Quebrachitol-induced gastroprotection against acute gastric lesions: role of prostaglandins, nitric oxide and K+ ATP channels.

The effect of Quebrachitol (2-O-methyl-L-inositol), a bioactive component from Magonia glabrata fruit extract was investigated against gastric damage induced by absolute ethanol (96%, 0.2 ml/animal) and indomethacin (30 mg/kg, p.o.), in mice. Quebrachitol at oral doses of 12.5, 25, and 50mg/kg markedly attenuated the gastric lesions induced by ethanol to the extent of 69%, 64%, and 53% and against indomethacin by 55%, 59%, and 26%, respectively. While pretreatment with TRPV1 antagonist capsazepine (5mg/kg, i.p.) failed to block effectively the gastroprotective effect of quebrachitol (25mg/kg) against ethanol damage, the non-selective cyclooxygenase inhibitor indomethacin (10mg/kg, p.o.), almost abolished it. Furthermore, quebrachitol effect was significantly reduced in mice pretreated with L-NAME, or glibenclamide, the respective inhibitors of nitric oxide synthase and K(+)(ATP) channel activation. Thus we provide the first evidence that quebrachitol reduces the gastric damage induced by ethanol and indomethacin, at least in part, by mechanisms that involve endogenous prostaglandins, nitric oxide release, and or the activation of K(+)(ATP) channels.

Cadmium, mercury and lead in medicinal herbs in Brazil.

Samples of herbal medicine used in Brazil were analyzed, after nitric digestion, for the content of cadmium, mercury and lead, by atomic absorption spectrophotometry. Fifteen samples of ginkgo biloba (Ginkgo biloba), 13 of celastraceae (Maytenus ilicifolia), 14 of cascara buckthorn (Rhamnus purshiana), 13 of eggplant (Solanum melongena), 15 of horse chestnut (Aesculus hippocastanum), 13 of Brazilian ginseng (Pffafia glomerata), 17 of centella asiatic (Hydrocotyle asiatica), 13 of guarana (Paullinia cupana), 12 of artichoke (Cynara scolymus) and five samples of chlorella (Chlorella pyrenoidosa) were analyzed. Cadmium, mercury and lead were not detected (limit of quantifications of 0.20, 0.01 and 2.0 mg/kg, respectively) in any sample of artichoke, eggplant and guarana. Cadmium was found in samples of the other medicinal herbs at levels up to 0.74 microg/g and mercury up to 0.087 microg/g. Three samples of horse chestnut contained 153, 156 and 1480 microg Pb/g, while the highest concentration found in the other samples analyzed was 22 microg Pb/g. The estimated lead intake through the consumption of horse chestnut reached 440% of Provisional Tolerable Weekly Intake (PTWI), and might be of concern to consumers if the medicine was taken on a long-term basis. Cadmium and mercury exposure through the herbal medicines does not appear to be of health concern.