White sweet potato ameliorates hyperglycemia and regenerates pancreatic islets in diabetic mice.

BACKGROUND: White sweet potato (WSP) has many potential beneficial effects on metabolic control and on diabetes-related insulin resistance. The antihyperglycemic effects of Tainung No. 10 (TNG10), a variety of WSP in Taiwan, warrant investigation. OBJECTIVE: To investigate the antidiabetic activity of WSP (Ipomoea batatas L. TNG10) and the mechanisms for interventions using whole leaves or tubers of WSP in diabetic mice. DESIGN: Mice were co-administered with streptozotocin and nicotinamide to induce diabetes and then treated with an experimental diet including either 10% WSP tuber (10%-T) and 30% WSP tuber (30%-T) or 0.5% WSP leaf (0.5%-L) and 5% WSP leaf (5%-L). After 8 weeks' treatment, their plasma glycemic parameters, lipid profiles, and inflammatory marker were analyzed. Their pancreases were removed for histopathologic image analysis; proteins were also extracted from their muscles for phosphoinositide 3-kinase pathway analysis. RESULTS: The 30%-T or 5%-L mice had lower plasma glucose, insulin, glucose area under the curve (AUC), homeostatic model assessment of insulin resistance (HOMA-IR), alanine transaminase, triglyceride, and tumor necrosis factor alpha levels. In all diabetic mice, their Langerhans's area was reduced by 60%; however, after 30% WSP-T or 5% WSP-L diets, the mice demonstrated significant restoration of the Langerhans's areas (approximately 30%). Only in 5%-L mice, slightly increased expression of insulin-signaling pathway-related proteins, phosphorylated insulin receptor and protein kinase B and membrane glucose transporter 4 was noted. CONCLUSIONS: WSP has antihyperglycemic effects by inducing pancreatic islet regeneration and insulin resistance amelioration. Therefore, WSP has potential applications in dietary diabetes management.

Evaluation of white sweet potato tube-feeding formula in elderly diabetic patients: a randomized controlled trial.

BACKGROUND: Elderly people with type 2 diabetes mellitus (T2DM) have an increased risk of diabetes-related microvascular and macrovascular complications, thus diabetic patients with a functioning gastrointestinal tract but without sufficient oral intake require enteral nutrition (EN) formulas to control blood glucose. White sweet potato (WSP) was a kind of sweet potato could provide a healthy carbohydrate source to EN formula. The aim of this study was to examine at risk of malnutrition T2DM patients whether a WSP-EN would attenuate glucose response and elevate nutritional index compared to a standard polymeric formulas. METHODS: In this randomized, parallel, placebo-controlled, pilot clinical trial to investigate the effects of EN with WSP on aged residents with T2DM in long-term care institutions. In total, 54 eligible participants were randomly assigned to either the non-WSP-EN or WSP-EN group. For 60 days, the WSP-EN group received a WSP formula through nasogastric tube via a stoma with a large-bore syringe. The participants received EN of standard polymeric formulas without WSP in the non-WSP-EN group. RESULTS: The body weight, body mass index, Mini Nutritional Assessment score, and Geriatric Nutritional Risk Index were significantly higher in the WSP-EN group (p < 0.05). Moreover, the WSP-EN intervention reduced glycated hemoglobin levels (6.73% ± 1.47% vs. 6.40% ± 1.16%), but increased transferrin (223.06 ± 38.85 vs. 245.85 ± 46.08 mg/dL), high-density lipoprotein cholesterol (42.13 ± 10.56 vs. 44.25 ± 8.43 mg/dL), and vitamin A (2.45 ± 0.77 vs 2.74 ± 0.93 µM) levels (p < 0.05). In addition, there was no important side effects including gastrointestinal intolerance with prescribed doses in our WSP-EN treated patients when compared with control ones. CONCLUSIONS: The results suggest WSP incorporated into enteral formulas can improve nutrition status and glycemic control in elderly diabetic patients. TRIAL REGISTRATION: NCT02711839, registered 27 May 2015.

Inhibitory effects of cultured Dendrobium tosaense on atopic dermatitis murine model.

Dendrobium tosaense is one of the most valuable Chinese medicines and well developed health food. Atopic dermatitis (AD) is a chronic skin disease that occurs mainly in childhood. The pathogenesis of atopic dermatitis had been studied in BALB/c mice modeling by skin-inoculated ovalbumin (OVA) with 2,4,6-trinitro-1-chrolobenzene (TNCB). These mice exhibit features of chronic dermatitis, including skin rash, mast cells infiltration, and elevated serum anti-OVA specific IgE and cytokines modulation. In this study, a standardized ethyl acetate extract of D. tosaense (DtE) was used to protect these mice from the OVA/TNCB-induced skin lesions of atopic dermatitis. The results indicated an increased population of natural T regulatory cell was accompanied by immunosuppression in cytokine profiles and anti-OVA IgE level to significantly reduce Th2 polarization. Finally, toluidine blue staining indicated mast cell infiltration and degranulation was reduced in skin lesion. Our results were shed light on the usage of D. tosaense in AD.

Alkaline alpha-galactosidase degrades thylakoid membranes in the chloroplast during leaf senescence in rice.

Here, we studied the functional role of a chloroplast alkaline alpha-galactosidase (OsAkalphaGal) in the breakdown of thylakoid membranes during rice (Oryza sativa) leaf senescence. We assayed the enzyme activity of recombinant OsAkalphaGal with different natural substrates and examined the effect of ectopic OsAkalphaGal expression in rice plants. Recombinant OsAkalphaGal showed at least a two-fold greater substrate-binding affinity and a 10-fold greater turnover rate to galactolipid digalactosyl diacylglycerol than the raffinose family of oligosaccharides (verbascose, stachyose, raffinose) and melibiose. The OsAkalphaGal null mutant (osakalphagal) displayed a delayed leaf senescence phenotype. OsAkalphaGal complementation in osakalphagal recovered OsAkalphaGal expression and showed a senescence phenotype similar to that of wild-type plants. Transgenic plants overexpressing OsAkalphaGal (UbiP-OsAkalphaGal) exhibited retarded plant growth and development, and showed a pale-green phenotype coupled with a reduced chlorophyll content to 42% in newly unfolded leaves. UbiP-OsAkalphaGal leaves also showed a 29-fold increase in alkaline alpha-galactosidase activity compared with wild-type leaves. An ultrastructural study of Ubi-OsAkalphaGal chloroplasts in newly unfolded leaves revealed abnormal grana organization. Our findings strongly suggest that OsAkalphaGal is a thylakoid membrane-degrading enzyme involved in the degradation of digalactosyl diacylglycerol during rice leaf senescence.