Flavonoids Diversification in Organs of Two Prosopis Farcta (Banks & Sol.) Eig
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Journal of Applied Sciences Research 1(2): 130-136, 2005 © 2005, INSInet Publication Flavonoids Diversification in Organs of Two Prosopis Farcta (Banks & Sol.) Eig. (Leguminosea, Mimosoideae) Populations Occurring in the Northeast and the Southeast of Tunisia 1F. Harzallah-Skhiri and 2H. Ben Jannet 1Laboratoire de Biologie Végétale et botanique, Ecole Supérieure d’Horticulture et d’Elevag de Chott-Meriem, 4042 Chott-Meriem, Tunisie. 2 Laboratoire de Chimie des Substances Naturelles et de Synthèse Organique, Faculté des Sciences de Monastir, 5000 Monastir Tunisie Abstract: The patterns of P. farcta flavonoids were investigated in branches, leaves, roots, flowers and pods without seeds (pericarps) of two plant populations belonging to this species occurring in the northeast (Nabeul locality) and the southeast (Gabès locality) of Tunisia. Sixteen constant phenolic compounds were identified in P. farcta plant material: Vicenin-2, Apigenin C-glycoside, Iso-orientin (=Luteolin 6-C-glucoside), Myricetin 3-O-glucoside, Vitexin, Luteolin 7-O-glucoside, Isovitexin, Quercetin 3-O-glucoside, Rutin, Quercetin 3-O-galactoside, Chrysoeriol 7-O-glucoside, Kaempferol 3-O-rutonoside, Isorhamnetin 3-O-rutinoside, 5-deoxyluteolin, Caffeic acid derivative and Luteolin, six among them were major at least in one organ. Four unidentified compounds were found diversely distributed in organs. A relative similarity was found in the compounds identified in plants from the two populations although the occurrence of one unidentified compound only in branches of Gabès plants. In addition, all Nabeul or Gabès plant organs have not the same major flavonoid. The present data support the hypothesis of the occurrence in Tunisia of two varieties for the species P. farcta such as mentioned in literature and permit to specify the chemotype race of each plant populations only by analysing pericarp flavonoids. Key words: Prosopis farcta, flavonoids, plant organs, locality, chemotype race. INTRODUCTION Those investigations lead to propose varieties and hybrids.[8] Species belonging to the genus Prosopis L. In several biosystematical and evolutionary studies, (Leguminosae, subfamily Mimosoideae) are multipurpose, secondary compounds like flavonoids have been very providing a range of products including timber, firewood, valuable for obtaining information about relationships and livestock feed, human food and beverages, fibres and the hybrid origin of taxa. [9-13] Nevertheless, Markham et al. tannins. They are also valued for shade, shelter belts, bee [14] reported about intra-individual variation of phenolics forage and as nitrogen-fixing soil improvers. [1] and its implication for chemosystematics. Prosopis was difficult taxonomically because of the Carman [15] has carried out a general study on the limitation of its species, which are often without sharp chromatographic characterisation of different Prosopis morphological discontinuities.[2-5] Hybridization and species. Bragg et al. [7] have reported on the perhaps transitional forms from one species to another chromatographic variation within the P. juliflora seem to be frequent as has been suggested by several complex and Palacios and Bravo [16] have studied the authors.[6] Despite its great polymorphism and its large morphology and flavonoid chromatographies of geographic distribution through-out the drier subtropical Prosopis species and hybrids of the Argentinian and tropical regions of the world taxa within Prosopis Chaquena region. have received various taxonomic treatment based on Because flavonoids are routinely used for systematic interspecific morphologic variation. Species of Prosopis studies [15] and may exhibit ecogeographic variations [17] we specially those from section Algarrobia are examined two ectopically differentiated populations of morphologically variable causing taxonomic difficulty.[7] P. farcta occurring in Tunisia. Corresponding Author: F. Harzallah-Skhiri, Laboratoire de Biologie Végétale et botanique, Ecole Supérieure d’Horticulture et d’Elevag de Chott-Meriem, 4042 Chott-Meriem, Tunisie, 130 J. App. Sci. Res. 1(2): 130-136, 2005 Prosopis farcta, is a shrub that grows naturally in volume of 10 ml and a sample of each of the extracts was two distinct areas, one in the northeast and the second in analysed for flavonoids content by HPLC. the southeast of Tunisia. [18,19] This species is well adapted Flavonoids of methanol and acetone extracts were to drought and high temperatures and exhibit a high analysed by HPLC using a reversed phase analytical degree to salt tolerance. [20,19] It plays also an essential column (RP18) equipped with detector which measured at ecological role in the protection and improvement of soils UV. Individual components were identified by comparison since its root system grows vertically as well as laterally of their UV spectra with those indicated in literature [24] in the soil. The species provides firewood for local and with those of authentic standards. Importance of each population, livestock feed and bee forage.