Fresh rhizomes of C. longa used in this work were obtained from Eke Awka market, Awka South Local Government Area, Anambra State, Nigeria and identified by a taxonomist with the Department of Botany, Nnamdi Azikiwe University, Awka, Anambra State.

The experimental analyses were carried out at Laboratory of the Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka and Multi-user Science Laboratory, Zaria, Kaduna State.

The harvested rhizomes were carefully washed with clean water. They were then peeled, steamed for 10 minutes to remove the raw odour. It was later dried in the oven at a temperature of 65˚C. After drying, the rhizomes were milled into powder and tightly packaged in a polythene bag kept at room temperature until required for use.

The crude protein, moisture, crude fiber, and fat contents of the sample were determined according to the methods of Association of Official Analytical Chemists [15]. Determination of ash content was done by ashing at 550˚C for 3 hours. The Kjeldah method was employed to determine the crude protein content. The crude fiber content was determined by digestion method and crude fat content was determined by Soxhlet extraction method. Total soluble carbohydrate was determined by the difference of the sum of all the proximate compositions from 100%.

The GC-MS analysis of bioactive compounds from the different extracts of the leaves was done using Agilent Technologies GC systems with GC-7890A/ MS-5975C model (Agilent Technologies, Santa Clara, CA, USA) equipped with HP-5MS column (30 m in length × 250 μm in diameter × 0.25 μm in thickness of film). Spectroscopic detection by GC-MS involved an electron ionization system which utilized high energy electrons (70eV). Pure helium gas (99.995%) was used as the carrier gas with flow rate of 1 mL/min. The initial temperature was set at 50˚C - 150˚C with increasing rate of 3˚C/min and holding time of about 10 min. Finally, the temperature was increased to 300˚C at 10˚C/min. One microliter of the prepared 1% of the extracts diluted with respective solvents was injected in a split-less mode. Relative quantity of the chemical compounds present in each of the extracts of B. luzonica was expressed as percentage based on peak area produced in the chromatogram.

Bioactive compounds extracted from different extracts of B. luzonica were identified based on GC retention time on HP-5MS column and matching of the spectra with computer software data of standards (Replib and Mainlab data of GC-MS systems).

Vitamins A, C and E were determined respectively by the calorimetric, titrimetric and Futter-Mayer colorimetric methods of Kirk and Sawyer [16] with absorbance measured at 325 nm and 410 nm for Vitamins A and E respectively. Vitamins B₁ and B₂ were estimated spectrophotometrically at 216 nm and 242 nm respectively. Vitamins B₃ and B₆ were titrated to greenish blue and green colour end-points using 0.1 ml perchloric acid and 2 - 3 drops of crystal violet as indicator while vitamin B₁₂ content was measured spectrophotometrically at 361 nm by the method of Kirk and Sawyer [16]. Vitamins D and K were determined spectrophotometrically at 450 nm and 503 nm respectively using the methods as described by Zakaria et al. [17].

Heavy metal contents were determined using Varian AA240 Atomic Absorption Spectrophotometer according to the methods described by American Public Health Association [18].

Sample proteins were hydrolyzed prior to derivatization. A 0.1 g lyophilized sample was weighed into a 16- × 125-mm screw-cap Pyrex (Barcelona, Spain) tube, 15 mL of 6N hydrochloric acid was added, and the tube was thoroughly flushed with N₂, quickly capped, and placed in an oven at 110˚C for 24 h (17). After hydrolysis, the tube contents were vacuum filtered (Whatman #541, Maidstone, England) to remove solids, the filtrate was made up to 25 mL with water, and an aliquot of this solution was further filtered through a 0.50-μm pore-size membrane (Millipore, Madrid, Spain). A standard solution containing 1.25 μmol/mL of each amino acid in 0.1N hydrochloric acid was created. Derivatization of sample was done by the method of AOAC as described by Elkin and Griffin [19].

Data was subjected to statistical analyses using Statistical Package for the Social Sciences International Business Machine (SPSS IBM) version 21.0 (SPSS Inc., Illinois Chicago, USA). Data were presented as mean ± SD of triplicate determinations.

