Plantago lanceolata L. (plantain) is an interesting multipurpose perennial species whose aerial parts are used in herbal medicine due to its precious phytochemicals and are palatable to animals. Moreover, peculiar traits such as drought tolerance, an extended growth season and a deep root system, make plantain a promising pioneer plant for quarry reclamation based on the use of native species. This study evaluated the effects of different environmental conditions and seasons on the accumulation of the bioactive compounds of its aerial organs. An autochthonous plantain population was grown in three locations in Sardinia (Italy). Leaves, peduncles and inflorescences were collected between October 2020 and July 2021. Phenolic contents and antioxidant capacity were determined. The analysis of the individual phenolic compounds was performed using liquid chromatography. In leaves, the content of total phenolics, antioxidant capacity and total flavonoids were significantly influenced by location and season. Total phenolic content ranged from 65 to 240 g gallic acid equivalent kg⁻¹, whereas total flavonoids were from 16 to about 89 g catechin equivalent kg⁻¹. Neochlorogenic, chlorogenic, cryptochlorogenic acids, verbascoside, diosmin and luteolin were identified in the methanolic extracts of leaves, peduncles and inflorescences. Verbascoside was the main antioxidant isolated from plantain extracts. Results evidenced an increasing accumulation pattern of phenolics from vegetative stage to flowering, followed by a decrement towards the seed ripening as well as site-specific differences with amounts of phenolics even 25% higher for same plantain accession.

Guayule (Parthenium argentatum) is one of the most promising alternatives to produce natural rubber. As the guayule leaves represent a waste byproduct in the rubber extraction process, their exploitation might contribute to the valorization of the whole plant biomass. The specific aim of our study was to determine the antioxidant capacity and the content of phenolic compounds in leaves and twigs of different guayule lines cultivated in a Mediterranean environment. The antioxidant capacity and the contents of phenolic were affected significantly by guayule accession and harvest time. Overall means in twigs represented about 60% of the corresponding leaf values for antioxidant capacity as DPPH (1,1-diphenyl-2-picrylhydrazyl) and not tannic phenolic and about 55% as ABTS (2,2′-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt), total phenolic, tannic phenolic and total flavonoid contents. Five individual phenolic compounds were identified in methanolic extracts of leaves. Neochlorogenic acid (62.5–174.8 mg g⁻¹ DW) and chlorogenic acid (28.6–41.1 mg g⁻¹ DW) were the most abundant phenolic acids. In addition to the compounds quantified in leaves, cynarin was identified only in twigs and for the first time in guayule biomass. Our results indicate that guayule leaves and twigs represent a rich source of antioxidants for potential applications in fodder, nutraceutical and pharmacological sectors.

Background: The genetic diversity of Sardinian pear germplasm has received limited attention regarding its chemical composition. Understanding this composition can aid in the setting up of resilient, extensive groves that offer multiple products and ecosystem services. This research aimed at investigating the antioxidant properties and phenolic compounds of ancient pear cultivars grown extensively in Sardinia (Italy); Methods: the cultivars Buttiru, Camusina, Spadona, and Coscia (as a reference) were compared. Fruit samples were manually peeled and cut. Their flesh, peel, core, and peduncle were frozen separately, lyophilized, and milled before being analysed; Results: The content of total phenolics (TotP), total flavonoids (TotF), condensed tannins (CT), and antioxidant capacity in each fruit part varied significantly among the cultivars. The TotP content was high in the peduncle (42.2–58.8 g GAE kg⁻¹ DM) and low in flesh (6.4–17.7 g GAE kg⁻¹ DM); Conclusions: the highest values of antioxidant capacity, TotP, NTP, TotF, and CT were found in the flesh of the cultivar Buttiru and in the peel of the cultivar Camusina. Chlorogenic acid was the major individual phenolic compound in peel, flesh and core, whereas arbutin was mostly present in the peduncle. Results can contribute to revise target exploitations of underutilized ancient pear cultivars.

Mediterranean pasture and forage legumes are important components of sustainable production systems. Subterranean clover and sulla represent key species having proven high agronomic value and traits for production and multiple services. Our research investigated the potential of the abovementioned species as a source of phenolic compounds and antioxidants for contributing to support their full exploitation in the fodder, animal welfare, and nutraceutical sectors. Antioxidant capacity, as well as the content of total phenolic compounds and individual phenolic compounds, was determined in subterranean clover and sulla shoots at the vegetative, flower bud, flowering, and seed ripening phenological stages. The antioxidant capacity and the phenolic content were affected significantly by harvest time. In subterranean clover, 10 individual phenolic compounds were detected, and isoflavones were the most abundant (3.19–18.27 mg·g⁻¹ DM). Eleven phenolic compounds were identified in sulla shoots, and chlorogenic acid (0.76–3.43 mg·g⁻¹ DM) and diosmin (3.64–4.94 mg·g⁻¹ DM) were the most represented compounds at the vegetative and flower bud stage. On the basis of our findings, a complementary utilization of both legume species is suggested; this might ensure the exploitation of all phenolic compounds in view of the potential benefits for animal production and health.