Toxicological safety assessment of AP-Bio®, a standardized extract of Andrographis paniculata in Sprague Dawley rats

Andrographis paniculata, commonly known as green chiretta, is a traditionally used plant in India, China, and Southeast Asian countries for its varied health benefits including immune health. The objective of the present study was to assess the safety of AP-Bio®, a standardized A. paniculata extract in Sprague Dawley rats by following the Organisation for Economic Cooperation and Development (OECD) test guidelines of acute and 90-day repeated dose sub-chronic toxicity studies. AP-Bio® did not show any treatment-related clinical signs of toxicity or mortality during the 14-day observation period in animals tested in the single-dose acute oral toxicity study up to a dose of 5000 mg/kg body weight. In the 90-day repeated dose sub-chronic oral toxicity study, no treatment-related adverse clinical signs were observed in any of the treated groups (300, 600, and 900 mg/kg). All treated animals showed usual weight gain and comparable feed intake. The ophthalmoscope examination did not reveal any abnormalities. Also, no toxicologically significant changes were observed in urinalysis, hematology, and blood chemistry parameters. Absolute organ weights and relative organ weights of vital organs did not differ significantly compared to control. Gross and histopathological findings did not show any remarkable and treatment-related changes. Results of the safety evaluation showed the median lethal dose (LD50 ) of AP-Bio® was found to be more than 5000 mg/kg rat body weight and the no observed adverse effect level (NOAEL) of AP-Bio® was found to be 900 mg/kg rat body weight.

Ocimum tenuiflorum extract (HOLIXERTM): Possible effects on hypothalamic-pituitary-adrenal (HPA) axis in modulating stress

Ocimum tenuiflorum is a sacred medicinal plant bestowed with multiple health benefits. This plant is traditionally considered an adaptogen. Many scientific studies have indicated the anti-stress potential of Ocimum tenuiflorum but with higher doses. The present study investigated the effects of HolixerTM (a clinically studied standardized Ocimum tenuiflorum extract) on modulating stress using two in vivo models, namely the swim endurance study in mice and forced swim test in rats. In addition, we explored the mechanism of action of HolixerTM on the HPA axis using two in vitro cell-based assays to check for its inhibitory effect on cortisol release and CRF1 receptor antagonistic activity. Ocimum tenuiflorum extract enhanced the swimming time in mice, reduced the stress-induced increase in immobility time, and prevented the increase in corticosterone in rats subjected to the forced swim test. Further, Ocimum tenuiflorum extract inhibited cortisol release and exhibited a significant CRF1 receptor antagonist activity. Thus, Ocimum tenuiflorum extract was found effective in managing stress, and the effect could be due to the inhibition of cortisol release and the antagonistic effect on the CRF1 receptors.

A flavonoid rich standardized extract of Glycyrrhiza glabra protects intestinal epithelial barrier function and regulates the tight-junction proteins expression

BACKGROUND

Intestinal epithelial barrier dysfunction predisposes to many gastrointestinal, metabolic, and psychological disorders. A flavonoid rich extract of Glycyrrhiza glabra (FREG) has previously been reported to possess anti-inflammatory, antioxidant, and antiulcer properties.

AIM

To investigate the effect of FREG (GutGard^®) on restoring intestinal barrier function in tumor necrosis factor-alpha (TNF-α) stimulated human colonic adenocarcinoma cell monolayer (Caco-2) and 2,4,6-Trinitrobenzenesulfonic acid (TNBS) induced ulcerative colitis in rats.

METHODS

In in vitro, human intestinal Caco-2 cell monolayers were treated with TNF-α in the presence or absence of FREG and the paracellular permeability to FITC-conjugated 4-kD dextran (FD4) was measured to evaluate protection against the barrier dysfunction. In in vivo, intestinal barrier dysfunction was induced in male albino Wistar rats via intrarectal instillation of TNBS. Subsequently, the rats were treated orally with either FREG at 6.25, 12.5, and 25 mg/kg body weight, or Mesacol (250 mg/kg) for 5 days. On day 5, intestinal epithelial permeability was assessed with FD4 leakage into the serum. Also, colonic inflammation, colon morphology, histology and macroscopic score, weight to length ratio were evaluated. The activity of myeloperoxidase (MPO), TNF- α, secretory IgA levels and tight junction proteins expression were evaluated in rat's colon.

RESULTS

FREG protected the intestinal epithelial barrier integrity in human intestinal Caco-2 cells in vitro. FREG administration significantly improved the intestinal epithelial barrier function as evident from significant reduction in FD4 leakage. The colon morphology, histology score, macroscopic score, colon weight to length ratio also indicates beneficial effects of FREG on barrier function. In addition, FREG regulated the tight junction proteins, and markedly decreased TNF-α, MPO levels and significantly increased the secretory IgA levels in TNBS induced colitis rats.

CONCLUSION

The study findings support the protective action of FREG on intestinal epithelial barrier integrity indicating its potential in protecting from implications of leaky gut.