The first commercial pure natural product introduced for therapeutic use as pure compound was morphine from opium poppy plant marketed by Merck in 1826, and is till date the strongest analgesic for extreme surgical and burn related pain. First semi-synthetic pure drug aspirin, based on a natural product salicin isolated from Salix alba, was introduced by Bayer in 1899, and was a master stroke in inflammation and associated pain. Isolation of early drugs such as cocaine, codeine, digitoxin, quinine and pilocarpine, took place, of which some are still in use. Recent drugs include Paclitaxel from Taxusbrevifolia for lung, ovarian and breast cancer, Artemisinin from traditional Chinese plant Artemisia annua to combat multidrug resistant malaria, Silymarin extracted from the seeds of Silybum marianum for the treatment of liver diseases.
Thus medicinal herbs and pharmacognosy science provide unlimited opportunities for new drug leads because of the unmatched availability of chemical diversity present within each plant. Due to an increasing demand for chemical diversity in screening programmes seeking therapeutic drugs from natural products, interest particularly in edible plants has grown throughout the world.
Natural product or herbal product industry
The natural products or the so called herbal industry, based on medicinal plants, is now a multibillion industry, using either crude medicinal plant parts, standardised powders, extracts, typical formulations of these powders or extracts as tablet or syrups or other dosage form, or as novel delivery systems with greater efficacy in the biological systems because of better absorption.
The industry includes the following products:
- Therapeutics
- Neutraceuticals
- Foods
- Crude drugs
- Standardised extracts/fractions
- Traditional formulations: Ayurvedic, Chinese medicines
- Phytopharmaceuticals
The global herbal medicine market is expected to witness a double-digit CAGR in the forthcoming period. The demand for herbal medicines is gaining positive attraction due to patient demand for herbal therapy. The key players in the herbal medicine market include Tsumura, Schwabe, Madaus, Weleda, Blackmores, Arkopharma, SIDO MUNCUL, Arizona Natural, Dabur, Herbal Africa, Nature’s Answer, Bio-Botanica, Potter’s, Zand, Nature Herbs, Imperial Ginseng, Yunnan Baiyao, Tongrentang, TASLY, Zhongxin, and others. Companies like Dabur, Himalaya, Zandu, Charak Pharma, Baidyanath have launched authentic products based on ayurvedic concepts and providing effective options to practitioners for healthcare management. Various multinational companies have modified their product portfolio strategies including phytopharmaceuticals as an important constituent of the portfolio along with synthetic and biological drugs and their formulations.
Other emerging areas in pharmacognosy
Phytoconstituents as Bioenhancers
Many phytoconstituents from medicinal plants have been found to increase the activity of another drug when given in combination with another drug. This may be done by various mechanisms of
action of bioenhancers, which may be
- Promoting the absorption of the drugs into the blood,
- Inhibiting or reducing the rate of biotransformation or breakdown of drugs in the liver or intestines,
- Modifying the immune system in such a way that the overall requirement of the drug is reduced substantially, increasing the penetration and efficacy of antimicrobials, into the pathogens even where they become persistors within the macrophages such as for mycobacterium tuberculosis and such others, modifying the signaling process between host and pathogen ensuring increased accessibility of the drugs to the pathogens,
- Enhancing the binding of the drug with target sites such as receptors, proteins, promoting the transport of nutrients and the drugs across the blood brain barrier, which could be of immense help in the control of diseases like cerebral infections, epilepsy, and other CNS problems.
New application of old molecules
There is growing evidence that the old molecules can be used for new applications through better understanding of molecular biology and clinical observations. For instance, the alkaloid, forskolin from Coleus forskohlii and phytochemicals from Stephaniaglabra, are now being rediscovered as adenylatecyclase and nitric oxide activators, which may help in preventing conditions including obesity and atherosclerosis.
Development and commercialisation of Novel Drug
Delivery Systems with increased bioavailability and therapeutic efficacy
In phytopharmaceutical development, formulation of nano delivery systems including polymeric nanoparticles, nanocapsules, liposomes, phytosomes, ethosomes, solid lipid nanoparticles and nanoemulsions offer advantages of increased solubility, availability, stability, decreased degradation, decreased toxicity, better macrophage distribution and others.
Regulatory filing of phytopharmaceuticals in different international markets
Depending on the country, a herbal product has to be approved for market authorisation after submitting regulatory compliance to agencies like US FDA, MHRA UK, MOH Dubai, TGA Australia, WHO etc with proof of identification, purity, phytomarker content for raw material and finished product absence of steroids and psychotropics, and bioactivity, and stability test certification, based on morphological, microscopical, physical, microbiological, chemical, safety and toxicity tests.
Thus, pharmacognosy as a branch needs to be looked up as a vast area and is yet to be tapped into its full potential. A synergy between various academic, government and private research institutes can lead to development and commercialisation of useful molecules and products for cost effective therapeutic management with reduced side effects.
u.sharma@expressindia.com