The values represented in Table 1 show that the turmeric plant under proximate analysis had 9.55 ± 1.20, 24.70 ± 1.56 and 1.12 ± 0.03 of moisture, ash and fiber respectively. The findings also showed fat, protein and carbohydrates contents of 5.32 ± 1.23, 2.15 ± 0.07 and 57.30 ± 1.69 respectively. Similarly the findings of this study corresponded with that of previous studies on turmeric conducted by Ikpeama et al. [20] and Imoru et al. [21]. This indicates that the plant could be good sources of carbohydrates and fat when compared to mean carbohydrate values obtained for other species of Curcuma such as C. amada, C. leucorrhiza, C. pseudomontana and plants usually employed for culinary purposes, reported in studies conducted by Rajkumari and Sanatombi [22]. The protein content was found to be 2.15% ± 0.07% in the present study. Protein is an essential component of human diet needed for the replacement of tissues, supply of energy and adequate amount of required amino acids for various biosynthetic molecules. Proteins are also required in synthesis of enzymes, hormones and antibodies [23]. Similarly, the high content of ash (24.70 ± 1.56) compares favorably with

Values are mean ± standard deviation of triplicate determinations.

values obtained for other Curcuma species and suggests that C. longa may be a potent source of minerals both major and trace. The crude fiber content of C. longa in the present study may suggest its detoxifying ability by removing potential carcinogens from the body, helps in bowel movement and prevents the absorption of excess cholesterol. Fiber adds bulk to food and prevents the intake of excess starchy food and may therefore guard against digestive tract metabolic conditions such as hypercholesteremic and diabetes mellitus [24]. Ayoola and Adeyeye [25] further explained that fiber also softens stool and therefore prevents constipation thus helping to fight colon cancer.

The vitamin analysis of the plant as represented in Table 2 showed a high mean content of vitamin A at 254 ± 2.19 followed by vitamins C and D at 19.47 ± 0.16 and 10.92 ± 0.92 respectively. In the same vein, the analysis revealed that the rhizome contained vitamin B₁, B₂, B₃, B₆ and B₁₂ at 1.98 ± 0.01, 2.18 ± 0.00, 2.25 ± 0.15, 0.08 ± 0.00 and 1.24 ± 0.00 respectively. Vitamin K was estimated at 7.08 + 0.02 in the plant. These findings corroborate previous studies of nutritional composition carried out on C. longa with similar values of Vitamins A, C and E in the rhizomes of the plant documented by Ikpeama et al. [20] and Imoru et al. [21]. Vitamin A content higher than that obtained for the present study was reported by Imoru et al. [21] whereas Ikpeama et al. [20] observed a lower value of B₁, B₂ and B₃ than the values of the study. These disparities may be due to the different methods employed in determination of the vitamin contents or differences in soil composition. The presence of vitamins in C. longa may elucidate its involvement as an antioxidant and anticancer agent in traditional phytomedicine and further implicate it as an ingredient in novel pharmacology products.

The mineral contents of C. longa are presented in Table 3. It contains Ca (38.689

Values are mean ± standard deviation of triplicate determinations.

Values are mean ± standard deviation of triplicate determinations.

± 0.114) as the highest element followed by Mg (19.75 ± 0.001) and K (9.204 ± 0.014). The rhizome also contains some heavy metals in considerable quantities such as Pb (0.374 + 0.002), Ar (1.496 ± 0.005), Ni (0.226 ± 0.003) and Hg (0.126 ± 0.003). These contents are significant of the nutritive value of C. longa. Calcium, as a micronutrient, plays a part in the regulation of muscle contraction and relaxation and is implicated in strong bones and teeth development [20] [26]. Normal extracellular calcium concentration is necessary for blood coagulation as explained by Ogidi et al. [23] and Okaka and Okaka [27]. The magnesium content of the plants was found to be 19.75 ± 0.001, considerably high in support of previous works on the plant. In a research publication by Hartwig [28], magnesium plays fundamental roles in genomic stability and DNA repair processes. Magnesium activates over 300 different enzymes and thus participates in many metabolic processes, which makes it a pivotal micronutrient, as well as functions in electrolyte transport across cell membranes [29] [30]. Several studies showed that magnesium ions are important for maintaining cell homeostasis because they are essential to the stabilization of cell membranes, especially in the red blood cells where they help maintain membrane integrity through the action of the potassium and calcium pumps [30] [31] [32]. With such significant roles and its presence in the plant, this may elucidate the involvement of the plant in phytomedicine as a blood purifier.

