Elemental, amino acid and phytochemical ...

Int. J. Med. Arom. Plants, ISSN 2249 – 4340

RESEARCH ARTICLE

Vol. 3, No. 2, pp. 200-203, June 2013

Elemental, amino acid and phytochemical constituents of fruits of three different species of eggplant Benjamin AMADI1, Nchekwube ONUOHA2, Chioma AMADI3, Amadike UGBOGU4, Majesty DURU5* 1

Department of Biochemistry, Imo State University, Owerri, Imo State, Nigeria

2

Department of Home Economics, Federal College of Education [Technical], Asaba, Delta State, Nigeria.

3

Center for Global Health and Development, College of Public Health, University of Nebraska MedicalCenter,984355 Medical Center Omaha, USA. 4,5

Department of Biochemistry, Abia State University, Uturu, Abia State, Nigeria.

Article History: Received 5th February 2013, Revised 21st April 2013, Accepted 22nd April 2013.

Abstract: The elemental (sodium, potassium, calcium, magnesium, phosphorus, iron and zinc) , amino acid (cystine, leucine, histidine, arginine, proline, alanine, lysine, methione, phenylalanine, threonine, and glycine ),and phytochemical constituents ( flavonoids, cardiac glycosides, cyanogenic glycosides, steroids, phytosterols and phlobatannins) of fruits of three different species viz., Solanum melongena, Solanum aethiopicum and Solanum macrocarpon of eggplant were studied using standard methods. The investiaged fruits contained appreciable amounts of the compounds investigated. The importance of these compounds lies in the body when these fruits are consumed. The present study has shown elemental, amino acid and phytochemical constituents of fruits of three different species of eggplant. Keywords: Amino acids; elemental; fruit species; phytochemicals; vegetables.

Introduction Vegetables are important in nutrition because they are complimented with foods to actualise balance diets (Ogunta 1998). They constitute important components of human diets. Olusanya (2008) noted that the term vegetables cover a wide range of plant foods. The same author broadly classified vegetables into root vegetables (carrots, turnips, turnips, etc), tuber vegetables (potatoes, yams, cocoyam, etc), green vegetables (spinach, cabbage, pumpkin leaves, etc), seed vegetables (peas, lentiles, soya beans, etc), and fruit vegetables (tomatoes, cucumber, okra, etc). Fruits of eggplants commonly known as garden egg, are also among the fruit vegetables as classified by Olusanya (2008). They belong to family Solanaceae and are widely consumed globally due to their nutritional as well as medicinal potentials. Garden egg fruit has many species, each species has many varieties and

these varieties come in different shape, colour and size (Akanitapichat et al. 2010). In Nigeria, fruit from eggplant is known as “Aṅara” or “Afufa” or “Mkpuruofe” in Igbo; “Igba” in Yoruba and “Gauta” in Hausa. The major species of the fruit widely consumed within Nigeria are S.melongena, S.aethiopicum, and S.macrocarpon. Their cultivation is widely spread to all parts of the country (Schipper 2004; Schipper 1994). Aside consumption, they are also used in tradition and as well during ceremonies. The herbalists in Nigeria also employ the fruits, or other parts of eggplant such as the leaves, stem, etc to formulate infusions, extracts, decoctions etc that are effective against diseases (Sofowara 1993;Gill 1992). Different researchers have noted that the ability of plants to have medicinal property lies in certain plant chemical compounds that are bioactive in nature. This study therefore investigated the elemental, amino acid, and phytochemical constit-

*Corresponding author: (E-mail) durumajestykelechukwu yahoo.com © 2013 Copyright by the Authors, licensee Open Access Science Research Publisher.

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Int. J. Med. Arom. Plants

uents of fruits of three different species of eggplants. Materials and methods Sample collection and preparation The fruits of Solanum melongena, S.aethiopicum, and S.macrocarpon used in the present study were purchased from a farm within Owerri Municipal, Imo State, Nigeria and were properly identified by Dr. F. N. Mbagwu of Plant Science and Biotechnology Department, Imo State University, Owerri, Nigeria. Fresh samples of the identified fruits were ground using simple electric blender. Their ground samples were used for analysis.

201 Constituents of fruits of three eggplant species

um and phosphorus elements among the investigated fruit species. S.melongena produced the highest amounts of magnesium, iron, and zinc; while S.macrocarpon produced highest amounts of potassium, copper and sodium elements (Table 1). These elements are needed for the wellbeing of the body. For instance, calcium is for strong bones, phosphorus aids the work of calcium, magnesium for cyclic AMP and other second messengers’ formation, potassium for acid-base balance, and sodium is for transmission of impulses (Onwuka 2005; Dahl 1972). Iron is a component of haemoglobin and helps in oxygen transport (Okwu and Morah,2004). Iron also works with ferrodoxin to influence many metabolic processes in man. Zinc content in plants could help them play valuable role in the management of diabetes (Okwu and Morah 2004).

Mineral analysis The samples were prepared for mineral analysis following the method described by (Okwu 2005). The flame photometric method was used in determining the sodium (Na) and potassium (K) contents of the investigated fruit species while atomic absorption spectrophotometer (Model: Unicam 939/959) method (AAS) was used for calcium (Ca), magnesium (Mg), phosphorus (P), iron (Fe), and zinc (Zn).

