Short Communication

Introduction

Worldwide, fruits and sometimes fruit nuts of many plants have been consumed for their nutritional benefits but, apart from that, they could be of a medical and pharmaceutical importance use to humans.  Terminalia  catappa  (T. catappa,  almond plant) from Combretaceae family is a large tree in the Leadwood tree family that grows mainly in tropical regions of Africa, Asia and Australia [1]. In Southern Nigeria, it is referred to as “Ebelebo” among the Binis, “Baushe” in Hausa and “Igi-furutu” in Yoruba [2]. The juice obtained from its fresh leaves has been used in preparation of medicinal lotion which is effective against scabies, leprosy, stomach ache and headache [3]. The tree provides several other dyes, tannins, timbers, carbohydrates, fuel plant and many other medicinal purposes [2]. T. catappa is a well-known herb in Ayurveda traditions in Indian. The ethno-medical uses of T. catappa includes modulatory activity of methanol extract of the leaves, wound healing activity of the  chloroform extract of the bark [4], anticancer potency of the ethanol extract of the leaves [5] and anti-oxidant, hepato-protective, anti-microbial, analgesic, anti-inflammatory, anti-diabetic and anti-aging activity [3]. Recent scientific investigations revealed that the methanol extract of T. catappa leaf extract exhibits the dosage-dependent increase in inhibitory effect on α-glucosidase enzyme and α-amylase enzyme [6]. T. catappa exhibits anti-tumor activity with high anti-oxidant levels and the anti-oxidant defense may be due to the presence of phenolic and flavonoid components [5]. Phytochemical screening of the tree bark and leaves contains saponins, alkaloids, glycoside, terpenes, volatile oils, steroid and phenols. While, the seeds are rich in oleic‑linoleic acid group, steroids, glycosides, phenolics and terpenes [7]. T. catappa has been observed to possess the anti-oxidant activity in a dose-dependent manner by DPPH assay, nirtic oxide assay, reducing power assay and H₂O₂ assay [8]. The plant also reverses the lipid levels to normal range and this shows anti-tumor and anti-lipidemic activities [9]. The leaves extract also inhibit the expression and activities of matrix metallo-proteinase-9 (MMP-9) by the assessment of mRNA levels in hepato-cellular carcinoma [10]. This research is aimed at determining the proximate composition, mineral elements and physicochemical parameters of T. catappa seed extract.

 

Materials and methods

Materials: All the chemicals used in this work were of analytical grade and obtained from Merck and Sigma Aldrich, Modderfontein Johannesburg 1645, South Africa.

Sample collection and treatment: The fruits of T. catappa were collected from tree grown in Benin city, Edo State, Nigeria. The fresh epicarps of the T. catappa fruit were peeled to expose the seeds. The exposed seeds were then air dried for seven days and cracked open to collect the nuts. The seed nuts were air-dried under normal laboratory conditions for four weeks and finally pulverized. The powder seed nuts were then used for the proximate analysis and the determination of mineral composition [11].

Proximate analysis: The proximate composition of the seed kernel was analyzed following standard methods [11], crude fat by Soxhlet method and moisture by vacuum oven, crude protein by Kjeldahl method and ash by ignition. Carbohydrate content was calculated by subtracting the values of all the other proximate analysis from 100 [11].

Mineral element determination: For the elemental analysis of the powder seeds, one gram of the sample was digested with concentrated HNO₃ and HClO₄. The sample was then filtered and made up to 50 ml with distilled water [11]. The metal concentrations were determined using an Atomic Absorption Spectrophotometer (Buck Scientific model 210) and a Flame Spectrophotometer (Sherwood, model 410). The mineral elements investigated were Iron (Fe), Zinc (Zn), Calcium (Ca), Magnesium (Mg), Potassium (K), Nickel (Ni), Sodium (Na), Cadmium (Cd), Cupper (Cu), Chromium (Cr) and Lead (Pb).

Physico-chemical analysis: The physicochemical analysis including acid value, saponification value, peroxide value and iodine value were determined according to standard methods [1].

 

Results

The results of the proximate analysis, mineral elements and physicochemical analysis of the seed oil extract of T. catappa seed nut are shown in

Tables 1, 2 and 3, respectively. Thus, a wide range of percentage among the constituents of T. catappa seed nut was found as shown in Table 1. Thus, carbohydrate, fat and crude protein were found in high percentage (33.3, 21.9 and 29.6% respectively) whereas, fibre, ash and moisture contents were found in very low percentage (08.5, 03.8 and 02.3%, respectively).

 

Table 1: Results of proximate composition

of T. catappa seed nut

 

 

 

In Table 2, different contents of mineral elements of the extract are given. Potassium, magnesium and zinc contents represent the highest, whereas, other elements are presented in a very low contents. However, lead (Pb) content was not detected in this extract.

 

 

Table 2: Mineral elements detected in hexane

extract of T. catappa seed nut

 

 

 

Table 3 shows acid, saponification, iodine and peroxide values of the crude oil hexane extract of T. catappa seed nut. A large variation was found among them with saponification value represents the high value and acid value was the lowest value.

