Characterization, Hypoglycemic Activity, and Antioxidant Activity of Methanol Extracts From Amomum tsao-ko: in vitro and in vivo Studies

Libin Xie; Dan Yu; Yanan Li; Huidong Ju; Jia Chen; Lianxia Hu; Longquan Yu

doi:10.3389/fnut.2022.869749

Characterization, Hypoglycemic Activity, and Antioxidant Activity of Methanol Extracts From Amomum tsao-ko: in vitro and in vivo Studies

Front Nutr. 2022 Jul 12:9:869749. doi: 10.3389/fnut.2022.869749. eCollection 2022.

Authors

Libin Xie¹, Dan Yu², Yanan Li¹, Huidong Ju¹, Jia Chen¹, Lianxia Hu¹, Longquan Yu¹

Affiliations

¹ Shijiazhuang Food Engineering Technology Research Center, School of Chemical Engineering, Shijiazhuang University, Shijiazhuang, China.
² Department of Nutrition, Third Hospital of Hebei Medical University, Shijiazhuang, China.

Abstract

The dried fruit of Amomum tsao-ko is well-known as a spice as well as a Chinese traditional herb. This study aimed to identify the bioactive constituents in the powder of methanol extract from Amomum tsao-ko (PMEAT) and to evaluate the hypoglycemic and antioxidant effects of PMEAT, in vitro and in vivo. We identified 36 phytochemicals in PMEAT by employing HPLC-MS/MS. PMEAT solution was found to have potent α-glucosidase-inhibiting activity (IC₅₀, 0.145 mg/mL) in vitro, twice as strong as that of acarbose (IC₅₀, 0.273 mg/mL). To investigate the hypoglycemic activity of PMEAT in vivo, we studied the impact of low-dose PMEAT (the addition of 100 mg/kg PMEAT to the mice diet) and high-dose PMEAT (200 mg/kg PMEAT addition) treatments in STZ-induced diabetic mice. After 6 weeks of intervention, significantly decreased fasting blood glucose (FBG) (p < 0.05), significantly decreased area under the curve (AUC) of the oral glucose tolerance test (p < 0.05), significantly decreased HOMA-IR (p < 0.05), and significantly increased HOMA-β (p < 0.05) were observed in the high-dose PMEAT group. Moreover, we performed an antioxidant activity experiment in vitro. The results showed that PMEAT had a strong ability to scavenge DPPH (IC₅₀, 0.044 mg/mL) as well as ABTS free radicals (IC₅₀, 0.040 mg/mL). In an animal experiment conducted on oxidative damage mice model which was induced by D-glucose and a high-fat diet, we observed significantly increased dismutase (SOD) (p < 0.01), glutathione (GSH) (p < 0.01), and glutathione peroxidase (GSH-Px) (p < 0.01) and significantly reduced malondialdehyde (MDA) and 8-ISO-prostaglandin-PGF2α (8-ISO-PGF2α), after treatment with PMEAT for 90 days. In conclusion, this study reveals the therapeutic potential of Amomum tsao-ko for the treatment of diabetes and helps us discover new antioxidant candidates from natural sources.

Keywords: Amomum tsao-ko; antioxidant effect; hypoglycemic effect; methanol extracts; mice.