A unique therapeutic approach to emesis and itch with a proanthocyanidin-rich genonutrient

Abstract

Background: We examined the therapeutic potential of a proprietary Croton palanostigma extract (Zangrado(R)) in the management of emesis and itch.

Methods: Emesis was induced in ferrets with morphine-6-glucuronide (0.05 mg/kg sc) in the presence of Zangrado (3 mg/kg, ip) and the cannabinoid receptor 1 antagonist, AM 251 (5 mg/kg, ip). Topical Zangrado (1%) was assessed for anti-pruretic actions in the 5-HT-induced scratching model in rats and evaluated in capsaicin-induced gastric hyperemia as measured by laser doppler flow. In the ApcMinmouse model of precancerous adenomatosis polyposis, mice received Zangrado (100 mug/ml in drinking water) from the age of 6 - 16 weeks for effects on polyp number. In RAW 264.7 cells Zangrado was examined for effects on lipopolysaccharide-induced nitrite production.

Results: Zangrado was a highly effective anti-emetic, reducing morphine-induced vomiting and retching by 77%. These benefits were not associated with sedation or hypothermia and were not reversed by cannabinoid receptor antagonism. Itch responses were blocked in both the morphine and 5-HT models. Zangrado did not exacerbate the ApcMincondition rather health was improved. Capsaicin-induced hyperemia was blocked by Zangrado, which also attenuated the production of nitric oxide by activated macrophages.

Conclusion: Zangrado is an effective anti-emetic and anti-itch therapy that is devoid of common side-effects, cannabinoid-independent and broadly suppresses sensory afferent nerve activation. This complementary medicine represents a promising new approach to the management of nausea, itch and irritable bowel syndrome.

Figure 1

Suppression of morphine-6-glucuronide-induced vomiting and retching in ferrets with Zangrado, and the effects of CB₁ receptor antagonism with AM 251. Ferrets treated with the opioid narcotic, morphine-6-glucuronide (M6G) display a substantial emetic response with on average over 12 episodes per hour. Zangrado administration (3 mg/kg ip) 15 minutes prior to M6G resulted in a 77% reduction in emetic episodes (n = 6, P < 0.01). Co-administration of Zangrado with the CB receptor antagonist, AM 251 (5 mg/kg, ip) failed to reverse the anti-emetic effects of Zangrado (n = 6). The slight increase in emetic episodes with AM 251 is comparable to that seen with ferrets treated with AM 251 alone and is thought to reflect the anti-emetic effects of endogenous cannabinoids [20,21].

Figure 2

Suppression of morphine-6-glucuronide-induced licking in ferrets with Zangrado, and the effects of CB₁ receptor inhibition of AM 251. Ferrets treated with M6G display a licking response which was quantified. Treatment with Zangrado (3 mg/kg, ip) reduced this licking response by 87% (n = 6, P < 0.01). Co-treatment with AM 251, the CB₁ receptor antagonist, failed to reverse the benefits of Zangrado on M6G-induced itch (n = 6).

Figure 3

Comparison of the cannabinoid receptor agonist, WIN 55,212-2 and Zangrado on body temperature in ferrets. Ferrets treated with the CB₁ receptor agonist, WIN 55,212-2 (1 mg/kg, ip) displayed a substantial reduction in body temperature when measured at 30 and 45 minutes after administration. In contrast, there was no effect of Zangrado (3 mg/kg, ip) on body temperature (n = 6, p < 0.05). Both agents were administered at effective anti-emetic doses.

Figure 4

Time course of the scratching response to subcutaneous 5-HT. Number of episodes of scratching in 5-min intervals over a one-hour period after injection of 5HT subcutaneously. (n = 5 per group) Controls got an injection of an identical volume of saline (100 μl).

Figure 5

Effects of Zangrado on 5-HT evoked scratching: Comparison between pretreatment and immediate post-treatment. Scratching episodes in response to saline injection (control, n = 5) and 5-HT (black column, n = 11) with vehicle treatment (50 μl of Dermabase crème) or the effects of 50 μl of zangrado (1%) crème applied 30 min (-30 Min column, n = 10) before the sc injection of 5-HT or immediately after (0 Min column, n = 8). The statistical difference between groups is noted in the figure.

Figure 6

Anti-pruretic effects between Zangrado and a commercial hemorrhoid crème. Subcutaneous 5-HT administration (black column, n = 11) evoked a significant scratching response over saline (control, *** p < 0.001). This scratching response was significantly attenuated by either topical administration of Preparation H (Prep H, purple column, * p < 0.01, n = 7) or Zangrado (red column, ** p < 0.001, n = 10), when applied immediately after the administration of 5-HT.

Figure 7

Effect of Zangrado on capsaicin-induced gastric hyperemia in rats. Capsaicin (320 μM) applied to the luminal surface of intact gastric mucosa results in a hyperemia as measured by laser Doppler flow. Rats pretreated with luminal Zangrado (0.2 mg/kg) ablated this hyperemia response (n = 5, P < 0.01).

Figure 8

Body Weight in Apc^Min/+mice over a 10 week treatment period with Zangrado or vehicle. Body weight (mean ± sem) of Apc^Min/+mice determined over a 10 week treatment period is shown for mice treatment with Zangrado (n = 5, 100 μg/ml in drinking water) or unaltered drinking water (control). The Zangrado treated mice displayed a greater body weight over this period than did control mice (n = 10). This trend was not statistically significant.

Figure 9

Polyp number in control or Zangrado treated Apc^Min/+mice. Apc^Min/+mice treatment with Zangrado (100 μg/ml in drinking water, n = 5) displayed a 26% reduction in the number of polyps when compared to vehicle control mice (n = 10). This trend was not statistically significant. There were no polyps noted in wild type mice.

Figure 10

Effects of Zangrado on the production of nitrite by LPS-activated macrophages. Murine macrophages, Raw 264.7 cells, treated with LPS (2 ng/ml) displayed a marked increase in nitrite production. Co-administration of Zangrado with LPS resulted in a significant reduction in nitrite production (n = 6, p < 0.05).