Phytochemical investigation refers to the systematic study of chemical compounds present in medicinal plants. It involves extraction, isolation, identification and characterization of bioactive constituents such as alkaloids, glycosides, tannins, flavonoids, terpenoids and others. This process helps determine the therapeutic value, purity, safety and quality of crude drugs.
Objectives of Phytochemical Investigation
- To identify the chemical constituents responsible for therapeutic effects
- To detect adulteration or contamination in crude drugs
- To standardize herbal formulations
- To discover new bioactive compounds for drug development
- To ensure safety, quality and efficacy of herbal medicines
Steps Involved in Phytochemical Investigation
1. Collection and Authentication of Plant Material
Medicinal plants must be collected from reliable sources and authenticated botanically to ensure correct identity. This prevents errors and adulteration.
2. Drying and Powdering
The plant material is shade dried to preserve active constituents and then powdered for extraction.
3. Extraction
Extraction is the process of removing active chemicals from the plant using suitable solvents.
Common extraction methods include:
- Maceration
- Percolation
- Soxhlet extraction
- Steam distillation
- Ultrasonic and microwave-assisted extraction
4. Preliminary Phytochemical Screening
This involves simple chemical tests to detect major groups of phytochemicals present in the extract.
Examples:
- Dragendorff’s test for alkaloids
- Bornträger’s test for glycosides
- Ferric chloride test for tannins
- Shinoda test for flavonoids
- Salkowski test for terpenoids
5. Isolation of Active Constituents
After screening, individual compounds are isolated using advanced separation techniques such as:
- Column chromatography
- Thin Layer Chromatography (TLC)
- High Performance Liquid Chromatography (HPLC)
- Gas Chromatography (GC)
- Preparative chromatography
6. Purification
The isolated compounds are purified to remove impurities. Repeated crystallization or advanced chromatographic techniques are used for purification.
7. Characterization and Identification
Purified compounds are identified using modern spectroscopic techniques:
- UV-Visible Spectroscopy
- Infrared Spectroscopy (IR)
- Nuclear Magnetic Resonance (NMR)
- Mass Spectrometry (MS)
These techniques help determine the structure, molecular weight and functional groups of the compounds.
Importance of Phytochemical Investigation
- Ensures the authenticity and purity of medicinal plants
- Prevents adulteration in crude drugs
- Helps understand pharmacological actions
- Useful in developing standardized herbal formulations
- Supports drug discovery and development from natural sources
- Ensures quality control for herbal medicines used globally
Applications of Phytochemical Investigation
- Standardization of Ayurvedic and herbal products
- Quality assessment of crude drugs in the pharmaceutical industry
- Identification of new therapeutic molecules
- Supporting research in pharmacognosy, phytochemistry and natural product chemistry
- Developing safe and effective nutraceuticals and cosmetics
