Hoehnea 31 (2): 175-179, 2 tab., 1 fig., 2004

Chemical composition ofseeds ofPeltophorum dubium Vog., a legume treefrom the Brazilian Caatinga vegetation with potential for sustainable use

ofbiodiversity in semi-arid regions

Marco Aurelio Siverio Mayworm J, Antonio Salatino J and Marcos Silveira Buckeridge2,3

Received: March 02, 2004; accepted: June J 8, 2004

ABSTRACT - (Chemical composition of seeds of PeltophorulIl dubiulIl Vag., a legume tree from the Brazilian Caatingavegetation with potential for sustainable use of biodiversity in semi-arid regions). The Brazilian Caatinga vegetation occursin a semi-arid region of the North-eastern Brazil which is also known as the dry polygon. Twenty three million people live inthis relatively poor region which is one of the largest populations in a semiarid region in a single country. PeltophorumdubiulIl is a legume tree native to the "caatinga" which is currently used to obtain wood for construction and saponins fromits leaves and bark for medicinal use. In this work, the biochemical composition of seeds from PeltophorulIl dubium hasbeen studied. We found that these seeds contain high amounts of protein (43.8% - higher than soybean for example) andthat its oil shows a composition similar to other edible oils. The seed endosperm stores an easily extractable gum (4.3% ofgalactomannan) whose mannose:galactose ratio is unusual (4.7), possibly being of great commercial value. The seeds alsostore some raffinose family oligosaccharides (ca. I%), raffinose occurring in very high proportion (65% of the members ofthe series). These data suggest that P. dubium might be a candidate for sustainable exploitation by the local population inthe caatinga.Key words: caatinga, Peltophorum, seed, sustainable use

RESUMO - (Composic;:ao quimica de sementes de Peltophorum dubiul1l Vag., uma leguminosa da caatinga brasileira compotencial para usa sustentavel da biodiversidade em regi6es semi-aridas). A caatinga e uma vegetac;:ao que apresentacaracterfsticas xeromorficas e ocorre em grande parte do semi-arido do nordeste brasileiro. Esta regiao e tambem conhecidacomo a polfgono da seca. Vinte e tres milh5es de pessoas vivem nesta regiao relativamente pobre, a qual constitui uma dasmaiores populac;:5es vivendo em uma regiao semi-arida em um unico pais. Peltophorulll dubium e uma arvore leguminosanativa da caatinga, a qual ja e usada para obtenc;:ao de madeira para construc;:ao civil e obtenc;:ao de saponinas a partir dasfolhas e da casca da arvore para usa medicinal. Neste trabalho, a composic;:ao bioquimica das sementes de Peltophorumdubiul11 foi estudada. Estas sementes contem grandes quantidades de proteina (43,8% - que e maior do que a de soja parexemplo) e a seu oleo apresentou uma composic;:ao similar a alguns oleos comestiveis. 0 endosperma das sementesarmazena uma goma de facil extrac;:ao (4,3% de galactomanano), cuja razao manose:galactose nao e usual (4,7), par essemativa sendo possivelmente de grande valor economico. As sementes tambem armazenam oligossacarfdeos da familiarafinosica (cerca de I% do peso seco das sementes), sendo a rafinose a principal componente (65% do total de membros daserie). Os dados apresentados sugerem que P. dubiulIl seja um bam candidato para explorac;:ao sustentada pelas populac;:5esda caatinga.Palavras-chave: caatinga, Peltophorum, semente, usa sustentavel

Introduction

The Brazilian vegetation named Caatinga occupies

834.666 km2 of the North-eastern region of Brazil

(Andrade-Lima 1981). It corresponds to approximately80% ofthe so called dry polygon, a political definitionof the semi-arid region of the Northeast of Brazil.According to Batista Filho & Batista (1996), ca. 23

million people were living in this region, which is one

of the largest populations living in a semi-arid region

in a single country. Due to the soil and climateconditions, agricultural production in this region has

been characteristically low, although some cotton, com,

bean and cassava are produced (Sampaio 1995).According to this author, some native plants to the

Caatinga are also employed for production of wood

1. Universidade de Sao Paulo, Instituto de Biociencias, Departamento de Botanica.2. Instituto de Botanica, Seyao de Fisiologia e Bioquimica de Plantas, Caixa Postal 4005, 01061-970 Sao Paulo, SP, Brasil.3. Corresponding author: msbuck@usp.br

176 Hoehnea31(2),2004

(Schinopsis brasiliensis Engl. and Astroniumurundeuva Engl.), fruit (umbu - Spondias tuberosaArr. Cam.) oil (oiticica - Licania rigida Benth. andlicuri - Syagrus coronata (Mart.) Becc.) and fibre(sisal - Agave sisalana).

