Journal of Medicinal Plants Phytochemical Variations in Lemon Verbena (Lippia citriodora H.B.K.) Plantlets Affected by Propagation Methods and Soil Type Moradi M (M.Sc.) 1, Mehrafarin A (Ph.D.) 2, Naghdi Badi H (Ph.D.) 2* 1- Department of Horticulture, Karaj Branch, Islamic Azad University, Karaj, Iran 2- Cultivation & Development Department of Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj, Iran *Corresponding author: Institute of Medicinal Plants, ACECR, Karaj, Iran P.O.Box: 31375-369, Tel: +98-26-34764010-8, Fax: +98-26-34764021 Email: [email protected] Received: 28 Jan. 2013 Accepted: 9 Feb. 2014 Abstract Background: Lemon verbena (Lippia citriodora H.B.K.) is an aromatic and medicinal plant of family Verbenaceae, which cultivated in North region of Iran. Objective: Evaluation of phytochemical characters in Lippia citriodora H.B.K. plantlets affected by propagation methods (micro-propagation and stem cutting) cultivated in different soil type (peat moss and mixture soil). Methods: This experiment was done in a randomized complete block design in three replications with four treatments. The treatments were propagation methods (micro-propagation and stem cutting) and soil type (peat moss and mixture soil). The volatile oil was extracted by hydro-distillation using clevenger-type apparatus and analyzed by GC and GC/MS. Results: The results indicated that the interaction effects of different soils and plantlets types had significant effect (p<0.05) on all studied parameters. The highest content of essential oil (0.79%), geranial (53.52%), neral (31.82%), limonene (11.29%), leaf dry weight (1.43 g) and SPAD value (20.85) were observed in treatment of MPP (micro-propagation plantlets cultivated in peat moss) and the lowest of that was obtained in treatment of SCM (stem cutting plantlets cultivated in mixture soil). Conclusion: The peat moss was the best bed in respect of phytochemicals and morpho- physiological traits in both types of in vitro and stem cutting propagation. The highest essential oil content was observed in treatment of micro-propagation cultivated in peat moss. Keywords: Lippia citriodora H.B.K., Micro-propagation, Peat moss, Soil type, Stem cutting 54 Volume 13, No. 49, Winter 2014 Phytochemical … Phytochemical Introduction tissue culture cultivated in peat moss probably The genus Lippia, (Verbenaceae) comprises have many differences in comparison with the approximately of 200 species which are compounds extracted from plants under indigenous to Southern and Central America natural conditions. Therefore, this study was and Africa [1]. Most of them are traditionally done to identify effect of peat moss on utilized as remedies for gastrointestinal and essential oil content and its components in respiratory problems. Some species have micro-propagated and stem cutting plantlets of shown antimalarial, antiviral and cytostatic L. citriodora. properties. It is believed that their essential oils and phenolic compounds (flavonoids) are responsible for these properties [2]. Material and Methods Lippia citriodora is cultivated mainly due Plant materials to the lemon-like aroma emitted from its This experiment was done in a randomized leaves that are utilized for the preparation of complete block design in three replications herbal tea, which is reputed to have with four treatments at the research antispasmodic, antipyretic, sedative and greenhouse of Institute of Medicinal Plants digestive properties [3]. The essential oil from (MPI), Iranian Academic Centre for its leaves has been shown to exhibit Education, Culture & Research (ACECR). The antimicrobial activity [4]. The chemical treatments were included propagation methods composition of the essential oil from the including micro-propagation (MP) and stem leaves of L. citriodora has also been studied cutting (SC), and soil types consisting peat and reviewed [5]. Limonene, geranial, neral, moss (P) and mixture soil (M). Peat moss is 1.8-cineole are the main constituents of the least decomposed form of the peat types, L. citriodora essential oil [5, 6]. typically tan to brown in color, lightweight, and The biotechnological tools are important to high in moisture-holding capacity with pH 3.8 to select, multiply, improve and analyze 4.3. The physico-chemical properties of peat medicinal plants. In vitro production of moss medium were presented in Table 1 [9]. secondary metabolites in plant tissue culture The stem segments were excised from the has been reported from various medicinal shoot tip, and then cultured on multiplication plants and also micro-propagation is the key medium containing MS basic salts (Murashige step towards commercial production of and Skoog, 1962) [10] supplemented with 30 secondary metabolites by plant biotechnology. g.l-1 sucrose, 0.5 mg.l-1 indole-3-butyric acids Micro-propagation allows the controlled (IBA), 0.1 mg.l-1 benzylaminopurine (BAP), production of genetically uniform