¹Department of Microbiology, Federal University Gusau, Nigeria ²Department of Biological Science, Federal University Gusau, Nigeria ³Department of Pharmaceutical Technology, School of Technology, Kano State Polytechnics, Nigeria

*Corresponding author: Muhammad Ali, Department of Microbiology, Federal University Gusau, Nigeria, E-mail: [email protected]. Received: July 30, 2020 Published: September 08, 2020

ABSTRACT

Vegetables are the major sources of vitamins, minerals and bioactive components such as phytochemicals and antioxidants that help in reducing the risk of diseases. The aim of the study was to determine the proximate composition, phytochemical screening and mineral composition of Vernonia amygdalina leaf extract. The proximate composition and phytochemical screenings were determined by using conventional laboratory methods, while the mineral composition of the leaves was determined by using atomic absorption spectrophotometer. The proximate analysis of the leaf extract showed that, it contains carbohydrates (37%), proteins (28.2%), fats (5.5%), crude fiber (11.6%), moisture content (8.4%) and ash content (9.3%). The preliminary phytochemical screening of V. amygdalina leaf extract revealed the presence of alkaloids, terpenoids, flavonoids, steroids, phenols, saponins, and tannins. Quantitative phytochemical analysis of the extract showed that the flavonoids are the most abundant constituent which is about 12.2%, followed by steroids, alkaloids, and phenols constituting 4.8%, 4.6%, and 3.6% respectively. The mineral analysis of the extract indicate the presence of calcium (61 mg/100g), potassium (61 mg/100g), magnesium (85.8 mg/100g), phosphorous (60.5 mg/100g), zinc (9 mg/100g), iron (15.2 mg/100g) and copper (5 mg/100g). From the findings of this study, it is concluded that V. amygdalina leaf has therapeutic potential and can be used in dietary supplements.

KEYWORDS: Minerals; Phytochemicals; Proximate analysis; Vernonia amygdalina

INTRODUCTION

Several compounds such as vitamins, minerals and bioactive components like phytochemicals and antioxidants which help in reducing the risk of chronic illness of vegetables [1]. According to English dictionary, vegetables are the plants raised for its edible part, such as leaves, roots, seeds, and flowers. Leafy vegetables have high nutritional components on consumption they provide proteins, vitamins, minerals, and fiber for body. They remain an important edible food and easily available diet for human especially in the rural areas [2]. The analysis of bioactive components (such as phytochemical and anti-oxidant composition) of vegetables, encourage their utilization as natural medicine in pharmaceutical industry with nutraceutical values [3]. Vegetables are essential for the developing and under developed countries where vitamins and mineral supply is inadequate to meet the nutritional requirement for rapid growing population.

V. amygdalina (bitter leaf) belongs to the family Astreraceae which has a characteristic feature of bitterness in taste. It is a small shrub (Figure 1) that can grow up to three meters and native to tropical Africa. The plant is also well distributed in Asia and more commonly found near drainage line and in natural forests [4]. The leaves of the plant are used for making soup and stew in tropical Africa and majorly used ethno-botanically for the treatment of different ailments [5]. V. amygdalina is a medicinal plant used in folk medicine for treatment of several diseases. The bitter taste of V. amygdalina can be reduced by boiling or soaking in water [6]. Several bioactive alkaloid saponins and tannins are present in the plant leaves. These bioactive components made out of V. amygdalina leaf acts as an antimicrobial agent in brewing industries [7]. Several ailments such as fever, kidney problems, hiccups, and stomach discomfort can be treated ethno-medically using extracts of V. amygdalina leaves and roots [6]. V. amygdalina leaf and root extracts are used as purgative, antifungal and anti-malaria agents [8]. In pharmaceutical industry, V. amygdalina has acquired special relevance recently due to possession of anti-tumorigenic properties [9]. Nutritionally, V. amygdalina leaves are used as appetizer and also used in production of soap [10] and has been used as food supplement for weaning babies [11].

