| Summary: | 博士 === 國立中興大學 === 農藝學系所 === 99 === Herba Dendrobii, commonly known as “Shi-hu”, has been used as a precious traditional Chinese medicine. It is expensive and adulteration are common due to high demand. The method to distinguish the herb from adulterant species is necessary. In the present study, internal transcribed spacers (ITS) region-based analysis was employed to ascertain the phylogenetic relationship among the 11 Dendrobium and two adulterant species Pholidota articulata and Flickingeria comate. Results showed that the length of the ITS regions among the thirteen species ranged from 635 to 641 bp and the GC ratio in ITS (ITS1 + 5.8S + ITS2) regions ranged from 50.55% to 57.25%. Dendrobium species was significantly different from one another by an average of 13.20% and from P. articulata and F. comate by 42.00% and 29.00% respectively. The molecular phylogenetic trees indicated that most of Dendrobium species are closely related and share common clad while both the adulterants outgroup and have separated clad. Therefore, ITS regions can be used as a molecular marker to differentiate medicinal Dendrobium spp. from one another and also from adulterants.
Dendrobium tosaense Makino is one of the most valuable Chinese medicines known as “Shi-hu” and well developed functional health food in Taiwan. Atopic dermatitis (AD) is a chronic inflammatory skin disease that occurs mainly in childhood. The pathogenesis of atopic dermatitis has been studied in BALB/c mice produced by administration of 2,4,6-trinitro-1-chrolobenzene (TNCB). These mice exhibit features of chronic contact dermatitis, including skin rash, an increased number of mast cells, and elevated serum IgE levels accompanied by a shift in cutaneous cytokine expression. In the current study, a standardized ethyl acetate extract of D. tosaense (DtE) was used to protect these mice from the TNCB-induced skin lesions simulating atopic dermatitis. Activated T cell differentiation, cytokine modulation, allergen-specific antibody estimation, skin pathology, and mast cell numbers in the skin lesions were determined. The resulting cytokine profiles and IgE level showed DtE to significantly reduce Th2 polarization. An increased number of modulated natural T regulatory cells were accompanied by increased immunosuppression in the spleen and decreased mast cell infiltration into the skin lesions. Our results indicate that the administration of DtE can modulate cytokine expression and T cell subpopulations by regulating mast cell infiltration and thus alleviate the atopic dermatitis.
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