Preclinical and clinical research on the toxic and neurological effects of cassava (Manihot esculenta Crantz) consumption

Amazonian useful plants described in the book "Le Pays des Amazones" (1885) of the Brazilian propagandist Baron de Santa-Anna Nery: a historical and ethnobotanical perspective

BACKGROUND

Frederico José de Santa-Anna Nery (1848-1901) was a Brazilian Baron who referred to himself as a "volunteer propagandist" for Brazil in Europe, serving as an immigration agent to publicize the living conditions in the Amazon region, advocating for its development and modernization at the end of the nineteenth century. Santa-Anna Nery's most famous book is "Le Pays des Amazones" (The Lands of the Amazons), first published in 1885, which the author dedicated a chapter to introduce and report on the Amazonian useful plant species and its relationship with humans. The aim of this work is to understand the historical context and ethnobotanical value of the plant species in the Brazilian Amazon at the end of the nineteenth century through an analysis of the book "Le Pays des Amazones" (1885) by Baron de Santa-Anna Nery, as well as to bring to light the historical importance of this very influential propagandist, who has been forgotten nowadays.

METHODS

The original book "Le Pays des Amazones" (1885), as well as the original 3rd edition and its translated version into Portuguese, was carefully analyzed and all information about plants was systematized, with botanical names being updated. Finally, using the scientific name of medicinal plants alone or in combination with their traditional use, a search was carried out in databases in order to indicate current pharmacological studies that provide evidence about the described traditional uses.

RESULTS

A total of 156 plant species were identified in the book, although 132 species had their scientific names updated. These species belong to 45 different families, with Fabaceae and Arecaceae the most represented, and 109 plants are Brazilian native. Considering only the 36 medicinal plants, the main medicinal indications reported were astringent, purgative/laxative, stimulant and tonic, vermifuge, febrifuge, sudorific, emetic, diuretic and antidysenteric. Regarding other useful plants (non-medicinal), 97 species were cited for food, constructions and buildings, spices and condiments, ornaments and objects, carpentry, textile fibers, gums, oils, balms and essences, pigments and tanning, hunting and fishing.

CONCLUSIONS

When the book "Le Pays des Amazones" is analyzed from a timeless perspective, with a particular focus on historical ethnobotany, it is possible to observe the economic, social, and political importance of many useful plants for the Amazon at the end of the nineteenth century and how the relationship between local people, indigenous communities, and immigrants was established with plant biodiversity.

Supplementation with Manihot esculenta Crantz (Cassava) leaves' extract prevents recognition memory deficits and hippocampal antioxidant dysfunction induced by Amyloid-β

OBJECTIVE

The Manihot esculenta Crantz (Cassava) is a typical South American plant rich in nutrients and energetic compounds. Lately, our group has shown that non-pharmacological interventions with natural antioxidants present different neuroprotective effects on oxidative balance and memory deficits in AD-like animal models. Here, our objective was to evaluate the neuroprotective effects of Cassava leaves' extract (CAS) in an AD-like model induced by amyloid-beta (Aβ) 25-35 peptide.

METHODS

Male Wistar rats (n = 40; 60 days old) were subjected to 10 days of CAS supplementation; then, we injected 2 μL Aβ 25-35 in the hippocampus by stereotaxic surgery. Ten days later, we evaluated object recognition (OR) memory. Cassavas' total polyphenols, flavonoids, and condensed tannins content were measured, as well as hippocampal lipid peroxidation and total antioxidant capacity.

RESULTS

CAS protected against Aβ-induced OR memory deficits. In addition, Aβ promoted antioxidant capacity decrease, while CAS was able to prevent it, in addition to diminishing lipoperoxidation compared to Aβ.

DISCUSSION

We show that treatment with Cassava leaves' extract before AD induction prevents recognition memory deficits related to Aβ hippocampal injection. At least part of these effects can be related to the Cassava leaves' extract supplementation effects on diminishing lipid peroxidation and preventing a decrease in the hippocampal total antioxidant capacity in the hippocampus of AD-like animals without adverse effects. Once cassavais a plant of warm and dry ground that can adapt to growon various soil types and seems to resist several insects, our results enable Cassava to be considered asa potential preventive intervention to avoid or minimizeAD-induced memory deficits worldwide.