Several studies conducted on different parts of V. amygdalina indicated that it contains different bioactive components such as alkaloids, flavonoids, tannins, saponins, triterpenoids, and many more [12]. These bioactive components are responsible for their different pharmacological properties such as anti-malaria, antimicrobial, antioxidant, anti-inflammatory, anti-diabetic, antithrombotic, laxative, anticancer, antihelmintic, and hypoglycemic among others [13,14]. Considering the nutritional values of V. amygdalina, the study was conducted to determine the proximate, phytochemical and mineral composition of V. amygdalina leaf extract.

                          Figure 1: V. amygdalina plant

S/N	Nutrients	Composition (mg/100g)
1	Carbohydrate	37.00 ± 1.50
2	Protein	28.20 ± 1.20
3	Fats	5.50 ± 0.23
4	Crude fibre	11.60 ± 0.30
5	Moisture content	8.40 ± 0.04
6	Ash content	9.30 ± 0.23

Table 1: Proximate analysis of V. amygdalina leaf.

 

Phytochemical Screening

Table 2 represents the result of preliminary phytochemical screening of V. amygdalina leaf extract. Both qualitative and quantitative results were presented. The following phytochemicals were obtained; flavonoid, alkaloid, saponin, tannin, terpenoid, phenol and steroid. On the other hand, flavonoid has the highest content (12.2%), followed by steroid (4.8%), alkaloid (4.6%) and phenol (3.6%).

S/N	Phytochemicals	Qualitative screening	Quantitative screening (%/100g)
1	Alkaloid	+	4.60±0.23
2	Flavonoid	+	12.20±1.30
3	Saponin	+	2.70±0.5 0
4	Steroids	+	4.80±0.25
5	Terpenoid	+	1.70±0.04
6	Phenol	+	3.60±0.20
7	Tannin	+	1.20±0.03

 

Table 2: Qualitative and quantitative phytochemical screening of V. amygdalina leaf extract. Key: + = Present, - = absent of phytochemical.

Mineral Analysis

Table 3 represent the mineral analysis of V. amygdalina leaf. The result in mg/100mg indicated that magnesium has the highest composition (61mg/100g), followed by calcium (65.5mg/100g), potassium (61mg/100g) and phosphorous (60.5mg/100g). others include; iron (15.2mg/100g), zinc (9mg/100g) and copper (5.3mg/100g).

 

S/N	Minerals	Composition (mg/100g)
1	Potassium	61.00
2	Calcium	65.50
3	Magnesium	85.80
4	Phosphorous	60.50
5	Zinc	9.00
6	Iron	15.20
7	Copper	5.30

Table 3: Mineral analysis of V. amygdalina leaf.

DISCUSSION

The preliminary phytochemical screening of V. amygdalina leaves extract revealed the presence of saponins, flavonoids, tannins, terpenoids, alkaloids, phenols, and steroids. These bioactive components are beneficial to human health exhibiting different biochemical and pharmacological actions as well as possessing antioxidant activity [21]. Several studies were conducted to determine and characterized various bioactive components of V. amygdalina leaf extracts [7,22-24]. This resulted in screening of various bioactive components such as alkaloids, flavonoids, tannins, saponins, and phenolics [13,25]. Findings from the present study correlate with those of Atangwho IJ, et al. [26] and Ndukwe OK, et al. [27].

Alkaloids play an important metabolic roles and development in the system of living organisms [28]. It is beneficial chemical to plants serving as repellent to parasites and predators. The alkaloid is known to contain antimicrobial agents which accounted for its antimicrobial activity [3]. Flavonoid is believed to contain antioxidant agents and it is reported that it reduce the oxidation of low-density lipoprotein, lower cholesterol level and triglyceride [29]. It is also expressed in plant in respond to microbial attack suggesting their antimicrobial property [30]. Saponins limit the growth and viability of cancer cell by reacting with cholesterol rich membrane of cancer cell [31]. Pharmacologically, saponin is responsible for most cellular activities related to cell division and growth in human and has incivility effect on inflammation. Hence, V. amygdalina leaves can be utilized for the management of inflammation [32,33]. Steroid is important pharmaceutically for production of drugs due to possession of compound showing similarities to sex hormones [34]. Terpenoids are known to possess anticancer, anti-parasitic, antimicrobial, antifungal, immunomodulatory, anti-inflammatory, antiviral, anti-allergic and antispasmodic properties [35]. Phenolics are reported to possessed antioxidant property which prevents oxidative damage of cell due to present of free radical scavengers [36]. The phenolics lower the risk of heart diseases and provide anti-inflammatory activity due to their ability to neutralize or scavenge free radicals [37]. Tannins are known to have potential antiviral activity [38] as well as anticancer agent [39].

