Anti-hyperuricemia activity and its mechanism of flavonoid extract from saffron floral bio-residues / 中国中药杂志

A hyperuricemic rat model induced by adenine and ethambutol was established to investigate the anti-hyperuricemia activity and its mechanism of the flavonoid extract from saffron floral bio-residues. Sixty-seven SD rats were randomly divided into control group, model group, positive control group, and flavonoid extract groups(with 3 doses), respectively, and each group contained 11 or 12 rats. The hyperuricemic model was established by continuous oral administration of adenine(100 mg·kg~(-1)) and ethambutol(250 mg·kg~(-1)) for 7 days. At the same time, the positive control group was given allopurinol(20 mg·kg~(-1) per day) and the flavonoid extract groups were given the flavonoid extract at doses of 340, 170 and 85 mg·kg~(-1) per day, respectively. On day 8, rat serum, liver, kidney, and intestinal tissues were collected, and the levels of uric acid in serum and tissue, the xanthine oxidase activities and antioxi-dant activities in serum and liver were evaluated, and the kidney histopathology was explored. In addition, an untargeted serum metabolomics study was performed. According to the results, the flavonoid extract effectively reduced the uric acid levels in serum, kidney and ileum and inhibited the xanthine oxidase activities and elevated the antioxidant activities of serum and liver in hyperuricemic rat. At the same time, it reduced the levels of inflammation factors in kidney and protected renal function. Moreover, 68 differential metabolites of hyperuricemic rats were screened and most of which were lipids and amino acids. The flavonoid extract significantly retrieved the levels of differential metabolites in hyperuricemic rats, such as SM(d18:1/20:0), PC[18:0/18:2(92,12Z)], palmitic acid and citrulline, possibly through the following three pathways, i.e., arginine biosynthesis, glycine, serine and threonine metabolism, and histidine metabolism. To sum up, the flavonoid extract of saffron floral bio-residues lowered the uric acid level, increased the antioxidant activity, and alleviated inflammatory symptoms of hyperuricemic rats, which may be related to its inhibition of xanthine oxidase activity and regulation of serum lipids and amino acids metabolism.

Dissolving mechanism of strain P17 on insoluble phosphorus of yellow-brown soil

Strain P17 was a bacterial strain identified as Bacillus megaterium isolated from ground accumulating phosphate rock powder. The fermentation broth of strain P17 and the yellow-brown soil from Nanjing Agricultural University garden were collected to conduct this study. The simulation of fixed insoluble phosphorous forms after applying calcium superphosphate into yellow-brown soil was performed in pots, while available P and total P of soil were extremely positive correlative with those of groundwater. Then the dissolving effect of strain P17 on insoluble P of yellow-brown soil was studied. Results showed that Bacillus megaterium strain P17 had notable solubilizing effect on insoluble phosphates formed when too much water-soluble phosphorous fertilizer used. During 100 days after inoculation, strain P17 was dominant. Until the 120th day, compared with water addition, available P of strain P17 inoculation treated soil increased by 3 times with calcium superphosphate addition. Besides available P, pH, activity of acid and alkaline phosphatase and population of P-solubilizing microbes were detected respectively. P-solubilizing mechanism of P-solubilizing bacteria strain P17 seems to be a synergetic effect of pH decrease, organic acids, phosphatase, etc.