Plants Civilization and Health: Lecture 1 Introduction PDF

Plants Civilization and Health Introduction Civilization refers to a complex human society, in which people live in groups of settled dwellings comprising cities.  Importance of plants to human and its role in civilization Civilization would have been impossible without pla...

Plants Civilization and Health Introduction Civilization refers to a complex human society, in which people live in groups of settled dwellings comprising cities.  Importance of plants to human and its role in civilization Civilization would have been impossible without plants. Only after human recognized importance of plant as food, fodder, shelter, clothing, etc. along with beginning of domestication of plants and animals, humans really become humans. Agriculture is one of the major reasons for what has allowed us the spare time to develop modern medicine, refrigerators, computers, and internet.  Before the advent of agriculture, men and his ancestors were dependent for food upon their activities as gatherers and hunters. The human species, known as Homo sapiens, had existed about 195,000 years ago. For most of that time, humans survived by gathering wild plants and hunting animals in their natural environment, living in caves, searching for food from dawn until dusk, chasing beasts or being chased by them, always hungry and worried when he would find his next meal. This earliest and longest period of human history was called the Palaeolithic or Old Stone Age, which began between one and two million years ago. Hunters and gatherers 99% of mankind’s existence on Earth has been as a HUNTER & GATHERER! A 19th century engraving of an Indigenous Australian encampment.  The Paleolithic or Old Stone Age lasted about 10,000 years. During this period there was no agriculture, but chipped stone tools and weapons were made. The period was succeed by the Mesolithic or Middle Stone Age, which was a period of transition when agriculture begun. It lasted for several thousand years. Last came the Neolithic or New Stone Age, where agriculture became well developed. Agriculture continued to expand, with the use of metals, up to the present day. Agriculture arose independently in different areas over several thousand years. Paleolithic Societies  How farming helped? Early Stone Age man was able to eat berries for sugars and vitamins, nuts for oils and roots which furnished starches as a carbohydrate source; he depended on meat for most of his protein. The emergence of farming resulted in a whole new way of living. Farming meant that people did not need to travel to find food. Instead, they began to live in settled communities, and grew crops or raised animals on nearby land.  They built stronger, more permanent homes and surrounded their settlements with walls to protect themselves. The transition to agriculture was a critical trigger for the development of more complex societies since it allowed people to establish permanent settlements and live together in far greater numbers than ever before.  The shift toward agriculture happened gradually over a long period of time, independently on all continents. Why this shift occurred can only be theorized, but the development of agriculture formed the basis of advanced civilization in both the Old and the New Worlds. The term "Old World" is used commonly to refer to Africa, Asia and Europe (Afro-Eurasia), and “New World is used commonly to refer North America, South America and Australia. The Old The New World World  Identification and use of technologies for progression of Agriculture An important trait to the development and spread of human societies as well as their ability to interact with their surroundings was the adoption of technological means to overcome difficulties imposed by unfriendly environments. Invention of tools, wood, skins to cover body, and fire allowed these groups to adopt a mobile existence and move into harsher ecosystems.  Throughout their travels, these groups continually effected the environment around them. Often these hunter-gatherers interfered with wild vegetation for the purpose of promoting the growth of a particular plant by sowing its seeds. They also uprooted and destroyed flora considered undesirable. These types of environmental modification were frequently aided by the use of fire.  Aside from the ability to clear large areas of land, fire was favoured because of its ability to increase nutrient cycles in the soil. As the people learned and started to cultivate crops, they also started to domesticate animals. This is the most significant single development in human history. In time, gathering, hunting and fishing lost importance in front of animal husbandry and plant cultivation. These people made food deposits and even built barns (cowsheds, storehouses).  