Paleomedicine and the use of plant secondary compounds in the Paleolithic and Early Neolithic

Medicinal plants meet modern biodiversity science

Plants have been an essential source of human medicine for millennia. In this review, we argue that a holistic, interdisciplinary approach to the study of medicinal plants that combines methods and insights from three key disciplines - evolutionary ecology, molecular biology/biochemistry, and ethnopharmacology - is poised to facilitate new breakthroughs in science, including pharmacological discoveries and rapid advancements in human health and well-being. Such interdisciplinary research leverages data and methods spanning space, time, and species associated with medicinal plant species evolution, ecology, genomics, and metabolomic trait diversity, all of which build heavily on traditional Indigenous knowledge. Such an interdisciplinary approach contrasts sharply with most well-funded and successful medicinal plant research during the last half-century, which, despite notable advancements, has greatly oversimplified the dynamic relationships between plants and humans, kept hidden the larger human narratives about these relationships, and overlooked potentially important research and discoveries into life-saving medicines. We suggest that medicinal plants and people should be viewed as partners whose relationship involves a complicated and poorly explored set of (socio-)ecological interactions including not only domestication but also commensalisms and mutualisms. In short, medicinal plant species are not just chemical factories for extraction and exploitation. Rather, they may be symbiotic partners that have shaped modern societies, improved human health, and extended human lifespans.

Medicinal plants of the upper Aswa River catchment of northern Uganda - a cultural crossroads

BACKGROUND

This paper presents a comparative inventory of medicinal plant taxa and their uses by smallholder farming communities of four cultures in the Aswa River catchment of northern Uganda, situated in the eastern Sudanian savanna parkland ecotype of sub-Saharan Africa. The purpose of the study was to document the ethnobotanical use of medicinal plants by the Lango, Acholi, Teso (Atesot) and Ethur (jo Abwor), in an historical moment before civil conflict and mass displacement of the respondent communities disrupted the inter-generational transmission of traditional technical knowledge within the study area.

METHODS

Following community consultations in four districts of northern Uganda during 1999-2000, interviews were conducted with holders of specialist knowledge on plants used as medicine on basis of a plant specimen allocated a voucher number and identified by the national herbarium. Use reports reflecting specific medicinal applications were compiled in aggregate to obtain a Relative Importance Index ranking. The commonality of medicinal taxa cited between each cultural interface was assessed by the Jaccard Index of Similarity, and the similarity of specific medicinal usage by taxon using Rahman's Similarity Index.

RESULTS

The data collected from 112 respondents comprise 280 medicinal use reports describing 263 applications for 62 medical conditions, citing 108 taxa from 44 botanical families of which Fabaceae comprised 20% of all use reports. No earlier mention could be found to corroborate 72 use reports (27% of the total), representing medicinal indications as yet undocumented, and potentially worthy of investigation. The RI values ranged between 15 and 94%, with 13 taxa having RI values above 50%. The JI ratios indicate the highest degree of similarity in the plant taxa used as medicine (21%) between the Lango and Teso cultures who share a common origin; however, Rahman's Similarity Index indicates the highest similarity of specific medicinal usage by taxon between the Lango and Acholi, who share a common language group through cultural assimilation over time.

CONCLUSIONS

As a comparative study, the results imply that cultural exchange and assimilation may be a greater driver of inter-cultural similarity of ethnopharmacological use of a given taxon, as compared to shared historical origins.

Direct evidence of the use of multiple drugs in Bronze Age Menorca (Western Mediterranean) from human hair analysis

Human hair dated to Late Prehistory is exceedingly rare in the Western Mediterranean. Archaeological excavations in the Bronze Age burial and cult cave of Es Càrritx, in Menorca (Balearic Islands) provided some human hair strands involved in a singular funerary rite. This finding offered the opportunity to explore the possible use of drug plants by Late Bronze Age people. Here we show the results of the chemical analyses of a sample of such hair using Ultra-High-Performance Liquid Chromatography-High Resolution Mass Spectrometry (UHPLC-HRMS). The alkaloids ephedrine, atropine and scopolamine were detected, and their concentrations estimated. These results confirm the use of different alkaloid-bearing plants by local communities of this Western Mediterranean island by the beginning of the first millennium cal BCE.

