Portulaca oleracea L. (purslane) belongs to the Portulaceae family and is an annual herbaceous plant. It originated in India, and has been distributed in multiple regions around the world, mainly in temperate and tropical regions such as Asia, Africa, Europe, etc. [1,2]. In different countries and language systems, the name purslane is different: it is called “rigla” in Egypt, “pigweed” in England, “pourpier” in France and “Ma-Chi-Xian” in China (Figure 1). In addition, some of its aliases can reflect its properties. In Brazil, it is called “unconventional edible plant”, which means it does not belong to a specific region or country and can even be consumed by most of the world’s population. In China, it is known as “vegetable for long life” due to its multiple benefits to the human body. Purslane is rich in nutrients such as malic acid, glucose, calcium, phosphorus and iron, as well as carotene and vitamins B, C and E. Regular consumption of purslane not only supplements the body with many nutrients, but also enhances immunity, lowers blood sugar and blood lipids and has a positive effect on protecting the eyes [3]. There are various ways to eat purslane; it is suitable for both fresh and dry food. It can be cold-mixed, stir-fried, or boiled in soup. It tastes delicious and refreshing, so it also has the effect of promoting appetite [4].

Purslane is not only a green, safe, nutritious and edible vegetable, but also a good medicine, with various health-promoting effects on the human body. In folk medicine, purslane is commonly used to treat various diseases, and has satisfying effects [5]. For example, in Afghanistan, purslane is used to prevent diarrhea and throat infections. Sri Lanka uses purslane to treat ulcers, wounds, burns and skin diseases. In Dominica and the West Indies, it is used to treat intestinal worms. In addition, purslane is known as a “natural antibiotic”, because it has a significant inhibitory effect on Typhoid bacillus, Escherichia coli and Dysentery bacillus. Officially, the 2020 edition of the Chinese Pharmacopoeia contains purslane, which is clinically used for eczema, snakebites, blood in stool, hemorrhoids, etc. Moreover, it is also included in the “Affinal Drugs and Diet” Catalogue issued by the Chinese Health Commission, indicating that its health benefits have been recognized by national authoritative departments. This also means that it has dual properties as a natural plant and can be safely eaten [6,7]. Therefore, purslane has attracted the attention of more and more researchers, as well as consumers who focus on dietary balance and physical health. Purslane is appearing more frequently on people’s dining tables as a healthy food source.

Its extensive clinical effects are closely related to its chemical composition. According to existing research and reports, purslane contains various chemical components, including polysaccharides, alkaloids, flavonoids and terpenoids [8,9]. Among them, polysaccharides, as an important macromolecule, have been increasingly studied due to their natural origin, safety and low toxicity. At present, multiple structurally diverse polysaccharides from purslane have been obtained through different extraction and purification methods. They have been proven to have health benefits for the human body, including anti-inflammatory, antidiabetic, antitumor, antiviral, anti-lead poisoning, antifatigue and immunomodulatory effects [10]. This gives it broad application prospects in fields such as food, pharmaceuticals, cosmetics and animal husbandry.

