A recent review article published within the journal Foods describes the health advantages and other useful characteristics of various flowering plants.

Study: Exploring Plants with Flowers: From Therapeutic Dietary Advantages to Progressive Sustainable Uses. Image Credit: Shan 16899 / Shutterstock.com

Background

Using edible flowers has increased significantly lately, mainly due to their dietary and medicinal properties. Flowers are wealthy sources of many bioactive compounds, including carotenoids, phenolic compounds, vitamins C and E, saponins, and phytosterols.

In its place food source, flowers significantly contribute to food security and environmental sustainability. Nevertheless, some flowers may contain toxic substances, thus making them not suitable for consumption.

Many post-harvest treatments, including refrigeration, crystallization, lyophilization or freeze-drying, sugar canning, and preservation in distillates, have been developed to extend the shelf-life and quality of flowers. Despite these advancements, edible flowers are mainly sold fresh and chilled without another post-harvest treatments.

Nutrients and bioactive compounds in edible flowers

The recognition of edible flowers is increasing due to their dietary and health advantages. Evidence indicates that the consumption of some edible flowers can provide every day really useful amounts of certain minerals, including magnesium, phosphorous, and potassium. Nevertheless, boiling some flowers may reduce their mineral content.

Different parts of flowers contain different amounts of nutrients. Pollen, for instance, has high amounts of proteins, amino acids, carbohydrates, and lipids.

Nectar has balanced amounts of sugars, amino acids, proteins, inorganic ions, lipids, organic acids, and alkaloids. Petals and other parts of flowers function potential sources of vitamins, minerals, and bioactive compounds.

Phenolic compounds and carotenoids are the most important bioactive compounds present in flowers. Recent evidence indicates that about 60% and 54% of known edible flowers contain carotenoids and phenolic compounds, respectively. Nevertheless, it has been observed that flowers containing high amounts of carotenoids don’t generally contain high amounts of phenolic compounds and vice versa.

Flavonols, akin to quercetin, kaempferol, isorhamnetin, myricetin, and their derivatives, are the important class of flavonoids present in flowers. Flavones akin to luteolin, apigenin, acacetin, and chrysoeriol are the second major class of flavonoids. Amongst phenolic acids, chlorogenic acid, caffeic acid, caffeoylquinic acid, protocatechuic acid, and gallic acid are present in edible flowers.

Hydroxy xanthophylls and xanthophylls containing hydroxyl and epoxide groups are probably the most common sorts of carotenoids present in edible flowers. Provitamin A carotenes and colorless carotene phytoene will also be present in flowers. In Renealmia alpinia (Rottb.) Maas, a medicinal plant typically present in rainforests in Mexico, extremely high amounts of provitamin A carotenes have been reported.

Health advantages of edible flowers

Bioactive compounds present in edible flowers are related to many health advantages, including antioxidants, anti-inflammatory, anticancer, anti-obesity, hepatoprotective, neuroprotective, gastroprotective, antidiarrheal, anti-microbial, antispasmodic, analgesic, and astringent properties.

About 97% of known edible flowers are related to therapeutic properties. Specifically, about 32%, 26%, and 14% of flowers have been identified to have immunomodulatory, anti-microbial, and gastro-protective properties, respectively.

Previous in vitro studies have observed high antioxidant activity in begonias, roses, garden nasturtiums, daylily, calendula, Japanese rose, Daurian rose, daylily, and chrysanthemum. Moreover, many edible flowers, including hibiscus, rose, chrysanthemum, tagetes, cosmos, coral vine, lesser bougainvillea, jasmine, honeysuckle rose, cassia fistula, chives, calendula, and pomegranate flowers exhibit anticancer effects against a wide selection of cancers including those affecting the liver, colon, brain, skin, bladder, prostate, and breast.

Chrysanthemums. Image Credit: Old Man Stocker / Shutterstock

Anti-inflammatory properties have been identified in Roselle, Hangzhou white chrysanthemum, wild chrysanthemum, honeysuckle, and daylily flowers. Moreover, anti-obesity effects have been attributed to Roselle, magnolia, and waterlily flowers.

High levels of lutein and zeaxanthin, each carotenoids, have been detected within the petals of tagete flowers. These carotenoids are known to have protective effects against ocular pathologies, akin to age-related ocular degeneration.  

Other advantages of flowers

Food production accounts for about 40% of land use and 70% of freshwater use, that are significant obstacles to achieving a sustainable ecosystem. Contamination of soil and water on account of human activities is one other major problem within the context of food production and security.

Phytoremediation is a means of using plants to remove contaminants and pollutants from the environment. Plant roots can absorb and immobilize heavy metals present in soil, which may then be converted into volatile forms and released into the atmosphere through stomata, a process otherwise referred to as phyto-volatilization.      

Plants may also degrade soil pollutants through phyto-degradation or rhizodegadation through using enzymes or soil contaminants using microorganisms within the rhizosphere, respectively. Phyto-extraction is one other vital approach typically used for industrial applications.   

Within the textile industry, flower-derived dyes are gaining popularity due to the potential environmental and health hazards related to synthetic dyes. Recent evidence indicates that flowers like jasmine and saffron purple petals will be used to supply bioethanol and an environmentally friendly additive for bentonite-based drilling fluids, respectively.

Porous carbon nanosheets will be produced by carbonizing paper flowers. These materials will also be utilized in energy storage and dye removal.