Plant Extracts - all you need to know


We all know how important it is to eat plenty of plant foods in the form of vegetables and fruits. Plants not only provide vitamins and minerals, but also a wealth of ‘phytonutrients’ (plant compounds) that can support our health and keep our body in balance. For thousands of years, traditional cultures have used extracts of plants and herbs as natural remedies, to maintain health and stay free from disease.

Types of plant extracts

Plant extracts can include herbs and herbal medicines. They can also include extracts not classified as herbs, such as grapefruit seed extract, elderberry extract, garlic, or spices such as cinnamon, turmeric or ginger.

Herbal medicines

Substances classed as ‘herbal medicines’ in the UK have to have a traditional herbal registration (THR) to be sold direct to the public. The process of gaining a traditional herbal registration means that the quality, safety, and traditional use of the herb and the product itself are independently evaluated and verified. It also means that the manufacturer/brand is able to show on the label the traditional use of the product and how it can help us for specific health conditions – for example, some Echinacea products state on the label “To relieve the symptoms of the common cold and influenza type infections based on traditional use only.”

Some other herbs and herbal products are classified as ‘food supplements’ rather than herbal medicines. They don’t have to go through this process to be sold, and cannot be labelled as being helpful for a particular condition. More on these in the next section.

Here are some examples of herbs that can be found as ‘herbal medicines’ with a THR. You can find out what they can be helpful for by looking the individual labels or product descriptions.

  • Echinacea
  • St John’s wort
  • Milk thistle
  • Arnica (in topical form)
  • Valerian
  • Devil’s claw
  • Black cohosh
  • Agnus castus
  • Feverfew
  • Pelargonium

Herbs as food supplements

As mentioned above, some herbal products can be sold as ‘food supplements’ and so do not have to go through the process of traditional herbal registration. Here are some examples, and some of the potential health benefits they have been researched for.


Examples of research/potential benefits


Memory and cognition (thinking, reasoning etc.) [1], circulation [2].

Siberian ginseng (Eleutherococcus)

Athletic performance/endurance [3], stress and fatigue [4].


Anti-parasitic, anti-bacterial and anti-fungal properties [5,6,7].

Olive leaf

Anti-viral and anti-bacterial properties [8,9], supporting healthy blood pressure [10,11].

Saw palmetto

Relieving symptoms of benign prostatic hyperplasia (prostate enlargement) [12] and male pattern hair loss [13].


Reducing anxiety [14], supporting energy, balancing the immune system [15].

Dandelion leaf

Diuretic effects [16].


Reducing anxiety, sedative effects and supporting sleep [17,18].

Artichoke leaf

Supporting digestion, e.g. reducing indigestion symptoms [19] and IBS symptoms [20]; supporting healthy cholesterol levels [21].


Menopausal symptoms (especially hot flushes) [22], memory and cognition [23].


To make things more confusing, some companies have gone through the process of obtaining a traditional herbal registration for their version of these herbal products, and this means they are able to advertise on the label how the product can help us. One example is A Vogel’s Ginkgoforce, which can state on the label “To relieve the symptoms of Raynaud’s syndrome and tinnitus, based on traditional use only.”

Non-herbal plant extracts

There are also many plant extracts that are not herbs at all. Here are just a few of them, again with some of the potential health benefits they have been researched for.

Plant extract

Examples of research/potential benefits


Reducing nausea [24] and other digestive disturbances [25], relieving pain and inflammation [26].


Anti-bacterial, anti-parasitic, anti-fungal and anti-viral activity [27], and reducing blood ‘stickiness’ to support cardiovascular health [28].


Anti-inflammatory, anti-bacterial and anti-parasitic effects [29], protecting against neurodegenerative conditions (e.g. Alzheimer’s) [30].

Pycnogenol® (pine bark extract)

Antioxidant and anti-inflammatory properties [31], supporting veins and capillaries [32].

Grapefruit seed extract

Anti-bacterial and also anti-fungal, anti-parasitic, and anti-viral activity [33].


Anti-inflammatory and pain-relieving effects in osteoarthritis [34,35].


Helping to prevent recurrent urinary tract infections [36].


