AUTHOR=Xie Libin , Yu Dan , Li Yanan , Ju Huidong , Chen Jia , Hu Lianxia , Yu Longquan 

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

JOURNAL=Frontiers in Nutrition

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.869749

DOI=10.3389/fnut.2022.869749

ISSN=2296-861X

ABSTRACT=<p>The dried fruit of <italic>Amomum tsao-ko</italic> 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 <italic>Amomum tsao-ko</italic> (PMEAT) and to evaluate the hypoglycemic and antioxidant effects of PMEAT, <italic>in vitro</italic> and <italic>in vivo</italic>. We identified 36 phytochemicals in PMEAT by employing HPLC-MS/MS. PMEAT solution was found to have potent α-glucosidase-inhibiting activity (IC<sub>50</sub>, 0.145 mg/mL) <italic>in vitro</italic>, twice as strong as that of acarbose (IC<sub>50</sub>, 0.273 mg/mL). To investigate the hypoglycemic activity of PMEAT <italic>in vivo</italic>, 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) (<italic>p</italic> &lt; 0.05), significantly decreased area under the curve (AUC) of the oral glucose tolerance test (<italic>p</italic> &lt; 0.05), significantly decreased HOMA-IR (<italic>p</italic> &lt; 0.05), and significantly increased HOMA-β (<italic>p</italic> &lt; 0.05) were observed in the high-dose PMEAT group. Moreover, we performed an antioxidant activity experiment <italic>in vitro</italic>. The results showed that PMEAT had a strong ability to scavenge DPPH (IC<sub>50</sub>, 0.044 mg/mL) as well as ABTS free radicals (IC<sub>50</sub>, 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) (<italic>p</italic> &lt; 0.01), glutathione (GSH) (<italic>p</italic> &lt; 0.01), and glutathione peroxidase (GSH-Px) (<italic>p</italic> &lt; 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 <italic>Amomum tsao-ko</italic> for the treatment of diabetes and helps us discover new antioxidant candidates from natural sources.</p>