Ethnobotany, Pharmacology and Chemistry of Medicinal Orchids from Veracruz

Orchidaceae is a large family of 1,260 species in Mexico, of which 433 grow in the state of Veracruz, Mexico. Although economically important in horticulture because of the beauty of their flowers, researches have done little work regarding their medicinal properties. This paper aimed to present the results of ethnobotanical, pharmacological and active compounds research on Veracruz medicinal orchids. The ethnobotanical information was obtained by consulting the Atlas of the Mexican Traditional Medicine Plants, Veracruz Medicinal Flora Database （CITRO-UV project） and through field work in the Nahuatl community of Cuautlajapa, Veracruz. To obtain pharmacological and active compounds information of registered species, a search was carded out through MEDLINE （USA National Library of Medicine Journal Citation database）. Twelve medicinal orchids were recorded for Veracruz, i.e., Epidendrum chlorocorymbos Schltr., Habenaria floribunda Lindl., Isochillus latibracteatus A. Rich. ＆ Galeotti, lsochillus major Schltdl. ＆ Cham., Mormodes maculata var. unicolor （Hook.） L. O. Williams, Oestlundia luteorosea （A. Rich. ＆ Galeotti） W. E. Higgins, Oncidium ascendens Lindl., Scaphyglottis fasciculata Hook., Sobralia macrantha Lindl., Spiranthes eriophora （Rob. ＆ Greenm.）, Stanhopea oculata （G. Lodd.） Lindl. and Vanilla planifolia Andrews. Only two species have been investigated in terms of their pharmacology and active compounds. Also, information for another five species closely related to already identified ones was obtained. Given the relative poverty of current information on the topic, this paper demonstrates the need to further study the ethnobotanical, pharmacological and chemical aspects of the region＇s medicinal orchids.

Perspective and challenges of mycorrhizal symbiosis in orchid medicinal plants

The family Orchidaceae is of the most diverse taxon in the plant kingdom,and most of its members are highly valuable herbal medicines.Orchids have a unique mycorrhizal symbiotic relationship with specific fungi for carbohydrate and nutrient supplies in their whole lifecycle.The large-scale cultivation of the medicinal plant Gastodia elata is a successful example of using mycorrhizal symbiotic technology.In this review,we adopted G.elata and Dendrobium officinale as examples to describe the characteristics of orchid mycorrhiza and mycorrhizal benefits for host plants’growth and health(e.g.biotic and abiotic stress and secondary metabolite accumulation).The challenges in applying mycorrhizal technology to the cultivation of orchid medicinal plants in the future were also discussed.This review aims to serve as a theoretical guide for the cultivation of mycorrhizal technology in medicinal orchid plants.

Acclimatization of in Vitro-derived Dendrobium

The successful ex vitro establishment of Dendrobium plantlets raised in vitro determines the quality of the end product(cut flowers or potted plants) in commercial production for economic gain. When in vitro Dendrobium plantlets are transplanted from the culture room to greenhouse conditions, they may desiccate or wilt rapidly and can die as a result of changes in the environment, unless substantial precautions are taken to adapt plantlets to a new environment. The acclimatization of in vitro-grown Dendrobium plantlets to an ex vitro environment by gradually weaning them towards ambient relative humidity and light levels facilitates better survival of young and physiologically sensitive plantlets.Dendrobium plantlets raised in vitro must thus undergo a period of acclimatization or transitional development to correct anatomical abnormalities and to enhance their physiological performance to ensure survival under ex vitro conditions. The most common approach to improve the survival of Dendrobium plantlets upon transfer to an ex vitro environment is their gradual adaptation to that environment. Under such conditions, plants convert rapidly from a heterotrophic or photomixotrophic state to an autotrophic growth, develop a fully functional root system,and better control their stomatal and cuticular transpiration. Gradual adaptation is carried out in a greenhouse by decreasing relative humidity using fog or mist chambers and by increasing light intensity using shading techniques. This review details the acclimatization and ex vitro survival of Dendrobium plants produced in vitro. This advice is also useful for other orchids.