BackgroundWalnut (Juglans regia L.), that belongs to the Juglandaceae family, is one of the nuts commonly found in Chinese diets. Researchers had obtained peptides from walnut protein hydrolysates, and these peptides exhibited the high antioxidant activities. The objective of this study was to develop a simple and convenient method for a facile and reproducible preparation of antioxidant peptides from walnut protein hydrolysates.ResultsWalnut proteins were extracted from walnut kernels using continuous countercurrent extraction process, and were separately hydrolyzed with six types of proteases (neutrase, papain, bromelain, alcalase, pepsin, and pancreatin). Then, hydrolysates were purified by ultrafiltration. The yields and purity of the peptides prepared using neutrase and papain were 16 and 81 % at least, respectively, higher than others, and had low molecular weight, 99 % of which were less than 1500 Da. Furthermore, the bioassay indicated that the two peptides exhibited the high antioxidant activities in the DPPH (IC50 values: 59.40 and 31.02 µg/mL, respectively), ABTS (IC50 values: 80.36 and 62.22 µg/mL, respectively), and superoxide radical scavenging assay (IC50 values: 107.47 and 80.00 µg/mL, respectively).ConclusionsThe method combines the advantages of generality, rapidity, simplicity, and is useful for the mass production of walnut peptides.Graphical AbstractPreparation of antioxidant peptides from walnut (Juglans regia L.) protein hydrolysates

After Memoregain(®) treatment, patients with AD showed no obvious aggravation of cognitive function, independent living ability, and overall conditions but were stable throughout the study. Comparison with other long-term medications with acetylcholinesterase inhibitors suggests that Memoregain(®) has a potential to be a possible treatment option for mild to moderate AD. Large trials with bigger population are required to confirm.

Poria cocos, called fuling, is a famous tonic in traditional Chinese medicine that reportedly possesses various pharmacological properties, including anti-inflammation and immunomodulation. However, few studies have investigated the effects of P. cocos on allergic diseases, such as allergic asthma. Allergic asthma is caused primarily by Th2 immune response and characterized by airway inflammation. This study first demonstrated the anti-allergic and anti-asthmatic effects of P. cocos extract (Lipucan®). P. cocos extract distinctly exhibited reduced inflammatory cell infiltration in the peribronchial and peribronchiolar regions compared to the asthma group in the histological analysis of pulmonary tissue sections. Prolonged P. cocos extract administration significantly reduced eosinophil infiltration, PGE2 levels, total IgE, and OVA-specific IgE. Moreover, P. cocos extract markedly suppressed Th2 cytokines, IL-4, IL-5, and IL-10. On the other hand, P. cocos extract significantly elevated IL-2 secretion by Th1 immune response. In addition, P. cocos extract elevated the IFN-γ level at a lower dose. We also observed that P. cocos extract increased the activity of NK cells. Our results suggest that P. cocos extract remodels the intrinsic Th1/Th2 response to prevent or alleviate allergy-induced asthma or symptoms.

Walnut has been reported to have beneficial effects on improving cognitive performance. This randomized double-blind placebo-controlled clinical trial evaluates the clinical effectiveness and safety of walnut oligopeptide (WO) on memory enhancement, cognition, and sleep quality in teenagers and elderly people. Eighteen teenagers and 18 elderly people were, respectively, randomly allocated to placebo, low dosage (170 mg), and high dosage (340 mg) WO administration groups (n = 6 per group in each population). After 90 days of administration, the Wechsler Adult Intelligence Scale (WAIS) score was significantly increased and the global Pittsburgh Sleep Quality Index (PSQI) score was significantly decreased in the WO administration group. In addition, the average scores for test subjects of Chinese, Mathematics, and English examinations were significantly increased from the baseline for the teenagers in the WO administration group. Our results support the claim that WO has the potential to become a new option for nutritional intervention, to enhance the memory, cognitive ability, and sleep quality of teenagers and elderly people. This study was approved by the Institutional Review Board of the Shanghai Nutrition Society and registered at the Chinese Clinical Trial Registry ( http://www.chictr.org.cn ) with an ID number of ChiCTR1900028160.

Cistanche tubulosa aqueous extract (CTE) is already used as a botanical prescription drug for treating dementia in China. Our previous studies reported that phenylethanoid glycosides of CTE have anti-Alzheimer’s disease (AD) activity by inhibiting amyloid β peptide (Aβ) aggregation and deposition. However, recent studies considered that the phenylethanoid glycosides may be metabolized by intestinal bacteria, because all analysis results showed that the bioavailability of phenylethanoid glycosides is extremely low. In this study we demonstrate how iron chelation plays a crucial role in the Aβ aggregation and deposition inhibition mechanism of phenylethanoid glycosides of CTE. In addition, we further proved phenylethanoid glycosides (1–3) could reach brain. Active CTE component and action mechanism confirmation will be a great help for product quality control and bioavailability studies in the future. At the same time, we provide a new analysis method useful in determining phenylethanoid glycosides (1–3) in plants, foods, blood, and tissues for chemical fingerprint and pharmacokinetic research.