Anti-viral effects, especially against influenza viruses [37].



If you are taking any medications or have any medical condition, please consult your healthcare practitioner before taking herbal medicines or other plant extracts. This is perhaps even more important with herbs and herbal medicines than with other supplements, as interactions with medication are common.

Regarding safety of long-term use, this is very dependent on the individual herb or plant extract – again, it is best to seek professional advice on this matter.



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  2. Boelsma E et al. Evidence of the regulatory effect of Ginkgo biloba extract on skin blood flow and study of its effects on urinary metabolites in healthy humans. Planta Med. 2004 Nov;70(11):1052-7.
  3. Kuo J et al. The effect of eight weeks of supplementation with Eleutherococcus senticosus on endurance capacity and metabolism in human. Chin J Physiol. 2010 Apr 30;53(2):105-11.
  4. Deyama T, Nishibe S, Nakazawa Y. Constituents and pharmacological effects of Eucommia and Siberian ginseng. Acta Pharmacol Sin. 2001 Dec;22(12):1057-70.
  5. Dorman HJ, Deans SG. Antimicrobial agents from plants: antibacterial activity of plant volatile oils. J Appl Microbiol. 2000 Feb;88(2):308-16.
  6. Force M, Sparks WS, Ronzio RA. Inhibition of enteric parasites by emulsified oil of oregano in vivo. Phytother Res. 2000 May;14(3):213-4.
  7. Soylu S et al. Antifungal effects of essential oils from oregano and fennel on Sclerotinia sclerotiorum. J Appl Microbiol. 2007 Oct;103(4):1021-30.
  8. Micol V et al. The olive leaf extract exhibits antiviral activity against viral haemorrhagic septicaemia rhabdovirus (VHSV). Antiviral Res. 2005 Jun;66(2-3):129-36. Epub 2005 Apr 18.
  9. Aziz NH et al. Comparative antibacterial and antifungal effects of some phenolic compounds. Microbios. 1998;93(374):43-54.
  10. Cherif S et al. A clinical trial of a titrated Olea extract in the treatment of essential arterial hypertension. J Pharm Belg. 1996 Mar-Apr;51(2):69-71.
  11. Khayyal MT et al. Blood pressure lowering effect of an olive leaf extract (Olea europaea) in L-NAME induced hypertension in rats. Arzneimittelforschung. 2002;52(11):797-802.
  12. Wilt TJ et al. Saw palmetto extracts for treatment of benign prostatic hyperplasia: a systematic review. JAMA. 1998 Nov 11;280(18):1604-9.
  13. Prager N et al. A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopecia. J Altern Complement Med. 2002 Apr;8(2):143-52.
  14. Cooley K et al. Naturopathic care for anxiety: a randomized controlled trial ISRCTN78958974. PLoS One. 2009 Aug 31;4(8):e6628. doi: 10.1371/journal.pone.0006628.
  15. Mishra LC, Singh BB, Dagenais S. Scientific basis for the therapeutic use of Withania somnifera (ashwagandha): a review. Altern Med Rev. 2000 Aug;5(4):334-46.
  16. Clare BA, Conroy RS, Spelman K. The diuretic effect in human subjects of an extract of Taraxacum officinale folium over a single day. J Altern Complement Med. 2009 Aug;15(8):929-34. doi: 10.1089/acm.2008.0152.
  17. Akhondzadeh S et al. Passionflower in the treatment of generalized anxiety: a pilot double-blind randomized controlled trial with oxazepam. J Clin Pharm Ther. 2001 Oct;26(5):363-7.
  18. Ngan A1, Conduit R. A double-blind, placebo-controlled investigation of the effects of Passiflora incarnata (passionflower) herbal tea on subjective sleep quality. Phytother Res. 2011 Aug;25(8):1153-9. doi: 10.1002/ptr.3400. Epub 2011 Feb 3.
  19. Holtmann G et al. Efficacy of artichoke leaf extract in the treatment of patients with functional dyspepsia: a six-week placebo-controlled, double-blind, multicentre trial. Aliment Pharmacol Ther. 2003 Dec;18(11-12):1099-105.