Homo medicus: The transition to meat eating increased pathogen pressure and the use of pharmacological plants in Homo

The human lineage transitioned to a more carnivorous niche 2.6 mya and evolved a large body size and slower life history, which likely increased zoonotic pathogen pressure. Evidence for this increase includes increased zoonotic infections in modern hunter-gatherers and bushmeat hunters, exceptionally low stomach pH compared to other primates, and divergence in immune-related genes. These all point to change, and probably intensification, in the infectious disease environment of Homo compared to earlier hominins and other apes. At the same time, the brain, an organ in which immune responses are constrained, began to triple in size. We propose that the combination of increased zoonotic pathogen pressure and the challenges of defending a large brain and body from pathogens in a long-lived mammal, selected for intensification of the plant-based self-medication strategies already in place in apes and other primates. In support, there is evidence of medicinal plant use by hominins in the middle Paleolithic, and all cultures today have sophisticated, plant-based medical systems, add spices to food, and regularly consume psychoactive plant substances that are harmful to helminths and other pathogens. We propose that the computational challenges of discovering effective plant-based treatments, the consequent ability to consume more energy-rich animal foods, and the reduced reliance on energetically-costly immune responses helped select for increased cognitive abilities and unique exchange relationships in Homo. In the story of human evolution, which has long emphasized hunting skills, medical skills had an equal role to play.

Evaluating natural medicinal resources and their exposure to global change

Medicinal plants and their bioactive molecules are integral components of nature and have supported the health of human societies for millennia. However, the prevailing view of medicinal biodiversity solely as an ecosystem-decoupled natural resource of commercial value prevents people from fully benefiting from the capacity of nature to provide medicines and from assessing the vulnerability of this capacity to the global environmental crisis. Emerging scientific and technological developments and traditional knowledge allow for appreciating medicinal plant resources from a planetary health perspective. In this Personal View, we highlight and integrate current knowledge that includes medicinal, biodiversity, and environmental change research in a transdisciplinary framework to evaluate natural medicinal resources and their vulnerability in the anthropocene. With Europe as an application case, we propose proxy spatial indicators for establishing the capacity, potential societal benefits, and economic values of native medicinal plant resources and the exposure of these resources to global environmental change. The proposed framework and indicators aim to be a basis for transdisciplinary research on medicinal biodiversity and could guide decisions in addressing crucial multiple Sustainable Development Goals, from accessible global health care to natural habitat protection and restoration.

Treatment of Gastrointestinal Disorders-Plants and Potential Mechanisms of Action of Their Constituents

The worldwide prevalence of gastrointestinal diseases is about 40%, with standard pharmacotherapy being long-lasting and economically challenging. Of the dozens of diseases listed by the Rome IV Foundation criteria, for five of them (heartburn, dyspepsia, nausea and vomiting disorder, constipation, and diarrhoea), treatment with herbals is an official alternative, legislatively supported by the European Medicines Agency (EMA). However, for most plants, the Directive does not require a description of the mechanisms of action, which should be related to the therapeutic effect of the European plant in question. This review article, therefore, summarizes the basic pharmacological knowledge of synthetic drugs used in selected functional gastrointestinal disorders (FGIDs) and correlates them with the constituents of medicinal plants. Therefore, the information presented here is intended as a starting point to support the claim that both empirical folk medicine and current and decades-old treatments with official herbal remedies have a rational basis in modern pharmacology.

