ANTIOXIDANT AND ANTIBACTERIAL ACTIVITIES OF TARAXACUM OFFICINALE FLOWERS

• DOI: https://doi.org/10.22533/at.ed.1595322522107

• Palavras-chave: Flores de dente-de-leão; Fenólicos, Flavonóides, Atividade antioxidante, Atividade antibacteriana

• Keywords: Dandelion flowers; Phenolics, Flavonoids, Antioxidant activity, Antibacterial activity

• Abstract: One of the biggest threats to global biodiversity is the spread of exotic plant invasions, which have serious repercussions for the economy, human health, and natural ecosystems. Thus, the ability of invasive plant species to acquire resources is often superior to that of native species, which helps them thrive in new habitats(1). Assessing invasive plant species' potential for revaluation may encourage their usage as a replacement source of bioactive compounds and, as a result, assess their potential as alternate health-promoting strategies. Recently, there has been a shift in research from eradicating invasive plants to using them as valuable sources of biomass, as plant biomass can be a valuable resource for the bioeconomy(2,3). For instance, Iyer et al.(4) described Ulex europaeus, Viciasativa, Cytisus scoparius, Chamaenerion angustifolium, Pteridium aquilinum, and Buddleja davidii, globally invasive plant species as valuable alternative protein sources. More recently, Purmalis et al.(5) showed high polyphenols content with high radical scavenging activity in leaves and flowers of Lupinus polyphyllus, Impatiens glandulifera, Heracleum sosnowskyi, Solidago canadensis, Echinocystis lobata, and Elodea canadensis. Despite everything, invasive plants' potential for valorization depends on the composition of their main and secondary metabolites(6,7). Likewise, Acacia dealbata and Solidago canadensis are rich in compounds with pesticidal or biostimulant effects suitable for agricultural purposes(8,9). So, invasive plants biomass exhibits specific properties (functional, biological, medicinal.) that can be used directly or serve as a basis to develop new products. Taraxacum officinale F.H. Wigg. (dandelion), a member of the Asteraceae family, is nowadays very important for its pharmacological effect and as a food source, due to it containing several bioactive compounds and nutritionally valuable substances(10). Dandelion is considered a major weed, particularly on lawns, where it is difficult to eliminate because its long taproot easily splits when pulled out, allowing it to remain in the soil and re-sprout. Despite this, it is edible and frequently appears on lists of unusual edible plants, known as "PANC" (unusual Edible Plants). It has a global distribution, being very common in Portugal and the Iberian Peninsula, where it grows in fields, lawns, roadsides and places with damp soils. Dandelion is traditionally used raw, in salads, dried to make infusions, or cooked. Virtually all its parts are used: leaves, flowers, and roots. Additionally, the root can be roasted for use as a coffee substitute. Its therapeutic applications are various, owing mostly to its traditional uses. Because it had favorable consequences, it stimulated the repetition of information passed down from generation to generation. Taraxacum officinale is a popular medicinal plant used for liver diseases. Vitamin A stimulates the immune system, while vitamin B improves human metabolism. Additionally, this plant contains a lot of minerals, including iron, copper, and potassium. Thus, several caffeic acid derivatives (chicoric, caftaric, chlorogenic, neochlorogenic, 1,5-and 3,5-dicaffeoylquinic acids) and flavonoids (glycosides of apigenin, luteolin, quercetin, isorhamnetin, kaempferol) were identified(11). Also, sesquiterpene lactones, triterpenoids, polysaccharides, phytosterols, and volatile oils are included in dandelion plants(10). Multiple pharmacological studies have demonstrated the antiviral, antibacterial, anti-inflammatory, immune-regulating, antioxidant, anti-tumor, and other effects of the Taraxacum genus(10-12). Concerning the necessity to better understand dandelion composition and the potential use of its biomass, the aim of this study was to characterize the total polyphenolic and flavonoid content, antioxidant activity (DPPH, FRAP) and antimicrobial activity of hydroalcoholic extracts from dandelion flowers from Portugal. Compositional analysis of this species provides an addition to existing knowledge, therefore indicating potential differences in comparison to territories where this plant is native. Moreover, for plant biomass usage for bioenergy, typically the whole plant is used, leading to another aim of the study, which is to describe the composition of polyphenols and flavonoids in different parts of the plants, which can foster the development of more precisely aimed biotechnologies and applications of plant extracts in the bioeconomy.