1.1 HISTORICAL PERSPECTIVE
Every era had seen successive development of use of natural products (NPs) to benefit societies and is passed on to another with improvement in its effectiveness through generations. Approximately, 5000 years ago, medicinal plants’ were the first candidates to be used and the early evidences have been found on a Sumerian clay slab from Nagpur. The inscriptions mentioned about 250 various plants and 12 recipes for drug preparation from plants like poppy, henbane, and mandrake (Kelly, 2009). The Chinese Emperor Shen Nung was the first to have documented a book called Pen T’Sao, circa 2500 BC, which defines 365 drugs from dried parts of medicinal plants including Rhei rhisoma, Theae folium, camphor, the great yellow gentian, podophyllum, ginseng, cinnamon bark, jimson weed, and ephedra (Wiart, 2006; Petrovska, 2012). Likewise, ancient Indian Vedas including the Charaka and Samhitas, which dates back to 1000 BC, recognized 341 medicinal plants and 516 drugs of the Indian Ayurvedic system (Dev, 1999; Kapoor, 2017). Many plant extracts of pomegranate, castor oil plant, senna, aloe, onion, fig, willow, coriander, juniper, common centaury, and so on have been mentioned along with garlic, a collection of 700 plant species used for therapeutics in Ebers Papyrus, circa 1550 BC (Tucakov, 1964). Talmud, the holy book of Jews, refers to the use of aromatic plants as incense or myrtle (Dimitrova, 1999). Homer’s epics, The Iliad and The Odysseys (ca. 800 BC), also mentions use of 63 plant species as pharmacotherapeutic agents (Toplak Galle, 2005). Greek scholars such as Herodotus and Pythagoras (500 BC) mentioned about the therapeutic values of garlic, castor oil, mustard, and cabbage. Hippocrates (459–370 BC) categorized nearly 300 medicinal plants conferring to their functional effects. Common centaury (Centaurium umbellatum Gilib.) and wormwood were administered against fever; garlic was used against intestine parasites; opium, deadly nightshade, mandrake, and henbane were consumed as narcotics; haselwort and fragrant hellebore were considered emetics; oak and pomegranate as astringents; while sea onion, parsley, celery, garlic, and asparagus were used as diuretics (Bojadzievski, 1992; Gorunovic and Lukic, 2001). Theophrast (371–287 BC), also known as the “Father of Botany,” was given due credit for cataloging more than 500 medicinal plants (Bazala, 1943; Nikolovski, 1995). The era from 23 to 79 AD was distinguished by two important contemporaries in pharmacy, Dioscorides (77 AD) and Pliny the Elder (23–79 AD). Both were credited to have traveled and documented more than 1000 medicinal plants (Tucakov, 1990; Toplak Galle, 2005). Galen (131–200 AD), a Roman physician, familiarized numerous new plants as remedial drugs which Dioscorides had not described, for example, Uvae ursi folium is used as an uroantiseptic and a mild diuretic. Some plants were used as insecticides, namely, Veratrum album, Alium sativum, Urtica dioica, Cucumis sativus, Achilea millefolium, Lavandula officinalis, Artemisia maritime L., and Sambuci flos (Bojadzievski, 1992) and by the seventh century, Ocimum basilicum, Rosmarinus officinalis, Iris germanica, and Mentha viridis were being used in cosmetics.
In the middle ages, particularly between 16th and 18th centuries, monasteries and churches took over the skills of healing and cultivation of medicinal plants, thereby; preparation of drugs were mostly restricted to a few handful of plants like sage, mint, anise, savory, tansy, and Greek seed (Tucakov, 1990). The silk route trade relations introduced the Arabs to numerous new plants in pharmacotherapy, mostly from India, and they used deadly nightshade, aloe, coffee, henbane, ginger, saffron, strychnos, pepper, curcuma, rheum, cinnamon, senna, and so forth. The European physicians consulted the Arab works, for instance; De Re Medica by John Mesue (850 AD), Canon Medicinae by Avicenna (980–1037), and Liber Magnae Collectionis Simplicum Alimentorum Et Medicamentorum by Ibn Baitar (1197–1248), in which over 1000 medicinal plants were documented (Tucakov, 1965). Though traditional people still used medicinal plants primarily as simple forms; the demand for compound drugs was increasing. During these period, simple pharmaceutical preparations by infusions, decoctions, and macerations using medicinal plants was also introduced and the compound drugs mainly contained of medicinal plants, rare animals, and minerals (Bojadzievski, 1992; Toplak Galle, 2005). Meanwhile, the great expedition by Marco Polo (1254–1324) and by Vasco dè Gama (1498) helped Europe develop rich cultivation of new medicinal plants like Cinchona, Cacao, Ipecacuanha, Ratanhia, Jalapa, Podophylum, Lobelia, Vanilla, Senega, tobacco, Mate, red pepper, as well as quinine bark Cinchona succirubra.
Early 19th century was marked by the beginning of scientific pharmacy. The earliest report of chemistry of NP was heralded by the work of Friedrich Wilhelm. With improved knowledge of chemistry and pharmacy; discovery, characterization, and isolation of lead compounds from the medicinal plants were available. Alkaloids were isolated from poppy (1806), ipecacuanha (1817), strychnos (1817), quinine (1820), pomegranate (1878), and other plants. Adam Serturner (1803), a German pharmacist, was known to sequester morphine from opium poppy (Papaver somniferum) (Huxtable and Schwarz, 2001). Glycosides, tannins, saponosides, etheric oils, vitamins, hormones, and so on, were also characterized and substantiated (Dervendzi, 1992).
An impediment was observed in the use of medicinal plants as drugs in the late 19th and early 20th centuries, owing to shortcomings incurred during the process of drying of medicinal plants. Moreover, synthetic preparations of alkaloids and glycosides were being used in therapeutics. Much effort was devoted to study the cultivation of medicinal plants which ascertained numerous forgotten plants like Aconitum, Hyosciamus, Punica granatum, Stramonium, Filix mas, Secale cornutum, Opium, Colchicum, Styrax, Ricinus, with more stabilization methods being proposed, especi...
