No. 6, pp. 78-81 DETERMINATION OF THE VOLATILE CONSTITUENTS OF LIVERWORT Porella densifolia (HEPATICAE) BY USING GAS CHROMATOGRAPHY/MASS SPECTROMETRY (GC/MS) Dang Ngoc Quang Hanoi National University of Education E-mail: quangdn@hnue.edu.vn Abstract. Twelve volatile constituents were identified from Liverwort Porella densifolia (Hepaticae) collected at Ham Rong Mountain, Sapa, Lao Cai Province by gas chromatography/mass spectrometry (GC/MS). The volatile constituents including some monoterpenes (β-myrcene, α- pinene and camphene); two major sesquiterpenes, deoxopinguisone and bicyclogermacrene-2 were identified. The results indicated that Vietnamese liverworts P. densifolia are closely related with those from Japan and India. This is the first report on the volatile constituents of Vietnamese Liverwort. Keywords: Liverworts Porella densifolia (Hepaticae), Sapa, Lao Cai Province, β-myrcene, α-pinene, camphene, deoxopinguisone, bicyclogermacrene-2, gas chromatography/mass spectrometry (GC/MS). 1. Introduction Liverworts are small plants and their taxonomic identification is quite diffi- cult. In modern classification, liverworts Porella densifolia (Hepaticae) comprise of 6,000 species [1]. The chemistry of liverwort has been the subject of intensive investigations because liverworts contain cellular oil bodies and produce a number of terpenoids, aromatic compounds and acetogenins, several of which show inter- esting biological activities such as allergenic contact dermatitis, insecticidal, insect antifeedant, cytotoxic, piscicidal, muscle relaxant, plant growth regulatory, anti- HIV, DNA polymerase beta inhibitory, anti-obesity, neurotrophic, nitric oxide (NO) production inhibitory, antimicrobial and antifungal activities [2-5]. So far, there is no report on the chemical investigation of Vietnamese Liverwort. In this paper we report our investigation on volatile constituents of liverworts Porella densifolia col- lected at Ham RongMountain, Sapa, Lao Cai Province by gas chromatography/mass spectrometry (GC/MS). 2. Content 2.1. Experiments ∗ General procedure: 78 Determination of the volatile constituents of liverwort Porella densifolia (Hepaticae)... GC-MS was carried out on a Hewlett Packard mass selective detector 5971 A and a gas chromatograph 5890 Series II using a fused silica gel column coated with DB-17 (30 m x 0.25 mm i.d., film thickness 0.25 µm) and He as carrier gas (1 ml/min). The temperature programming of GC-MS analysis was performed from 50◦C to 250◦C, at 4◦C/min and finally isothermal at 250◦C for 10 min. ∗ Plant material: The whole plant of Porella densifolia was collected in Sapa, Lao Cai Province in April 2004 by D.N. Quang and identified by Prof. Dr. Y. Asakawa (Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Japan). A voucher specimen (LVN-01) has been deposited in the Herbarium at Faculty of Chemistry, Hanoi National University of Education. 2.2. Results and discussion To obtain the volatile chemical constituents from P. densifolia, the fresh sam- ple was extracted with diethyl ether. The diethyl ether extract was filtered through a small glass column packed with silica gel using diethyl ether to give a green oil, which was directly analyzed by thin layer chromatography (TLC) and GC-MS. The GC-MS chromatogram is shown in Figure 1. Each constituents appeared on GC-MS was identified by comparison of its retention time and mass spectrum with those of authentic samples [6] and our library databases. Table 1. The volatile constituents of liverwort P. densifolia No. Volatile constituents Retention time (minute) Percentage* (%) Quality** (%) 1 β-Myrcene 7.96 1.31 86 2 α-Pinene 8.32 4.40 94 3 Camphene 8.71 5.92 91 4 Bicyclogermacrene-1 20.85 9.12 91 5 Elemene 22.32 0.41 91 6 (E)-β-Farnesene 23.10 2.73 93 7 α-Caryophyllene 23.96 0.44 90 8 Striatene 24.61 9.38 94 9 Bicyclogermacrene-2 25.11 18.28 97 10 Pinguisone 26.80 0.33 91 11 Deoxopinguisone 31.99 19.51 88 12 4-Carbomethoxydeoxopinguison 32.17 4.48 91 *: Percentage of total volatile constituents in the extract of P. densifolia; **: The identical percentage of MS of each constituent with that in database. Table 1 describes the chemical constituents of the diethyl ether extract of P. densifolia. Accordingly, three monoterpenes (β-myrcene, α-pinene, camphene) were detected, however they are only minor compounds. The remaining compounds 79 Dang Ngoc Quang are sesquiterpenes, of which deoxopinguisone (19.51%) and bicyclogermacrene-2 (18.28%), striatene (9.38%) and bicyclogermacrene-1 (9.12%) are four major com- pounds. The selected structures of volatile constituents in P. densifolia are shown in Figure 2. Comparing with the volatile constituents of P. densifolia collected in Japan [7] and India [8], all of them showed that they produced abundant sesquiter- penes such as pinguisane and bicyclogermacrene (Figure 2). The result of this study has an agreement with previous publications [7, 8], proving that pinguisone and bicyclogermacrene sesquiterpenes are chemotaxonimic markers for P. densifolia. Figure 1. The GC-MS chromatogram of ether extract of P. densifolia Figure 2. Selected structures of volatile constituents in P. densifolia 80 Determination of the volatile constituents of liverwort Porella densifolia (Hepaticae)... 3. Conclusion GC-MS analysis of ether extract liverwort Porella densifolia collected in Ham Rong Mountain, Sapa, Lao Cai Province has led to the determination of 12 compo- nents. It shows that deoxopinguisone (19.51%) and bicyclogermacrene-2 (18.28%) are two major sesquiterpenes. This investigation indicates that Vietnamese liver- worts P. densifolia are closely related with those from Japan and India. This is the first report on the volatile constituents of Vietnamese Liverwort. REFERENCES [1] Y. Asakawa, (Herz W., Kirby G. W., Moore R. E., Steglich W. and Tamm Ch., eds), 1995. Progress in the Chemistry of Organic Natural Products. Springer, Wien, New York, Vol. 65, p. 1. [2] Y. Asakawa, 2004. Chemosystematics of the Hepaticae. Phytochemistry. 65, pp. 623-669. [3] Y. Saritas, M. M. Sonwa, H. Iznaguen, W. A. Knig, H. Muhle, R. Mues, 2001. Volatile constituents in mosses (Musci). Phytochemistry, 57, pp. 443-457. [4] Y. Asakawa, 1999. 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