Potassium content which was also observed to be high (9.204 ± 0.014) in this study supported previous reports [33] of its presence in most agricultural plants. It helps to maintain body weight and regulate water and electrolyte balance in the blood and tissues thereby controlling blood pressure [34]. It is also involved in regulating muscle contraction and nerve impulse transmission [20]. Sodium was also found to be a mineral constituent of the dried rhizomes under analysis (7.06 ± 0.014) and its presence may have implicative functions in treatment of heart diseases as was indicated by Ogidi et al. [23].

Trace amount of manganese (1.446 ± 0.044) was observed in the plant as shown by the present study. Manganese is involved in activating enzyme-catalyzed reactions such as decarboxylations, phosphorylations, reductions and hydrolysis reactions. Manganese regulates blood sugar levels, the production of energy and cell reproduction. It may be involved as a cofactor in enzymes of oxidative stress such as superoxide dismutase.

The presence of heavy metals such as lead, mercury, arsenic, nickel and mercury as observed in the present study may probably explain the role of the plant in phytoremediation or the bio-concentration of these metals in the soil from where the plant rhizome were obtained. It may also indicate the degree of environmental contamination in the farm area though the amounts sequestered in the dried rhizomes under study are minimal compared to amounts obtained in areas of dense environmental pollution or plants of phytoremediation. Since heavy elements may have little or no beneficial biochemical roles or biological functions, its presence may be for the benefit of the plant in secondary metabolic processes requiring the elements.

The amino acid profile of the plant is presented in Table 4. Eighteen out of the

Values are mean ± standard deviation of triplicate determinations.

twenty amino acids were identified in the analysis. Amino acid composition of protein isolates is an indicator of their nutritive value. The concentrations of essential amino acids and non-essential amino acids of isolated protein were present. The isolated protein contained ten essential amino acids and eight non-essential amino acids of the twenty amino acids. These data showed that the plant had a complete protein fraction. Of the essential amino acids present, arginine (6.55 g/100 g) was found maximum while glutamate (9.65 g/100 g) was presented maximum as a non-essential amino acid in the isolated protein. Overall, aspartate (9.78 g/100 g) was found in higher concentration followed by glutamate (9.65 g/100 g) and arginine (6.55 g/100 g). In a previous study, Enemor et al. [2] indicated that the presence of the essential amino acids in the plant under analysis may demonstrate its potential and involvement in body building activities, cell proliferation and stabilization of protein complexes in wound healing. Figure 1 shows the chromatogram obtained for the amino acid profiling of C. longa.

The present study identified several phenolic compounds with varying retention times as obtained by GC-MS analysis presented in Table 5. Figures 2-5 show

the GC-MS chromatograms obtained after the analysis of the dried C. longa plant for secondary antimetabolites. They include the flavonoids, sterols and tannins. Phenolic compounds are ubiquitously distributed phytochemicals synthesized through the shikimic acid and phenylpropanoid pathways and have been linked to the potentiating effects of human health through the prevention of several diseases due to their antioxidant property. More specifically in a study documented by Huang et al. [35], these may allude the bioactivities of the plant responsible for its chemo-preventive properties such as antioxidant, anti-carcinogenic, anti-inflammatory effects and also contribute to their inducing apoptosis by arresting cell cycle, regulating carcinogen metabolism and ontogenesis expression, inhibiting DNA binding and cell adhesion, migration, proliferation or differentiation and blocking signaling pathways. For example, Subramani and Casmir [36] explained that the flavonoids prevent the oxidation of low-density lipoprotein, lowers the blood levels of cholesterol and triglycerides thereby reducing the risk for the development of atherosclerosis. Okwu [37] also reported the ability of the plant to have vaso-dilatory and inhibitory effects on platelet aggregation thereby preventing coronary heart. On the other hand, saponins have been reported to have beneficial effects on blood cholesterol levels. They bind with bile salts and cholesterol in the intestinal tract and cause a reduction of blood cholesterol by preventing its re-absorption. As noted by Oakenfull and Sidhu [38], the non-sugar part of saponins also has antioxidant activity which may help to reduce risk of heart diseases.