Evaluation of the Phytochemical Constituents of Extracts of Kigelia africana Fruit and Sorghum bicolor, Stalk in Lagos Nigeria

The use of herbal medicines and phytonutrients or nutraceuticals with numerous secondary metabolites continues to expand rapidly across the world, with many people now resorting to these products to treat various health challenges in different national healthcare settings. Therefore, the Original Research Article Obianagha et al.; JPRI, 33(10): 49-58, 2021; Article no.JPRI.66343 50 study is aimed at evaluating the phytochemical composition in the fruit extract of Kigelia africana and Sorghum bicolor stalks bought from the Mushin market in Lagos, Nigeria to ascertain its numerous pharmacological activities and identify the various chemical compounds responsible for these activities. Ethanol extracts of identified fresh fruits of K. africana and S. bicolor stalks (L) were prepared for phytochemical screening using established methods for Alkaloids, Tannins, Phenols, Flavonoids, and Terpenoids testing as well as Gas Chromatography-Mass Spectrometry Analysis (GC-MS) for the analysis of the extracts. The chemical constituents present in both extracts were tannins, phenols, flavonoids, and saponins as well as alkaloids found only in K. africana. Also, the chromatogram of K. africana revealed the presence of forty-four (44) phytochemical constituents. At the same time, that of S. bicolor were twenty-nine (29) phytochemical constituents that could contribute to the medicinal quality of the plant with 9, 12Octadeadienoic acid (Z, Z), and 13-Docosenoic acid, methyl ester, (Z) found as the major compounds respectively. The K africana and S. bicolor African indigenous plants in Lagos, Nigeria, possess different phytocomponents of scientific importance, biological action, and potential medicinal properties. There is a need for more standardization and purification of this herbal formulation for the treatment of diseases.


INTRODUCTION
There has been a rapid increase in the usage of herbal medicines and phytonutrients across the world, with many people now resorting to these products to treat various health challenges in different national healthcare settings [1]. The fact that orthodox drugs have been reported to be restricted by their secondary failure rates and accompanying undesirable side effects made herbal drugs gain even more popularity [2,3] . Consequently, the use of herbal remedies has now been widely embraced in many developed countries, with complementary and alternative medicines (CAMs) now becoming mainstream [4,5]. Thus, exploring plants and their constituents to develop plant-based medicine is key to achieving a successful modern herbal practice breakthrough. Different parts of African indigenous plants with potential medicinal properties like K. africana and S. bicolor have been used by herbal medicine practitioners to treat various diseases in Nigeria [6]. The Kigelia plant has medicinal properties not only because of its perceived characteristics such as bitterness, astringent taste, or smell but also because of forces that it seems to emit in connection with its location, orientation, and association with other plants [7].
Traditional healers commonly used it to treat a wide range of skin ailments like fungal infections, boils, psoriasis, and eczema. It also has internal applications, including the treatment in dysentery, ringworm, tapeworm, post-partum hemorrhage, malaria, diabetes, pneumonia, and toothache [7]. The Shona people tend to use the bark or root as powder or infusion for application to ulcers, drunk or applied in the treatment of pneumonia, as a gargle for toothache and the leaves in a compound applied for backache. In West Africa, the root and unripe fruit is used as a vermifuge and treatment for hemorrhoids and rheumatism [7,8]. The bark is traditionally used as a remedy for syphilis and gonorrhea. The fruits and bark ground and boiled in water are also taken orally or used as an enema in treating children's stomach ailments -usually worms. The unripe fruit is used in Central Africa as a dressing for wounds, hemorrhoids, and rheumatism. Venereal diseases are commonly treated with tree extracts, usually in palm wine as oral medication [7].
The K. africana plant has many medicinal properties due to the presence of numerous secondary metabolites.
On the other hand, Sorghum is very important in the world's human diet, with over 300 million people dependent on it [11]. It is grown for grain, forage, syrup, and sugar with the Grain sorghum as a staple cereal and the large juicy stems containing as much as 10% sucrose. Apart from using the seed as food, other industrial uses of the stems and fibers can be brewing beer and corn malt.
Also, all sorghum and Sudan grass-related species have the potential to smother weeds, suppress nematode species, and penetrate compacted subsoil [12]. Other workers reported Sorghum bicolor as an anti-abortive, cyanogenetic, demulcent, diuretic, emollient, intoxicant, and poison [13,14]. The root is used for malaria in southern Rhodesia; the seed has been used for breast disease and diarrhea; the stem for tubercular swellings [14]. In China, the seeds are used to make alcohol. The leaves primarily consist of carotenoids, flavonoids, and phenolic acids with small amounts of chlorophyll (a and b), lycopene, and β-carotene. The leaves' fatty acid profiles revealed palmitic, stearic, oleic, and linoleic acid as predominant, with each having greater than 5% of the total fatty acid identified. These findings' nutritional implication is that diets prepared with the leaves provide natural antioxidant and essential fatty acids that could fight cardiovascular-related diseases [8]. The various phytochemical constituents of all the plants' parts make them so relevant in clinical practice to treat human beings' multiple diseases over thousands of years across the world. Thus, Complementary and Alternative Medicine (CAM) has been able to apply the knowledge to managing many diseases in Nigeria. Aside from proven efficacy, the general public believes that traditional medicinal products are safer because they are non-processed. However, there is a need for a scientific basis for developing a standardized herbal product or new drug formulation. Though research is being done on other parts of the plants (stem, bark, and leaves), there is very little published in Nigeria regarding K. africana fruit and S. bicolor stalk. Therefore, the study aims to evaluate the phytochemical composition of the fruit extract of Kigelia africana and S. bicolor stalk bought from the Mushin market in Lagos, Nigeria, ascertain its numerous pharmacological activities and identify the various chemical compounds responsible for these activities.

