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Food as Medicine
Purslane (Portulaca oleracea, Portulacaceae)

Editor’s note: In the Food as Medicine article series, HerbalEGram highlights a conventional food and briefly explores its history, traditional uses, nutritional profile, and modern medicinal research. Each article also features a nutritious recipe for an easy-to-prepare dish to encourage readers to experience the extensive benefits of these whole foods. With this series, we hope our readers will gain a new appreciation for the foods they see at the supermarket and frequently include in their diets.

By Hannah Bauman

Overview

Purslane (Portulaca oleracea) is an annual succulent in the Portulacaceae family, which contains 25-30 genera.1 It is a groundcover plant with a creeping, prostrate growth habit and stems that produce alternate fleshy oval leaves.2 With sufficient moisture, purslane can produce flowers throughout the year. The flowers are small and yellow with five heart-shaped petals and produce a seed capsule that contains numerous small, round black seeds.3 Purslane is frost-sensitive but tolerates drought conditions and poor soil.2

The plant likely originated in the eastern Mediterranean and western Asia and has a long history of use as food and medicine from Italy to China.3 It is currently naturalized globally. All aerial parts of purslane (stem, leaf, flower, and seed) are edible and taste salty and slightly sour.2

Historical and Commercial Uses

Purslane is known as ma chi xian in Chinese and verdolagas in Spanish. Common names in English include common purslane, garden purslane,Botanical illustration of purslane by Otto Wilhelm Thome, 1885 and little hogweed.2 Purslane can be eaten raw, cooked, juiced, or pickled.4,5 When cooked, purslane becomes mucilaginous and can be used to thicken soups and stews. Some native North American peoples powdered the seeds for use as a flour, dried the stems for winter rations, and used the plant to feed sheep.5,6 Purslane is not a popular commercial ingredient or consumer product, but it is often used as fodder for livestock and poultry. Due to the nutrient-dense nature of purslane, chickens that consume the aerial parts produce eggs with a high omega-3 fatty acid content.3,7

Purslane was mentioned in the writings of Greek physician Pedanius Dioscorides and the Roman naturalist Pliny the Elder in the first century.8 In his treaty De Materia Medica, Dioscorides described purslane as an astringent and prescribed it as a remedy for headaches, inflammation, bladder disorders, dysentery, and hemorrhoids, among other conditions.9 It was widely cultivated throughout Europe in the Middle Ages and was grown in monasteries.8 Archeological sites from different areas seem to confirm that purslane was in common use and not an incidental plant, as fossilized remains were found in garbage sites.

In Palestine, purslane has a history of use for renal failure.10 On the African continent, it has been traditionally used in Nigeria as a fertility aid; in Sierra Leone to treat hernias, stop bleeding, and induce abortion; and in the Democratic Republic of the Congo as a treatment for gonorrhea.10-12

In several Indian traditional medicine modalities, including Ayurveda, Unani, and Siddha medicine, purslane was used to treat indigestion, ulcers, edema, eye diseases, and bronchial asthma. According to the foundational Ayurvedic texts Charaka Samhita and Sushruta Samhita, cooked purslane was used to treat excessive mucus, cough, diarrhea, dysentery, and hemorrhoids.10

Purslane has been used in traditional Chinese medicine (TCM) for millennia, where it is called the “vegetable for long life.” In the TCM paradigm, it is considered cold in nature and used to cool the blood, stop bleeding, clear heat, and neutralize toxins. Dried aerial parts were indicated for treatment of fever, dysentery, diarrhea, carbuncles (a cluster of boils), eczema, and hematochezia (blood in the stool).13

In Western herbal medicine, purslane has been indicated topically for burns, eczema, insect bites, and boils, and internally for edema.3,7 In addition, it is considered a febrifuge and antiseptic. The leaves, stems, and flowers have been used for edema, atherosclerosis, liver disorders, ulcerative colitis, eye disorders, and muscle spasms.14 The seeds have been used for restless sleep, cholecystitis (gallbladder inflammation), joint pain, syphilis, arthritis, and psoriasis, while the juice has been used as an adjunct treatment for dysentery, intestinal worms, sexually transmitted infections, and warts.

