[Amphibians in Spanish popular medicine and the pharmacopoeia of Pliny and Dioscorides]

Histological Study of Glandular Variability in the Skin of the Natterjack Toad—Epidalea calamita (Laurenti, 1768)—Used in Spanish Historical Ethnoveterinary Medicine and Ethnomedicine

Simple Summary

Common toads, including the natterjack toad (Epidalea calamita), have been used since ancient times for remedies, and thus constitute excellent biological material for pharmacological and natural product research. After a previous analysis of the historical-folk therapeutic use of amphibians in Spain, a histological study was carried out to provide a complementary ethnopharmacological view through the analysis of the integumentary heterogeneity of the serous (venom) and mucous glands from two adult specimens. Plastic-embedded semi-thin sections showed that serous/venom glands are cytologically homogeneous in spite of their genetic and biochemical complexity, leading to a cocktail that remains stored until extrusion. On the contrary, mucous glands, working continuously, show a more complex cytological variation and regional heterogeneity, which suggests an adaptive variability, leading to an invisible topographic map of skin toxicity. Natterjack toad-based folk remedies are usually extracted from the whole animal as a therapeutic unit in ethnoveterinary practice. However, a new ethnopharmacological vision could emerge from the study of tegumentary regional variation.

Abstract

Common toads have been used since ancient times for remedies and thus constitute excellent biological material for pharmacological and natural product research. According to the results of a previous analysis of the therapeutic use of amphibians in Spain, we decided to carry out a histological study that provides a complementary view of their ethnopharmacology, through the natterjack toad (Epidalea calamita). This species possesses a characteristic integument, where the parotoid glands stand out, and it has been used in different ethnoveterinary and ethnomedical practices. This histological study of their glandular variability allow us to understand the stages through which the animal synthesises and stores a heterogeneous glandular content according to the areas of the body and the functional moment of the glands. To study tegumentary cytology, a high-resolution, plastic embedding, semi-thin (1 micron) section method was applied. Up to 20 skin patches sampled from the dorsal and ventral sides were processed from the two adult specimens collected, which were roadkill. Serous/venom glands display a genetic and biochemical complexity, leading to a cocktail that remains stored (and perhaps changes over time) until extrusion, but mucous glands, working continuously to produce a surface protection layer, also produce a set of active protein (and other) substances that dissolve into mucous material, making a biologically active covering. This study provides a better understanding of the use of traditional remedies in ethnoveterinary medicine.

Chemical and Pharmacological Screening of Rhinella icterica (Spix 1824) Toad Parotoid Secretion in Avian Preparations

The biological activity of Rhinella icterica parotoid secretion (RIPS) and some of its chromatographic fractions (RI18, RI19, RI23, and RI24) was evaluated in the current study. Mass spectrometry of these fractions indicated the presence of sarmentogenin, argentinogenin, (5β,12β)-12,14-dihydroxy-11-oxobufa-3,20,22-trienolide, marinobufagin, bufogenin B, 11α,19-dihydroxy-telocinobufagin, bufotalin, monohydroxylbufotalin, 19-oxo-cinobufagin, 3α,12β,25,26-tetrahydroxy-7-oxo-5β-cholestane-26-O-sulfate, and cinobufagin-3-hemisuberate that were identified as alkaloid and steroid compounds, in addition to marinoic acid and N-methyl-5-hydroxy-tryptamine. In chick brain slices, all fractions caused a slight decrease in cell viability, as also seen with the highest concentration of RIPS tested. In chick biventer cervicis neuromuscular preparations, RIPS and all four fractions significantly inhibited junctional acetylcholinesterase (AChE) activity. In this preparation, only fraction RI23 completely mimicked the pharmacological profile of RIPS, which included a transient facilitation in the amplitude of muscle twitches followed by progressive and complete neuromuscular blockade. Mass spectrometric analysis showed that RI23 consisted predominantly of bufogenins, a class of steroidal compounds known for their cardiotonic activity mediated by a digoxin- or ouabain-like action and the blockade of voltage-dependent L-type calcium channels. These findings indicate that the pharmacological activities of RI23 (and RIPS) are probably mediated by: (1) inhibition of AChE activity that increases the junctional content of Ach; (2) inhibition of neuronal Na+/K+-ATPase, leading to facilitation followed by neuromuscular blockade; and (3) blockade of voltage-dependent Ca2+ channels, leading to stabilization of the motor endplate membrane.

Knowledge and interactions of the local community with the herpetofauna in the forest reserve of Quininí (Tibacuy-Cundinamarca, Colombia)

BACKGROUND

The study of human-nature relationship has made possible to understand the life dynamics of the communities and the biodiversity with which they cohabit. Although there has been a rise of ethnobiological studies over the last decade, little is known about human interaction with herpetofauna in South America and Colombia. In this work, we analyzed the knowledge, perception, and interaction of a local community located in the forest reserve of Quininí (RFPCQ) in Cundinamarca (Colombia), concerning to the herpetofauna that inhabits the area.

