Evaluation of Comparative Morphological and Phytochemical Studies on the Seeds Extracts of Cocos nucifera (L.) and Elaeis guineensis Jacq. (Arecaceae)

Area of the Study

The research was conducted in the Botany Laboratory of Nnamdi Azikiwe University, located in Awka. Collection and Identification of Plant Specimens .

The seeds of Cocos nucifera and Elaeis guineensis were sourced from the Eke-Awka market located in Awka South Local Government Area of Anambra State, Nigeria. A plant taxonomist from the Department of Botany at Nnamdi Azikiwe University, Awka, verified the authenticity of the seeds.

Morphological Studies

The plants were primarily examined in their natural habitat. A random selection of four samples from each species was made for observation. The total heights of these plants were measured from the ground level to the apex of the crown, and the diameter at breast height was also determined. The overall form and visual characteristics of the crown were observed. Additionally, the quantity of fronds per plant was documented, and the length of a fully developed frond was assessed from its base to its tip. The count of leaflets on one side of the frond was also conducted, along with the measurement of the length and width of various leaflets taken from different sections of the frond. The

color and texture of the leaflets were recorded, along with the texture of the trunk and the spacing between leaf scars (internodes). An evaluation of the fruits was conducted, and a thorough examination of the root systems was performed. Additionally, key components of the plants were captured using a digital camera.

Phytochemical Studies

Sample Preparation: Dried nuts were rinsed and processed using an electric blender. Each of the ground samples, weighing 100 g, was immersed in 500 ml of water for duration of 24 hours. The extracts were subsequently filtered using cheesecloth. The resulting solutions, yielding 50%, were concentrated utilizing a rotary evaporator before undergoing testing.

A qualitative phytochemical analysis of the extracts was performed to determine the presence of various phytochemicals, including flavonoids, alkaloids, phenols, tannins, saponins, and oxalate and beta carotene.

The analysis was carried out in accordance with the standard methodology outlined by Harborne, and modified by Ilodibia, et al. [18]. A quantitative phytochemical analysis of the extracts was performed to ascertain the percentage contents of the aforementioned phytochemicals, using standard techniques. The flavonoids, phenols, oxalate and beta carotene contents were determined following the standard method described by Barros, et al. [19]. saponins content was determined using the standard procedure as outlined by Obadoni, et al. [20] while tannins and alkaloids contents were determined following the standard method described by AOAC [21]. Data Analysis The statistical method used for data analysis was One- Way-Anova (F-Test) to analyze the data at p < 0.05. Duncan’s Multiple Range Test (DMRT) was then used to separate the means and data were expressed as mean ± standard deviation of triplicate.

Morphological Results

Observations regarding the morphology of C. nucifera and E. guineensis indicate that both species are characterized as single-stemmed palm trees (Figures 1 & 2). C. nucifera can attain heights of up to 30 meters, while E. guineensis reaches a maximum height of 20 meters. The leaves of these species are arranged alternately and exhibit a pinnate, feather-like structure, featuring a central midrib and numerous leaflets that are spirally arranged, with a parallel venation pattern. Each crown comprises 30 to 40 leaves, with C. nucifera reaching lengths of up to 6 meters and E. guineensis extending to 5 meters. The leaf surface of C. nucifera is characterized by its smooth texture, in contrast to the textured, rugose surface of E. guineensis, which features small, stiff hairs. The petiole of C. nucifera measures 2.11 meters in length and is thick, fibrous, and woody, while E. guineensis has a shorter petiole at 1.53 meters, which is also thick and fibrous but exhibits a slightly woody quality. Both species generate small yellowish flowers that cluster at the base of their leaves, subsequently maturing into fruit. Their stems are robust, fibrous, and woody, exhibiting a columnar, straight, and unbranched structure, characterized by enduring leaf bases and a slight bulge at the base. Recorded measurements are as follows: stem height—30 m (C. nucifera) and 20 m (E. guineensis); stem diameter—45 cm and 14 cm; internode length—27 cm and 17 cm; node diameter—10 cm and 6 cm. The bark is thick, hard, and rough, varying in color from grayish- brown to brown (Table 1). Both species possess a fibrous root system, with a deep taproot and numerous adventitious roots spreading outward.