Plant Materials
The fresh fruits of K. Africana (Lam.) Benth (Fam. Bignoniaceae) and S. bicolor stalks (L) Moench (Fam. Poaceae) were bought from different sellers in the Mushin market in Lagos suburb, Nigeria, in November 2014. The fruits and stalks were identified and authenticated by the Department of Botany, Faculty of Science, University of Lagos, Nigeria. The specimens were given voucher no LUH 6487 (K. africana) and no LUH 6488 (S. bicolor) respectively and were deposited in the Department's Herbarium. The plant materials were washed with a copious amount of clean tap water and spread to drain, then cut into small pieces and dried in an oven at a temperature of 45 0 C for seven days.

Preparation of Extracts
The dried materials were pulverized to a coarse powder with an electric grinder. The powdered materials of K. Africana fruits (3200 g) and S. bicolor stalks (3150 g) were macerated with 25 liters of hydroethanol (2:8) respectively and allowed to stand for seven days, with regular stirring. The extracts were clarified by filtration (Sofowora, 1993) using What man no.4 filter paper. They were then concentrated using a rotary evaporator then dried in a laboratory oven (45°C) to a dry weight of 243.12 g (7.60 %w/w yield) for K. africana and 174.94 g (5.60 %w/w yield) for S. bicolor, respectively.

Phytochemical Screening
The

Gas Chromatography-Mass Spectrometry analysis (GC-MS)
GC-MS analysis of the extracts was performed using GCMS-QP2010SE SHIMADZU system. The charged fragments were detected, and the subsequent spectra obtained were used to identify the molecule. Helium gas was used as the carrier gas with a constant flow rate of 1 ml/ min with an injection volume of 2 μl (split ratio of 10:1) and injection temperature of 25°C. The oven temperature was programmed from 60°C -(10°C/min) to 160°C (2 min) -(15°C/min) to 400°C (4 min). The column type DB-5ms was 30 m x 0.25 µm x 0.25 mm. The gaseous compoundsanalyzed interact with the column walls, which is coated with different stationary phases. This causes different compounds to elute at a different time, known as the compound's retention time. Identification was based on molecular structure, molecular mass, and calculated fragments. Interpretation on mass spectrum GC-MS was conducted using the database of National Institute Standard and Technology (NIST), having more than 62,000 patterns. The name, molecular weight and structure of the components of the test materials were ascertained. Each component's relative percentage amount was calculated by comparing its average peak area to the total areas. The spectrum of the unknown component was compared with the component stored in the NIST Library [21].