Native American tribes throughout the North American continent had myriad uses for purslane, including for earaches and as an antidote to poisoning, analgesic, anthelmintic, and a poultice for burns and general panacea.6

Nutrients and Phytochemicals

Green purslane leaves on a purplish stemPurslane is a vitamin- and mineral-rich plant and among the plant sources with the highest contents of omega-3 fatty acids.15 While the aerial parts of purslane contain alpha-linolenic acid (ALA), the highest content of this omega-3 fatty acid is found in the seed.4 Cultivated purslane varietals tend to contain more total fatty acid content than wild-grown.16

Purslane aerial parts contain approximately 192 mg/100 g dry weight total fatty acids, an order of magnitude more than spinach (Spinacia oleracea, Amaranthaceae) leaf, which has a total fatty acid content of approximately 19 mg/100 g, or kale (Brassica oleracea, Brassicaceae) leaf, which contains approximately 24 mg/100 g. Looking specifically at ALA, purslane aerial parts contain approximately 98 mg/100 g, compared to 11 g/100 g for spinach and 17 g/100 g for kale. Purslane’s fatty acid content has a desirable 1:3 omega-6 fatty acid to omega-3 fatty acid ratio, which is associated with an amplified anti-inflammatory effect.15

Purslane seeds and aerial parts also contain eight out of the nine amino acids considered essential.15 Flavonoids found in purslane include kaempferol, myricetin, luteolin, apigenin, quercetin, genistein, and genistin.13 Flavonoids are antioxidant compounds that help protect the body from inflammation in a variety of ways, including by neutralizing free radicals that cause oxidative stress. Purslane also contains various polysaccharides, which are potential therapeutic agents against type 2 diabetes mellitus due to their ability to modulate blood glucose and blood lipids. (Table 1)

 

Table 1. Nutrients and Bioactive Compounds in Purslane15,17

Phytochemical

Compound Type

Plant Part

Associated Properties

Alpha-linolenic acid

Omega-3 fatty acid

Seed, aerial parts

Anti-inflammatory, cardioprotective, immunomodulatory

Apigenin

Flavonoid

Leaf and stem

Antioxidant, anti-inflammatory, neuroprotective

Beta-carotene

Carotenoid

Aerial parts

Converts to vitamin A in the body; antioxidant

Glutathione

Tripeptide

Aerial parts, seed

Antioxidant

Kaempferol

Flavonoid

Leaf and stem

Antioxidant, anti-inflammatory, antimicrobial

Portulosides A and B

Monoterpene glucoside

Aerial parts

Antibacterial, fungicidal

 

Modern Research and Potential Health Benefits

While human clinical trials on purslane are few, the plant’s high ALA content and associated anti-inflammatory effects are of interest to researchers as a potential treatment for conditions such as cardiovascular disease, asthma, and cancer. Additionally, other compounds in purslane may have antimicrobial effects and benefits for neurodegenerative conditions.

Anti-Asthmatic Activity

Close up of purslane leaves, rounded green succulent leaves arranged in a rosette pattern. Image courtesy of Gayle EngelsAsthma is a chronic condition characterized by airway and lung inflammation. Several constituents of purslane, notably quercetin, have been shown to inhibit smooth muscle contraction and cell proliferation in in vitro and in vivo models. The mechanism of action may be a complex interaction between quercetin, ALA, and other anti-inflammatory compounds in purslane that decrease pro-inflammatory cytokines while boosting immune cell production. In addition, purslane extract has been found to act as a bronchodilator and stimulate tracheal muscles in an animal model.17

In clinical trials, patients with asthma reported significantly improved pulmonary function after taking a purslane extract. The effects were comparable to those of theophylline syrup, a conventional bronchodilator that was originally derived from tea (Camellia sinensis, Theaceae) but now is produced commercially by chemical synthesis.18

Antidiabetic Activity

In animal studies, purslane alleviated insulin resistance, increased insulin sensitivity, and improved lipid metabolism. An aqueous extract of purslane prevented diabetic vascular inflammation and endothelial dysfunction in mice. This is likely due in part to purslane’s polysaccharides.13

A clinical trial correlated purslane seed powder supplementation in patients with type 2 diabetes with increased high-density lipoprotein (HDL) cholesterol levels and decreased low-density lipoprotein (LDL) cholesterol levels, triglycerides, fasting and post-meal blood glucose, and body weight. The results were comparable to those of the active control group who took metformin, a conventional diabetes medication based on a natural chemical compound found in goat’s rue (Galega officinalis, Fabaceae).19

Neuroprotective Activity

The antioxidants in purslane scavenge free radicals and protect cells from oxidation, as well as induce apoptosis (pre-programmed, normal cell death) and mitigate dopamine depletion.13 These characteristics indicate that purslane may have value as an adjunct therapy for neurodegenerative conditions such as Parkinson’s disease. In animal studies, purslane extracts protected nerve cells from hypoxic damage, reduced damage caused by hypoxia, and increased neuron viability. An alkaloidal purslane extract significantly inhibited acetylcholinesterase (AChE) activity in a dose-dependent manner in vitro.20 The use of AChE inhibitors is currently a treatment strategy for Alzheimer’s disease.