Folklore, Animal Self-Medication, and Phytotherapy-Something Old, Something New, Something Borrowed, Some Things True

The use of medicines was long considered by Western schools of thought to be a a domain unique to humans; however, folklore/Traditional Ecological Knowledge (TEK) from around the world suggests that animals have also long provided inspiration for the discovery of some medicinal plants used to treat humans and their livestock. Searching for medicinal knowledge from animals depends on the recognition of their ability to select and effectively use medicinal plants to prevent or actively ameliorate disease and other homeostatic imbalances. The interdisciplinary field of animal self-medication is providing scientific evidence for this ability in species across the animal kingdom and lends support to animal-origin medicinal plant folklore and recent ethnomedicinal information. Here, 14 case studies of purported animal-inspired plant medicines used by cultures around the world are presented together with ethnomedicinal and pharmacological evidence. Based on this evidence, the diversity and potential mode of self-medicative behaviors are considered. Over 20 animal species, including llama, sloth and jaguar in South America, reindeer and yak in Eurasia, langur and macaque in Asia, and chimpanzee, wild boar, porcupine and elephant in Africa, are linked to these case studies, representing a variety of potential preventative or therapeutic self-medicative behaviors. These examples provide an important perspective on what is likely to have been a much wider practice in the development of human traditional medicine. A role for animal self-medication research in the rejuvenation of old therapies and possible new discoveries of phytotherapies for human and livestock health is encouraged.

Reconstructing Neanderthal diet: The case for carbohydrates

Evidence for plants rarely survives on Paleolithic sites, while animal bones and biomolecular analyses suggest animal produce was important to hominin populations, leading to the perspective that Neanderthals had a very-high-protein diet. But although individual and short-term survival is possible on a relatively low-carbohydrate diet, populations are unlikely to have thrived and reproduced without plants and the carbohydrates they provide. Today, nutritional guidelines recommend that around half the diet should be carbohydrate, while low intake is considered to compromise physical performance and successful reproduction. This is likely to have been the same for Paleolithic populations, highlighting an anomaly in that the basic physiological recommendations do not match the extensive archaeological evidence. Neanderthals had large, energy-expensive brains and led physically active lifestyles, suggesting that for optimal health they would have required high amounts of carbohydrates. To address this anomaly, we begin by outlining the essential role of carbohydrates in the human reproduction cycle and the brain and the effects on physical performance. We then evaluate the evidence for resource availability and the archaeological evidence for Neanderthal diet and investigate three ways that the anomaly between the archaeological evidence and the hypothetical dietary requirements might be explained. First, Neanderthals may have had an as yet unidentified genetic adaptation to an alternative physiological method to spare blood glucose and glycogen reserves for essential purposes. Second, they may have existed on a less-than-optimum diet and survived rather than thrived. Third, the methods used in dietary reconstruction could mask a complex combination of dietary plant and animal proportions. We end by proposing that analyses of Paleolithic diet and subsistence strategies need to be grounded in the minimum recommendations throughout the life course and that this provides a context for interpretation of the archaeological evidence from the behavioral and environmental perspectives.

Complexity and sophistication of Early Middle Paleolithic flint tools revealed through use-wear analysis of tools from Misliya Cave, Mount Carmel, Israel

The Early Middle Paleolithic (EMP) is a less-studied phase of the Levantine Middle Paleolithic, attributable to the small number of sites discovered. Drawing on the dense archaeological accumulations at Misliya Cave, Mount Carmel, Israel, the present study seeks to trace EMP daily activities and behavioral patterns through the prism of use-wear analysis. The emergence of the laminar and Levallois technologies that form the EMP toolkit is investigated to reveal other dimensions of tool novelties. Through microscopic analyses, integrated with experimentation, the most outstanding aspect revealed in this study is the extensive evidence of hafting, which included the use of binding together with various techniques for tool design. A unique treatment was identified, never reported before, entailing the abrasion of cortical surfaces and protruding dorsal ridges. Other aspects include the clear preference for pointed tools as a leading morphological trend and the use of retouch as a mean to create durable working edges and facilitate grip arrangements. The analysis demonstrates the venue of use-wear to trace a wide variety of practices, including consumption-related (processing hunted game and edible plants) and craft-related (hide processing, woodworking, and perhaps stone working) activities that otherwise hardly leave a trace in the archaeological record. By exploring these features, the research provides important insights into early hominin behavior and way of life during the EMP, emphasizing the novelties brought by the earliest Homo sapiens out of Africa.