Female naturalists and the patterns of suppression of women scientists in history: the example of Maria Sibylla Merian and her contributions about useful plants

BACKGROUND

This work reunites many women naturalists who registered knowledge about native flora in scientific expeditions around the globe between the seventeenth and nineteenth centuries. Since male naturalists are more recognized in this period of time, we aimed to list female naturalists that published plant descriptions and observations, focusing on the work of Maria Sibylla Merian and to analyze her trajectory as an example to discuss the patterns of the suppression of women scientists. A second aim was to inventory the useful plants described in Maria Sibylla's Metamorphosis Insectorum Surinamensium and find pharmacological evidence about the traditional uses described for those plants cited as medicinal and toxic.

METHODS

A survey of female naturalists was carried out by searching information in Pubmed, Scielo, Google Scholar and Virtual Health Library. Once Maria Sibylla published her book Metamorphosis Insectorum Surinamensium by her own, without male co-authors, and also this book is one of the only to have text and illustrations altogether and there are reports indicating information on useful plants in this work, she and her book were chosen as subject of this research. All the information was tabulated by dividing the plants into food, medicinal, toxic, aromatic or other uses. Finally, with the combinations of the scientific name of medicinal and toxic plants with information about their popular uses, a search was carried out in databases in order to indicate current pharmacological studies that reported evidences about the traditional uses described.

RESULTS

We found 28 women naturalists who participated in scientific expeditions or trips, or in a curiosity cabinet, or who were collectors of Natural History between the seventeenth and nineteenth centuries. All these women illustrated botanical species and/or recorded their everyday or medicinal use or reported their observations in the form of a published work, letters or diaries. Also, the trajectory of Maria Sibylla Merian revealed that her scientific relevance has been neglected from the eighteenth century by mechanisms of suppression, most of the time by male depreciation, which can be seen as a pattern for suppression of women in science. However, Maria Sibyllas' contributions have been valued again in the twenty-first century. In Maria Sibylla's work, 54 plants were identified, 26 of them used for food, 4 of them aromatic, 8 medicinal, 4 toxic and 9 other uses.

CONCLUSION

This study evidences that there are female naturalists whose work could be an important source for ethnopharmacological studies. Researching about women scientists, talking about them and highlighting the gender bias present in the scientific academy about the way the history of science is told is essential for the construction of a more diverse and richer scientific academy. The traditional use of 7 of 8 medicinal plants and 3 of 4 toxic plants reported was correlated with pharmacological studies, highlighting the importance of this historical record and its potential to direct strategic research in traditional medicine.

Adaptations in the transformation of cassava (Manihot esculenta Crantz; Euphorbiaceae) for consumption in the dietary management of diabetes: the case of Palikur, or Parikwene People, from French Guiana

Introduction

In the French overseas department of French Guiana, in South America, nutrition therapy for the management of diabetes is based on French guidelines. However, this region is demographically diverse and includes several populations of Indigenous Peoples, Parikwene among others, also called Palikur. Due to socio-economical, cultural, and geographical differences, along with distinctions in the local food system, dietary recommendations, which many consider in the context of post-colonial power dynamics, are not well suited to local populations. In the absence of suitable recommendations, it is hypothesized that local populations will adapt their dietary practices considering diabetes as an emerging health problem.

Methods

Seventy-five interviews were conducted with community members and Elders, as well as healthcare professionals and administrators providing services to the Parikwene population of Macouria and Saint-Georges de l'Oyapock communes. Data regarding the representation of cassava (Manihot esculenta Crantz) consumption and diabetes were collected via semi-structured interviews and participant observation (i.e., observation and participation in community activities), namely via participating in activities related to the transformation of cassava tubers at swidden and fallow fields.