Table 1: Elemental concentration of Solanum fruit species (mg/100g). Element S.melongena S.aethiopicum S.macrocarpon Calcium 1.64±0.01 9.03±0.03 3.31±0.05 Magnesium 2.49±0.23 0.14±0.06 1.20±0.02 Iron 2.01±0.17 0.32±0.10 0.98±0.13 Potassium 238.10±0.45 200.50±0.29 245.37±0.63 Copper 0.01±0.00 0.03±0.00 0.05±0.01 Sodium 160.12±2.18 147.32±1.07 171.19±0.20 Zinc 0.24±0.03 0.16±0.01 0.11±0.08 Phosphorus 2.80±0.16 4.51±0.90 3.84±0.56

Results are mean and standard deviations of triplicate determinations.

Phytochemical Screening Flavonoids, cardiac glycosides, cyanogenic glycosides, steroids, phytosterols, phlobatannins were screened as described by AOAC (1990). Amino acid analysis Amino acids screened in the investigated fruit species were done using the methods described by Akubugwo et al. (2006) while their quantitative determinations were done following the methods of Spackman et al. (1985). Results Plants elements are the minerals found in plants. They are sometimes referred to as inorganic or ash constituents (Olusanya 2008). S.aethiopicum fruit produced the highest calciAmadi et al.

Most phytochemicals are known for their active roles in the protection of plants. Phytochemical results of the investigated fruit species (Table 2) revealed that flavonoids were present in high concentrations in S.aethiopicum and S.macrocarpon fruit species, cardiac glycosides were present in moderate concentrations in S. aethiopicum and S.macrocarpon, cyanogenic glycosides were low in all the investigated samples, steroids were moderate in S. aethiopicum, phytosterols were present in high concentration in S.aethiopicum while phlobatannins were only present in S.aethiopicum fruit sample. Aside cyanogenic glycosides, other phytochemicals found in the fruit species are relatively important in the body of humans. Flavonoids function by scavenging hydroxyl radicals, superoxide anions, and lipid peroxy radicals (Allan and Miller 1996), cardiac glycosides are associated with the proper functioning of the heart, steroids http://www.openaccessscience.com [email protected]



are important due to their relationship with some sex hormones (Okwu 2001). Table 2: Phytochemical screening of Solanum fruit species. Anti-nutrient

S. melongena Flavonoids ++ Cardiac glycosides + Cyanogenic glyco+ sides Steroids + Phytosterols ++ Phlobatannins +

S. S. aethiopicum macrocarpon +++ +++ ++ ++ + + ++ +++ -

++ -

+++ = Present in high concentration; ++ = Present in moderate concentration; + = Present in low concentration.

Table 3: Amino acid screening of Solanum fruit species. Amino acid S. melongena S. aethiopicum S.macrocarpon Cystine + + + Leucine ++ ++ ++ Histidine + ++ ++ Arginine ++ ++ +++ Proline + + + Alanine ++ ++ +++ Lysine + ++ ++ Methionine + + + Phenylalanine ++ ++ ++ Threonine + ++ + Glycine ++ ++ ++

+++ = present in high concentration; ++ = present in moderate concentration; + = present

tion of Solanum fruit species investigated. Amino acids such as cystine, leucine, histidine, arginine, proline, alanine, lysine, methionine, phenylalanine, threonine, and glycine were the amino acids found in the fruit species. Uwakwe and Ayalogu (1998) noted that amino acids are the basic building blocks of proteins. Quantitative study of these amino acids (Table 3) revealed that aside cystine which was in highest amount in S. aethiopicum fruit specie, S.macrocarpon fruit specie produced the highest amounts of other amino acids investigated this study. The importance of these amino acids is in their biological functions in the body. Growth and maintenance of nitrogen balance; formation of hormones such as thyroxine and adrenaline; promotion of prostrate health; production of histamine; production of glutamate, prevention of muscle breakdown during exercise, aiding the liver in processing of fats, etc, are among the functions of these amino acids found in the investigated fruit species in the present study (Okaka and Okaka 2005). Conclusion This study has shown the elemental, amino acids, and phytochemical constituents of three different species of eggplants fruits. These compounds are bioactive and could be behind the nutritional and medicinal potentials of the fruits.

in low concentration. Table 3: Quantitative amino acid composition of Solanum fruit species (g/100 g protein). Amino acid S. melongena S. aethiopicum S.macrocarpon Cystine 5.46±0.18 7.43±1.00 7.01±0.86 Leucine 48.12±0.27 53.08±0.49 60.30±1.24 Histidine 10.97±0.42 17.05±0.18 18.02±0.31 Arginine 38.20±1.86 41.96±1.10 59.80±0.98 Proline 9.56±0.11 11.25±0.54 12.47±0.65 Alanine 23.94±0.39 27.50±0.78 38.21±0.33 Lysine 11.16±0.10 36.04±0.41 41.95±0.28 Methionine 4.10±0.28 7.48±0.31 7.90±0.27 Phenylalanine 27.33±0.81 34.09±0.20 36.74±1.01 Threonine 10.46±0.60 16.17±0.31 18.00±0.85 Glycine 19.80±0.19 26.30±0.55 31.06±0.72

Results are mean and standard deviations of triplicate determinations.

Table 1 and Table 2 showed amino acid screening and quantitative amino acid composiAmadi et al.

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