European Journal of Experimental Biology Open Access

Keywords

Proximate; Amino acid; Fatty acid

Introduction

Plant derived foods are associated with reducing disease risks, particularly cardiovascular disease and some cancer. Plants are sources of a number of nutrients that may have beneficial effect on health, such as vitamin C, dietary fibre and minerals [1]. Proximate analysis gives a partitioning of food into six fraction: moisture, ash, crude protein, crude fibre, lipid and carbohydrate. The ash content of a food is used to measure the inorganic residue of the food [2]. Dietary fibre helps in lowering blood glucose concentration and reduces the chance of gastrointestinal problems such as constipation and diarrhoea [3]. Carbohydrate functions as a source of energy; required for the biosynthesis of glycogenic amino acids and inco-operated in RNA and many nucleotides (ribose sugar). Whereas proteins are necessary for growth and tissue maintenance; appropriate pH maintenance; defence and detoxification of harmful substance; formation of essential body components such as hormones and transport of nutrients.

Proteins are the basis for the major structural components of animal and human tissue. Amino acids are the building blocks of proteins which contain a carboxylic acid group and an amino group. Amino acids are essential in the synthesis of proteins and precursors in the formation of secondary metabolism molecules that participate in cell signaling, gene expression and homeostasis regulation, protein phosphorylation, synthesis of hormones and antioxidant capacity. Also, amino acids participate in various physiological processes such as skeletal muscle function, atrophic conditions, sarcopenia and cancer [4].

Fatty acids on the other hand, are carbon chains with a methyl group at one end of the molecule (designated omega, w) and a carboxyl group at the other end. Fatty acids have high energy level, are components of cell membrane (phospholipids), used for insulation and are also involved in gene regulation (transcription) [5]. There are essential [linoleic acid (C18:2n-6, n-6) and α-linolenic acid (C18:3n-3), an n-3] and non-essential fatty acids. The essential fatty acid helps in reducing cardiovascular diseases [6,7]. Hence the objective of this study is to determine the proximate, amino acids and fatty acids composition of Eremomastax polysperma, Brillantaisia owariensis leaves and Sorghum vulgare leaf-sheath.

Materials and Methods

Collection of plant sample

The plants; Sorghum vulgare leaf sheath was bought from mile 3 market while Eremomastax polysperma and Brillantaisia owariensis were gotten from a farm at Rumokoro (Lat 4.88999; long 6.96922) all in Port Harcourt, Nigeria. The plants were identified with voucher numbers: UPH/V/1325 (Brillantaisia owariensis) and UPH/V/1326 (Sorghum vulgare, synomyms sorghum bicolr) and UPH/V/1346 (Erempmastax polysperma) . They were dried and ground into fine powder with a blender and stored in an air tight container.

Proximate determination

The moisture, ash, lipid, proteins, crude fibre and carbohydrate content were determined according to AOAC (2011) method [8]. The energy value of the plants was calculated using % protein X4+% Lipid X9+% carbohydrate X4 (atwater factor) [9].

Amino acid and fatty acid determination

Amino acid contents were determined using HPLC and fatty acid composition was determined using gas chromatography.

Statistical analysis

Datas obtained were expressed as mean ± sem and subjected to one way-ANOVA using SPSS, with value p ≤ 0.05 is significantly different.

Results

Discussion

Proximate analysis is the process by which the major components or constituents of food material are determined to establish whether the food is normal or contaminated [2]. The Proximate composition of Sorghum vulgare leaf-sheath, Brillantaisia owarensis and Eremomastax polysperma is shown in Table 1. The moisture content of each was 91.03 ± 0.22%, 75.79 ± 0.24% and 75.55 ± 0.06% for Sorghum vulgare leafs heath, Brillantaisia owarensis and Eremomastax polysperma respectively. The fat content of Sorghum vulgare leaf-sheath, Brillantaisia owariensis and Eremomastax polysperma was 0.16 ± 0.01%, 0.33 ± 0.01% and 0.30±0.01% respectively. The dietary fibre of Brillantaisia owariensis (14.46 ± 0.01%) was significantly higher than (p ≤ 0.05) and Eremomastax polysperma (3.23 ± 0.01%) and Sorghum vulgare leaf-sheath (3.75 ± 0.01%). The protein and ash content of Eremomastax polysperma (3.80 ± 0.05%;3.91 ± 0.01%) was significantly higher than (p ≤ 0.05) Brillantaisia owariensis (1.61 ± 0.01% ;3.39 ± 0.01%) and Sorghum vulgare leaf-sheath(1.21 ± 0.05%; 1.74 ± 0.03%).