 

 

Table 3: Chemical parameters of the crude

oil hexane extract of T. catappa seed nut

 

 

Discussion

In this study, the moisture content obtained for the almond seed nuts was to be 02.34%. Moisture content helps to determine storage time. Low moisture content is important for storage quality and shelf life of seeds. The moisture content indicates that almond seed can thus be kept for a long time. Furthermore, most researches have inferred that low moisture in seeds reduces the microbial activities and decreases unwarranted fermentation [1]. The lower moisture content recorded may be due to the fact that the almond seeds were air dried for 28 days. The ash content of a sample is an indication of the level of minerals present [12]. The values of ash content reported from different locations in Nigeria appear to fall within a similar range of 02.00% - 05.00%. According to the previous report [13], low ash content of seeds could be credited to the fact that during maturation, inorganic ions migrate from different parts of the plant to the region of active growth. This value was also lower than those obtained for almond seeds from other countries like Ivory Coast (04.60%) but higher than 03.78% reported in the seeds from Malaysia [14]. The crude fiber content obtained in this work was 08.50% and higher than 03.11% obtained by Akpabio [12]. The high amount of protein content obtained in this work suggests that almond nut can be used to supplement other dietary sources. Therefore, it is recommended that almond nut be added to the meals of individuals in order to increase the protein content. From other study, the seed contains carbohydrates, protein, fat, fiber, iron, ascorbic acid, arachidic acid and β-carotene are in good proportion [15].

Amongst the minerals determined, the concentration of potassium was the highest (54.7 mg/kg) and Cr had the least quantity (0.18 mg/kg) while Ni, Cd and Pb were beyond detection limit. Iron had a quantity of 6.40 mg/kg. On comparison with the work of Mandloi [15], phosphorus, potassium, niacin, riboflavin and thiamin were also detected in the seed. Therefore, almond seed could be recommended as a dietary supplement for people who need essential minerals and iron. The World health Organization (WHO) recommended daily allowance for zinc is 11 mg. Therefore, almond nut when properly processed will be a good source for zinc due to its high value. Potassium had a quantity of 54.7 mg/kg which plays a role in many body functions including transmission of nerve signals, muscle contractions, fluid balance and various chemical reactions.

The chemical parameters of the oil extract shown below in this study indicated an acid value of 0.102 mg KOH/g of oil which is attributable to its low free fatty acid value of 0.051. This value was low when compared to 0.787 mg KOH/g of almond nut oil obtained from India [12]. However, Ogbeide and others [16] reported a much higher level acid value of 2.94 mg KOH/g. The saponification value obtained showed a value of 151.278 mg KOH/g which less than the value 326.08 mg KOH/g is obtained [16]. The saponification value obtained in this work could suggest that the almond seed has a few proportions of low molecular weight fatty acids and the difference observed could be as a result of method of extraction of the oil from the seed. Other report, however, indicated that almond nut oil contains higher proportions of low molecular weight fatty acids [1]. Rancidity begins to occur in oil when the peroxide value ranges from 20.0 mg/g oil to 40.0 mg/g oil. The peroxide value obtained in this work was 8.93 meq/kg and this low values of peroxide value are indicative of low levels of oxidative rancidity of the oils and suggest high levels of antioxidants [1]. It has been asserted that oils with iodine value less than 100 mg I₂/100g are non-drying oils, and consequently, the lesser the number of unsaturation the lower the susceptibility of such oil to oxidative rancidity [17]. The iodine value obtained in this work was 47.186 g/100 g which is less than 131.37 g/100 g obtained by [16] and 121.19 g/100 g obtained by [1]. The iodine value obtained was less than 100 g/100 g, thus, almond nut oil cannot be placed in the class of drying oil. 

Conclusion: Terminalia catappa seed nuts contain essential minerals required for nutritional and medicinal purposes, and the low moisture content of the oil indicates that products or formulations from the nuts will possess longer shelf life.

References

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4.      Khan AA, Kumar V, Singh BK, Singh R (2014) Evaluation of wound healing property of Terminalia catappa on excision wound models in Wistar rats. Drug Research (Stuttg). 64 (5): 225-228. doi: 10.1055/s-0033-1357203.

5.      Pandya NB, Tigari P, Dupadahalli K, Kamurthy H, Nadendla RR (2013) Antitumor and antioxidant status of Terminalia catappa against Ehrlich ascites carcinoma in Swiss albino mice. Indian Journal of Pharmacology. 45 (5): 464-469. doi: 10.4103/0253-7613.117754.

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7.      Mininel FJ, Leonardo-Junior CS, Espanha LG, Resende FA, Varanda EA, Leite COF, Vilegas W, Dos Santos LC (2014) Characterization and quantification of compounds in the hydroalcoholic extract of the leaves from Terminalia catappa Linn. (Combretaceae) and their mutagenic activity. Evidence-Based Complementary and Alternative Medicine. 67-69. 2014: 676902. doi: 10.1155/2014/676902.

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9.      Naitik P, Prakash T, Kotresha D, Rao NR (2012) Effect of Terminalia catappa on lipid profile in transplanted fibrosarcoma in rats. Indian Journal of Pharmacology. 44 (3): 390-392. doi: 10.4103/0253-7613.96345.

10.  Yeh CB, Yu YL, Lin, CW, Chiou HL, Hsieh MJ, Yang SF (2014) Terminalia catappa attenuates urokinase-type plasminogen activator expression through Erk pathways in hepatocellular carcinoma. BMC Complementary and Alternative Medicine. 14:141. doi: 10.1186/1472-6882-14-141.

11.  Association of Official Analytical Chemists AOAC (2015) Official methods of analysis of the association of official analytical chemists, 5^th Edn. Association of official analytical chemists, Virginia, USA. ISBN: 0-935584-42-0.

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13.  Monnet YT, Gbogouri A, Koffi, PKB, Kouamé LP (2012) Chemical characterization of seeds and seed oils from mature Terminalia catappa fruits harvested in Côte d’Ivoire. International Journal of Bioscience. 2: 110-124. Corpus ID: 86147763.

14.  Siew NG, Ola L, Muhammad KS, Hussain N, Sulaiman R (2015) Physicochemical properties of Malaysian-grown tropical almond nuts (Terminalia catappa). Journal of Food Science and Technology. 52 (10): 6623-6630. doi: 10.1007/s13197-015-1737-z.

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