Molecular study and in-depth transcriptome analysis of Phyllanthus amarus leaves identifying lignans and other secondary metabolites biosynthetic pathway gene/s

Healing with plants of medicinal significance is as old as mankind itself. The awareness of usage of medicinal plants by human beings for the treatment of diverse ailments, is a result of thousands of years of struggles, since, by trial and error, man distinguished between the beneficial and poisonous plants. Ample evidence from various sources - be it written documents, preserved monuments, and even original plant medicines supporting the connection between man and his search for drugs innature dates from the far past. Be it the Indian Holy Books like the Vedas dating around 5000 B.C., or the Chinese book “Pen T’Sao,” written by Emperor Shen Nung in 2500 B.C. describing 365 drugs derived from various dried parts of medicinal plants - various such historical sources relevant for the study of medicinal plants’ use are present. The oldest written evidence of the use of medicinal plants for preparation of drugs has been found on a Sumerian clay slab from Nagpur, approximately 5000 years old (Kelly, 2009). The Ebers Papyrus written in 1550 B.C. refers to 700 plant species and drugs used for therapy such as pomegranate, castorbean, aloe, senna, garlic, onion, fig, willow, coriander, juniper, common centaury, etc. Homer's epics - The Iliad and The Odysseys created in 800 B.C. refer to 63 plant species from the Minoan, Mycenaean, and Egyptian Assyrian pharmacotherapy. Herodotus (500 B.C.) referred to castor oil plant, Orpheus to the fragrant hellebore and garlic, and Pythagoras to the sea onion (Scilla maritima), mustard, and cabbage. The works of Hippocrates (459 B.C. - 370 B.C.) contain about 300 medicinal plants classified by physiological action. Theophrast (371 B.C. - 287 B.C.) gained the epithet of “the father of botany” for his great merits for the classification and description of medicinal plants. He generated a classification of more than 500 medicinal plants known at the time in his books “De Causis Plantarium”— Plant Etiology and “De Historia Plantarium”—Plant History. Celsus (25 B.C. - 50 A.D.), the renowned medical writer quoted approximately 250 medicinal plants such as aloe, henbane, flax, poppy, pepper, cinnamon, the star gentian, cardamom, false hellebore, etc. in his work “De re medica”. In ancient history, the most prominent writer on plant drugs was Dioscorides, “the father of pharmacognosy” who wrote the work “De Materia Medica”. This classical work of ancient history offers plenty of data on the medicinal plants constituting the basic materia medica until the late Middle Ages and the Renaissance. Pliny the Elder (23A.D. - 79 A.D.), a contemporary of Dioscorides, who travelled throughout Germanyand Spain, wrote about approximately 1000 medicinal plants in his book “Historia naturalis.