Plant-Based Drugs Quiz

Plant-Based Drugs

• Approximately 70,000 plant species have been screened for medicinal properties.
• Many antitumor drugs (e.g., paclitaxel, camptothecin) are plant-derived.
• About 8 out of 10 drugs for infections, cardiovascular disease, cancer, or immunosuppression are plant-derived or derivatives.
• Only about 1 in 10,000 screened compounds are proven safe and effective.
• Many drug leads fail in late-stage clinical trials.
• Plant-based chemicals are often considered safer and more effective than synthetic alternatives.

Plant-Based Drug Types

• Polysaccharides: Have immunomodulatory/immunostimulatory effects (e.g., Ganoderma lucidum, Cordyceps sinensis, Açaí fruit).
• Flavonoids: Found in most plants, with diverse bioactive properties. Have a heterocyclic ring structure (aromatic and benzopyran rings). Examples include flavones, isoflavones, flavonols, flavonones, and xanthones.
• Proteins: From some herbs used as natural protein supplements for convalescents.
• Alkaloids: Found in various plants and have diverse applications.
  • Morphine and aspirin are derived from natural sources (opium poppy and willow bark, respectively).
  • Artemisinin (from Artemisia annua), used for multidrug-resistant malaria; silymarin (from Silybum marianum) for liver disease; galantamine (from Galanthus nivalis) for Alzheimer's.
  • Apomorphine (semi-synthetic morphine derivative) for Parkinson's, Tiotropium (atropine derivative) for COPD;
  • Cannabis sativa yields dronabinol and cannabidiol for pain relief; Capsicum annuum yields capsaicin for pain relief.
  • Nitisinone is a derivative of Leptospermone (from Callistemon citrinus), used to treat antityrosinaemia; -Alkaloids are finding reapplication as nitric oxide activators for obesity and atherosclerosis prevention.
• Other compounds: Bicyclol (synthetic derivative of a compound from Schisandra chinensis) for hepatitis B treatment. Schisandra chinensis fruit contains schisandrin C and compounds with anti-steatotic effects. Curcumin (from turmeric) has multiple molecular targets with various bioactivities (anticancer, antiviral, antiarthritic, etc.).

Traditional Herbal Medicine (THM)

• THM is used extensively for primary healthcare in China and India.
• THM data, gained over decades, can contribute to more successful plant-derived drug discovery.
• Indian THM is heavily documented in Ayurveda, providing information on various compounds such as alkaloids from Rauwolfia serpentina, psoralens, alkaloids from Holarrhena antidysenterica, guggulsterons, bacosides from Bacopa monnieria, piperidines, curcumins, lignans, glycosides, polyphenols, and steroidal lactones.
• Berberine (from goldthread; Coptis chinensis) has potent antibiotic and anti-inflammatory properties and is used for various conditions.
• Modern technology is being used for quality control and standardization of THM products.
• Over 100 billion USD is being spent globally on herbal drug discovery.
• China has ~1,500 patented THM products; ~8,400 in clinical trials, and ~13,000 herbs used.

Plant Harvesting Concerns

• Overharvesting of medicinal plants (e.g., Cypripedium pubescens, Trillium erectum, Aletris farinose) threatens several species.
• Up to 70% of endangered plants in China are medicinal.
• Herb farming and agrotechnology are important for sustainability.

Drug Discovery Challenges

• Single-target approaches fail to account for complex human physiology and the multiple factors affecting diseases.
• Multi-target effects of some compounds can be beneficial or dangerous.
• The ADMET (absorption, distribution, metabolism, excretion, and toxicity) approach is critical to evaluating any plant-derived compound for drug efficacy.

Future Directions

• Modern technology aids quality control and standardization of plant-derived drugs.
• Hybrid molecules linking different drug molecules could lead to novel treatments.
• Research is attempting to overcome the bioavailability issues of some plant-derived compounds.
• Plant-based and synthetic drugs are being brought under the same regulatory umbrella.
• Complementary alternative medicine (CAMTs) are gaining recognition for the use of plant-derived drugs.