Studies On The Antidiabetic And Antinephritic Activities Of Tuber Melanosporum Via Modulation On Oxidative Stress

Tuber melanosporum is an edible and medicinal mushroom with unique flavours and high nutritional value,which is praised as "the Black Diamond on Table".Many researches indicate various pharmacological effects of Tuber melanosporum such as the antioxidation in vitro,incrasing immunity,anti-tumor effect,regulation of hematopoietic function and dysmenorrhea.However,the antioxidation in vivo and the antidiabetic and antinephritic activities of Tuber melanosporum have not been reported yet.In this study,we first detected the main components of Tuber melanosporum,and subsequently studied its antioxidative activity in vivo and the antidiabetic and antinephritic activities,which provide foundation for the development of new health care products for the treatment of diabetes and kidney complications.This paper is mainly as follows:The quantities of the main TM components including total sugar,reducing sugar,protein,total ash,crude fat,crude fiber and total polyphenol were measured using the phenol-sulfuric acid method,direct titration,the Kjeldahl method,combustion method,Soxhlet extraction,double differences method and the Folin-phenol reagent method,respectively.The quantities of triterpenoids,mannitol,vitamins and amino acid were measured using high performance liquid chromatography(HPLC).The composition of fatty acids was measured using gas chromatographic method(GC).Total flavonoids,total sterols and carotenoids were measured using colorimetry.Mineral contents were measured using microwave digestion method.It can provide the basis for the establishment of quality standards of Tuber melanosporum and the following experiment.BALB/c mice were used to preliminarily investigate the antioxidation of Tuber melanosporum in vivo.The results indicated that Tuber melanosporum could enhance the rotating times,running times and swimming times.Besides,the decreased MDA levels and the enhanced SOD and GSH-Px levels in serum,liver and muscle,and the decreased ROS levels and the enhanced glycogen and ATP levels in liver and muscle were observed after Tuber melanosporum treatment,which indicated the effect to regulate oxidative stress damage and improve movement performance.Db/db mice models were used to study the antidiabetic and antinephritic activities of Tuber melanosporum via modulation on oxidative stress.Mice were given Tuber melanosporum by oral administration for eight weeks,the bodyweights and blood glucose were measured once a week.Resullts showed that Tuber melanosporum could increase body weights and plasma glucose levels and reduce organ indexes of the spleen and kidney of db/db mice.Eight weeks’ oral administration of Tuber melanosporum decreased serum levels of glycated hemoglobin,triglyceride and total cholesterol,and increased hepatic glycogen content and serum levels of pyruvate kinase and high-density lipoprotein cholesterol in the mice,suggesting hypoglycemic and hypolipidemic effects.Tuber melanosporum could improve levels of renal injury related indicators such as NAG,6-ketoPGF1α and MMP-9,regulate levels of inflammatory factors such as IL-2,IL-6 and IL-10,and lighten the phenomenon of inflammatory cell infiltrations and thickened basement membrane of renal tubular epithelial cells in kidney,which showed the renal protective effect.Overproduction of ROS and hypoactivities of SOD,GSH-Px and CAT were observed in the serum and kidneys of the db/db mice.Tuber melanosporum also visibly upregulated the expressions of CAT,HO-1,HO-2,SOD2 and Nrf2,and downregulated the expressions of PKC-α,p-JAK2,p-STAT3 and p-NF-κB in the kidneys.In summary,we found the antidiabetic and antidiabetic nephritic effects of TM in db/db diabetic mice through the modulation of oxidative stress.