METHODS

We performed semi-structured surveys containing 30 questions categorized into three groups: academic knowledge (1), use and cultural beliefs (2), and interactions (3) related to the herpetofauna that occurs in the region. The obtained data in question groups 1 and 2 are presented as a qualitative summary. For the question group 3, we assigned the answers to a hostility value according to the possible reaction of each individual interviewed in a hypothetical encounter with the herpetofauna and built tendency charts in order to see the positive or negative reactions due to the birthplace (urban/rural) and gender (male/female).

RESULTS

The community recognized the presence of amphibians and reptiles that cohabit their space, as well as their potential habitats. Besides, the role of herpetofauna was recognized in the magical/religious traditions for some inhabitants of the region, mainly associated with the fate and cure of chronic diseases. In general, the perception of amphibians and reptiles varied according to the origin and gender of the people, which tend to have a more positive perception of reptiles than compared to amphibians in most cases.

CONCLUSIONS

Although there was a general lack of knowledge on the part of the inhabitants of the RFPCQ about the biological and ecological aspects of herpetofauna, the population recognized the basic information about the habitats of these animals within the reserve area. There is a wide variety of uses of amphibians and reptiles in traditional medicine. Greater efforts should be made in the transmission and dissemination of knowledge about the ecological functions of herpetofauna.

DNA Barcoding for the Identification and Authentication of Animal Species in Traditional Medicine

Animal-based traditional medicine not only plays a significant role in therapeutic practices worldwide but also provides a potential compound library for drug discovery. However, persistent hunting and illegal trade markedly threaten numerous medicinal animal species, and increasing demand further provokes the emergence of various adulterants. As the conventional methods are difficult and time-consuming to detect processed products or identify animal species with similar morphology, developing novel authentication methods for animal-based traditional medicine represents an urgent need. During the last decade, DNA barcoding offers an accurate and efficient strategy that can identify existing species and discover unknown species via analysis of sequence variation in a standardized region of DNA. Recent studies have shown that DNA barcoding as well as minibarcoding and metabarcoding is capable of identifying animal species and discriminating the authentics from the adulterants in various types of traditional medicines, including raw materials, processed products, and complex preparations. These techniques can also be used to detect the unlabelled and threatened animal species in traditional medicine. Here, we review the recent progress of DNA barcoding for the identification and authentication of animal species used in traditional medicine, which provides a reference for quality control and trade supervision of animal-based traditional medicine.

The therapeutic use of the dog in Spain: a review from a historical and cross-cultural perspective of a change in the human-dog relationship

In Spain, studies about traditional knowledge related to biodiversity have focused on vascular plants. For this reason, our review concentrates on the identification and inventory of zootherapeutic resources, particularly those involving the dog (Canis lupus familiaris Linnaeus, 1758) throughout the twentieth century to the present. A qualitative systematic review in the fields of ethnomedicine, ethnozoology and folklore was made. Automated searches in the most important databases and digital libraries were performed. All related works were examined thoroughly and information was obtained from 55 documentary sources. We have listed a total of 63 remedies to treat and/or prevent 49 human illnesses and conditions. In 20 of the documented reports the whole animal was used and the use of pups was recommended in 12 cases. Saliva was the healing element in 10 remedies, and faeces were the therapeutic basis for nine, while bitch's milk was for seven of them. Skin, fur and meat were next in significance. Currently, healing remedies based on the use of the dog are not part of Spanish ethnomedicine and considering them so would be ahistorical. Indeed, the custom of allowing a dog to lick one's wounds to assist in their healing and cicatrisation has survived in only a few groups of people. However, we can state that the ethnomedical use of the dog exists and has been transferred to "animal-assisted therapy".

The use of wild vertebrates in contemporary Spanish ethnoveterinary medicine

ETHNOPHARMACOLOGICAL RELEVANCE

This review documents the wide and varied repertoire of traditional practices based on the use of wild vertebrates in Spanish ethnoveterinary medicine (EVM) from the early 20th century to the present. Empirical practices, both ritual and magical, are recorded, and these EVM data are compared with those of other countries in the Mediterranean Region and Latin America. The data collected here could form a scientific foundation for future inventories of traditional knowledge and help in the discovery of new drugs for livestock.

MATERIALS AND METHODS

A qualitative systematic review of international and national databases in the fields of ethnobiology, ethnoveterinary medicine, folklore and ethnography was made. Information was obtained from more than 60 documentary sources.

RESULTS

We recorded the use of 30 wild vertebrates and a total of 84 empirical remedies based on the use of a single species. The two most relevant zoological groups are reptiles and mammals. A wide diversity of body parts or products have been and are used. The meat and skin of snakes are the animal products most commonly used. These zootherapeutic resources have been and are used to treat or prevent ca. 50 animal diseases or conditions, in particular digestive and reproductive ailments, together with some infectious diseases. Sheep, cattle and equines form the group of domestic animals in which the greatest number of useful species are employed. In addition, many remedies and practices of the magical type are documented. In comparison with other culturally related areas, this is a rich heritage.

CONCLUSIONS

Contemporary Spanish EVM practices amass a great richness of wild animal-based remedies. A diversity of animal parts or products have been used, offering a cultural heritage that could be a fundamental step in the discovery of new and low-cost drugs for treating livestock and alternative materials for pharmaceutical purposes. This overview contributes to the inventory of some uses and rituals seriously threatened by the progressive loss of local veterinary knowledge.