Effects of the Methanolic Leaf Extract of Palisota Hirsuta in Post-Surgical Wound Management

Abstract

This study evaluated the use of the methanolic leaf extract of Palisota hirsuta in postsurgical wound management using different wound models in rats. It also assessed the antibacterial activity of the plant extract as well as the possible toxic effects on the liver, kidney and blood. The yield of the methanolic leaf extract of Palisota hirsuta (PHLE) was 5.98 % w/w and it was dark green, pasty in consistency with a pungent smell. In the excision wound model, PHLE at 1% and 4 % significantly (p<0.05) increased the percentage wound contraction from days 6 - 21 post-surgery when compared with Petroleum Jelly and Cicatrin®. The PHLE –treated rats in group V (4 % PHLE) showed best activity in wound contraction when compared with rats in groups III (1 % PHLE) and IV (2 % PHLE) throughout the duration of the experiment. The epithelialization period of the PHLE-treated rats in group V (4 %) was significantly (p<0.05) lower than those of the control groups I and II. In the incision wound model, the wound breaking strength was significantly (p<0.05) higher in the PHLE and Cicatrin® treated groups compared to PJ-treated group. The rats that received 4 % PHLE also showed the highest wound breaking strength. In the deadspace wound model, the level of hydroxyproline production was significantly (p<0.05) increased by PHLE at 25, 50 and 100 mg/kg. There was also a significant (p<0.05) increase in the dry weight of the granulation tissue by PHLE (50 and 100 mg/kg) compared to the control. In the agar diffusion assay, PHLE induced no inhibition zones against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. In the sub-acute toxicity study, there were no significant (p>0.05) variations in the ROW of the kidney, liver and spleen of the rat groups on day 14. The PHLE at 40 mg/kg led to significantly (p<0.05) higher ROW of the heart on day 14 when compared with control but, by day 28, no significant (p>0.05) alteration was observed. The PHLE at 20 mg/kg significantly (p<0.05) reduced the size of the spleen on day 28. Also on day 28, PHLE at 20, 40, and 160 mg/kg significantly (p<0.05) reduced the ROW of the liver. The PHLE significantly (p<0.05) increased the RBC count at 20, 40, and 60 mg/kg and Hb concentration (20 and 40 mg/kg). There was no significant (p>0.05) alteration of the PCV, total white blood cell (WBC) and differential WBC counts by PHLE. The serum biochemistry assay revealed no alteration in the serum AST, ALT, ALP, total protein by day 14 excepting total bilirubin. But by day 28, bilirubin level was not significantly (p>0.05) different from the control. Serum ALP, AST level was significantly (p<0.05) reduced while ALT level was significantly increased by PHLE though within the normal range. Creatinine level was not affected by PHLE. In conclusion, the methanolic leaf extract of P. hirsuta was well tolerated by the animals as no sign of toxicity was observed throughout the period of study. The extract showed wound healing activity by improving wound contraction, epithelialization period, hydroxyproline content, wound breaking strength and granulation tissue formation.