Commentary

Portulaca oleracea (purslane)


 

References

Portulaca oleracea, also known as purslane, has long been used in various traditional medicine systems to relieve pain and edema.1Portulaca oleracea is a warm-climate annual plant originally found in the Middle East, North Africa, and the Indian subcontinent and now cultivated in the Arabian peninsula; Japan, where it is an abundant garden plant from spring to fall;2,3 and throughout the world.

The use of P. oleracea, a member of the Portulacaceae family, as a vegetable as well as herbal medicine dates back several centuries.4 In modern times, purslane has been found to be rich in antioxidants, particularly omega-3 fatty acids, vitamins C and E, beta-carotene, melatonin, and glutathione, as well as several minerals.5,6,7 Currently, it is considered one of the top ten most common plants in the world, and one of the most-used medical plants according to the World Health Organization.6 It is considered a weed in the United States, but is eaten in many parts of the world.

Dr. Leslie S. Baumann

Dr. Leslie S. Baumann

Antioxidant activity

Using two different assays, Uddin et al. determined in 2012 that P. oleracea cultivars exhibited significant antioxidant activity through various growth stages. In addition, the researchers suggested that purslane could provide multiple minerals as well as antioxidants in the context of nutraceutical products and functional food.7 Early this year, Silva et al. studied the antioxidant activity of P. oleracea leaves, flowers, and stems from two different locations in Portugal, with assays revealing significantly greater antioxidant activity in the stems of both samples compared to the leaves and flowers. However, the phenolic extracts of all three plant sections from both samples were found to protect DNA against hydroxyl radicals. The investigators concluded that their findings, particularly related to high antioxidant activity, support the potential benefits of purslane consumption to human health.8

A 2014 analysis of 13 collected purslane accessions revealed significant mineral content (particularly potassium, followed by nitrogen, sodium, calcium, magnesium, phosphorus, iron, zinc, and manganese) and showed that antioxidant activity was more strongly associated with ornamental as opposed to common purslane, the latter of which was richer in mineral content.6

Anti-inflammatory activity

In 2000, Chan et al. found that a 10% ethanolic extract of the dried leaves and stem of a P. oleracea cultivar displayed significant anti-inflammatory and analgesic properties after topical and intraperitoneal, but not oral, administration in comparison to diclofenac sodium, a synthetic drug used as active control. They added that these activities corresponded to the reputed effects of the traditional uses of the wild species.9

Wound healing activity

Rashed et al. reported in 2003 that a crude extract of P. oleracea accelerates wound healing. They used Mus musculus JVI-1 to show that fresh homogenized crude aerial parts of the plant topically applied on excision wound surfaces reduced wound surface areas and increased tensile strength. The best documented contraction was associated with a single dose of 50 mg, followed by two doses of 25 mg each.10

Oral lichen planus treatment

In 2010, Agha-Hosseini et al. conducted a randomized double-blind placebo-controlled 3-month study to assess the effectiveness of purslane in the treatment of oral lichen planus. Thirty-seven symptomatic patients (confirmed by biopsy) were divided into a purslane treatment group (n = 20) and a placebo group (n = 17). The investigators reported that partial to complete clinical improvement was observed in 83% of the treatment group, with no response in the remaining 17%, whereas partial improvement was seen in 17% of the placebo group, 73% had no response, and the condition was aggravated in 10% of the placebo group. No adverse side effects were reported in either group, and the researchers concluded that purslane was clinically effective in treating oral lichen planus and warrants consideration as a treatment option for the disorder.5

Other activities

In 2001, Radhakrishnan et al. identified several neuropharmacological actions, particularly anti-nociceptive and muscle-relaxing activity, with a range of effects on the central and peripheral nervous system observed in animal studies.1 The betacyanins found in P. oleracea have subsequently been found to confer a protective effect against neurotoxicity, specifically, ameliorating the D-galactose-induced cognitive deficits in senescent mice.11P. oleracea also has been shown to efficiently eliminate the endocrine-disrupting chemical bisphenol A from a hydroponic solution.12

In 2012, Yan et al. showed that three newly isolated homoisoflavonoids, known as portulacanones, and the compound 2,2’-dihydroxy-4’,6’-dimethoxychalcone selectively exhibited in vitro cytotoxic activities against four human cancer cell lines.2

Conclusions

This antioxidant-rich plant is found throughout the world and has long been associated with traditional health care. Modern research into its potential dermatologic uses is ongoing, but the evidence is relatively scarce. There are indications that the antioxidant, anti-inflammatory, and wound healing activity reportedly exhibited by purslane may be harnessed for various cutaneous applications. However, much more research is necessary to determine how extensive a role purslane may play in skin care.

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