Results and Discussion

Parikwene have adapted the transformation of cassava tubers for their consumption in the management of diabetes.The importance of cassava tubers as a staple and core food to the Parikwene food system was established by identifying it as a cultural keystone species. Narratives illustrated conflicting perceptions regarding the implication of cassava consumption in the development of diabetes. Adaptations to the operational sequence involved in the transformation of cassava tubers led to the production of distinct cassava roasted semolina (i.e., couac), based on organoleptic properties (i.e., sweet, and acidic couac). Preferences for the consumption of acidic couac were grounded in the Parikwene knowledge system, as well as attention to diabetes related symptoms and glucometer readings.

Conclusion

These results provide important insights related to knowledge, attitudes, and practices in developing locally and culturally adapted approaches to providing dietary recommendations in the treatment of diabetes.

Cassava (Manihot esculenta Crantz): A Systematic Review for the Pharmacological Activities, Traditional Uses, Nutritional Values, and Phytochemistry

Cassava (Manihot esculenta Crantz) is considered one of the essential tuber crops, serving as a dietary staple food for various populations. This systematic review provides a comprehensive summary of the nutritional and therapeutic properties of cassava, which is an important dietary staple and traditional medicine. The review aims to evaluate and summarize the phytochemical components of cassava and their association with pharmacological activities, traditional uses, and nutritional importance in global food crises. To collect all relevant information, electronic databases; Cochrane Library, PubMed, Scopus, Web of Science, Google Scholar, and Preprint Platforms were searched for studies on cassava from inception until October 2022. A total of 1582 studies were screened, while only 34 were included in this review. The results of the review indicate that cassava has diverse pharmacological activities, including anti-bacterial, anti-cancer, anti-diabetic, anti-diarrheal, anti-inflammatory, hypocholesterolemic effects, and wound healing properties. However, more studies that aim to isolate the phytochemicals in cassava extracts and evaluate their pharmacological property are necessary to further validate their medical and nutritional values.

Prevalence, profile and associations of cognitive impairment in Ugandan first-episode psychosis patients

Introduction

The MATRICS consensus cognitive battery (MCCB) is the gold standard for neuropsychological assessment in psychotic disorders but is rarely used in low resource settings. This study used the MCCB to determine the prevalence, profile and associations of various exposures with cognitive impairment in Ugandan first-episode psychosis patients.

Methods

Patients and matched healthy controls were recruited at Butabika Hospital in Uganda. Clinical variables were first collated, and after the resolution of psychotic symptoms, a neuropsychological assessment of seven cognitive domains was performed using the MCCB. Cognitive impairment was defined as two standard deviations (SD) below the mean in one domain or 1SD below the mean in two domains. Descriptive statistics determined the prevalence and profile of impairment while regression models determined the association between various exposures with cognitive scores while controlling for age, sex and education.

Results

Neuropsychological assessment with the MCCB found the burden of cognitive impairment in first-episode psychosis patients five times that of healthy controls. The visual learning and memory domain was most impaired in first-episode psychosis patients, while it was the working memory domain for the healthy controls. Increased age was associated with impairment in the domains of the speed of processing (p < 0.001) and visual learning and memory (p = 0.001). Cassava-rich diets and previous alternative and complementary therapy use were negatively associated with impairment in the visual learning (p = 0.04) and attention/vigilance domains (p = 0.012), respectively. There were no significant associations between sex, history of childhood trauma, or illness severity with any cognitive domain.

Conclusion

A significant burden of cognitive impairment in Ugandan first-episode psychosis patients is consistent with prior data from other contexts. However, the profile of and risk factors for impairment differ from that described in such work. Therefore, interventions to reduce cognitive impairment in FEP patients specific to this setting, including dietary modifications, are required.

Toxic Damage to Motor Neurons

Abstract—Amyotrophic lateral sclerosis (ALS) is a multifactor disease in the development of which both genetic and environmental factors play a role. Specifically, the effects of organic and inorganic toxic substances can result in an increased risk of ALS development and the acceleration of disease progression. It was described that some toxins can induce potentially curable ALS-like syndromes. In this case, the specific treatment for the prevention of the effects of the toxic factor may result in positive clinical dynamics. In this article, we review the main types of toxins that can damage motor neurons in the brain and spinal cord leading to the development of the clinical manifestation of ALS, briefly present historical data on studies on the role of toxic substances, and describe the main mechanisms of the pathogenesis of motor neuron disease associated with their action.

