Pinostrobin attenuates azoxymethane-induced colorectal cytotoxicity in rats through augmentation of apoptotic Bax/Bcl-2 proteins and antioxidants

Objectives: Pinostrobin (5-hydroxy-7-methoxyflavanone; PN) is a natural active ingredient with numerous biological activities extensively utilized in tumour chemotherapy. The present study investigates the chemo-preventive potentials of PN on azoxymethane-mediated colonic aberrant crypt foci in rats. Methods: Sprague Dawley rats clustered into five groups, normal control (A) and cancer controls were subcutaneously injected with normal saline and 15 mg/kg azoxymethane, respectively, and nourished on 10% tween 20 and fed on 10% tween 20; reference control (C), injected with 15 mg/kg azoxymethane and injected (intraperitoneal) with 35 mg/kg 5-fluorouracil (5-FU); D and E rat groups received a subcutaneous injection of 15 mg/kg azoxymethane and nourished on 30 and 60 mg/kg of PN, respectively. Results: The acute toxicity trial showed a lack of any abnormal signs or mortality in rats ingested with 250 and 500 mg/kg of PN. The gross morphology of colon tissues revealed significantly lower total colonic aberrant crypt foci incidence in PN-treated rats than that of cancer controls. Histological examination of colon tissues showed increased aberrant crypt foci availability with bizarrely elongated nuclei, stratified cells and higher depletion of the submucosal glands in cancer controls. PN treatment caused positive modulation of apoptotic (Bax and Bcl-2) proteins and inflammatory cytokines (TNF-α, IL-6 and IL-10). Moreover, rats fed on PN had significantly higher antioxidants (superoxide dismutase) and lower malondialdehyde concentrations in their colon tissue homogenates. Conclusion: The chemoprotective efficiency of PN against azoxymethane-induced aberrant crypt foci is shown by lower aberrant crypt foci values and higher aberrant crypt foci inhibition percentage, possibly through augmentation of genes responsible for apoptotic cascade and inflammations originating from azoxymethane oxidative stress insults

Gastroprophylactic Effects of p-Cymene in Ethanol-Induced Gastric Ulcer in Rats

The prevalence of gastric ulcers has increased in recent years, mainly because of non-steroidal anti-inflammatory drug utilization. Therefore, the current study investigates the gastroprotective effect of p-Cymene on absolute ethanol-induced acute gastric mucosal hemorrhagic lesions in rats. Thirty Sprague Dawley rats were randomly separated into five groups: normal control, ulcer control, reference, and two experimental groups. The normal and ulcer control groups were orally fed with 0.5% carboxymethylcellulose (CMC). The reference group was fed orally with 20 mg/kg omeprazole. The experimental groups were fed with 30 mg/kg and 60 mg/kg p-Cymene, respectively. After one hour, the normal group was fed with 0.5% CMC, and groups 2–5 were given absolute alcohol. After another hour all rats were sacrificed. The ulcer control group showed severe superficial hemorrhagic gastric mucosal lesions with decreased gastric mucus secretion and pH of gastric content. p-Cymene significantly reduced ethanol-induced gastric lesions, as evidenced by increased mucus and pH of gastric content, decreased ulcer area, reduced or absence of edema, and leucocyte infiltration of the subcutaneous layer. In gastric mucosal homogenate, p-Cymene displayed a significant increase in superoxide dismutase (SOD), catalase (CAT) activities, prostaglandin E2 (PGE2), and significantly reduced the malondialdehyde (MDA) level. In addition, p-Cymene increased the intensity of periodic acid–Schiff (PAS) stain of the gastric epithelium, and produced up-regulation of the HSP 70 protein and down-regulation of the Bax protein of the stomach epithelium, as well as a reduction in the levels of tumor necrotic factor-alpha and interleukin-6, while the level of interleukin-10 was increased. p-Cymene decreased the level of TNF-a and IL-6, and increased the level of IL-10. Acute toxicity with a higher dose of 500 mg/kg p-Cymene did not manifest any toxicological signs in rats and could enhance defensive mechanisms against gastric mucosal lesions. p-Cymene showed gastroprotective effects that could be attributed to its antioxidant nature, or its ability to increase mucus secretion, increase endogenous enzymes (SOD, CAT, PGE2), reduce MDA level, up-regulate HSP 70 protein, down-regulate Bax protein, and modulate inflammatory cytokines