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Phytochemical Results

Qualitative Phytochemical Compositions of the seeds of Cocos nucifera and Elaeis guineensis: The qualitative phytochemical results of the seeds of C. nucifera showed the presence of phenol, flavonoid, tannin, carotenoid, alkaloids, saponins and oxalate (Table 2). The seeds of E. guineensis also showed the presence of the phytochemical as that of C. nucifera except tannins and alkaloids which was absent in it. The table below shows phytochemicals present in both species of C. nucifera and E. guineensis.

GAE: Gallic acid equivalent CE: Catechin equivalent TAE: Tannic acid equivalent Values are in mean ± standard deviation of triplicate determination. Means on the same row but with different superscript are significantly different at (p<0.05). Table 3: Quantitative Phytochemical Composition of The Seeds of Cocos nucifera and Elaeis guineensis Phytochemical Compositions.

Quantitative Phytochemical Composition of the Seeds of Cocos nucifera and Elaeis guineensis: The Table 3 presents the quantitative analysis of phytochemical compositions between Palm Kernel and Coconut. The results indicate significant differences in the concentrations of various compounds. For Palm Kernel, the phenolic content was found to be 41.72 ± 1.03 mgGAE/100g, while Coconut had a lower phenolic concentration of 1.31 ± 0.15 mgGAE/100g. Flavonoids were also markedly higher in Palm Kernel at 142.88 ± 4.14 mgCE/100g compared to 38.79 ± 0.60 mgCE/100g in Coconut. Other compounds such as tannins (Palm Kernel: 0.00; Coconut: 35.82 ± 1.00 mgTAE/100g), carotenoids (Palm Kernel: 0.19 ± 0.01 mg/100g; Coconut: 0.19 ± 0.01 mg/100g), alkaloids (Palm Kernel: N/A; Coconut: 0.32 ± 0.02%), saponins (Palm Kernel: 0.92 ± 0.06%; Coconut: 0.76 ± 0.01%), and oxalates (Palm Kernel: 1.05 ± 0.08 mg/g; Coconut: 0.50 ± 0.02 mg/g) further illustrate these differences. The means are expressed as mean ± standard deviation, and the differences are statistically significant at p < 0.05, as indicated by different superscripts.

Values are in mean ± standard deviation of triplicate determination. Means on the same row but with different superscript are significantly different at (p<0.05). Discussion The morphological characteristics of C. nucifera and E. guineensis showed significant similarities, such as their habit as single-stemmed palm trees, which grow up to 30m and 20m, respectively. Both species have a spiral leaf arrangement with pinnate, feather-like leaves. However, differences were observed in their leaf and stem morphology. C. nucifera exhibits smooth and glabrous leaves, while E. guineensis has rugose leaves with small stiff hairs, which provide a more textured surface. The petiole of C. nucifera is longer (2.11m) compared to E. guineensis (1.53m), and this difference in petiole length also reflects in their leaf and stem dimensions, with C. nucifera generally having larger leaf and stem measurements.

These observations aligned with previous studies by Tomlinson [22] who described the general morphological characteristics of palm species, noting that leaf texture and petiole length can vary significantly between species within the same family, depending on their environmental adaptations. The distinct characteristics such as the rough, scaly stem of E. guineensis compared to the smoother stem of C. nucifera also tallied with the findings by Dransfield, et al. [23] who reported similar morphological distinctions among palm species.

The phytochemical analysis of Cocos nucifera and Elaeis guineensis revealed significant differences in their bioactive compound, each contributing uniquely to potential health- related applications.

The phytochemical analysis revealed notable differences between the two species. E. guineensis exhibited significantly higher levels of phenols, flavonoids, saponins, and oxalates compared to C. nucifera, which was richer in tannins and alkaloids. The higher phenol content in E. guineensis (41.72 mgGAE/100g) compared to C. nucifera (1.31 mgGAE/100g) suggests that E. guineensis may possess stronger antioxidant properties, as phenolic compounds are known for their antioxidant activity [24].