Antitumor Activity

Large clusters of purslane leaves. Image courtesy of Gayle Engels.Purslane seed extract mitigated cell viability in a lab culture of human liver cancer cells in a dose-dependent manner.1 Portulacerebroside A, a compound found in purslane, stimulated liver cancer cell apoptosis, and portulacanones B–D showed selective cytotoxic activity against brain and lung cancer cells.13

In animal studies, purslane polysaccharides, which have antiviral and analgesic activities, inhibited tumor growth and increased immune response.1

Other Uses

Purslane contains many compounds with antimicrobial effects, and purslane extract may have viability as an antimicrobial agent. A methanolic extract of purslane was found to be effective against Gram-negative bacteria strains such as Escherichia coli, Pseudomonas aeruginosa, and Neisseria gonorrhoea and Gram-positive strains such as Staphylococcus aureus, Bacillus subtilis, and Streptococcus faecalis.10,13 It was also effective against Candida albicans.

In a pilot study, 30 patients with abnormal uterine bleeding were given capsules of roasted purslane seed powder for two consecutive menstrual cycles.10 Twenty-six patients (87%) reported that they achieved menstrual regulation, and no adverse events were reported.

Consumer Considerations

The oxalates in purslane may be toxic in high amounts.2 While leafy plants such as spinach contain a higher amount of oxalic acid per serving, purslane should be consumed in small amounts or avoided entirely by those with kidney problems, particularly kidney stones.3,15

Purslane grows easily throughout most temperate zones and currently has no known sustainability concerns. The IUCN Red List of Threatened Species categorizes P. oleracea as a species of “Least Concern.”21 When harvesting, the young leaves and stems are preferred for eating raw, while the older growth, which has a stronger taste, may be more palatable when cooked.5

Nutrient Profile22
Per 1 cup purslane (approx. 43 g)

Macronutrients:

8.6 calories
0.9 g protein
1.5 g carbohydrate
0.2 g fat

Micronutrients:

Very good source of:

Vitamin A: 568 IU (11.4% DV)
Vitamin C: 9 mg (10% DV)

Good source of:

Magnesium: 29.2 mg (7% DV)
Copper: 0.05 mg (5.5% DV)
Iron: 0.9 mg (5% DV)

Also provides:

Riboflavin (Vitamin B2): 0.06 mg (4.6% DV)
Potassium: 212 mg (4.5% DV)
Manganese: 0.1 mg (4.3% DV)
Calcium: 28 mg (2.2% DV)
Pyridoxine (Vitamin B6): 0.03 mg (1.8% DV)
Thiamin (Vitamin B1): 0.02 mg (1.7% DV)
Phosphorus: 18.9 mg (1.5% DV)
Dietary Fiber: 0.4 g (1.3% DV)
Folate (Vitamin B9): 5.2 mcg (1.3% DV)
Niacin (Vitamin B3): 0.2 mg (1.3% DV)
Vitamin K: 1.16 mcg (1% DV)
Zinc: 0.1 mg (1% DV)

Trace Amounts:

Pantothenic Acid (Vitamin B5): 0.01 mg (0.2% DV)

DV = Daily Value as established by the US Food and Drug Administration, based on a 2,000-calorie diet.

Recipe: Purslane Tzatziki
Courtesy of Susan Belsinger23

Ingredients:

  • 2 cups Greek yogurt
  • 1 large cucumber, peeled and grated or chopped fine
  • 3 large cloves garlic, pressed or minced
  • 2 tablespoons chopped fresh dill or spearmint, or a combination (optional)
  • 2 handfuls purslane leaves
  • 1 tablespoon lemon juice or red wine vinegar
  • Salt and freshly ground pepper

Directions:

  1. In a bowl, combine the yogurt, cucumbers, garlic, chopped herbs, purslane, and lemon juice or vinegar. Season with salt and pepper to taste.
  2. Refrigerate for about an hour before serving. The tzatziki will keep in the fridge for about 48 hours.