With rising living standards and changing dietary trends, people are becoming more health-conscious, and greens are becoming popular with a wide range of consumers [76]. Purslane is rich in pectin polysaccharides and has good absorption properties [77]. Therefore, adding purslane to flour not only improves the softness of the dough but also increases the nutritional value of the bread. Using four different concentrations of purslane (0%, 5%, 10% and 15%) added to the flour, the absorption, mix stability and softness, as well as the protein, fat, moisture and fiber content of the bread, were investigated as the concentration of purslane flour increased. The results showed that the best prescription containing 10% purslane flour had the best acceptability in terms of sensory characteristics, color, flavor, texture and overall preference. The addition of purslane to bread not only improves the taste of bread, but also has health benefits. It is well known that the sensory perception of consumers is crucial for the distribution of products on the market. Purslane as a food product can not only improve the nutritional and bioactive composition of the product, but can also influence its sensory perception and processing properties. Therefore, it is worthwhile to try the addition of purslane to the development of new bread products. In addition, purslane polysaccharides as a thickening agent can be added to yoghurt as a stabilizer, not only to enhance its gel network structure, effectively reduce whey precipitation, improve gel texture and enhance yoghurt stability, but also to blend a unique and acceptable flavor [78]. As polysaccharides act as a carbohydrate, they can provide nutrients to the fermenting flora of yoghurt and participate in biochemical reactions as well as the synthesis of organic matter, increasing the different nutritional properties of yoghurt, such as improving immunity, regulating intestinal flora and being beneficial to human health. In addition, a health wine prepared by fermenting purslane with other herbs is rich in purslane polysaccharides, flavonoids and other nutritional components, with functions such as lowering blood sugar and improving immunity, as well as antibacterial and anti-inflammatory functions. The production process has been patented, and is in force (CN103642623A) [79]. Moreover, widely consumed as a wild vegetable in Europe, Africa and Asia, as well as in some parts of Australia, purslane has a slightly sour and savory flavor to its stems and leaves, and is commonly found in salads, soups and stews [80]. As an edible plant, purslane is highly nutritious, and can be used to clear heat and detoxify the body if simmered in a soup with green beans. As a result, research into its use as a functional food has recently attracted a lot of attention. Purslane is extremely abundant worldwide and is simple and inexpensive to grow. The research and market development of purslane is therefore very promising, and deserves to be studied in depth in the context of food industrialization.

Purslane contains a variety of chemical components such as flavonoids, organic acids, alkaloids, polysaccharides and terpenoids, making it a natural plant with a wide range of pharmacological activities. Pharmacological studies have shown that purslane has a variety of therapeutic effects, and is used clinically for antibacterial, anti-inflammatory and free-radical-scavenging and immune-boosting purposes [81,82]. In recent years, there has been increasing interest in the polysaccharides extracted from purslane. Pharmaceutical research on purslane polysaccharides has focused on the treatment of diabetes, as well as anti-inflammatory, antitumor, antiviral, antifatigue, anti-lead poisoning and immunomodulation effects. Because of its abundance, safety, and low toxicity, it has great potential and value for exploitation. In China, purslane is an important part of traditional Chinese medicine formulations with immunosuppressive and viral suppressive effects. For example, purslane soup, which uses purslane as major component, is mainly used for the treatment of bacillary dysentery and enteritis, which may be related to the anti-inflammatory and immunomodulatory effects of purslane polysaccharides. Purslane is also used in combination with other herbs for the treatment of bowel cancer, where the antitumor effects of purslane polysaccharides may play a role in the treatment. It is also used as an anti-inflammatory and antibacterial agent by decocting fresh purslane in water or wine and pounding it externally, or by taking its juice and using it in water. Purslane polysaccharides have anti-inflammatory properties, and it can be assumed that the polysaccharides play their corresponding role in this process. In addition to this, in the field of pharmaceutical technology, one patent discloses the use of a purslane polysaccharide in the preparation of an antiacute lung injury drug. Some studies have also shown that purslane polysaccharide (POL-P3b) can be used as a novel immune adjuvant in the treatment of breast cancer. Moreover, purslane polysaccharides can be used as an edible adjuvant or nutraceutical to boost the immune system for antitumor, hypoglycemic and immune-boosting effects. However, further research is needed to determine the mechanism of action of purslane polysaccharides in specific foods and the anticancer activity in beverages to protect the health interests of consumers. In conclusion, with the continuous development of science and technology, the mechanism of action of purslane will be further studied and elucidated, which will lead to better pharmaceutical applications and further contribution to the human treatment of chronic diseases such as tumors and diabetes.

