Fresh leaves and stems of P. amarus obtained from Delta State University environment and identified by the plant Curator (Mr Sunday Nimehe and Victor Speaman) in the Department of Pharmacognosy, Faculty of Pharmacy, University of Benin, Benin city, Nigeria where a voucher specimen was deposited for reference. Ethanol (70%), citric acid, glycerin and 1,1-diphenyl-2-picrylhydrazil, DPPH (Sigma Aldrich, Germany). All other chemicals used were of analytical grade and were used without further purification. 100 g of dried plant material was extracted with 1000 ml aqueous ethanol

using a Soxhlet extractor for 24 h. The supernatant was collected and the solvent evaporated using Rotary Evaporator (CH-9230 Flawil, Switzerland). The extract was stored in a refrigerator in an airtight container for further study and formulation. To prepare ABT-888 liquid oral form of the extract, the following steps were taken: (a) Preparation of simple syrup BP: 667 g of sucrose was dissolved in sufficient distilled water to obtain 1000 ml of concentrated simple syrup.

The solution was filtered and the simple syrup was used as vehicle. The different parameters of the various oral formulations were assessed such as pH, physical appearance (colour, taste and odour), and density. Stability study of the oral liquid syrup was carried out at different temperature (i.e. at 4 °C, 27 °C (room temperature) and 47 °C).7 The free radical scavenging capacity of the extracts was determined using DPPH.8 LEE011 DPPH solution (0.004% w/v) was prepared in ethanol. The different formulations were developed in 10 ml distilled water to a final concentration of 0.1 mg/ml. 4-Aminobutyrate aminotransferase After adding 1 ml of freshly prepared DPPH solution, it was incubated for 20 min at 25 °C, they were read spectrophotometrically at 517 nm wavelength.

Vitamin C (ascorbic acid) was used as a reference standard and developed to the same concentration of 0.1 mg/ml. Control sample was also prepared containing the same volume but without any extract or reference standard. Percentage scavenging activity of DPPH was evaluated using Equation 1. equation1 D%=AC−ATAC×1001where D = scavenging activity of extract, AC = absorbance of control and AT = absorbance of test sample. The formulae for the 6 formulations are presented in Table 1. The taste score of the different formulations are presented in Table 2. The physicochemical properties of the extract and formulations of P. amarus such as colour, odour, taste, viscosity, specific gravity and pH are shown in Fig. 1 and Fig. 2 and Table 3 and Table 4. The extract of P. amarus is brown in colour with a characteristic odour and a bitter taste; these were also partly transferred to the formulations. The development of such herbal formulation will mark an important advancement in developing P. amarus into an acceptable oral liquid phytomedicine.