[19] phenolic compound was estimated by the corresponding Pods and seeds of this plant, collected at different pick area. localities, differ in form, size and color, though those collected at each locality show considerable uniformity. Analysis conditions: HPLC consists of a Waters LC600 Study of root, stems and pollen morphology allows pump and a 996 photodiode array detector which distinguishing also high differences between the two measured at UV. HPLC was fitted with a Merck population.[21,22] So, we suppose the presence in Tunisia (Darmstadt, Germany) LiChrospher 100RP-18 (250x 4.0 mm of the two varieties, previously mentioned by Burkart.[3] i.d.; 5 µm particle size) column using a 20 min linear Here we have used chemosystematic approaches to gradient of 25-100% MeOH in 1% aq. HOAc at 1ml/min. investigate the problems of plant disjunctions.[23] So, Eluting solvents were 2% aq. HOAc and MeOH, HOAc, flavonoid chemistry of all organs of P. farcta plants from H2O in proportion of 18:1:1. The column temperature was two localities was utilized to distinguish between the two 30°C. population. In the present paper, two ecotypically-differentiated RESULTS AND DISCUSSIONS population of Prosopis farcta developed in two distinguished areas were examined for their flavonoids Yield in phenolic compounds within locality and organ: and we report on the intra-specific variation of phenolic Yield in phenolic compounds varied within organ and compounds in each organ of the species. Systematic and locality (Table 1). Most of phenolic compounds were ecological implications of the flavonoids data for the P. extracted with methanol. Flowers from Prosopis farcta farcta complex were discussed. Gabès population showed the highest amount of phenolic compounds found in the methanolic extract (78.6%). MATERIALS AND METHODS Except leaves and branches, the other organs from P. farcta Gabès population gave more phenolic compounds Plant material: Plant materiel used in this investigation both with acetone and methanol. The lowest yields in was obtained from wild populations of P. farcta flowering phenolic compounds were obtained in the case of shrubs developed in two distinct localities in Tunisia: branches and pericarps. Gabès and Nabeul. All voucher specimens are deposited in the Ecole Supérieure d’Horticulture et d’Elevage, Phenolic composition of different P. farcta organs: The Botanic Laboratory Herbarium, Chott-Meriem, Tunisia. data were given in table 2. Composition of the different Mature pods were collected in October (for Gabès) or plant part of P. farcta shows a relative similarity between November (for Nabeul). the two localities. Sixteen constant phenolic 500 g of adult branches, leaves, roots, flowers and compounds were identified in P. farcta plant pods without seeds (pericarps) were air dried slightly material: Vicenin-2, Apigenin C-glycoside, Iso-orientin above room temperature, grounded with a mortar and (=Luteolin 6-C-glucoside), Myricetin 3-O-glucoside, weighed. Vitexin, Luteolin 7-O-glucoside, Isovitexin, Quercetin 3-O-glucoside, Rutin (= Quercetin glycoside I), Quercetin Extraction and analysis of flavonoid compounds: Powder 3-O-galactoside (= Quercetin glycoside II), Chrysoeriol of each plant part was placed in a Soxhlet apparatus and 7-O-glucoside, Kaempferol 3-O-rutonoside, Isorhamnetin extracted at room temperature by petroleum ether. Until 3-O-rutinoside, 5-deoxyluteolin, Caffeic acid derivative 12h, waxes and pigments were eliminated. The plant and Luteolin, six among them were major at least in one materiel was re-extracted successively with acetone and organ. Four unidentified compounds were diversely methanol. All extracts were concentrated by rotary distributed in organs: C1 in branches of Gabès plant evaporation at 40°C. The concentrated extracts were population, C2 and C3 in branches and flowers and C4 in resuspended in 80% aq. acetone or MeOH to a total pericarps of Nabeul and Gabès plant populations. 131 J. App. Sci. Res. 1(2): 130-136, 2005 Table 1: Yield in phenolic compounds within locality and organ. Acetone extract Yields % Organs Nabeul locality Gabès locality Branches 0.9 0.6 -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Leaves 4.2 2.5 --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------