Recently, a screening of the lipids and proteinsfrom seeds of species adapted to the Caatinga hasbeen performed by MaywOlm & Salatino (1996a).These authors found high amounts of oil along withprotein in seeds of Aspidosperma pyrifolum Mart(Apocinaceae), Jatropha molissima (Pohl.) Baill.(Euphorbiaceae) and Cardiospermum corindumLinn. (Sapindaceae).

According to Bautista (1986) approximately 40%of the species of the Caatinga belong to the familyLeguminosae followed by Anacardiceae (ca. 4%),Apocinaceae, Bignoniaceae, Boraginaceae andEuphobiaceae (ca. 3.5%).

Although many species from the Cerrado andAtlantic Forest of South-eastern Brazil have beenscreened for their contents of lipids (Mayworm &Salatino 1996b) and storage polysaccharides(Buckeridge & Dietrich 1990, Buckeridge et al.1995a) only one species that occurs in the Caatinga(Dimorphandra mol/is) has been studied (Buckeridgeet al. 1995b). This species contains high amounts ofgalactomannan (near 40% of seed dry weight) andstudies focused on the industrial extraction andutilisation in food and paper industries have beenperformed (Panegassi et al. 2000, Lima et at. 2003).

Peltophorum dubium Vog., (Leguminosae­Faboideae) is a tree from the Caatinga which has beenused to obtain wood for construction. According toPio Correa (1981) its leaves have medicinal utilityprobably related to the presence ofsaponins. Sherbeinyet al. (1979) cites Gnamm (1949) who mentions that24-31 % of tannins can be found in the bark of thetree. In this work, we present the composition ofprotein (quantitative only), lipids and carbohydratesof the seeds of Pelt%rum dubium and use thesedata to discuss chemosystematic aspects as well asthe possibility of sustainable use this species in semi­arid regions ofBrazil.

Material and methods

Samples ofmature fruits (combined from severaltrees) were collected in an area of 'caatinga' locatedin Itatim, State of Bahia, Brazil. Voucher specimensfrom samples are deposited in the Herbarium of theDepartment of Biological Sciences at the University

of Feira de Santana (HUEFS). The fruits were keptin the shade until dehiscence and the seeds weremaintained in a refrigerator prior to analysis. The seedsused in this work come from different populations ofP dubium which were pooled so that the compositionoflipids and carbohydrates would reflect an average.

The contents of total nitrogen was determinedby the micro-Kjeldahl method and the results wereexpressed as total proteins, using the factor 6.25(AOAC 1995).

Seeds (2 g) were ground and homogenised witha mortar and pestle. Oil extraction was performed inSoxhlet with n-hexane for 10 h. The solvent wasevaporated under reduced pressure, transferred toamber vials, while the remaining solvent waseliminated under N2 flow. The vials were kept undervacuum until constant weight was attained (Zygadlo& Guzman 1986, Ferlay et al. 1993). The glycerideswere saponified for 2 h with 100 g L- 1 KOH underreflux. After acidification with 2 M HCI until pH4.0-5.0 was attained, the fatty acids were extractedwith chloroform (Grunwald & Endress 1988) and thesolvent was evaporated in a rotary evaporator underreduced pressure followed by N 2 flow. The fatty acidswere derivatised to the corresponding methyl esterswith a freshly prepared ethereal solution ofdiazomethane. The methyl esters were analysed byGC-MS with a 5890 ser. II Plus HP chromatographinterfaced with a ChemStation System 5889B HPmass spectrometer, using a HP Ultra-l capillarycolumn (25 m x 0,25 mm) offused silica and heliumas carrier gas at a flow of 1 cm 3 min-I. Thetemperatures of the column involved a programstarting at 150°C for 5 min, then raising thetemperature until 210°C at 4°C min-I was attainedand maintaining an isothermal period of60 min. Thetemperatures of injector and detector were 250°C.The ionisation was accomplished by the electron impacttechnique at 70 eV. The identification ofthe compoundswas achieved by comparison with standards andcomparison of the mass spectra obtained with thoseof the Wiley 275 library.

Samples of seeds of Peltophorum dubium wereharvested and dried at 80°C. After grinding, the lowmolecular mass carbohydrates were extracted fourtimes from sample powders with 80% ethanol at 80 °Cfor 15 min (Buckeridge et al. 1995b). Sugars wereidentified by High Performance Anion ExchangeChromatography (HPAEC) using a chromatographfrom Dionex, (DX-500) equipped with a Pulsed

M.A.S. Mayworm, A. Salatino & M.S. Buckeridge: Chemical composition of Pellophorlllll c1l1billlll 177

Results and Discussion

Table I. Chemical composition ofquiescent seeds ofPeltoplIo/7/111dllbiulII. Values are given as % of the dry weight of the seed.