Two fatal cases of acetone cyanohydrin poisoning: case report and literature review

Acetone cyanohydrin (ACH), an organic cyanide, is mainly used in the production of methyl methacrylate (MMA), and it also exists in cassava roots, the main calorie source in some tropical countries. ACH can decompose spontaneously or enzymatically into acetone and highly toxic hydrogen cyanide (HCN) and be potentially toxic to its contacts. Given that limited forensic studies and case reports on fatal ACH poisoning are available, herein, we present a report of two fatal cases of ACH poisoning in which the two victims, with postmortem cyanide blood concentrations of 4.22 μg/ml and 4.07 μg/ml, suffered from acute poisoning of ACH due to a traffic accident. Furthermore, a literature review of cyanide poisoning case reports from 2000 to 2020 was carried out, and 28 subjects with cyanide poisoning were presented, including the age, sex, cause of poisoning, autopsy findings and the cyanide concentration in the blood. ACH poisoning lacks specific and reliable autopsy findings for diagnosis, and relevant toxicological studies are necessary. Due to the chemical properties of ACH that allow it to easily decompose, the toxicological analysis of acetone and cyanide in biological samples is essential for the diagnosis of ACH poisoning.

Konzo risk factors, determinants and etiopathogenesis: What is new? A systematic review

Konzo is a toxico-nutritional upper motor neuron disease causing a spastic paraparesis in schoolchildren and childbearing women in some African countries. Almost a century since the first description of konzo, its underlying etiopathogenic mechanisms and causative agent remain unknown. This paper aims at refreshing the current knowledge of konzo determinants and pathogenesis in order to enlighten potential new research and management perspectives. Literature research was performed in PubMed and Web of Science databases according to the PRISMA methodology. Available data show that cassava-derived cyanide poisoning and protein malnutrition constitute two well-documented risk factors of konzo. However, observational studies have failed to demonstrate the causal relationship between konzo and cyanide poisoning. Thiocyanate, the current marker of choice of cyanide exposure, may underestimate the actual level of cyanide poisoning in konzo patients as a larger amount of cyanide is detoxified via other unusual pathways in the context of protein malnutrition characterizing these patients. Furthermore, the appearance of konzo may be the consequence of the interplay of several factors including cyanide metabolites, nutritional deficiencies, psycho-emotional and geo-environmental factors, resulting in pathophysiologic phenomena such as excitotoxicity or oxidative stress, responsible for neuronal damage that takes place at sparse cellular and/or subcellular levels.

Effects of Cassava Juice (Manihot esculenta Crantz) on Renal and Hepatic Function and Motor Impairments in Male Rats

Cassava (Manihot esculenta Crantz) is a plant that contains neurotoxins such as linamarin and lotaustraline. Its long-term consumption is associated with neuronal damage and contributes to the development of motor impairment in humans and rats. We investigated the effects of the consumption of cassava juice on renal and hepatic function and motor impairments in male rats. The rats received the vehicle, non-toxic and toxic doses of cassava juice, or linamarin as a pharmacological control, over 35 consecutive days. The effects were evaluated in an open field test, rotarod, and swim test. The toxic cassava dose and linamarin resulted in motor impairments in the rotarod and swim test from day 7 of treatment. The toxic cassava dose and linamarin increased the parameters that indicate renal and hepatic damage, with the exception of total protein and albumin levels. Behavioral variables that show motor incoordination (i.e., latency to fall in the rotarod) were negatively correlated with biochemical parameters of renal and kidney damage, whereas spin behavior was positively correlated. Our data indicate that chronic oral consumption of cassava juice caused renal and hepatic damage that was correlated with motor coordination impairment in rats, similarly to their principal neurotoxic compound, linamarin.