The chemical analysis and biological effects of ginger (Zingiber officinale)
Introduction. Giner, a traditional Chinese herbal medicine, is used to treat digestive disordrs in particular to alleviate symptoms of nausea and/or vomiting. Aims. Major aims were to measure the concentration of -gingerol (6G), and elements in fresh ginger rhizome juice (GJ) by HPLC and ICP-AES and investigate their effects on gastrointestinal functions. Methods. Short circuit current (I[sub]sc) effects of 6G and the dietary phytochemicals quercetin and kaempferol (100 [mu]M) were measured in a Caco-2 cell monolayer. In vitro isometric recording was used to investigate GJ (50 [mu]L, 200 [mu]L), 6G [1.59x10[sup]-5M-1x10[sup]-4M), a selected combination of elements (K [4.6x10[sup]-2M], Mg [7.4x10[sup]-3M], Mn [8.3x10[sup]-4M], Na [1.1x10[sup]-3M, Ca [5.1x10[sup]-4M]), and a "faux" ginger juice on contractile activity of proximal and distal stomach and duodenum segments from 'Suncus murinus'. The effect of 6G (1x10[sup]-2Mx1x10[sup]-4M, po.) and a ginger capsule suspension on motion-induced emesis was investigated in vivo in 'Suncus'. Results. The concentration of 6G in GJ was 239.43 [plus or minus] 7.92 mg/L. 6G had no effect on I[sub]sc], however quercetin and kaempferol caused a significant increase on I[sub]sc and the ATP - induced chloride ion secretion. GJ (50 [mu]L and 200 [mu]L) caused a dose-realted biphasic effect resulting in an overall increase in tension on both regions of the stomach at 25 minutes and an inhibitory effect on duodenal contractions. "Faux" GJ (200 [mu]L) only partially accounted for the effects of GJ. 6G and a ginger capsule suspension had no antiemetic activity in vivo. Conclusions. Quercetin and kaempferol may be able to augment the signalling in the intestinal epithelia resulting in an increase in fluid secretion which could facilitate stool passage. "Faux" GJ did not fully account for the motility effects of GJ, indicating that there were ither bioactive constituents present in GJ (e.g. -shogaol). GJ was most effective on the duodenum, suggesting this as a target for an enteric coated ginger capsule for gastrointestinal disorders.