Anti-inflammatory effects of the Zingiber officinale roscoe constituent 12-dehydrogingerdione in lipopolysaccharide-stimulated Raw 264.7 cells.

Ginger has long been used worldwide as a spice, seasoning, and wine and is also used as a traditional medicine. There have been no previous studies of the potential beneficial effects of the ginger constituent 12-dehydrogingerdione (12-DHGD). We investigated the anti-inflammatory effect of 12-DHGD on lipopolysaccharide (LPS)-stimulated Raw 264.7 cells. The cytotoxicity of 12-DHGD was measured using the MTT assay, and production of prostaglandin E2 (PGE2 ) and the inflammatory cytokines interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α was measured by ELISA. Production of nitric oxide (NO) was measured using Griess reagent and expression of cyclooxygenase-2 (COX-2) and inducible NO (iNOS) enzymes was assessed by reverse transcriptase-polymerase chain reaction. Treatment of Raw 264.7 cells with 12-DHGD significantly inhibited LPS-stimulated production of NO (at 12-DHGD concentrations of 150 and 200 ng/ml), IL-6 (at 50, 100, 150, and 200 ng/ml), and PGE2 (at 200 ng/ml). Consistent with the effects on NO and PGE2 production, 12-DHGD treatment also inhibited the LPS-stimulated increase in iNOS and COX-2 mRNA levels. However, 12-DHGD did not affect production of IL-1ß or TNF-α in response to LPS. 12-DHGD, a constituent of ginger, is a potent inhibitor of proinflammatory mediator production in Raw 264.7 macrophage cells.

Dietary aloin, aloesin, or aloe-gel exerts anti-inflammatory activity in a rat colitis model.

AIMS: Aloe has been a very popular folk remedy for inflammation-related pathological conditions despite the lack of studies reporting its efficacy in vivo. The present study evaluated the anti-inflammatory effects of aloe components (aloin, aloesin and aloe-gel) known to be biologically active in the rat model of colitis. MAIN METHODS: Male Sprague Dawley rats were fed experimental diets for 2 weeks before and during the induction of colitis. Drinking water containing 3% dextran sulfate sodium (DSS) was provided for 1 week to induce colitis. At the end of the experimental period, clinical and biochemical markers were compared. KEY FINDINGS: Plasma leukotriene B(4) (LTB(4)) and tumor necrosis factor-α (TNF-α) concentrations were significantly decreased in all groups supplemented with aloe components compared to the colitis control group (p<0.05). Animals fed both a 0.1% and 0.5% aloesin supplemented diet showed colonic myeloperoxidase (MPO) activities which were decreased by 32.2% and 40.1%, respectively (p<0.05). Colonic mucosa TNF-α and interleukin-1ß (IL-1ß) mRNA expressions were significantly reduced in all animals fed aloin, aloesin, or aloe-gel (p<0.05). SIGNIFICANCE: Dietary supplementation of aloe components ameliorates intestinal inflammatory responses in a DSS-induced ulcerative colitis rat model. In particular, aloesin was the most potent inhibitor. Further studies are required for a more complete understanding of the specific mechanism of the action of these supplements.

Intestinal absorption of aloin, aloe-emodin, and aloesin; A comparative study using two in vitro absorption models.

Aloe products are one of the top selling health-functional foods in Korea, however the adequate level of intake to achieve desirable effects are not well understood. The objective of this study was to determine the intestinal uptake and metabolism of physiologically active aloe components using in vitro intestinal absorption model. The Caco-2 cell monolayer and the everted gut sac were incubated with 5-50 microM of aloin, aloe-emodin, and aloesin. The basolateral appearance of test compounds and their glucuronosyl or sulfated forms were quantified using HPLC. The % absorption of aloin, aloe-emodin, and aloesin was ranged from 5.51% to 6.60%, 6.60% to 11.32%, and 7.61% to 13.64%, respectively. Up to 18.15%, 18.18%, and 38.86% of aloin, aloe-emodin, and aloesin, respectively, was absorbed as glucuronidated or sulfated form. These results suggest that a significant amount is transformed during absorption. The absorption rate of test compounds except aloesin was similar in two models; more aloesin was absorbed in the everted gut sac than in the Caco-2 monolayer. These results provide information to establish adequate intake level of aloe supplements to maintain effective plasma level.

Evaluation of aloin and aloe-emodin as anti-inflammatory agents in aloe by using murine macrophages.

The aloe ingredients responsible for physiological effects and the concentrations required to exert their biological activities are not fully understood. This study compares the anti-inflammatory effects of aloin and aloe-emodin with other polyphenols. Our results demonstrated that aloe-emodin dose-dependently inhibited inducible nitric oxide synthase (iNOS) mRNA expression and nitric oxide (NO) production at 5-40 microM. In addition, the levels of cyclooxygenase-2 (COX-2) mRNA and prostaglandin E2 (PGE2) production were suppressed by 40 microM aloe-emodin. Aloin also suppressed the production of NO at 5-40 microM, although it did not suppress PGE2 production. The present results indicate that aloin and aloe-emodin possibly suppress the inflammatory responses by blocking iNOS and COX-2 mRNA expression. The anti-inflammatory effect of aloe-emodin was comparable to that of kaempferol and quercetin, indicating aloe-emodin as a possible key constituent responsible for the anti-inflammatory activity of aloe.

Plasma, tissue and urinary levels of aloin in rats after the administration of pure aloin.

Aloin is a physiologically active anthraquinone present in aloe. There are two isomers of aloin, aloin A and aloin B, occurring as a mixture of diastereomers. The objective of this study was to determine the bioavailability and tissue distribution of aloin. Rats were gavaged with 11.8g/kg aloin, and the levels of aloin and its conjugates were measured in plasma, tissues, and urine. Plasma aloin level showed a peak at 1hr after the administration and the concentration was 59.07+/-10.5 ng/ml. The 24 h cumulated urinary aloin was 0.03% of the initial dose. These results suggest that aloin is absorbed and reaches a peak plasma level within 1-1.5 h after the administration and a significant portion is possibly metabolized or is excreted in feces. These results can apply to the determination of the adequate intake level of aloe and aloe products to achieve the desired biological effect, and to interprete in vitro study results.