The phytochemical study was performed in methanol and chloroform extract. As shown in table 1 the amount of tannins, phenols, alkaloids, flavonoids, and glycosides was detected higher in methanol extract, whereas terpenoids, steroids and saponins were more predominant in chloroform extract.
Extraction yield, Total Phenolic Contents (TPC) and Total Flavonoid Content (TFC)
The extraction yield of P. bengalensis leaves obtained by maceration in methanol and chloroform was 3.8% and 4.4% respectively of dry weight. The TPC and TFC were quantified which are expressed in mg of GAE/g and mg of QE/g respectively as shown in Table 1. The methanol extract fraction showed the higher TPC (57.96 ± 19.35 mg of GAE/g extract) compared with the chloroform extract (21.89 ± 2.47 mg GAE/g extract). Similarly, TFC was also found higher in methanol fraction (40.53 ± 1.87 mg of QE/g extract) compared to chloroform fraction (6.90 ± 1.17 mg of QE/g extract).
DPPH radical scavenging assay
The antiradical activity of the extract was measured by the ability to scavenge DPPH free radicals, compared with the standard ascorbic acid. As shown in Figure 1 and Figure 2 both extract PBME (IC50 = 168 ±13.57 µg/ml) and PBCE (IC50 = 280.7 ± 15.49µg/ml) showed the considerable free radical scavenging property as compared to standard ascorbic acid (IC50 = 18.39±4.62 µg/ml),
Acute toxicity study (LD50 determination)
No prominent sign of toxicity and mortality was recorded among experimental animals at all administered dose of the crude methanol and chloroform extract of P. bengalensis. Since no death was recorded at the maximum administered dose, the LD50 of the plant was found to be higher than 5000 mg/kg.
The data presented in Figure 3 shows that PBME (200 mg/kg), and PBCE (200mg/kg), used in this experiment did not increase (P > 0.05) time latency after 30 and 60 min of the hot plate test. The other fractions PBME (400 mg/kg), PBCE (400mg/kg) exhibited significant (P < 0.001; P < 0.05) increase in time latency at the same time interval. However, after 90 min all the extracts except PBCE (200 mg/kg) (P > 0.05) increase the time latency. Multiple comparisons of the treatments revealed that PBME (400 mg/kg) comparatively has highest latency time at 90 min compared to tramadol. Whereas, latency time decrease at 120 min but tramadol was still increasing. Similarly, percent analgesia indicated that among extract/fractions; PBME and PBCE 400 mg/kg dose more convincingly (P < 0.001) increased the percent analgesia as compared to the percent analgesia of tramadol. The highly noticeable increase of percent analgesia was recorded after 90 min of the administration as shown in Figure 4. Antipyretic effect The results presented in Table 2 shows that pyrexia was induced 18th h after the injection of Brewers' Yeast to rats. All the extract fraction PBME, PBCE, and paracetamol decrease (P < 0.05) the temperature, 1 h after the administration to rats. More pronounced reduction in body temperature was distinctly observed 2 h after the administration of PBME and PBCE at both dose level (200 and 400 mg/kg) as compared to control rats. Similarly, percent inhibition in pyrexia indicated that among extract/fractions; PBME (400 mg/kg) more convincingly (P < 0.001) inhibit pyrexia percentage after 1 to 3 h, as compared to paracetamol. Whereas after 4 h paracetamol is showing more inhibition in pyrexia percentage then PBME (400 mg/kg) as shown in Figure 5 and 6 Anti-inflammatory activity The data presented in figure 7 shows that PBME and PBCE P. bengalensis and standard indomethacin; did not reduce (P > 0.05) in paw edema volume after 1 h of the carrageenan injection. However, significant (P < 0.01; P < 0.001) reduction in paw volume was determined 2 h after the drug administration and the paw volume was decreased at both the doses level (200 mg/kg, 400 mg/kg) of PBME and PBCE as compared to control rats. Multiple comparison of the percent inhibition of edema volume after 2 h indicated that among extract fractions; PBME (200 mg/kg), PBCE (400mg/kg), and PBME (400 mg/kg) more convincingly (P < 0.001) inhibited the paw volume as compared to the percent inhibition of paw edema volume of indomethacin. More distinct inhibition of percent paw edema was recorded after 3 h which gradually decrease after 4 h of the carrageenan as in figure 8