The science behind 20 secondary metabolites

Plants are remarkable factories that produce thousands of different compounds. These compounds, known as secondary metabolites, have astonishing characteristics, which is why they have been used for a variety of reasons since ancient times. Almost every product we utilize in our everyday lives today is based on one or more secondary metabolites. Can you, on the other hand, think of the name of a secondary metabolite? Caffeine or morphine are probably the ones you remember most. While they are well-known, they represent only two of the approximately 500,000 compounds known today.

So, here we give you information on 20 commonly used plant secondary metabolites in pharmaceutical and cosmetic industries, with their functions and origin:

1. Papaverine

It is an alkaloid obtained from Papaver somniferum that can also be produced synthetically. Papaverine is famous in the pharmaceutical industry as a direct-acting smooth muscle relaxant and vasodilator used in the treatment of hypertension. Also, it exhibits antiviral activity against viruses such as HIV, and does not report narcotic effects like other compounds produced by the same plant species.

2. Quinine

Have you ever had a leg cramp at night? Well, quinine is an alkaloid useful for treating it! This compound is extracted from Cinchona bark and is mainly used as an antimalarial drug since 1633. It also acts as a mild antipyretic (reduce fever), analgesic, hair conditioning, and flavoring agent.

3. Kaempferol

Obtained from diverse plants such as green tea and broccoli, this flavonoid is often used as an antioxidant and anti-inflammatory in cosmetic formulations. Also, it can be used as a dye, emollient, softener, and conditioner. In recent studies, it was suggested that it can be a potential inhibitor of Covid-19 virus.

4. Quercetin

This compound is classified as a flavonoid and can be obtained from onion, citrus fruits, among others. If you use skincare and make-up products, quercetin is present in your life. In the cosmetic industry, it is widely used as an antioxidant and UV protector. In the food industry, quercetin is used as a dietary supplement.

5. Lutein

It is commonly obtained from green plants such as spinach. Lutein uses are mainly associated with the food industry, but it can also be used in the cosmetic industry as a skin-conditioning agent.

6. Codeine

This compound, as well as papaverine, is extracted from the poppy plant (Papaver somniferum). Codeine is a weak narcotic analgesic used against mild to moderate pain. It is also used as a sedative, cough suppressant, and antidiarrheal agent.

7. Atropine

Have you ever heard about organophosphate pesticides? These chemicals are toxic to human health and were used in agricultural practices decades ago. Atropine is an agent used to treat poisoning by organophosphates and other drugs. It is extracted from Atropa belladonna, and it is also used as an anti-arrhythmia drug.  

8. Capsaicin

Do you know what makes chili peppers hot? Capsaicin is the answer! This compound found in chili peppers does more than just adding the spice. It is a topical analgesic agent used for the symptomatic relief of neuropathic pain. Also, in the cosmetic industry, it is used as a skin-conditioning agent, and as a repellent in agriculture.

9. Berberine

This alkaloid is found in Hydrastis canadensis and a variety of other plant species. It is poisonous, yet it is also used to treat a variety of illnesses, including diabetes, obesity, and Helicobacter pylori infection, due to its putative antioxidant and antibacterial effects.

10. Piperine

This alkaloid, extracted from Piper nigrum and other plant species, is mostly used in the cosmetic sector, particularly in fragrances as a scent. Some researches have shown that it may have anti-disease properties, although this has yet to be verified.

11. Anatabine

Nicotine is an alkaloid present in cigarettes that makes them addictive. However, there is an alkaloid that has nicotine mimetic activities without addictive properties. This compound found in plants of the Solanaceae family (which includes tobacco and tomato) is anatabine. It can be used in treating nicotine withdrawal symptoms and as an anti-inflammatory agent.

12. Betulin

It is a natural compound present in Betula papyrifera with applications in the cosmetic industry due to its anti-inflammatory and antimicrobial properties. Besides, it is used as an analgesic and antineoplastic (chemotherapy) drug.

