The method described by51 was used with modification. One gram of the sample was soaked in 20 ml of 20% ethanol, heated in a water bath at 55 °C for 4 h, and stirred well. The content was filtered and re-extracted with 20 ml of 20% ethanol and shaken vigorously (not heated). This was filtered and the filtrate was added with the first filtrate. The filtrate was then reduced to one-quarter of its value in the water bath at 90 °C. This content was later poured into a separating funnel and 20 ml of diethyl ether was added into it. The content was shaken vigorously and attach back to the tripod stand. Aqueous / lower layer of the content was collected and ether/ upper portion containing fatty substances was discarded. The aqueous layer was then poured back into the funnel, and n- butanol was added and then shaken vigorously. A clean pre-weighed beaker was used to collect the butanol layer in the weighed beakers and evaporated to dryness. The residue was later dried in an oven until a constant weight is obtained.

Phytate content was determined as described by52 with modification. Sample of I g of the sample was put into a flask, 50 ml of 2% HCL was added and soaked for 3 h and then filtered. The filtrate (25 ml) was poured into another 250 ml conical flask and thiocyanate solution was added as an indicator. To attain the normal acidity, 53.5 ml of distilled water was added. The solution was then titrated against the standard Iron 111 chloride solution (0.00195 g of iron per ml) until a brownish yellow colour persisted for 5 min.

Phytate was calculated as follows:

The method described by Aina et al. (2012) and modified by Unuofin et al. (2017) was adopted to determine the content of oxalate in the sample. Briefly, 1 g of the ground sample was poured into a conical flask, 75 ml of 3 M sulphuric acid was added and mixed well for an hour using a magnetic stirrer. The solution was filtered and 25 ml of the filtrate was collected and heated to 85 °C and kept at a temperature above 70 °C throughout the experiment. The hot aliquot of the filtrate was titrated against 0.05 M/l of KMnO4 until the light pink colour, which persists for 15 s, was reached; this is the endpoint of the reaction. The oxalate content was calculated by taking 1 ml of 0.05 M/l of KMnO4 as equivalent to 2.2 mg oxalate.

The method of53 was adopted to determine the alkaloid content in the samples. Acetic acid (10%) was prepared in ethanol and 1 g of the sample was soaked in 50 ml of 10% acetic acid for 4 h. The content was later filtered using a vacuum pump and concentrated in a water bath to a small quantity. Concentrated Ammonium hydroxide was added dropwise until precipitate (until the cloudy fumes cease). The solution was allowed to cool down, then filtered using the pre-weighed filter paper. The filter paper retained the precipitate/ residue. The precipitate on the filter paper was oven-dried and weighed.