Flavonoid Composition and Antitumor Activity of Bee Bread Collected in Northeast Portugal

Abstract

Bee bread (BB) is a fermented mixture of plant pollen, honey, and bee saliva that worker bees use as food for larvae, and for young bees to produce royal jelly. In the present study, five BB samples, collected from Apis mellifera iberiensis hives located in different apiaries near Bragança, in the northeast region of Portugal, and one BB commercial sample were characterized by high-performance liquid chromatography coupled to a diode array detector and electrospray mass spectrometry (HPLC-DAD-ESI/MS) in terms of phenolic compounds, such as flavonoid glycoside derivatives. Furthermore, the samples were screened, using in vitro assays, against different human tumor cell lines, MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), HeLa (cervical carcinoma) and HepG2 (hepatocellular carcinoma), and also against non-tumor liver cells (porcine liver cells, PLP2). The main phenolic compounds found were flavonol derivatives, mainly quercetin, kaempferol, myricetin, isorhamnetin and herbacetrin glycoside derivatives. Thirty-two compounds were identified in the six BB samples, presenting BB1 and BB3 with the highest contents (6802 and 6480 µg/g extract, respectively) and the highest number of identified compounds. Two isorhamnetin glycoside derivatives, isrohamnetin-O-hexosyl-O-rutinoside and isorhamnetin-O-pentosyl-hexoside, were the most abundant compounds present in BB1; on the other hand, quercetin-3-O-rhamnoside was the most abundant flavonol in BB3. However, it was not possible to establish a correlation between the flavonoids and the observed low to moderate cytotoxicity (ranging from >400 to 68 µg/mL), in which HeLa and NCI-H460 cell lines were the most susceptible to the inhibition. To the authors’ knowledge, this is the first report characterizing glycosidic flavonoids in BB samples, contributing to the chemical knowledge of this less explored bee product.

Bee bread as a functional product: Chemical composition and bioactive properties

“…1), the results show the presence of thirteen compounds, mainly flavonols glycoside derivative, especially quercetin, kaempferol, isorhamnetin, and methylherbacetrin derivatives. The identification of the phenolic compounds present were performed taking into account a previous study performed by Sobral et al (2017) using Portuguese bee bread samples, and the flavonol glycoside profile was very similar to the samples analyzed in that work. Of all the detected compounds isorhamnetin-O-hexosyl-O-rutinoside is the main phenolic compound present in this BB sample.…”

“…In addition, they found that variables such as soil and climate do not appear to influence these compounds in the type of samples studied. Nevertheless, Sobral et al (2017) studied BB from different origins and detected differences in the phenolic composition of these samples. The antioxidant activity results (Table 4) revealed a total antioxidant capacity of 143 ± 22 mg equivalent of AA/g, the lower EC 50 was registered for the reducing power assay (EC 50 = 0.19 ± 0.03 mg/ mL), followed the ABTS assay (EC 50 = 0.50 ± 0.04 mg/mL), and DPPH assay (EC 50 = 0.98 ± 0.06 mg/mL).…”

“…Bee bread nutritional value is higher than bee pollen and it is more digestible due to the presence of a higher content of free amino acids and easily assimilated sugars (Kieliszek et al, 2018). In comparison with other bee products, studies on bee bread are scarce and limited especially concerning their chemical composition (Bakour et al, 2017;Kaplan, Karaoglu, Eroglu, & Silici, 2016;Sobral et al, 2017;Tavdidishvili, Khutsidze, Pkhakadze, Vanidze, & Kalandia, 2014;Čeksteryte et al, 2016;Čeksteryte & Jansen, 2012) and there are few reports regarding preclinical studies (Bakour et al, 2017; https://doi.org/10.1016/j.lwt.2019.02.008 Received 24 November 2018; Received in revised form 1 February 2019; Accepted 3 February 2019 T 2017).…”

Bee Collected Pollen and Bee Bread: Bioactive Constituents and Health Benefits

“…Five BB samples were screened, using in vitro assays, against different human tumor cell lines, HeLa, HepG2, MCF-7, NCI-H460, and also against non-tumor liver cells (porcine liver cells, PLP2) [104]. From all the tested samples, BB3 was the only one to inhibit the growth of all tested cell lines, solely inhibiting the growth of HepG2.…”

Analysis of improved nutritional composition of bee pollen (Brassica campestris L.) after different fermentation treatments

“…Bee bread may provide a significant amount of polyunsaturated fatty acids for the human body. Phytochemicals, such as flavonoid glycoside derivatives, widely exist in bee bread and have anticancer and antioxidant activities (Sobral et al, 2017). In the honeycomb, the conditions of fermentation process are quite complicated, and thus, producing bee bread by artificial simulations is difficult; however, it is technologically feasible to use BP as raw material by fermentation to obtain a nutraceutical for humans (Salazar-Gonz alez & D ıaz-Moreno, 2016).…”