13. Papain

It's strange to believe that papaya may be used for things other than eating. Papain, a metabolite produced by two papaya species (Carica papaya and Vasconcellea cundinamarcensis) has been used for the treatment of inflammation and pain by topical administration. Also, it is said to have tooth-whitening properties and is useful for scar treatment.

14. Zeaxanthin

Almost all yellow vegetables and plants owe their color to zeaxanthin. This pigment is synthesized by Rosa canina, paprika, corn and saffron plants. Zeaxanthin is available as a dietary supplement for eye health benefits, and an anti-inflammatory agent in the cosmetic industry.

15. Curcumin

It is an active component in Curcuma longa that exhibits anti-inflammatory, hypoglycemic, antioxidant, wound-healing, and antimicrobial activities. Curcumin is being investigated for the treatment of various clinical conditions, especially as an antineoplastic agent against different kinds of cancer. In cosmetics, it is used as a colorant.

16. Allicin

This compound isolated from Allium sativum has anti-fungal and anti-microbial properties. It is mainly used against human pathogens such as Pseudomonas and Streptococcus.

17. Camptothecin

From the Chinese tree Camptotheca acuminate, this secondary metabolite shows anti-cancer activity. As a result, it has been widely used as a therapeutic drug against various forms of cancer to the point of reaching an annual demand of over US$2 billion.

18. Geraniol

Geraniol has a broad spectrum of pharmacological activities including antimicrobial, anti-inflammatory, antioxidant, anti-cancer, and neuroprotective. It is mainly found in essential oils of rose and citronella.

19. Galantamine

Alzheimer’s disease is a type of dementia that is progressive and affects memory. Although it does not have a cure, there are a few medicines that can help improve the symptoms. One of them is galantamine! It is found in Galanthus woronowii and was approved by FDA in 2001 for Alzheimer’s treatment.

20. Essential oils

Whether from true lavender (Lavandula officinalis), tea tree (Melaleuca alternifolia), cinnamon (Cinnamomum zeylanicum), and others, essentials oils are an important ingredient in cosmetic formulations because they have diverse biological activities from analgesic, antiseptic to stimulatory and anti-inflammatory.

We hope you find this article interesting and in case you want to know how to produce any of these compounds, you can read the article “Techniques for Secondary Metabolites Production”.

Keep an eye on this space for additional intriguing articles on many facets of plant science.

By Valeria Franco Franklin | 30-05-2022


  • Balandrin, M. F., & Klocke, J. A. (1988). Medicinal, Aromatic, and Industrial Materials from Plants. Medicinal and Aromatic Plants I, 3–36. doi:10.1007/978-3-642-73026-9_1 
  • Faccio G. (2020). Plant Complexity and Cosmetic Innovation. iScience, 23(8): 101358.
  • Gorlenko, C. L., Kiselev, H. Y., Budanova, E. V., Zamyatnin, A. A. Jr., & Ikryannikova, L. N. (2020). Plant Secondary Metabolites in the Battle of Drugs and Drug-Resistant Bacteria: New Heroes or Worse Clones of Antibiotics? Antibiotics (Basel), 9(4): 170. doi: 10.3390/antibiotics9040170.
  • Isah, T., Umar, S., Mujib, A., Sharma, M. P., Rajasekharan, P. E., Zafar, N., & Frukh, A. (2017). Secondary metabolism of pharmaceuticals in the plant in vitro cultures: strategies, approaches, and limitations to achieving higher yield. Plant Cell, Tissue and Organ Culture (PCTOC), 132(2), 239–265. doi:10.1007/s11240-017-1332-2 
  • Kim, S., Chen, J., Cheng, T., Gindulyte, A., He, J., He, S., Li, Q., Shoemaker, B. A., Thiessen, P. A., Yu, B., Zaslavsky, L., Zhang, J., & Bolton, E. E. (2019). PubChem in 2021: new data content and improved web interfaces. Nucleic Acids Res49(D1): D1388–D1395.
  • Twaij, B. M., & Hasan, M. N. (2022). Bioactive Secondary Metabolites from Plant Sources: Types, Synthesis, and Their Therapeutic Uses. Int. J. Plant Biol, 13: 4–14. https://