Strawberry Fragaria x ananassa cv. Festival: A Polyphenol-Based Phytochemical Characterization in Fruit and Leaf Extracts

Abstract

Berry fruits are an important dietary source of health-promoting antioxidant polyphenols. Interestingly, berry leaves of diverse species, including strawberries, have shown higher bioactive phytochemical content in the leaves than in the fruit. Moreover, the vegetative part of the plants is usually discarded, representing a presumably large source of underutilized bioactive biomass. In this investigation, the polyphenol profiles of tropical highland strawberry (Fragaria x ananassa cv. Festival) leaves and fruits were compared by high-performance liquid chromatography coupled with a diode array detector (UHPLC-DAD) and mass spectrometry (HPLC-MS). The total polyphenol strawberry leaf extracts exhibited a 122-fold-higher total polyphenol content and 13-fold higher antioxidant activity (ORAC) than strawberry fruits, and they showed evidence of possible photoprotective effects against UV damage in human melanoma cells (SK-MEL-28) and in murine embryo fibroblasts (NIH/3T3), together with promising anti-proliferative activities against the same melanoma cells. Seven polyphenols were confirmed by HPLC-DAD in the leaf extracts, with differences depending on fraction solubility. Moreover, three substituted quercetin derivatives, three substituted kaempferol derivatives, two anthocyanins, and catechin were confirmed in the soluble fraction by HPLC-MS. Given their higher total polyphenol content and bioactive activities, underutilized strawberry Festival leaves are a potential source of apparently abundant biomass with prospective bioactive applications.

Eliciting Polyphenols in Strawberry Leaves: Preliminary Experiments in Fragaria × ananassa cv. Festival

“…Two other polyphenols, rutin and (+)-catechin, were present only in the in vivo (in trace amounts) or in the in vitro plants, respectively. As reported before for this cultivar [15], gallic acid was the most abundant polyphenol found in the leaves, both in vivo (in the insoluble fraction) and in vitro, under most treatments (except for the cysteine-treated in vivo plants, where rutin was the more abundant polyphenol). Moreover, in accordance with the total polyphenol results, gallic acid concentrations were also higher in the in vitro plants (Table 2) relative to the greenhouse-grown seedlings (Table 3).…”

“…(+)-Catechin and chlorogenic acid were also absent in untreated greenhouse-grown strawberry ( F. × ananassa cv. Festival) leaves according to a previous report, where quercetin was also found in much lower concentrations [ 15 ]. These three compounds warrant further investigation in the future as possible targets for polyphenol elicitation in strawberry leaves.…”

“…From a global production of over 12 million tons per year, around 20% of strawberry production corresponds to vegetative waste, which is generally discarded [ 13 , 14 ]. Nonetheless, strawberry leaves have been found to exhibit higher polyphenol content and higher antioxidant activity than strawberry fruits, representing a presumably relevant source of unexploited bioactive biomass [ 15 ]. Furthermore, as a temperate crop, tropical highland strawberry crops have been less studied, even though increased polyphenol accumulation and diversity has been shown to occur in other crops under the higher temperatures, longer photoperiods, and the increased UV irradiation conditions of lower latitudes [ 16 ].…”

Kinetic modeling of valuable phenolic compounds extraction from strawberry and apple agro‐industrial by‐products

“…Global strawberry production was about 9.2 million tons, while apple production reached 75.5 million tons in 2021 (Salas-Arias et al, 2023).…”

“…Strawberries and apples are among the most widely produced and consumed fruits worldwide due to their versatility and nutritional and bioactive properties (Güzel & Akpınar, 2019). Global strawberry production was about 9.2 million tons, while apple production reached 75.5 million tons in 2021 (Salas‐Arias et al, 2023). These fruits have a variety of bioactive compounds, like phenolic compounds such as ellagitannins, phenolic acids, and flavonoids like anthocyanins in strawberries (Nowicka et al, 2019; Van de Velde et al, 2018; Villamil‐Galindo & Piagentini, 2022), catechins, proanthocyanidins, and flavonols in apple (Farinha et al, 2023; Mourtzinos & Goula, 2019).…”