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Phytochemistry: The Study of Plant-Derived Chemicals and Phytochemicals
Phytochemistry is a branch of biochemistry that involves the study of chemicals released by plants. These chemicals play an important role in plants because they help them to grow, to defend themselves, and interact with the environment.
In 2025, Researchers at Brightseed, which is a US-based company, conducted a metabolomics study to understand the effects of pasteurization on almonds.
In the study, 3 types of California almonds, Monterey, Nonpareil, and Independence, were used, which differ in shell consistency, harvest time, and kernel size. 530 phytochemicals were extracted, mostly metabolites and lipids, 17 bioactive substances, 6 of them previously not reported. These phytochemicals were β‑sitosterol, isorhamnetin, polyphenols, and flavonoids.
Phytochemicals such as β-sitosterol and isorhamnetin are essential to humans as they are related to cardiovascular health, cognitive function, and anti-inflammatory activity. Plants produce a wide variety of phytochemicals, and many of them possess vital health benefits. Although not all plants have nutritional value, they produce bioactive compounds that can be used in medicine, cosmetics, skin care, and therapies, etc
In this article, we will discuss some of the applications of phytochemicals, such as their role as immunomodulators, use in chemotherapy, and how they contribute to nutraceuticals.
What are Phytochemicals?
Phytochemicals are naturally occurring chemical compounds that are released by plants, and they play a vital role in the development and maintenance. They are also secondary metabolite and these compounds are not just essential for plant growth and development but also are beneficial to humans. Many of them have biological activities inside us, such as antioxidants, anti-inflammatories, and immune system support, contributing to our overall health and nutrition, and helping prevent diseases. The study of phytochemicals is known as phytochemistry, which emphasizes their identification, classification, and functions.
Classification of Major Phytochemical Groups
They are classified by structure and biosynthetic origin. The following are the major groups:
| Phytochemical Group | Examples | Source | Properties |
| Phenolic Compounds | Flavonoids, phenolic acids, tannins, stilbenes | Onions, apples, berries, grapes, green tea, peanuts, etc | It has antioxidant and anti-inflammatory properties |
| Terpenoids (Isoprenoids) | Carotenoids, saponins, essential oils | Carrots, tomatoes, spinach, mint, citrus fruits, eucalyptus, etc | They contribute colouration, aroma, and defence against pests |
| Alkaloids | Caffeine, morphine, quinine | Coffee, tea, opium poppy, Cinchona bark, goldenseal, etc | They are mostly toxic to herbivores but exhibit pharmacological activity in humans |
| Sterols and Phytosterols | β-sitosterol, campesterol, stigmasterol | Nuts, seeds, vegetable oils, soybeans, legumes, etc | They support cardiovascular health and modulate cholesterol levels |
| Sulfur-Containing Compounds | Allicin, glucosinolates | Garlic, onions, broccoli, cabbage, Brussels sprouts, etc | They are antimicrobial and promote detoxification |
What are the biochemical pathways involved in phytochemical synthesis?
Plants have certain biochemical pathways that result in the production of primary metabolites or phytochemicals. The following are the specialized biochemical pathways:
- The shikimate pathway produces aromatic amino acids and polyphenols
- Mevalonate and Methylerythritol phosphate pathways produces terpeniods and carotenoids
- The polyketide pathway produces tannins and flavonoids
- Amino Acid Derived Pathways produce alkaloids and sulphur-containing compounds
These pathways are strictly regulated and are often activated during an external or environmental force, such as stress, pathogen attacks, or during their development stages, indicating their ability to adapt.
What is the role of Phytochemicals in Plants and Human health?
In plants, these secondary metabolites help the plants to fight against herbivores, pathogens, and UV radiation form sun. Apart from acting as a defense mechanism, they also function as signalling molecules, helping in attracting pollinators, etc.
In humans, some of the phytochemicals are bioactive, which means they have a biological role inside us, such as acting as antioxidants, anticancer, and immunomodulatory agents. These phytochemicals support metabolism, cardiovascular, and cognitive health by interacting at molecualr level. E.g, compounds like flavonoids modulate the cell signalling pathways, plant sterols support cholesterol homeostasis, and polyphenols help to balance gut microbiota.