RESULT
The results obtained in this study are shown in Tables and Figures below.  Table 2 shows the GC-MS analysis of hydroethanolic fruit extract of K. Africana with the identification of phytochemical constituents confirmed based on peak area %, retention time, molecular formula and molecular weight, with 9, 12-Octadeadienoic acid (Z, Z) found as the major compound.

DISCUSSION
Herbal medicine has received greater attention as an alternative to orthodox medicine in recent times, leading to a subsequent increase in herbal medicine preparations [3,22]. In rural communities, the exclusive use of herbal medicines prepared with single or combinations of different plant species parts and dispensed by herbalists without formal training for the management of various diseases is still a widespread practice. This requires that experimental research be conducted to ascertain these herbal products' safety and efficacy and establish their active components [23]. Herbal medicines, also since the prehistoric era, have been recognized and acknowledged to be effective in the treatment of both pathological and pathogenic diseases. Their use in the treatment of certain conditions where orthodox drugs could only serve as palliatives is widespread now [24].
Herbal medicines' pharmacological and physiological activities could be attributed to myriads of various classes of secondary products present in them. They could be employed in the treatment of various disease states. The phytochemical screening carried out on the two extracts revealed the presence of phenols, flavonoids, and saponins as the chemical constituents present in both extracts as well as (alkaloids in K. africana only). Although, Inspection of the published reports [25] revealed a significant variation in the chemical composition of K. africana fruits, the constituents identified in this study aggress with a previous study done in Nigeria [6] where the constituents were essentially the same. It is important to note that most of the constituent isolated, which were plant constituents such as polysaccharides, polypeptides, glycopeptides, triterpenoids, steroids, xanthones, flavonoids, coumarins, phenols, iridoids, alkyl disulphides, inorganic ions, and guanidine, has been reported to exhibit antioxidant properties and as well are associated with antidiabetic activities [26]. Other workers [10] also reported the presence of phenyl propanoid identified as 6-p-coumaroyl-sucrose phenylethanoid and flavonoids glycosides in the fruits of K. africana. Flavonoids and phenols have since been associated and reported to have measurable antioxidant activities [27].
Furthermore, the GC-MS analysis revealed the presence of forty-four (44) phytoconstituents in K. Africana and twenty-nine (29) in S. bicolor with the identification of phytochemical constituents confirmed based on peak area %, retention time, molecular formula, and molecular weight. The most abundant phytoconstituents in K. Africana obtained from this study were Linoleic acid, Palmitic acid, Ester compound, Alcoholic compound, Flavonoid fraction Phenylpropanoids. It is of note that most of these compounds have been reported to have significant medical importance. Linoleic plays a unique role in heart health support, as shown in Randomized clinical trials [29]. Also, palmitoleic acid (POA) has demonstrated anti inflammatory and lipidlowering effects in preclinical and human epidemiological and intervention trials [30]. Organic esters are used in the manufacture of painkillers e.g.
Aspirin while Alcoholic compounds in their various forms can be used as an antiseptic, disinfectant, and antidote [31].On the other hand, flavonoid fraction has been documented as an oral phlebotropic drug [32] and Phenyl propanoids for medicinal use as an antioxidant, UV screens, anticancer, anti-virus, anti-inflammatory, wound healing, and antibacterial agents [33].
Likewise, the most abundant phytoconstituents in S. bicolor stalk obtained from this study were Erucic acid, Fatty acid ester, and Omega 9 fatty acid. Ester compound and Lauric acid. Every one of these compounds has also been reported to play a critical role in medical science. hexadecanoic acid ethyl ester has the same functions as outlined in K. africana, hexadecanoic acid methyl ester has been reported as an antioxidant, 5-Alpha reductase inhibitor, as hypocholesterolemic [21], cis-11-Eicosenoic acid methyl ester as an antiinflammatory, antioxidant, antiarthritic [34] then dodecanoic acid methyl ester as an antioxidant, antibacterial and antiviral [35].

CONCLUSION
The hydroethanolic extracts of K. Africana fruit and S. bicolor stalks, African indigenous plant from Lagos Nigeria, possess different Phyto components of medicinal importance and biological action potential therapeutic properties. There is a need for more standardization and purification of these herbal formulations for the treatment of diseases.

CONSENT
It is not applicable.