Influence of environment on the leaf morpho-anatomy and histochemical of the ayahuasca leaf: Populations cultivated in extra-Amazonian regions

Abstract

Psychotria viridis Ruiz & Pav. (Rubiaceae) occurs naturally throughout the Amazon and it is traditionally used by indigenous communities, being incorporated into religious use in urban contexts over the last few decades. It is known and cultivated in many regions of South America for possessing valuable bioactive alkaloids. In this paper, we described P. viridis leaf morphology, anatomy and histochemistry from three populations cultivated in the southeastern Brazil, in order to identify possible adaptations to local environment and management. All plants presented terminal stipules and basic morpho-anatomical patterns of leaves, consistent with most species of the genus, as heterogeneous dorsiventral mesophyll, uniseriate epidermis, presents large cells with prominent vacuoles and druses. Unicellular non-glandular trichomes and multicellular starry trichomes were present in the primary and secondary veins. Amphi-hypostomatic leaf pattern, not yet described for the species, was common in all studied plants. Variation in the presence of domatia in the same population indicates that this structure cannot be used for taxonomic determination of P. viridis, as already described for other species of the genus. Presence of secretory ducts and reduction in stomata density and leaf area represent the main morpho-anatomic adaptations of plants from drier and warmer climates. Histochemical tests were positive for alkaloids, polysaccharides, proteins and phenolic compounds, being negative for starch only in plants subjected to water stress. We concluded that the morpho-anatomical and histochemical alterations found in the plants of this study resulted from seasonal water deficit adaptations and to maintain or attract mutualistic organisms.

Assessment of environmental condition and drying process of the plants on the concentration of alkaloids and cytotoxicity of traditional Ayahuasca Tea

“…During the study, the TF ecosystem exhibited an average annual rainfall of 2.585 mm and soil water retention capacity greater than the CAMP ecosystem who presented an average annual rainfall rate of 1.847 mm, which is approximately 30% less than TF [38]. CAMP had still a longer summer period, which is common in the region and has already been confirmed in other studies [15,39], the soil is poor in minerals and there is high leaching caused by the water intensity of rainfall [30,40]. Considering the plant-environment relationship interferes with secondary metabolites produced by plants [19,20,24,41,42], these factors together make the plants from CAMP ecosystem to suffer a period of water stress, which does not occur with the TF plants.…”

“…Regarding origin, plant-environment relationship interferes with the secondary metabolism process, acting as a driving force for the biosynthesis of phytochemicals in plants [19,20]. This approach was reported by Miranda et al [15] for P. viridis, the species that contributes with DMT, but in this study the authors did not report the alkaloid content in the tea. Another factor that influences secondary plant metabolism is the genetic diversity within the species, well described for the species used in the Ayahuasca beverage and for other medicinal species [18,21].…”

“…This work allowed to verify the influence of the environment and the drying process of Banisteriopsis caapi stems and Psychotria viridis leaves in the concentration of four psychotropic alkaloids present in Ayahuasca tea, prepared according to traditional ritual. Considering the great interest in the use of Ayahuasca for religious purposes and for treating various neurological and psychiatric conditions, studies of these variables provide important contributions to establish the necessary parameters to ensure reproducibility of the psychotropic and pharmacological effects [4,15,[33][34][35][36][37].…”

“…Both sites share the same broad climate type, considered as humid equatorial Af, according to Koppen [26], without clear stabilization seasons and marked by annual rain seasonally [27]. Each ecosystem in this study was characterized according to data previously described in the literature [15,28,29] and by field observations. For all analyzes, the plant material was collected from individuals randomly chosen within each area, five individuals of wild B. caapi and 20 P. viridis trees cultivated in an agroforest, between 6 and 10 am in January/2016, August/2016, November/2017 and February/2019 were collected.…”

“…The incorporation of this beverage for healing purposes and religious support in urban contemporary society emerged from indigenous and caboclas populations of tropical forests [10]. Studies of the bioactive compounds of Ayahuasca tea [1,[11][12][13] and of the plants that are used for the preparation [14,15] were prompted by increased religious and therapeutic use of Ayahuasca in the United States and several other countries in Europe, but also by the worldwide trend for psychedelic therapy research. The entheogenic effect of Ayahuasca was attributed to a direct relationship with DMT content, that when taken orally is inactivated by visceral monoamine oxidase (MAO).…”