The phenolic content in E. guineensis (41.72 mgGAE/100g) is substantially higher than in C. nucifera (1.31 mgGAE/100g). Phenolic compounds are integral to plant defense mechanisms and have been associated with various health benefits, including antioxidant, anti-inflammatory, and anticancer activities. The high phenolic content in E. guineensis suggests a strong potential for antioxidant activity, which is crucial for combating oxidative stress—a factor in chronic diseases like cancer and cardiovascular disorders [25].

This observation is consistent with the findings of Vuong, et al. [26], who noted that plants exposed to more challenging environmental conditions often accumulate higher levels of phenolics. This adaptive trait enhances their survival while also increasing their value as sources of natural antioxidants. Given the rising demand for natural antioxidants in the food and cosmetic industries, E. guineensis could serve as a viable alternative to synthetic antioxidants like BHT and BHA.

Flavonoids are crucial phytochemicals known for their role in plant pigmentation, UV protection, and defense against pathogens. The study showed that E. guineensis has a significantly higher flavonoid content (142.88 mgCE/100g) compared to C. nucifera (38.29 mgCE/100g). Flavonoids are linked to a multitude of health benefits, including protection against heart disease, cancer, and neurodegenerative conditions [27].

The high flavonoid concentration in E. guineensis aligned with research by Yao, et al. [28], which highlights the potential of flavonoids to reduce oxidative stress and inflammation— key contributors to cardiovascular diseases. This suggests that E. guineensis could be particularly valuable in developing functional foods or nutraceuticals aimed at cardiovascular health, offering a natural source of these beneficial compounds.

Saponins, found in both species but slightly higher in E. guineensis (0.92%) than in C. nucifera (0.76%), are known for their cholesterol-lowering, immune-boosting, and anticancer properties [29]. The slightly elevated saponin levels in E. guineensis indicated its potential for more effective applications in health products targeting cholesterol management and cancer prevention.

Oxalates, which are more prevalent in Elaeis guineensis (1.05 mg/g) compared to Cocos nucifera (0.50 mg/g), have both beneficial and adverse effects. While high oxalate levels can reduce mineral bioavailability and contribute to kidney stone formation, in moderate amounts, oxalates may play a role in plant defense. The higher oxalate content in E. guineensis suggested the need for caution in dietary applications, particularly for individuals prone to kidney stones.

The absence of tannins and alkaloids in E. guineensis is noteworthy, especially when compared to C. nucifera, which contains these compounds. Tannins are polyphenolic compounds with antioxidant and antimicrobial properties, often contributing to the astringency and bitterness of plant- based foods [30].

The lack of tannins in E. guineensis may make its extracts more palatable for certain applications, especially where bitterness is undesirable.

Similarly, the absence of alkaloids in E. guineensis is significant. Alkaloids, present in C. nucifera, are known for their pharmacological activities, including analgesic, anti- inflammatory, and anticancer effects.

This difference suggested that C. nucifera may have a broader range of medicinal applications, particularly in pain management and anti-inflammatory treatments, where alkaloid activity is advantageous.

The significantly higher flavonoid content in Elaeis guineensis (142.88 mgCE/100g) compared to Cocos nucifera (38.29 mgCE/100g) suggested that E. guineensis may have more potent anti-inflammatory and cardioprotective effects, as flavonoids are important bioactive compounds with various health benefits [31]. The absence of tannins and alkaloids in E. guineensis, contrasted with their presence in C. nucifera, indicated potential differences in medicinal applications, with C. nucifera possibly being more suited for antimicrobial treatments where tannins and alkaloids are beneficial. These findings are consistent with those of Adewusi, et al. [32] who also reported higher phenolic and flavonoid content in E. guineensis compared to other palm species, further validating the results of this study [33, 34].

The distinct phytochemical profiles of Cocos nucifera and Elaeis guineensis underscore their varied potential applications in health, nutrition, and industry. The high phenolic and flavonoid content in E. guineensis suggested it may be particularly effective as a natural antioxidant and anti-inflammatory agent, while the presence of tannins and alkaloids in C. nucifera indicated its potential for use in antimicrobial and medicinal applications. These findings provide a foundation for further exploration into the specific uses of these species based on their unique phytochemical compositions.