The proximate composition of V. amygdalina leaf according to the present study contains a high amount of protein and carbohydrate. However, there are moderate amount of fiber, ash, moisture and little amount of fat. This result supported the findings of Owu D, et al. [40] that V. amygdalina contains carbohydrate, protein, fiber, fats, amino acid, minerals and vitamins. High content of carbohydrate (37%) in V. amygdalina leaf from this study indicated that it is a good source of energy [3]. Presence of protein in V. amygdalina is very vital. The proteins are building blocks need to built-up hormones, enzymes, brain chemicals, and nucleic acids. Antibodies produced by protein are used to fight against germs [41]. From the result of the present study, V. amygdalina leaf contains crude fiber of about 11.6% and this justified the work of Yeap SK, et al. [42] who reported that V. amygdalina leaves contained 6.5 to 29.2% of crude fiber. The fiber inhibits the intake of starchy food and hence, prevents body metabolic condition such as diabetes and cholesterol [43]. According to the present study, V. amygdalina contain low fat (5.5%). This agrees with the report of Yeap SK, et al. [42] who reported crude fat values ranging from 2–15%. The food providing 1–2% of fat is sufficient for healthy human as excess fat consumption has implication and may lead to certain cardio-vascular disorder [44].

Analysis of mineral composition of V. amygdalina leaf in this study confirmed the presence of both trace (zinc, iron and copper) and major (potassium, phosphorous, calcium and magnesium) elements. This justifies the vitality of the plant leaf nutritionally rich when consumed by animals or humans. Minerals play an important metabolic role in the body of animals, such activities include maintenance of acid balance in the body, production and activity of enzymes and so on [3]. Presence of potassium in the extracellular body fluid is vital; it conducts several functions to the body system such as regulation of osmotic pressure, conduction of nerve impulse and maintenance of acid-base balance [3]. Calcium played a major role in the formation and development of bones and teeth, coagulation of blood, contraction of muscle, normal functioning of heart and nervous system [45]. Presence of magnesium in the diet is essential for decreasing blood sugar as a result it improves the function of insulin [46], metabolism of fats, and carbohydrates [3]. Presence of zinc in V. amygdalina leaf made it important for nerve functioning and normal sexual development. Zinc is also vital for stimulating the activity of vitamins as well as formation of red and white blood cells [47]. Zinc is an integral part of many enzymes in the body and also plays an important role in proper functioning of body immunity [46]. Copper as a trace element is essential for cellular defense, mucous membrane protection, anti-anemic and vital for haemoglobin formation [47]. Despite the nutraceutical value of V. amygdalina, the plant can be toxic due to the unrefined nature of the preparation or lack of specificity in the application of the plant which could lead to over dosage of the herbal preparation. This may result in accumulation of toxic plant ingredient in the human system. A study conducted by Okwuzu JO, et al. [48] on cytotoxicity testing of aqueous extract of V. amygdalina showed high cytotoxic effects induced by V. amygdalina extract.  

CONCLUSION

Based on the findings of the present study, the V. amygdalina leaf extract contains an adequate amount of food substances, phytochemicals and mineral elements and thus provide a basic rationale for the use of the plant as herbal medicine and food substances.

ACKNOWLEDGEMENT

The authors hereby wish to acknowledge to the technical staff and management of Biochemistry Department of Bayero University Kano for provision of reagents and utilization of laboratory facilities.

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Copyright: Ali M, et al. ©2020. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Citation: Ali M. (2020). Determination of Proximate, Phytochemicals and Minerals Composition of Vernonia Amygdalina (Bitter Leaf). Nutraceutical Res 1(1): 1.