Introduction: The beneficial effects of resistant starch (RS) consumption on health in terms of reducing postprandial hyperglycaemia are evident. However, the potential of local Sarawak sago RS in regulating glucose has not been extensively studied. Objectives: This study aims to identify glucose-lowering effects of Sarawak sago RS, namely native (RS2) and chemically modified (RS4). Methodology: An oral glucose tolerance test (OGTT) was performed before and after 1 month treatment with sago RS2 and RS4 in spontaneously type 2 diabetes (T2D), Goto-Kakizaki (GK) rat. The mechanisms involved were further explored by screening the in vitro inhibitory activities of α-glucosidase and dipeptidyl peptidase (DPP)-IV. Histopathology examination for pancreas, kidney and liver tissues was done in response to sago RS intake using haematoxylin and eosin (H&E) staining. Results and discussion: The incremental area under the curve (iAUC) for blood glucose in RS-treated groups was decreased and significant in RS2-treated group ( p < 0.05). Improved iAUC for insulin and higher glucagon-like peptide (GLP-1) levels were observed in all RS-treated groups ( p < 0.05). Both sago RS may have potential roles in regulating glucose via α- glucosidase and DPP-IV inhibitory activities by reducing intestinal glucose absorption. For histopathology, although insignificant, sago RS2 and RS4 attenuated lesion scores of pancreatic tissue whereas the liver and kidney tissues significantly showed lesser lesion scores compared to the control diabetic group suggesting the potential of RS in reducing cell degeneration. Conclusion: Findings of this study indicates that RS2 showed greater glucose-lowering effect when compared to RS4, thus the therapeutic potential in the T2D management should be further explored.

The beneficial effects of resistant starch (RS) consumption on health in terms of reducing postprandial hyperglycemia are evident. However, the potential of local Sarawak sago RS in regulating glucose has not been extensively studied. This study aims to identify glucose lowering effects of Sarawak sago RS namely, native unmodified (RS2) and chemically modified (RS4). An oral glucose tolerance test was performed before and after one-month treatment with sago RS2 and RS4 in spontaneously type 2 diabetes, goto kakizaki rat. The mechanisms involved were further explored by screening the in vitro inhibitory activities of α-Glucosidase and DPP-IV. Histopathology examination for pancreas, kidney and liver tissues was performed in response to sago RS treatment using hematoxylin and eosin (H&E) staining.The blood glucose area under the curve (AUC) in RS-treated groups was decreased and significant in RS2-treated group (p<0.05). Improved insulin AUC and higher glucagon like peptide (GLP-1) levels were observed in all RS-treated groups (p<0.05). Sago RS2 and RS4 might have potential roles in regulating glucose via α- Glucosidase and DPP-IV inhibitory activities by reducing glucose absorption in the intestine. For histopathology study, although insignificant, sago RS2 and RS4 attenuated lesion scores of pancreatic tissue whereas the liver and kidney tissues significantly showed lesser lesion scores as compared to the control diabetic group suggesting the potential of RS in reducing cell degeneration which indeed requires further validation.Findings of this study suggests the therapeutic potential of sago RS in the T2D management which may justify further investigation to be done.

Resistant starch (RS) Sago (Metroxylon sagu) intake has been linked with the improvement in postprandial hyperglycemia and diabetes management via several modes of action including delayed glucose absorption and inhibition of carbohydrate digestion in the gastrointestinal tract. However, to our knowledge, studies on local Malaysian sago RS associated with hepatic glucose production has not been reported elsewhere. Thus, this study was done to identify the underlying mechanisms of local Malaysian RS sago native and modified known as sago RS type 2 (sago RS2) and type 4 (sago RS4) respectively in glucose regulations by analyzing the targeted genes in hepatic glucose pathways. In this study, gene expression associated with Glucose and Glycogen Metabolism Pathways analysis in the liver of spontaneously type 2 diabetic rat, Goto kakizaki treated with water (control), Hi Maize (positive control), sago RS2 and RS4 was done using Rat Glucose Metabolism RT² Profiler PCR Array which consist of 84 genes. The results showed that several genes were significantly up- and down-regulated in the diabetic rats treated with Sago. Taldo1 was significantly upregulated whereas G6PC, Sdhb and Rplp1 genes were significantly downregulated in the rat liver treated with sago RS2. In the rat liver treated with sago RS4, Idh3g gene was significantly upregulated whereas G6pc, Pdk3, Eno3, Sdhb, Galm and Tkt genes were significantly downregulated. The gene expressions identified are associated in the blood glucose homeostasis involving the regulation and enzymatic pathways of glucose and glycogen metabolisms. In conclusion, the genes identified might be useful for therapeutic targets in glucose lowering effects by reducing hepatic glucose output indicating potential of our local sago in managing diabetes.