Preventive effect of <i>Dioscorea japonica</i> on squamous cell carcinoma of mouse skin involving down-regulation of prostaglandin E₂ synthetic pathway

Abstract

Hyperproduced prostaglandin E2 by cyclooxygenase-2 and microsomal prostaglandin E synthase-1 evokes several pathophysiological responses such as inflammation and carcinogenesis. Our recent study demonstrated that Dioscorea japonica extract suppressed the expression of cyclooxygenase-2 and microsomal prostaglandin E synthase-1 and induced apoptosis in lung carcinoma A549 cells. In the present study, we investigated the effects of Dioscorea japonica on squamous cell carcinoma of mouse skin. Dioscorea japonica feeding and Dioscorea japonica extract topical application suppressed the expression of cyclooxygenase-2, microsomal prostaglandin E synthase-1, interleukin-1β and interleukin-6 and inhibited tumor formation, hyperplasia and inflammatory cell infiltration. Immunohistochemical analyses showed the immunoreactivities of cyclooxygenase-2 and microsomal prostaglandin E synthase-1 in tumor keratinocytes and stronger immunoreactivities of cyclooxygenase-2 and hematopoietic prostaglandin D synthase in epidermal dendritic cells (Langerhans cells). Treatment with Dioscorea japonica decreased the immunoreactivity of cyclooxygenase-2 and microsomal prostaglandin E synthase-1. These results indicate that Dioscorea japonica may have inhibitory effects on inflammation and carcinogenesis via suppression of the prostaglandin E2 synthetic pathway.

Assessment of Functional Food Dioscorea Japonica Paste As A Thickened Liquid For Elderly With Dysphagia

“…We have been exploring food functionality for the prevention of chronic inflammation by targeting the synthetic pathway of proinflammatory lipid mediators, such as prostaglandin (PG) E2 and leukotrienes, derived from ω-6 arachidonic acid. In our previous study, we have demonstrated that Dioscorea japonica, a wild yam, suppresses the activity of cyclooxygenase-2 (COX-2) and microsomal prostaglandin E (PGE) synthase-1, which are key enzymes in the production of proinflammatory PGE2, and has anti-inflammation and anti-carcinogenesis [12,13]. Recently, it is reported that diosgenin, a functional ingredient of Dioscorea japonica, downregulates COX-2 expression selectively in macrophages via glucocorticoid receptor and improves LPS-induced liver inflammation [14].…”

Effects of Rhizome Extract of Dioscorea batatas and Its Active Compound, Allantoin, on the Regulation of Myoblast Differentiation and Mitochondrial Biogenesis in C2C12 Myotubes

“…Yam is also known to have digestive functions in the stomach and intestines, as well as immune-regulatory and antiaging effects. In modern pharmacology, the yam has been studied for its effects on asthma [ 7 ], cancer [ 8 , 9 , 10 ], diabetes [ 11 , 12 ], and liver damage [ 13 ], as well as its anti-oxidation, anti-inflammation, and anti-aging effects [ 14 , 15 ]. The yam contains various compounds such as dioscin [ 16 ], steroidal saponins [ 16 , 17 ], saponins, gallic acid, vanillic acid [ 14 ], allatoin [ 12 ], and protodioscin [ 18 ].…”

“…Allantoin, a diureide of glyoxylic acid, is an active and abundant component of yam [ 10 , 12 , 20 ]. In vivo studies have shown allantoin to have anti-asthmatic [ 20 ], antidiabetic [ 12 , 21 ] and antihypertensive [ 22 ] activities, as well as memory-enhancing effects in Alzheimer’s disease [ 23 ].…”

Effects of Rhizome Extract of <em>Dioscorea Batatas </em>and Its Active Compound, Allantoin, on the Regulation of Myoblast Differentiation and Mitochondrial Biogenesis in C2C12 Myotubes

“…Yam contains various compounds such as dioscin [15], steroidal saponins [15,16], saponins, gallic acid, vanillic acid [13], allatoin [11], and protodioscin [17]. Allantoin, a diureide of glyoxylic acid, is an active and abundant component of yam [9,11,18]. In vivo studies have shown allantoin to have anti-asthmatic [18], anti-diabetic [11,19] and anti-hypertensive [20] activities, as well as memory-enhancing effects in Alzheimer's disease [21].…”

“…In modern pharmacology, yam has been studied for its effects on asthma [6], cancer [7][8][9], diabetes [10,11], and liver damage [12], as well as its antioxidation, antiinflammation, and antiaging effects [13,14]. Yam contains various compounds such as dioscin [15], steroidal saponins [15,16], saponins, gallic acid, vanillic acid [13], allatoin [11], and protodioscin [17].…”