Values are expressed as Mean±SEM. Values in a row with similar alphabetical superscript do not differ significantly p≤0.05

Table 1: Proximate composition of Sorghum vulgare leaf sheath, B. owariensis and E. polysperma.

Amino acids are the building block of proteins. There are essential and non-essential amino acids. The essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine and tryptophan and valine. The nonessential ones are arginine, cysteine, glycine, glutamine, proline, tyrosine, alanine, asparagine, aspartate, glutamate and serine [10]. Glycine for instance is needed during periods of rapid growth and for biosynthesis of porphyrins of haemoglobin. Glutamate along with cysteine and glycine are components of glutathione (antioxidant). Methionine protects the liver from damage by poisons such as carbon tetrachloride, arsenic and chloroform. Phenylalanine and tyrosine helps in foetal childhood brain development. Tryptophan is used for nicotinic acid synthesis and as a precursor of serotonin (a vasoconstrictor). Proline and hydroxyl-proline are present in haemoglobin and cytochromes and also in collagen of connective tissues [3]. Aspartic acid function is essential for purine, pyrimidine, asparagine and inositol synthesis. Valine maintains the balance of branched chain amino acids, whereas alanine is involved on hepatic autophagy, gluconeogenesis and transamination.

Leucine regulates the protein turnover (mTOR signaling) and gene expression. Glycine, lysine, threonine and glutamate help to maintain intestinal integrity and health [4,11]. The results on Tables 2 and 3 shows the amino acid composition of composition of Eremomastax polysperma, Sorghum vulgare leaf sheath and Brillantaisia owariensis. The total non-essential amino acid composition of Sorghum vulgare leaf-sheath (59.49g/100g) was higher than Eremomastax polysperma (53.09g/100g) and Brillantaisia owariensis (53.82g/100g), with glutamate (14.69,20.08 and 14.46g/100g) and aspartate (12.21,13.22 and 10.64g/100g) having a higher concentration for E. polysperma, S. vulgare and B. owariensis respectively. The total essential amino acid composition of Eremomastax polysperma (43.18g/100g) was higher than Brillantaisia owariensis (39.41g/100g) and S. vulgare (31.40g/100g), with lysine and cysteine concentration of B. owariensis (9.72; 9.45) been higher than E. polysperma (9.48;6.59g/100g) and S. vulgare (4.11 and 7.19g/100g).

Table 2: Non-essential amino acids composition of Eremomastax polysperma, Sorghum vulgare leaf sheath and Brillantaisia owariensis.

Table 3: Essential amino acids composition of Eremomastax polysperma, Sorghum vulgare leaf sheath and Brillantaisia owariensi.

The fatty acid content of Sorghum vulgare, Eremomastax polysperma and Brillantaisia owariensis is shown in Table 4. Fatty acids are carbon chain with a methyl group at one end and a carboxyl group at the other end of the molecule. Fatty acids can be saturated (straight chain hydrocarbon) or unsaturated (carbon-carbon double bond chains) fatty acids. The unsaturated fatty acids can be monounsaturated or polyunsaturated [5]. Fatty acids can also be essential or non-essential. The essential ones are required in diet, the body can-not synthesize them [examples are linoleic acid omega-6) and α-linolenic acid (omega-3)]. Essential fatty acids (EFA) are important for membrane fluidity and increases the number of receptors and other affinity to the respective hormones or growth factor. EFA has antibacterial, antiviral and antifungal properties; an example is linoleic acid which kills Staphylococcus aureus. Decosahexaenoic acid (DHA) a precursor of linoleic acid is a suppressor of pro-inflammatory cytokines(IL-1, IL-2, IL-6 and TNF-α), suggesting its anti-inflammatory properties [12]. For monounsaturated fatty acids such as oleic acid (C18:0), they function in inhibiting Low density lipoproteins (LDL)-cholesterol oxidation and slows down atherosclerosis formation. MUFA are resistant to peroxidation and preserves HDL level [3]. From Table 4, the concentration of Oleic acid of Sorghum vulgare leaf sheath (17.51%) was higher than Brillantaisia owarensis leaf (5.96%) and Eremomastax polysperma leaf (1.53%). The linoleic acid concentration of Eremomastax polysperma (10.44%) was higher than of Sorghum vulgare leaf sheath (0.03%) and absent in Brillantaisia owariensis leaf (0.00%).

Table 4: Fatty acid content of Sorghum vulgare, B. owariensis and E. polysperma.

Conclusion

The results obtained showed that these plants are sources of nutrients.

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