Antioxidant, antidiabetic and identification of phenolic constituents from Potentilla discolor Bge

Effect of Pretreatments on the Chemical, Bioactive and Physicochemical Properties of Cinnamomum camphora Seed Kernel Extracts

Cinnamomum camphora seed kernels (CCSKs) are rich in phytochemicals, especially plant extracts. Phytochemicals play a vital role in therapy due to their strong antioxidant and anti-inflammatory activities. Extracts from CCSK can be obtained through multiple steps, including pretreatment, extraction and purification, and the purpose of pretreatment is to separate the oil from other substances in CCSKs. However, C. camphora seed kernel extracts (CKEs) were usually considered as by-products and discarded, and their potential bioactive values were underestimated. Additionally, little has been known about the effect of pretreatment on CKE. This study aimed to investigate the effects of pretreatment methods (including the solvent extraction method, cold pressing method, aqueous extraction method and sub-critical fluid extraction method) on the extraction yields, phytochemical profiles, volatile compounds and antioxidant capacities of different CKE samples. The results showed that the CKE samples were rich in phenolic compounds (15.28-20.29%) and alkaloids (24.44-27.41%). The extraction yield, bioactive substances content and in vitro antioxidant capacity of CKE pretreated by the sub-critical fluid extraction method (CKE-SCFE) were better than CKEs obtained by other methods. CKE pretreated by the solvent extraction method (CKE-SE) showed the best lipid emulsion protective capacity. Moreover, the volatile substances composition of the CKE samples was greatly influenced by the pretreatment method. The results provided a fundamental basis for evaluating the quality and nutritional value of CKE and increasing the economic value of by-products derived from CCSK.

Low-glycemic foods with wheat, barley and herbs (Terminalia chebula, Terminalia bellerica and Emblica officinalis) inhibit α-amylase, α-glucosidase and DPP-IV activity in high fat and low dose streptozotocin-induced diabetic rat

Wheat, barley or wheat + barley and herbs (Terminalia chebula, Terminalia bellerica and Emblica officinalis) based low-glycemic-index (low-GI) foods were developed and studied α-amylase, α-glucosidase and DPP-IV inhibition property in vitro and in the streptozotocin-induced diabetic rats. The GI of products ranged from 47 to 53 than control white bread (GI = 95). Total phenolic (20.1 ± 1 mg gallic acid/g dry wt.) and flavonoids (15.2 ± 1 mg quercetin/g dry wt.) were higher in wheat + barley than barley (17.2 ± 1; 13.6 ± 2) and wheat (16.9 ± 1; 14.9 ± 2) products. The in vitro α-amylase (4-10%), α-glucosidase (5-17%) and DPP-IV (3-26%) inhibition (IC₅₀) of methanol extracts were higher than the aqueous extracts. The fasting blood glucose (50.85, 33.22 and 24.52%) and oral glucose tolerance (AUC = 32.1, 36.04, and 27.73%) was lower in barley, wheat, and wheat + barley fed diabetic groups than diabetic control group (1571.5 ± 13.5 mg/dL/120 min). Feeding wheat, barley, and W + B foods for 60 days inhibited the intestinal α-amylase (1.2, 1.1 and 1.5-folds), α-glucosidase (1.3, 1.2 and 1.7-folds) and DPP-IV (1.6, 1.5 and 2.1-folds) activity compared to diabetic control. Low-GI foods lower the systemic glucose level, inhibit the glycolytic enzymes and DPP-IV activity and hence desirable for diabetes management.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-021-05231-0.