 

Image Credits (top to bottom):

Portulaca oleracea. ©2021 Steven Foster
Illustration from Flora von Deutschland, Österreich und der Schweiz by Otto Wilhelm Thomé. 1886.
Portulaca oleracea. ©2021 Steven Foster
Portulaca oleracea. Image courtesy of Gayle Engels
Portulaca oleracea. Image courtesy of Gayle Engels

References

  1. Rahimi VB, Ajam F, Rakhshandeh H, Askari VR. A pharmacological review of Portulaca oleracea: Focusing on anti-inflammatory, anti-oxidant, immuno-modulatory and anti-tumor activities. Journal of Pharmacopuncture. 2019;22(1):7-15.
  2. Portulaca oleracea. North Carolina Extension Gardener Plant Toolbox. Raleigh, NC: North Carolina State University. Available at: https://plants.ces.ncsu.edu/plants/portulaca-oleracea/. Accessed July 23, 2021.
  3. Mahr S. Common purslane, Portulaca oleracea. Madison, WI: University of Wisconsin Horticulture Division Extension. Available at: https://hort.extension.wisc.edu/articles/common-purslane-portulaca-oleracea/. Accessed July 23, 2021.
  4. Desta M, Molla A, Yusuf Z. Characterization of physico-chemical properties and antioxidant activity of oil from seed, leaf and stem of purslane (Portulaca oleracea). Biotechnology Reports. 2020;27:e00512.
  5. Belsinger S, Tucker AO. The Culinary Herbal: Growing and Preserving 97 Flavorful Herbs. Portland, OR: Timber Press; 2016.
  6. Portulaca oleracea. Native American Ethnobotany Database website. Available at: http://naeb.brit.org/uses/search/?string=portulaca+oleracea. Accessed July 27, 2021.
  7. Wood R. The New Whole Foods Encyclopedia. New York, NY: Penguin Books; 1999.
  8. Cumo C, ed. Encyclopedia of Cultivated Plants: From Acacia to Zinnia. Santa Barbara, CA: ABC-CLIO; 2013.
  9. Iranshahy M, Javadi B, Iranshahi M, et al. A review of traditional uses, phytochemistry and pharmacology of Portulaca oleracea Journal of Ethnopharmacology. 2017;205:158-172.
  10. Kaur H. An analysis of pharmacological activities of Portulaca oleracea. International Journal of Pharmaceutical Sciences and Research. 2020;11(12):5995-6004.
  11. Adjanohoun EJ, Sita P. Contribution aux études ethnobotaniques et floristiques en République Populaire du Congo: Rapport présenté à l'A.C.C.T. Paris, France: Agence de Coopération Culturelle et Technique; 1988.
  12. MacFoy C. Medicinal Plants and Traditional Medicine in Sierra Leone. Bloomington, IN: iUniverse LLC; 2013.
  13. Zhou YX, Xin HL, Rahman K, Wang SJ, Peng C, Zhang H. Portulaca oleracea: A review of phytochemistry and pharmacological effects. Biomed Research International. 2015:925631.
  14. Butnariu M. Portulaca oleracea phytochemistry and pharmacological considerations. Annals of Pharmacology and Pharmaceutics. 2018;3(3):1149.
  15. Nemzer B, Al-Taher F, Abshiru N. Extraction and natural bioactive molecules characterization in spinach, kale, and purslane: A comparative study. Molecules. 2021;26:2515.
  16. Nemzer B, Al-Taher F, Abshiru N. Phytochemical composition and nutritional value of different plant parts in two cultivated and wild purslane (Portulaca oleracea L.) genotypes. Food Chemistry. 2020;320:126621. doi: 10.1016/j.foodchem.2020.126621.
  17. Khazdair MR, Anaeigoudari A, Kianmehr M. Anti-asthmatic effects of Portulaca oleracea and its constituents, a review. Journal of Pharmacopuncture. 2019;22(3):122-130.
  18. Malek F, Boskabady M, Borushaki M, Tohidi M. Bronchodilatory effect of Portulaca oleracea in airways of asthmatic patients. Journal of Ethnopharmacology. 2004;93(1):57-62.
  19. El-Sayed MIK. Effects of Portulaca oleracea seeds in treatment of type-2 diabetes mellitus patients as adjunctive and alternative therapy. Journal of Ethnopharmacology. 2011;137(1):643-651.
  20. Yang Z, Zhang D, Ren J, Yang M, Li S. Acetylcholinesterase inhibitory activity of the total alkaloid from traditional Chinese herbal medicine for treating Alzheimer’s disease. Medicinal Chemistry Research. 2012;21(6):734-738.
  21. Diop FN, Naas M. Portulaca oleracea. The IUCN Red List of Threatened Species. 2020:e.T164001A65924501. https://dx.doi.org/10.2305
  22. Purslane, raw. FoodData Central. United States Department of Agriculture Agricultural Research Service. April 2019. Available at: https://fdc.nal.usda.gov/fdc-app.html#/food-details/169274/nutrients. Accessed July 27, 2021.
  23. Belsinger S. Purslane in the Kitchen. Fine Gardening. Available at: finegardening.com/article/purslane-in-the-kitchen. Accessed July 29, 2021.
References