Acute toxicity and anti-hyperglycemic activities of pomelo (Citrus grandis (L.) Osbeck) peel extracts in the Mekong Delta of Vietnam

The aim of this study was to investigate the total flavonoid content (TFC), vitamin C content, and the anti-hyperglycemic activities of pomelo peel extract (PPE) from the flavedo and albedo of two pomelo cultivars namely Long Co Co and Thanh Kieu in the Mekong Delta of Vietnam. Thanh Kieu PPE possessed the highest TFC of 11.18 +/- 0.14 mg/100 g from the albedo while the highest vitamin C content was found in its flavedo (47.74 +/- 0.34 mg/100 g). PPE from the flavedo induced the mortality after 3-4 h of oral administration at a dosage of 5000 mg/kg. In the contrast, PPE from the albedo was considered a non-toxic extract. Albedo PPE from two cultivars was observed to attenuate the blood glucose level of alloxan-hyperglycemia induced mice (from roughly 350 mg/dL to 150 mg/dL) and there was no significant difference in the anti-hyperglycemic efficacy between albedo PPE and chemical drug (Glucophage). This finding showed potential in developing new functional food products or pharmaceutical alternatives from pomelo peels (an agro-waste) for anti-hyperglycemia.