The general composition of the seeds ofPeltophorum dubium is shown in table 1. The resultsindicate a relatively low level of lipids (2.3% of dryweight), which is a common feature of seeds fromplants of the Leguminosae (Mayworm & Salatino1996b, Gunstone et al. 1968, Gunstone et al. 1972,Chowdhury et al. 1986, Banerj i et al. 1984, Lagoet al. 1987). On the other hand, proteins were foundto be a quantitatively important component of theseeds (43.8% of dry weight), when compared tospecies known to be economically important for theircontent of proteins such as Lupinus mutabilis(45.3%), and Phaseoulus vulgaris (25%) (Sgarbieri1980). The total amount of carbohydrates (alcohol­soluble oligosaccharides plus water-solublepolysaccharides) is relatively low. The seeds containan endosperm which accumulates galactomannan(4.3% of dry weight) and raffinose family

Amperometric Detector (PAD). Monosaccharideswere eluted isocratically in a Carbopac PAl column,in 23 mM NaOH and raffinose family oligosaccharideswere eluted isocratically with 150 mM NaOH.

Galactomannan was extracted from powderedendosperm plus seed coat with hot water (80°C) for6h. After centrifugation (13,000 g, 15 min), precipitationwas performed with 3 volumes of ethanol. Theprecipitate was left overnight at 5°C, collected bycentrifugation, dried and weighed. This crudepolysaccharide was considered as the galactomannan(modified from Buckeridge & Dietrich 1990).

The monosaccharide composition of thepolysaccharides was determined after acid hydrolysisof samples (5 mg) in 72% (w/w) H2S04 at 30°C for30 min followed by 3% H2S04 for 1 hat 121°C in anautoclave. The total low molecular weightcarbohydrates were quantified colorimetrically (Duboiset al. 1956).

Fatty acids P. dubilllll P. !errllgineulII 1 P. inerllle2

Palmitc C 16:0 16.0 18.4 44.8Stearic C 18:0 6.4 8.9OleicC 18:1 26.9 17.5 44.2Linoleic C 18:2 50.7 52.7 11.0Linolenic C 18:3 0.8Arachidic C 20:0 1.0

oligosaccharides (ca. 1% of dry weight).The distribution offatty acids in the oil of seeds

ofPeltophorum dubium is shown in table 2. The maincomponent is linoleic acid (50.7%), followed by oleicacid (26.9%), palmitic acid (16%) and stearic acid(6.4%). As far as lipid composition is concerned, fromthe chemotaxonomic viewpoint Peltophorum dubiumseems to be closer to Peltophorumjerrugineum thanto Peltophorum inerme (table 2). Indeed, differencesin the number ofchromosomes ofdifferent species ofthe genus Peltophorum have been observed byGodblatt (1981), being n = 13 for P jerrugineuJIl andn = 14 for P inerme. The oil composition is comparableto oils cunently used in human diet (e.g. soybean)what makes P dubium a possible source of oils ofgood quality for the Caatinga Region. In general, thefatty acid composition of Peltophorum is notquantitavely similar to other seeds (including legumes)from the tropical forest (Gonyalves et al. 2002)although a common feature of most species is thepresence of relatively high proportions of palmitic(16:0) and linoleic acid (18:2).

I Miralles & Pares, 1980; 2Bhale & Bokadia, 1979

Table 2. Fatty acid composition of the oil ofquiescent seeds of3Pellopl1orwn species.

The analysis ofthe water-soluble polysaccharides(figure lA) and alcohol-soluble oligosaccharides(figure I B) were performed by HPAEC/PAD.Members of the raffinose family oligosaccharideswere found, raffinose being by far the principalcomponent (65%) followed by sucrose (11.7%) andstachyose (10.1 %). Monosaccharides (a mixture ofglucose and fructose) were also found as 13.2% ofthe alcohol soluble sugars (figure 1B).