  20. Walker AF, Middleton RW, Petrowicz O. Artichoke leaf extract reduces symptoms of irritable bowel syndrome in a post-marketing surveillance study. Phytother Res. 2001 Feb;15(1):58-61.
  21. Pittler MH, Thompson CO, Ernst E. Artichoke leaf extract for treating hypercholesterolaemia. Cochrane Database Syst Rev. 2002;(3):CD003335.
  22. Bommer S, Klein P, Suter A. First time proof of sage's tolerability and efficacy in menopausal women with hot flushes. Adv Ther. 2011 Jun;28(6):490-500. doi: 10.1007/s12325-011-0027-z. Epub 2011 May 16.
  23. Tildesley NT et al. Salvia lavandulaefolia (Spanish sage) enhances memory in healthy young volunteers. Pharmacol Biochem Behav. 2003 Jun;75(3):669-74.
  24. Lien HC et al. Effects of ginger on motion sickness and gastric slow-wave dysrhythmias induced by circular vection. Am J Physiol Gastrointest Liver Physiol. 2003 Mar;284(3):G481-9.
  25. Haniadka R et al. A review of the gastroprotective effects of ginger (Zingiber officinale Roscoe). Food Funct. 2013 Jun;4(6):845-55. doi: 10.1039/c3fo30337c. Epub 2013 Apr 24.
  26. Srivastava KC, Mustafa T. Ginger (Zingiber officinale) and rheumatic disorders. Med Hypotheses. 1989 May;29(1):25-8.
  27. Ankri S, Mirelman D. Antimicrobial properties of allicin from garlic. Microbes Infect. 1999 Feb;1(2):125-9.
  28. Steiner M, Li W. Aged garlic extract, a modulator of cardiovascular risk factors: a dose-finding study on the effects of AGE on platelet functions. J Nutr. 2001 Mar;131(3s):980S-4S.
  29. Araújo CC, Leon LL. Biological activities of Curcuma longa L. Mem Inst Oswaldo Cruz. 2001 Jul;96(5):723-8.
  30. Cole GM, Teter B, Frautschy SA. Neuroprotective effects of curcumin. Adv Exp Med Biol. 2007; 595: 197–212.
  31. Peng YJ et al. Pycnogenol attenuates the inflammatory and nitrosative stress on joint inflammation induced by urate crystals. Free Radic Biol Med. 2012 Feb 15;52(4):765-74. doi: 10.1016/j.freeradbiomed.2011.12.003. Epub 2011 Dec 13.
  32. Petrassi C, Mastromarino A, Spartera C. PYCNOGENOL in chronic venous insufficiency. Phytomedicine. 2000 Oct;7(5):383-8.
  33. Heggers JP et al. The effectiveness of processed grapefruit-seed extract as an antibacterial agent: II. Mechanism of action and in vitro toxicity. J Altern Complement Med. 2002 Jun;8(3):333-40.
  34. Cohen M. Rosehip - an evidence based herbal medicine for inflammation and arthritis. Aust Fam Physician. 2012 Jul;41(7):495-8.
  35. Winther K, Apel K, Thamsborg G. A powder made from seeds and shells of a rose-hip subspecies (Rosa canina) reduces symptoms of knee and hip osteoarthritis: a randomized, double-blind, placebo-controlled clinical trial. Scand J Rheumatol. 2005 Jul-Aug;34(4):302-8.
  36. Wang CH et al. Cranberry-containing products for prevention of urinary tract infections in susceptible populations: a systematic review and meta-analysis of randomized controlled trials. Arch Intern Med. 2012 Jul 9;172(13):988-96. doi: 10.1001/archinternmed.2012.3004.
  37. Zakay-Rones Z et al. Randomized study of the efficacy and safety of oral elderberry extract in the treatment of influenza A and B virus infections. J Int Med Res. 2004 Mar-Apr;32(2):132-40.


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      Dr. Lifestyle

      Dr. Lifestyle is our own collective of leading health, nutrition and fitness experts. Having several brains makes it really hard to decide what we feel like for breakfast (Chia Coconut Pudding, or a Green Smoothie?), but when it comes to health advice we are an all-knowing, hyper-intelligent, super human.