Phenolic fraction concentrate of Phoenix dactylifera L. seeds: A promising antioxidant and glucose regulator

Abstract

Context: The beneficial effects of natural polyphenolic compounds are increasingly emerging as powerful antioxidants and digestive boosters. Phoenix dactylifera seeds are recently identified as a healthy functional food with rich amounts of phenolic compounds. Aims: To analyzing the phenolic profile obtained from Moroccan variety of date seeds and evaluating the inhibitory capacity against digestive enzymes and the antioxidant potential of phenolic fraction concentrate (PFC) of date seeds as a promising antihyperglycemic agent. Methods: Lineweaver–Burk plot analysis was performed to evaluate PFC inhibitory effect against digestive enzyme activity in the presence of different doses of a substrate. Wistar rats were recruited to determine the acute and sub-acute oral toxicity of PFC. Finally, the optimal dose of PFC was selected and its effects on metabolic, hematological and biochemical parameters were determined. Results: High-performance liquid chromatography (HPLC) analysis revealed that PFC contains abundant amounts of phenolic acid: Caffeic acid, chlorogenic acid, 3,4-dihydroxybenzoic acid, p-hydroxybenzoic acid, and 3-hydroxybenzoic acid. PFC showed powerful antioxidant activity as determined by scavenging and reducing assays. PFC significantly inhibited alpha-amylase and alpha-glucosidase enzymes by 87.3% and 78.7%, respectively, via mixed manipulation of Km and Vmax. Acute toxicity examinations revealed PFC to be practically non-toxic with LD50 > 5000mg PFC/kg for both sexes of rats. The no-observed-adverse-effect-level (NOAEL) and lowest observed adverse effect level (LOAEL) for oral administration of PFC were 1000 and 2500 mg/kg for both sexes. Finally, the sub-acute study showed that a PFC dose of 50 mg/kg did not cause any changes in metabolic, biochemical and hematological parameters and was considered to be the optimal healthy dose for rats. Consequently, it induces improvement in glucose concentration in rats. Conclusions: The rational use of phenolic date seeds fraction presents powerful antioxidant and blood glucose regulating nutraceutical that could aid in diabetes mellitus management.

Phenolic fraction concentrates supplementation ameliorates learning and memory impairments in chronically stressed streptozotocin-diabetic rats by reducing brain tumor necrosis factor-α

“…As a result, previous research discovered that some phenolic acids such as caffeic and gallic acids protected rodents against chronic stressinduced disturbances (41,42). We suggest that the observed effects of PFCs in diabetic rats exposed to CMS might be linked to their significant amounts of phenolic acids, especially caffeic acid (25). In this context, interest in phenolic acid compounds has increased, mainly due to their anti-inflammatory, antioxidant, and antidiabetic properties against numerous chronic diseases.…”

“…A recent study has shown that monotherapy treatment with insulin did not protect patients against cognitive dysfunction and emotional disorders, including stress-related to T1DM (40). The exhibited PFCs effects might be explained by their significant antioxidant and antidiabetic effects (25). As a result, previous research discovered that some phenolic acids such as caffeic and gallic acids protected rodents against chronic stressinduced disturbances (41,42).…”

“…The PFC extraction of the date seeds was performed as described in our previous study (25). Date seeds were washed with tap water, let dry at 50°C in the oven for 48 hours, and ground until the obtention of seeds powder of 1-1.5 mm diameter.…”

“…The dose of insulin administered was divided into 2 separate injections: 2 UI in the morning and 4 UI in the afternoon, based on a previous study conducted by De Morais et al (30). However, the PFC administration protocol used (50 mg/ kg; once/day; per os), was based on our recent findings that the PFC showed in vitro and in vivo antioxidant and anti-hyperglycemic activities in addition to its safety for oral administration as evidenced by the acute and subacute oral toxicity studies conducted in vivo (25). Thus, the dose was regularly adjusted based on the body weight changes.…”

“…Accordingly, date seeds present a rich source of phenolic compounds with a range of significant biological activities (24). In addition to having antioxidant and antidiabetic activities (25), date seeds are also considered a promising anti-inflammatory product. Date seed extract has shown to be an anti-inflammatory agent due to its ability to control inflammatory mediators such as interleukin (IL)-1, IL-2, IL-6, interferon-gamma (IFN-γ) and TNF-α (26), and suppress the nuclear factor kappa B (NF-kB) translocation.…”