Phytochemistry is a branch of Biochemistry
Phytochemistry is a branch of biochemistry that deals with the study of chemicals produced by plants and the biochemical pathways that are responsible for their synthesis. Phytochemistry involves chemical characterization and metabolic profiling, which helps researchers to identify and quantify plant metabolites under different conditions. They use advanced analytical techniques such as LCMS, GC-MS, HPLC, and NMR, etc to analyze the chemical compositions and contribute to the development of medicine and nutraceutical research.
How Phytochemistry helps in Nutraceutical Development?
Phytochemistry acts as the scientific pillar for nutraceutical development by identifying and characterizing the bioactive compounds derived from plants that have health-promoting properties. Biochemical analysis helps select the plant’s bioactive compounds that can be standardized and optimized for the development of safe and effective nutraceutical products. The following are some recent developments that support the contribution of phytochemistry in nutraceutical development.
- Advanced nanotechnologies such as encapsulations of nanoparticles and liposomes can improve the bioavailability, stability of bioactive compound and the active delivery of the target.
- It has also raised the development of personalized medicines because by understanding the biochemical interactions of phytochemicals, we can tailor formulations that would target a specific health issue.
- It has helped in the development of products that can target gut microbiota by identifying the bioactive compounds that have beneficial effects on our gut microbiota.
These are some examples of the growing importance of phytochemistry in the innovation of nutraceutical products and research and development.
Role of Phytochemistry in Chemotherapy
Researchers have claimed that bioactive compounds have anticancer properties, such as flavonoids, alkaloids, terpenoids, and polyphenols. Biochemical mechanisms such as induction of apoptosis, inhibition of tumor cell proliferation, and modulation of oxidative stress and influence cancer signaling pathways. There are a few phytochemicals that can enhance the effectiveness of traditional drugs in chemotherapy when they are used alongside them.
Despite optimistic lab results, the clinical application of anticancer phytochemicals is challenging, such as limited absorption, possible interactions with chemotherapy drugs, and the need for standard dosage and carefully designed clinical trials.
Role as immunomodulators
Phytochemicals can also influence the function of the immune system, either by stimulating or suppressing the immune response to maintain a homeostatic balance. These phytochemicals are flavonoids, polyphenols, terpenoids, alkaloids, and polysaccharides. These bioactive compounds are generally derived from medicinal plants and herbs.
At the molecular level, phytochemicals that show immunomodulatory effects regulate the immune system by modulating the production of cytokines, antioxidant pathways, and immune cell responses.
These properties make the bioactive compounds a valuable asset in the treatment of inflammation and chronic illnesses such as autoimmune disorders, metabolic syndrome, and inflammatory conditions. Their natural source and multiple therapeutic effects highlight the expanding role of phytochemistry in the development of medicines and nutraceuticals, empahsizing on the immune system.
The Future of Phytochemistry
Advanced analytical technologies in biochemistry, such as metabolomics, high-resolution mass spectrometry, and artificial intelligence, are revolutionizing phytochemical research. These tools allow for the identification, quantification, and precise functional understanding of bioactive compounds produced by plants. At the same time, the rise of personalized nutrition and plant-based therapeutics is driving the development of targeted nutraceuticals designed to individual needs, such as genetics and gut microbiota profiles.
However, the rapid expansion of this field also presents challenges, such as in regulatory and standardization, including the need for consistent quality control, safety assessment, and scientifically proven health claims to maintain consumer trust and clinical relevance.
Phytochemistry is the study of chemical compounds produced by plants, focusing on their structure, biosynthesis, and biological functions. As a specialized branch of biochemistry, it connects plant science with human health by revealing how phytochemicals influence physiological processes. The growing recognition of phytochemicals in nutrition, medicine, and nutraceutical development highlights their importance in supporting immune function, disease management, and overall well-being. With continued advances in biochemical analysis and therapeutic applications, phytochemistry is expected to play an increasingly vital role in the development of plant-based nutraceuticals and health solutions. Be a part of this journey and arm yourself with the skills that recruiters are looking for with our Chromatographic Techniques.