Many natural plants are not only used as medicine, but can also be added to cosmetics for their effects [83]. With the in-depth study of purslane polysaccharides, it was found that they also have a high value and potential for use in everyday cosmetics. Purslane polysaccharides have good antiallergic, antibacterial and anti-inflammatory effects against various external skin irritations, and are also effective against acne, eczema, dermatitis and itchy skin [84]. According to incomplete statistics, an increasing number of people worldwide consider themselves to have sensitive skin, 38% of whom are men and 62% of whom are women. Cosmetics with antiallergic properties are therefore becoming increasingly important to consumer choice, and cosmetic ingredients with antiallergic activity, especially those of natural plant origin, are becoming more popular in the market [85,86]. Several studies have shown that purslane is effective in treating septic skin problems such as acne and pimples, and these effects are inextricably linked to the ingredient purslane polysaccharide. Purslane polysaccharides reduce the secretion of the inflammatory factor interleukin, which has some anti-inflammatory effects, thus soothing skin inflammation, which is the cause of acne pimples [87]. This has created a vast market and substantial economic benefits for the cosmetics industry, driven by consumer demand for natural plant actives, and purslane polysaccharides meet the consumer demand for a nontoxic source of product ingredients for the human body. This also suggests that the cosmetic industry should actively explore new and reliable natural plant-based skin care ingredients to improve the safety performance of their products. Creams containing purslane extract have been reported to improve dry, rough, red and flaky skin [88]. Based on the structural characteristics of polysaccharides, which have excellent moisturizing properties, it can be assumed that it is likely that the polysaccharides play a corresponding role. There are thousands of cosmetic products that use purslane extract as a main efficacious ingredient, such as Winona, MUJI and Bacitracin. However, the extent to which purslane polysaccharides can play a positive role in cosmetics is yet to be proven. There is still a long way to go when it comes to cosmetics based on polysaccharide molecules rather than aqueous extracts. In subsequent studies, the constitutive relationship, purification process, onset of action mechanism, penetration mechanism and processing compounding of purslane polysaccharides should be further explored in depth. It is believed that in the near future, purslane polysaccharide cosmetics will play a more important role in the field of skin care and cosmetics, and contribute to meeting the needs of consumers.

Due to the various pharmacological effects and fewer toxic negative effects of plant polysaccharides, polysaccharides have also been widely used in animal husbandry, such as Astragalus polysaccharides and Oxalis polysaccharides, both of which have been used to good effect [89,90]. Similarly, purslane polysaccharides can also have corresponding applications in animal husbandry. Ge Jian et al. showed that purslane polysaccharides could significantly increase the indices of the thymus, spleen and bursa of chicks, and significantly increase the levels of SOD, GSH-Px, CAT and T-AOC in chicks. The results showed that the cell proliferation index was mainly in the G1/G0 phase, with a few cells in the S and G2/M phases, and the cell cycles of different immune organs were similar. This indicates that purslane polysaccharides can promote the growth and development of chicken immune organs and the cell proliferation of chicken immune organs, enhance the immune function and improve the immunity of the organism, which is obviously a better alternative to the common feed. In addition, Zhang Ting et al. showed that horsetail polysaccharide has some protective effect on pig sperm. For example, the addition of 0.25 mg/mL of purslane polysaccharides to the traditional diluent TCG during the freezing of pig semen improved the viability, survival, plasma membrane integrity, acrosome integrity and mitochondrial activity of pig sperm after freezing. Therefore, the addition of purslane polysaccharides to feeds can be used to a certain extent as a substitute for antibiotics without affecting animal performance in order to improve animal food quality and meat safety. Although there are some preliminary studies on purslane polysaccharides in animal husbandry, there are still many problems to be solved, and further in-depth studies are needed. It is believed that with the improvement of the polysaccharide extraction process and further research, the application potential of purslane polysaccharides in livestock and poultry feed production will be further developed, and in the future, feed containing purslane polysaccharides may be mass-produced and used on a large scale (Figure 2).

In summary, purslane polysaccharides are an important material base component for purslane to play pharmacological and health functions. They are widely used and involve many fields. Therefore, the research and development work of purslane polysaccharides in various industries must be continuously and deeply carried out, especially in the field of food, so as to contribute to the extension of the deep food processing industry chain and the sustainable development of food and medicinal industry.