Diuretic Plants Cited in the “Moretum” Poem from the Appendix Vergiliana

Introduction

The purpose of this study is to describe the diet of Italian farmers at the beginning of the Roman Empire. The authors have examined the Moretum of Appendix Vergiliana in order to understand if the choice of the food and the way the food was prepared was sufficient and balanced. This diet was then compared with the Bible diet and the Regimen Sanitatis Salerni diet.

Methods

The analysis of the Moretum consisted in verifying that the described plants are the same plants that are farmed today then if they provided nutritional contents that were sufficient to live an healthy life.

Diuretic plants and food in ancient times

Ancient books of natural history are an important yet neglected source of information about the methods used by our ancestors to select and manipulate crops and medicinal plants. About three-quarters of the biologically active plant-derived compounds presently in use worldwide have been discovered through follow-up research to verify the authenticity of data from folk and ethno-medicinal uses (1). Nowadays, cultural and demographic changes threaten the conservation of this patrimony. The purpose of this study is to identify the diuretic plants listed in the Moretum, the Bible and Flos Medicinae or Regimen Sanitatis Salerni (13^th century) (2, 3). The existence of the kidney was well known during the biblical time, most likely through the study of the internal organs of the animals killed for sacrifice or for food. However, its role in making urine was not recognized until the 2^nd century (about 1400 years after the Old Testament), when Galen established the connection between the kidney and urine formation. There appear to be 13 references to the kidney in the Old Testament and one reference in the New Testament. Moreover, in the Bible, the kidneys were considered to be associated with the innermost part of the personality. They were viewed as central to the soul and to morality. Most of the biblical understanding of the anatomy of kidneys and their anatomic relationships appears to be derived from observations made in domestic animals (4, 5). Besides the religious importance of the Bible, because of its ancient origin it represents a relevant witness of the way of life of the people mentioned. The Holy Scripture is also the first text revealing the utility of plants for man, as natural sources of food, wood, fibers, oils and medicinal herbs. In the last 60 years, several distinguished botanists have attempted to identify the scientific names of the plants cited in the Bible (6–11). Nonetheless, these scholars have provided different lists of plants appearing in the Bible, none of which could be accepted as indisputable. The present state of research allows the listing of 206 species of Bible plants, of which 95 are recognized by all the contemporary researchers of biblical flora (12). The manner in which prescientific people selected and manipulated plants for their medicinal and edible qualities can be approached from such disciplines as ethno-pharmacobotany and the origins of human diet and medicine. In the following centuries botanical science survived almost exclusively as the study of medicinal herbs, with the exception only of Natural History written by Pliny the Elder (23–79 AD), which includes the teachings of Theophrastus, in which botany was regarded as a subject in its own right and not only from a medical point of view (13–15). Our knowledge of Greek pharmacognosy was preserved in Dioscorides' Materia Medica, written in about 60 AD (and, surprisingly, not quoted by Pliny) which for centuries served as the standard pharmacopeia of the West (16–18).

Results and discussion

The authors have analyzed the diet of the farmer Simulo. They assessed whether it was well balanced, and provided a sufficient caloric intake: The ‘focaccia’ and the vinegar provide most of the calories in the form of carbohydrates. Cheese provides proteins and many mineral salts. Olive oil provides a sufficient amount of monounsaturated fat from vegetables. Simulo's meal didn't just have a sufficient caloric intake for the physical labor he was about to do, but was also enriched by various herbs. These supply the body with a great quantity of vitamins, mineral salts, and proteins. Analyzing the herbs added to the focaccia after being ground in the mortar, highlighted their therapeutic properties. Many of them have anti-cancerous properties (rue, cabbage and garlic), and further studies showed beneficial effects on renal functions. These effects can be direct, such as the diuretic effect possessed with various intensity by all the herbs; they can also have indirect effects on the cardiovascular apparatus. Indeed, the beneficial effects of garlic on arteriosus pressure keep the kidney from aging and having complications (19–21).

Dioscorides had already listed onion, leek, and garlic among the plants with diuretic properties. The indirect action on the urinary apparatus can also be implemented by the balancing of renal functions with those of other apparatus. It is interesting to verify how the herbs previously mentioned induce a distribution of water in the organism, both that obtained through carbohydrate metabolism, and that ingested with meals. That is how dehydration and/or hyper-hydration are avoided.

The vegetables of Simulo's diet are rich in some electrolytes, especially those of potassium, those of magnesium that allow an exchange with sodium at a renal level, and can be easily eliminated with urine. It is known how an adequate intake of vitamin K has positive effects on arteriosus pressure. Vegetables with wide leaves (chard, lettuce, cabbage, etc.) are rich in vitamin K, which, besides having an important role in the hemostasis, take part in the production of osteocalcin and proteins of the bone matrix. Thus, these vegetables have a positive effect on metabolizing calcium, and help the kidney. Indeed, they favor the bone mineralization, as a sufficient protein matrix is present. As a consequence the kidney will receive a smaller amount of calcium, and calcium itself will not be deposited in other organs such as arteries, preventing their precocious aging (22).

Garlic has a direct action on arteriosus pressure; it reduces it in cases of hypertension: these properties preserve the kidney from sclerotic complications.

The saluretic and diuretic action of many herbs contained in Simulo's focaccia favor a normal elimination of body waste, so that they prevent hypercalciuria, and the likely formation of stones.

These herbs also have beneficial effects on the intestine: many of them favor digestion and the elimination of water, thus helping the body in eliminating waste and producing stool on daily basis. Simulo's body also gets benefits from using olive oil. Many studies show how the presence of olive oil in the diet has anti-arteriosclerosis effects, and favors a good plasmatic viscosity, protects the vascular endothelium and the entire cardiovascular apparatus, along with the cerebral, coronary and renal areas.

We may ask ourselves why Simulo used those herbs and not others. It is very hard to give an answer. Financial elements played a role, along with the tradition, and personal taste in selecting food (23, 24).

Indeed, ancient Greek and Roman authors such as Ippocrates, Dioscorides,

Pliny the Elder, and others described the use of herbs, edible and medicinal plants, or parts of them, because of their beneficial or healing properties.

About 1200 years after that time, those herbs were listed as medicinal plants in the Regimen Sanitatis Salerni, a manual of practical medicine describing the role of herbs in having a healthy life, with the human body in harmony with the entire creation.

Conclusion

There is advice on nutrition, on how to choose seasonal foods, and how to reach a proper caloric intake, while paying attention to the quality of the food we eat. These aspects may allow us to rediscover the origins of the Mediterranean diet by retracing the paths of its crops, with a focus on the benefits of this diet on kidney efficiency. Indeed, recent studies have shown that the organic Mediterranean diet reduces inflammation and endothelial dysfunction related to obesity and renal pathologies. Noteworthy, UNESCO has declared the Mediterranean diet as part of the oral and immaterial human heritage. The physician, the laboratory scientist and the ethno-botanist can now hopefully join forces in a united search for more effective diuretics. Finally, the loss of the empirical wisdom developed from human interactions with the environment over millennia is the loss of a fundamental part of our cultural heritage. Thus, Hippocrates' aphorism takes place, “Let your food be your medicine, and your medicine be your food”, while respecting cultivated nature as a gift from the gods.