Visual inspection of the broken seeds clearlyindicated the presence ofa vitreous endosperm, whichin legumes are usually associated with the presenceof galactomannan. It is interesting to note that theendosperm could be separated with great facility from

5.22.3

43.89.1

Yield(%)Compound

CarbohydrateLipidsProtein (N x 6.25)Water

178 Hoehnea 31 (2), 2004

200

nC

Rham

100

nC

monosaccharides

Sue

Minutes

14

14

Gal

Raf

Man

S"

19

19

A

B

mollis, another legume tree from the Caatinga, has aseed galactomannan that can be used in food and paperindustry (Panegassi et at. 2000, Lima et at. 2003), theunique structure of the galactomannan of P dubiumprompts it as an interesting option for more specificapplications, which normally demands less and wouldbe adequate to the lower yield found in this work.

Altogether, our results suggest the possibility ofproduction ofa structurally unique galactomannan fromseeds ofP dubium by a relatively easy dry procedure,the rest of the seed having potential to be used as asource oflipids and proteins which might be used forexample for animal (and maybe human) nutrition. Thus,our results suggest that the seeds of P dubium alongwith other legume seeds from the Caatinga (such asDimorphandra mol/is) could be part ofa programmefor sustainable exploitation of biodiversity by localpopulations.

Acknowledgements

Figure I. Analyses of the soluble sugars ofseeds ofPeltophorumdubiulII by High Perfomlance Anion Exchange Chromatographywith Pulsed Amperometric Detection. A) monosaccharidesproduced by acid hydrolysis of the water soluble polysaccharide(galactomannan) and B) oligosaccharides extracted with ethanol(80%, 80°C). Ara = arabinose, Gal = galactose, Gle = glucose,Man = mannose, Raf = rafinose, Rham = rhamnose,Sta = stachyose and Suc = sucrose.

the embryo using a blender. Indeed, analysis byHPAEC/PAD of the hot water solublepolysaccharides from seeds of Pettophorum dubiumrevealed the presence of galactomannan with amannose:galactose ratio of4.5 (figure 1A). This highmannose:galactose ratio is unusual in galactomannancontaining seeds of legumes (Buckeridge & Dietrich1990, Buckeridge et at. 1995a, Buckeridge et at. 2000)and it may be of high commercial value since it iscomparable to the galactomannan found in seeds ofCeratonia siliqua, which is normally required forspecific applications when interaction with otherindustrial polysaccharides (agar, carragenans, celluloseand xanthan for example) is needed. Thus, is spite ofthe relatively low yield ofgalactomannan, the possibilityof utilisation of P dubium galactomannan as asubstitute of carob gum in Brazil together with theeasy separation of endosperm from the embryoincrease the potential of P dubium as a source ofgalactomannan with commercial value. Although it hasbeen previously demonstrated that Dimorphandra

The authors wish to acknowledge Mr LucianoQ. Paganucci for the identification of plant material.

Literature cited

Andrade-Lima, D. 1981. The caatingas dominium. RevistaBrasileira de Botanica 4: 149-153.

AOAC. 1995. Official methods of analysis of theAssociation of Official Analytical Chem ists.Washington, DC, USA, pp. 149-158.

Bhale, R & Bokadia, M.M. 1979. Fatty acid compositionofPeftophoru//1 illerme seed oil. Bioresearch 3: 7-8.

Banerji, R, Chowdhury,A.R, Misra, G & Nigam, S.K.1984. Butter from plants. Fette, Seifen, Anstrichm 7:279-284.

Batista Filho, M., & Batista, L.V. 1996. Alimentayao enutriyao no Nordeste semi-arido do Brasil; situayao eperspectivas. Sitientibus 15: 287-299.

Bautista, H.P. 1984. Especies arb6reas da caatinga - suaimportancia economica. In: Anais do simp6sio sobrecaatinga e sua explorayao racional. Embrapa, Brasilia,pp.115-140.

Buckeridge, M.S. & Dietrich, S.M.C. 1990. Galactomannanfrom Brazilian legume seeds. Revista Brasileira deBotanica 13: 109-112.

Buckeridge, M.S., Panegassi, V.R., Rocha, D.C. &Dietrich, S.M.C. 1995a. Seed galactomannan in theclassification and evolution of the Leguminosae.Phytochemistry 38: 871-875.

Buckeridge, M.S., Panegassi, V.R. & Dietrich, S.M.C.1995b. Storage carbohydrate mobilisation in seeds ofDimorphandra mollis Benth. (Leguminosae) followinggem1ination. Revista Brasileira de Botanica 18: 171-175.

M.A.S. Mayworm, A. Salatino & M.S. Buckcridge: Chcmical composition of Peltophorum dub/um 179

Buckeridge, M.S., Dietrich, S.M.C. & Lima, D.V. 2000Galactomannans as the reserve carbohydrate in legumeseeds. In: A.K. Gupta & N. Kaur (eds.). Carbohydratereserves in plants: synthesis and regulation. Elsevier,Amsterdam, pp. 283-316.