Using a Paleo Ratio to Assess Adherence to Paleolithic Dietary Recommendations in a Randomized Controlled Trial of Individuals with Type 2 Diabetes

This study is a secondary analysis of a randomized controlled trial using Paleolithic diet and exercise in individuals with type 2 diabetes. We hypothesized that increased adherence to the Paleolithic diet was associated with greater effects on blood pressure, blood lipids and HbA1c independent of weight loss. Participants were asked to follow a Paleolithic diet for 12 weeks and were randomized to supervised exercise or general exercise recommendations. Four-day food records were analyzed, and food items characterized as "Paleolithic" or "not Paleolithic". Foods considered Paleolithic were lean meat, poultry, fish, seafood, fruits, nuts, berries, seeds, vegetables, and water to drink; "not Paleolithic" were legumes, cereals, sugar, salt, processed foods, and dairy products. A Paleo ratio was calculated by dividing the Paleolithic calorie intake by total calorie intake. A multiple regression model predicted the outcome at 12 weeks using the Paleo ratio, group affiliation, and outcome at baseline as predictors. The Paleo ratio increased from 28% at baseline to 94% after the intervention. A higher Paleo ratio was associated with lower fat mass, BMI, waist circumference, systolic blood pressure, and serum triglycerides at 12 weeks, but not with lower HbA1c levels. The Paleo ratio predicted triglyceride levels independent of weight loss (p = 0.046). Moreover, an increased monounsaturated/saturated fatty acids ratio and an increased polyunsaturated/saturated fatty acids ratio was associated with lower triglyceride levels independent of weight loss. (p = 0.017 and p = 0.019 respectively). We conclude that a higher degree of adherence to the Paleolithic diet recommendations improved fat quality and was associated with improved triglyceride levels independent of weight loss among individuals with type 2 diabetes.

The Therapeutic Potential of the Essential Oil of Thymbra capitata (L.) Cav., Origanum dictamnus L. and Salvia fruticosa Mill. And a Case of Plant-Based Pharmaceutical Development

This review performs a comprehensive assessment of the therapeutic potential of three native herbs of Crete (Thymbra capitata (L.) Cav., Salvia fruticosa Mill. and Origanum dictamnus L.), their phytochemical constituents, health benefits and issues relevant to their safety, within a translational context. Issues discussed comprise: 1) Ethnopharmacological uses of the three herbs, reviewed through an extensive search of the literature; 2) Systematic analysis of the major phytochemical constituents of each plant, and their medicinal properties; 3) To what extent could the existing medicinal properties be combined and produce an additive or synergistic effect; 4) Possible safety issues. We conclude with a specific example of the use of a combination of the essential oils of these plants as an effective anti-viral product and the experience gained in a case of a plant-based pharmaceutical development, by presenting the major steps and the continuum of the translational chain.

Paleomedicine and the Evolutionary Context of Medicinal Plant Use

Modern human need for medicines is so extensive that it is thought to be a deep evolutionary behavior. There is abundant evidence from our Paleolithic and later prehistoric past, of survival after periodontal disease, traumas, and invasive medical treatments including trepanations and amputations, suggesting a detailed, applied knowledge of medicinal plant secondary compounds. Direct archeological evidence for use of plants in the Paleolithic is rare, but evidence is growing. An evolutionary context for early human use of medicinal plants is provided by the broad evidence for animal self-medication, in particular, of non-human primates. During the later Paleolithic, there is evidence for the use of poisonous and psychotropic plants, suggesting that Paleolithic humans built on and expanded their knowledge and use of plant secondary compounds.