World’s First Civilization About 10,000 years ago, nomadic hunter-gatherers in the Fertile Crescent (in the modern Middle East) cultivated wheat and became the world's first farmers. They settled down into villages, domesticating animals and other vegetables to go along with their grain.  Food surpluses allowed the villagers to specialize, and soon their arts and technologies exploded, giving rise to the WORLD'S FIRST CIVILIZATION. In the Fertile Crescent, farmers grew tall, wild grasses, including an early type of barley, and primitive varieties of wheat called emmer and einkorn. Fertile Crescent was a crescent- shaped strip of land that stretched across the Levant region (now known as Israel, Lebanon, and Syria – middle east regions ), and around the edges of the Tarus and Zagros mountains. The Fertile Crescent had regular rainfall, soil rich in nutrients making it ideal for growing grains such as emmer and einkorn, and for raising herds of grass-eating animals such as sheep and goats.  Named for its rich soils, the Fertile Crescent, often called the “cradle of civilization,”. Two rivers, the Tigris and the Euphrates, regularly flooded the region, and the Nile River also runs through part of it. Irrigation and agriculture developed here because of the fertile soil found near these rivers.  Access to water helped with farming and trade routes. Soon, its natural riches brought travelers in and out of the Fertile Crescent. This led to an exchange of culture and ideas, and advancements in the region. Development and Spread of Agriculture Farming developed first in the Fertile Crescent. Barley and wild wheat were abundant  Development and Spread of Agriculture Farming then spread to parts of Asia, Africa and Europe. Agriculture was invented separately in the Americas much later (around 5000 B.C.)  Gradual Progression in Civilization The great progress in agriculture was made by the invention of the plow. People also found natural methods of fertilizing the soil. The periodic cultivation of pod vegetables enriched the soil on nitrogen. Cattle manure use as fertilizer is known for 5,000 years. Apart from these further inventions of clothing, color, various means of transportation for trade, etc added much to the progress in civilization  Agriculture Prompted New Ideas and Techniques Storage facilities for grains and seeds Basket-making Pottery Grinding stone Agricultural needs also encouraged certain kinds of science, supporting the human desire to learn more about weather or flooding. Discovery of metal tools Neolithic Pottery Grains grinding The term "Old World" is used commonly to refer to Africa, Asia and Europe (Afro-Eurasia), and “New World is used commonly to refer North America, South America and Australia. The Old The New World World In conclusion…. Mankind has a long history of hunting and gathering. Prehistoric societies evolved away from nomadic lifestyles approximately 10,000 years ago in many locations around the world. Agriculture contributes to the development of civilization. History of the Use of Plants in Health Care Historical Records of Plant Remedies Various historical records of plant remedies provide evidence of an age-old connection between plants and human health. Pun-tsao published around 1600 is a pharmacopoeia of thousands of herbal cures attributed to China’s legendary emperor, Shen-nung, who lived over 4,500 years ago.  Herbal medicine in South Asian countries, e.g. India, Bangladesh, Nepal, Sri Lanka, and Pakistan, dates back several thousand years to the Rig-Veda - collection of sacred texts which led to the establishment of a healthcare system known as Ayurveda meaning “science of life”. Not only a system of medicine but also a way of living One useful plant identified from the Rig-Veda was Rauvolfia serpentina (snakeroot). An active ingredient in snakeroot (reserpine) is widely used in Western medicine to treat high blood pressure and schizophrenia.  Historical Records of Plant Remedies (II) The Badianus Manuscript, created in the mid-16th century, is an illustrated document containing the traditional medical knowledge of the Aztecs of Central Mexico. A 4,000 year-old Sumerian clay tablet also holds records of plant remedies for various illnesses. The 3,500 year-old Ebers papyrus of ancient Egypt contains hundreds of plant remedies. Mandrake (Mandragora officinarum) was prescribed for pain relief and garlic (Allium sativum) for heart and circulatory disorders  Greek and Roman Pioneers of Herbal Medicine Herbal medicine can be traced back to the Greek physician Hippocrates, who believed that disease had natural causes and used various herbal remedies in his treatments. Dioscorides compiled information on more than 600 species of medicinal plants in De Materia Medica Many of the herbal remedies used by the Greeks and Romans (e.g., willow bark tea) have been incorporated into modern medicine. The active principle in willows (Salix species ) is salicin, the precursor to aspirin.  