and and 1 g.l-1 activated charcoal, and solidified pathogen-free plants, and makes studies on with 7 g.l-1 agar under aseptic conditions secondary metabolites feasible [7]. However, (Figure 1). The pH was adjusted to 5.87 most of the micro-propagation processes are followed by autoclaving at 121oC and 0.1 Mpa carried out on semi-solid media and several for 15 min. The cultures were incubated under studies have reported the media effect on a 16-h photoperiod (100 μmol.m-2.s-1) with a different medicinal plants culture [7, 8]. temperature of 24 °C [11] for 2 weeks, then Secondary metabolites produced by plant placed on adjacent benches in a plastic- 55 Moradi et al. covered greenhouse with mean maximum light Plantlets were transplanted in large pots intensity 660 μmol.m-2.s-1, and mean containing 1:1:1 of clay: sand: peat moss in temperature 24 °C for pre-acclimation (Figure May 2012. All plantlets were grown in a non- 1). Shoot tips were cut from the plants with a shaded greenhouse under natural sunlight (that sterile surgical blade. The shoot tips cuts mean maximum light intensity during the contained at least one axial bud and two experiment was 1200 μmol.m-2.s-1, relative leaves. The shoot cuts were rammed in 1% humidity 85 to 90%, and mean of indole-3-butyric acid (IBA). For the similar maximum/minimum temperature was stem cutting plantlets, nodal segments (10-15 approximately 28°C/20°C). The leaves of cm) with armpit buds were taken from the L. citriodora were harvested for determining apical portions of L. citriodora and then placed the essential oil content and its components at the same culture conditions mentioned after 3 months in August 2012. above. Table 1- Physico - chemical properties of peat moss medium Elements Content Unit N 93 g P2O5 176 " K2O 198 " + NH4 60 " B 0.33 " MgO 8.8 " OC 50 " Mo 2.2 " Zn 0.44 " Fe 0.99 " Mn 1.76 " Cu 1.32 " Water holding capacity 563 % Total porosity 87 " Bulk density 0.13 g.cm-3 CEC 165 meq.100g-1 pH 4.3 - EC 0.62 ds.m-1 56 Journal of Medicinal Plants, Volume 13, No. 49, Winter 2014 Phytochemical … A B C D E Figure 1- In vitro micro-propagation of L. citriodora induced by shoot multiplication. Sub-culturing (A, B), proliferation (C), pre-acclimation (D), and transfer of micro-propagated plantlet into greenhouse (E) Essential oil content and composition reference points in the calculation of the The essential oil of leaf plantlets were Kovats Indices (KI). Quantitative data were extracted by hydro-distillation for 3 h, using obtained from the electronic integration of the Clevenger-type apparatus [12]. The oils were Flame Ionization Detector (FID) peak areas. dried over anhydrous sodium sulphate [13]. Tentative identification of the compounds The volatile constituents were analyzed based on the comparison of their relative using an Agilent 6890 GC equipped with retention time and mass spectra with those of BPX5 capillary columns (30 m × 0.25 mm i.d. the NIST-98 and Wiley-275 library data of the 0.25 µm film thicknesses) and a mass GC-MS system and the literature data [14]. spectrometer Agilent 5973 as a detector. The Each analysis was performed in triplicate. carrier gas was helium, at a flow rate of 1 ml.min-1. For GC-MS detection, an electron Statistical analysis ionization system was used with ionization The data were analyzed using SPSS (ver 17.0) energy of 70 eV. Mass range was from 35-375 and for schema tradition Excel (ver 2003) amu, emission current 150 mA. The injector softwares. The differences among the means and MS transfer line temperatures were set at were determined using the Least Significance 220 °C and 290 °C, respectively. One micro- Differences (LSD) at p ≤ 0.05 level. liter of each sample was injected manually in splitless mode. C9-C20 n-alkanes were used as 57 59 Moradi et al. Results monoterpenes were the prevailing group (91.4 The results revealed that the essential oil and 46.74%, respectively) as compared to content in the stem cutting plantlets cultivated monoterpene hydrocarbons (14.6 and 11.96%, in mixture soil (MPP) and the micro- respectively). Also, the sesquiterpene propagated plantlets cultivated in peat moss hydrocarbons constituted only 16.68 and (SCM) treatment was 0.6% and 0.5%, 10.48% of the essential oil in MPP and SCP respectively. Analysis of variance for treatment, respectively. In the MPP treatment interaction effects of propagation methods and as compared to SCP, the fraction of soil types on phytochemicals characters of oxygenated monoterpene was higher, mainly L. citriodora was presented in Table 2. The due to an increase in geranial’s percentage. maximum and minimum essential oil content In MPP and MPM treatment, the major was obtained in the MPP and SCM treatment, monoterpene hydrocarbons were represented respectively. The MPP treatment had also by (E)-β-ocimene (2.81 and 1.91%), limonene significant effect (p≤0.05) on leaf dry weight (11.79 and 5.66%), respectively.