AbstractBackgroundBidens pilosa (BP) possessed anti-inflammatory, antioxidant, and immunomodulatory activities. Its beneficial effects on intestinal inflammation and oxidative stress in 2,4,6 trinitrobenzene sulfonic acid (TNBS) induced colitis in Wistar rats was evaluated.MethodsThirty female Wistar rats weighing 180–200 g were distributed into six groups (n = 5): non-colitic, untreated colitic and colitic rats treated graded doses of methanol extract of BP (50–400 mg/kg). Colitis was induced in rats by intracolonic instillation of 0.2 mL of 40 mg/mL TNBS. BP was administered two days pre-colitis induction and treatments continued until seven days post-colitis induction. A day after the last treatment, rats were euthanized, colon removed aseptically and response to treatment assessed. Phytochemical composition of BP was determined using the GC-MS.ResultsBP significantly reduced macroscopic colonic damage score, weight/length ratio, colonic lipid peroxidation level, leukocytes infiltration, and TNF-α level in comparison to untreated colitic rats (p ≤ 0.008). Similarly, treatment with 200 and 400 mg/kg BP prevented depletion of colonic glutathione level than other treatment groups (p ≤ 0.0002). Histological findings revealed that treatment with 400 mg/kg BP significantly preserved the mucosal epithelial layer. It also prevented ulceration and sloughing of the mucosal layers and reduced infiltration of inflammatory cells compared to other treatment groups. Among the 16 compounds identified were oleic acid (6.2%) and n-hexadecanoic acid (2.0%) with antioxidant anti-inflammatory activities.ConclusionsThe beneficial effects of BP in rat colitis might be related to the reduction of leucocytes infiltration, inhibition of oxidative stress and pro-inflammatory cytokines.

The effect of methanol extract of P. americana seeds on isolated ileal smooth muscle was studied for isometric response using 10 adult rabbits of both sexes. Reactivity and agonist-antagonist responses of rabbit ileum to the extract were determined in this study. The affinity, effective concentration to give 50% response (EC50) and maximum response were calculated from the concentration response curves (CRC) obtained. The result for the reactivity study showed the seed extract of P. americana caused concentration dependent relaxation of isolated rabbit ileum with threshold responses at concentration of 1×10−9 mg/ml and 120 mg/ml respectively. The extract-antagonist study showed an upward and right shift in CRC in the presence of phenoxybenzamine, a non-selective adrenergic antagonist, with the EC50 increased from 5.01 mg/ml to 12.59 mg/ml and affinity decreased from 0.20 to 0.08. Extract-antagonist study also showed a right and upward shift in the CRC with a greater magnitude in the presence of prazosin, an α1-adrenergic antagonist, with EC50 increased from 0.32 mg/ml to 25.12 mg/ml and a consequential decrease in the affinity from 3.13 to 0.04. In the presence of propranolol, a β-adrenergic antagonist, a downward and left shift in the CRC was observed with the EC50 and PA2 remaining constant at 0.1 mg/ml and 10 respectively. P. americana concentration-dependently reduced or inhibited gastric motility, increasing transit time which is important for food absorption, thus a pro-nutritive and antispasmodic effect. The interaction with α1-adrenoceptors is beneficially in heart failure management. The plant can be developed as a drug candidate for management of hypertension.

G. Don (CL) is used in folk medicine for the treatment of inflammatory disorders. Effort in this study is to evaluate the beneficial effect of the aqueous-methanol extract of leaf of CL in a rat model of acetic acid induced colitis. Male Wistar rats were distributed into 6 groups of 7 rats each; non colitic, untreated colitic and colitic rats treated with graded doses of CL (100-800 mg/kg). Rats were pre-treated for 2 days before colitis induction and thereafter for 7 days post colitic induction. 24 h after the last treatment, animals were sacrificed and colonic inflammation was evaluated both macroscopically and biochemically. Macroscopic damage score, weight/length ratio, myeloperoxidase (MPO) activity and tumor necrotic factor alpha (TNF-α) levels, were significantly higher in untreated colitic rats in comparison with non colitic rats (P<0.05). Treatment with CL significantly reduced the macroscopic damage scores, neutrophil infiltration (MPO activity) and TNF-α level (P<0.05). In addition, significantly prevented depletion of colonic GSH and (SOD) levels (P<0.05). It appears that the beneficial effect of methanol extract of leaf observed in this study is dose dependent and is related to its antioxidant and anti-inflammatory activity.