GENERAL INTRODUCTION TO THE DIFFERENT TYPES OF HEALTH-RELATED PLANTS Types of Health-Related Plants Plants relating to human and animal health fall into three broad categories: Those that heal and nourish – referred to as Medicinal or Remedial Plants Those that cause harm – described as Harmful or Injurious Plants. Those that influence the central nervous system – known as Phychoactive Plants Note: It is sometimes difficult to characterize a plant as belonging to only one of these categories Medicinal/Remedial Plants Many other medicinal/remedial plants have been identified for a broad range of uses including: Treatment of tooth decay and gum disorders (African chewing sticks) Treatment of respiratory diseases, fevers, pains, etc Sources of cosmetics Sources of antibiotics and pesticides Injurious/ Harmful Plants Injurious plants cause harm to man and animals in various ways Some may cause serious illness and even death when ingested (seeds of Ricinus communis), whereas others may cause allergies such as asthma, hay fever and dermatitis (pollen, fungal spores, Okra). Few contain substances which can modify both human and animal cells leading to heritable mutations Injurious plants may also be described as poisonous and allergenic plants Brief History of the Use of Plant Poisons (I) Assassination/Murder of political opponents Roman Emperor Claudius was assassinated by his fourth wife, Agrippina, who served him poisonous mushrooms because he was about to name Britannicus (son of another wife) as heir instead of her son Nero. Amanita phalloides (Death cap mushroom) Brief History of the Use of Plant Poisons (II) Formulation of Arrow Poisons Curare is a general term for a variety of plant-derived arrow poisons used by the indigenous people of South America. Some of the sources of curare are Strychnos toxifera and Chondrodendron tomentosum (synonym: Sciadotenia toxifera). South American Indians used curare to facilitate surgical procedures because of its ability to reversibly paralyze skeletal muscles. Arrow Poisons (cont’d) In Africa, plant sources of arrow poisons include Nerium oleander, Asclepias species (milkweeds) and Strophanthus hispidus The latter is also used in medicine for its influence on circulation One good reason to study medicinal plants Which plant part and in what quantity? Strophanthus hispidus Brief History of the Use of Plant Poisons (III) As Fish Poisons Most indigenous cultures used poisonous plants to catch fish. Grinding of the appropriate plant part releases the active ingredient which is then introduced into the water. Fish poisons were normally used in stagnant ponds or slow-flowing streams and rivers Plants that have been used for fish poisoning in West Africa include Tetrapleura tetraptera (Prekese)and Balanites aegyptiaca (Desert date) both of which have medicinal properties Other Harmful Effects of Plants Abbiw (1990) lists a host of plants in Ghana that are poisonous to livestock. These include leaves of: Lantana camara Paulinia pinnata Nerium oleander Some houseplants are also poisonous, posing particular danger to children and pets e.g. Dieffenbachia sp.  Psychoactive Plants These plants, which affect the nervous system, may be sub- divided into: Stimulants: those that excite and enhance psychomotor activity; e.g. cocaine, coffee, tea Hallucinogens: those capable of inducing a dream-like state plus hallucinations; e.g. marijuana Depressants: those that reduce mental and physical performance; e.g. alcohol The Dilemma of a Plant Scientist From whose perspective does one describe a plant as harmful or useful? Fish poisons kill fish, which are eaten by man Arrow poisons were originally used for hunting; thus they kill animals that are then eaten by man Fungicides, insecticides, herbicides and all other forms of pesticides kill other living organisms except man Where do we draw the line between a useful and a harmful plant? WHO’s Definition of a Medicinal Plant “Any plant which, in one or more of its organs, contains substances that can be used for therapeutic purposes or which are precursors for the synthesis of useful drugs”. This definition covers plants which contain substances that have been scientifically proven as being therapeutic, as well as those that are regarded as medicinal but have not yet been studied scientifically.  Summary There is an inextricable link between plants civilization and health Primeval ‘man’ – in search for food – experimented with nature and made interesting discoveries Current knowledge on medicinal plants is attributed mainly to traditional systems of healing developed by empirical means and handed down through many generations Unlike modern medicine, many indigenous healing systems recognize a strong link between physical and supernatural factors in one’s state of health and well-being