Chowdhury, A.R., Banerji, R, Tiwari, S.R., Misra, G &igam, S.K 1986. Studies on leguminous seeds III. Fette

Seifen Anstrichm 88: 144-146.

Dubois, M., Gilles, KA., Hamilton, J.K, Rebers, P.A. &Smith, F. 1956. Colorimetric method for determinationof sugars and related substances. Analytical Chemistry28: 350-356.

Ferlay, V., Mallet, G, Masson,A., Vccian, E. & Gruber,M. 1993. Composition en acide gras des huiles degraines d'especes spontanees du sud-estmediterraneen. Oliagineux 48: 91-97.

Goldblatt, P. 1981. Cytology and the phylogeny ofLeguminosae. In: R.M. Polhill & P.M. Raven (eds.).Advances in legumes systematics v. II. Royal BotanicalGarden Kew, England, pp. 427-463.

Gonl;alves, J.F.C., Fernandes, A.V., Oliveira, A.F.M.,Rodrigues, L.F. & Marenco, RA. 2002. Primary metabolismcomponents ofseeds from Brazilian Amazon tree species.Brazilian Journal ofPlant Physiology 14: 139-142.

Grunwald, C. & Endress, A.G. 1988. Oil, fatty acid andprotein content of seed harvest from de soybeansexposed to 0 3 and/or S02' Botanical Gazette 149: 283-288.

Gunstone, F.D., Taylor, GM., Cornelius, J.A. &Hammonds, T.W. 1968. ew tropical seed oils. II:Component acids of leguminous and other seed oils.Journal of Food Science and Agriculture 19: 706-709.

Gunstone, F.D., Steward, S.R., Cornelius, J.A. &Hammonds, T.W. 1972. New tropical seed oils. IV:Component acids of leguminous and other seed oilsincluding useful sources of crepenynic anddehydrocrepenynic acid. Journal of Food Science andAgriculture 23: 53-60.

Lago, RCA., Pereira, D.A., Siqueira, F.A.R, Szpiz, RR.& Oliveira, J.P. 1987. Estudo preliminar das sementese do oleo de cinco especies da Amazonia. ActaAmazonica 16/17: 369-376.

Lima, D.V., Chaves, RO. & Buckeridge, M.S. 2003. Seedstorage hem ice Iluloses as wet-end add iti ves inpapermaking. Carbohydrate Polymers 52: 367-373.

Mayworm, M.A.S. & Salatino, A. 1996a. Fatty acidcomposition of 'Cerrado' seed oils. Journal of FoodScience Agriculture 72: 226-230.

Mayworm, M.A.S. & Salatino, A. 1996b. Teores de oleo e

composiyao de acidos graxos de sementes de Cereusjalllacaru DC. (Cactaceae), Zizyphus joazeiro Mart.(Rhamnaceae) e Anadenanthera colubrina (Benth)Brenan val'. cebil (Griseb.) von Altschul. (Mimosaceae).Sitientibus 15: 201-209.

Miralles, J. & Pares, Y. 1980. Composition en acides grasde quelques huiles extraits de graines provenant desplantes du Senegal. Revue Francaise des Corps Gras27: 393-396.

Panegassi, V.R, Serra, GE. & Buckeridge, M.S. 2000.

Potencial tecnologico do galactomanano de sementesde faveiro (Dilllorphandra mol/is) para uso na indLlstriade alimentos. Revista Brasileira de Ciencia & Tecnologiade Alimentos 20: 406-415.

Pio Correa, M. 1984. Dicionario de plantas uteis doBrasil. v. III. Ministerio da Agricultura, Rio deJaneiro, 646 p.

Sampaio, E.V.S.B. 1995. Overview ofthe Brazilian caatinga.111: S.H. Bullock, H.A. Mooney & E. Medina (eds.).Seasonally dry tropical forest. Cambridge University,London, pp. 35-63.

Sgarbieri, V.c. 1981. Estudo do conteudo e de algumascaracteristicas das proteinas em sementes de plantasda familia Leguminosae. Ciencia e Cultura 32: 78-84.

Sherbeiny, A.E.A., Ansari, M.A., awwar, M.A.M. &Sayed, N.H. 1979. Flavonol glycosides and flavonolglucoside gallates from Peltophorum africanul/1. PlantaMedica 32: 165-170.

Zygadlo, J.A. & Guzman, C.A. 1986. Algunascaracteristicas de los lipidios seminales de tres especiesdel genero Condalia (Ramnaceae). Anales de laAsociacion Quimica Argentina 74: 41-44.