Estudo etnobotânico de plantas medicinais em comunidades de várzea do rio Solimões, Amazonas e aspectos farmacognósticos de Justicia pectoralis Jacq. forma mutuquinha (Acanthaceae)

Abstract

The use of medicinal plants, in association with its symbolic conceptions, have been valued in the whole world. The inhabitants of the amazonian floodplains have important collections of plants used for therapeutic purposes. The aim of this work was to realize an ethnobotanical study of the medicinal plants used in riverine communities in the Solimões River, in two localities of Manacapuru/AM and to contribute to the pharmacognostic characterization of a species with great informant agreement in the communities, Justicia pectoralis form mutuquinha (Acanthaceae) (mutuquinha). In the ethnobotanical study, informants were selected through the "snowball" method. Semi-structured interviews and participant observation were conducted. The informant agreement of species use was calculated and citations accumulation curves were constructed to compare the number of medicinal species and nosological categories listed in each locality. The anatomical and histochemical characterization of the leaves and stems of J. pectoralis forma mutuquinha was realized, according to usual laboratory methods. Informants are mostly elderly women. In both communities, 157 identified medicinal plant species distributed in 59 families were listed, besides 19 species not yet identified. The most represented families are Lamiaceae, Asteraceae, Fabaceae and Euphorbiaceae. 40% of species are exotic, featuring a dynamic pharmacopoeia. The local nosological conception is peculiar, with typical ―cultural‖ diseases. The humoral classification and the doctrine of signatures are present in the riverines‘ conceptions. Women and newborns‘ health have been highlighted in the local medical system. Most medicinal plants are herbaceous, supporting the idea of the importance of weeds in popular pharmacopoeias, and found in homegardens, which reflects the importance of domestication of plants used for therapeutic purposes. Food plants have large representation in the pharmacopoeias of the studied communities. Zingiber officinale Roscoe (Zingiberaceae) and Mentha cf. piperita L. (Lamiaceae) are plants with high informant agreement in both localities. The leaves are the most used plant parts in the preparation of medicines, decoction being the most common method. The characteristic periodic flooding of the Amazonian floodplains dictate the cycles of cultivation and availability of home remedies. The arrival of new religious beliefs in traditionally catholic communities seems to be a factor affecting the number of local nosological categories and the number of medicinal plants used. The leaves of J. pectoralis forma mutuquinha have uniseriate epidermis, dorsiventral mesophyll, are hypostomatic with diacytic stomata. Hydathodes were described at the base of the leaf blade. The petiole is concave-convex with an arc-shaped collateral central bundle. The stem has eustelic organization, typical of eudicotyledonous, with collateral bundles. Non- glandular and glandular trichomes and litocysths containing cystoliths occur in the epidermis of all the analyzed organs. Translucent droplets occur in abundance in cells of the chlorenchyma of the leaves and stems. The content of the glandular trichomes is mixed, complex and diverse, including essential oils, steroids, phenolic compounds and proteins and the chlorenchyma droplets contain oleoresins. These results indicate a great therapeutic potential of the species.