Study On The Effective Fractions From Prunus Mume To Treat Hyperuricemia And Gout And Their Mechanisms

Hyperuricemia and gout have been one of the chronic diseases related to modern life style.Natural products have been attracted extensive attention because of their potential beneficial effects on hyperuricemia and gout.The Chinese mei(Prunus mume Sieb.et Zucc.),which originating from China,is one of the major commercial fruit in East Asia.Although the mei culture has 7000-year long history in our country, basically stayed on the immaterial aspect for a long time.The P.mume industry is now meeting a huge challenge,because of lacking new products and sufficient investment.In a preliminary study of P.mume plant resource,our research team found several P.mume extracts had anti-gout function.Based on this background,the present study is carried out.In this study,the whole fruit of P.mume,'Da Ye Qing', was selected and separated into fruit(sarcocarp) and seed.Firstly,the extraction technology of total phenols and total flavonoids in P.mume fruit and seed were optimized with response surface method.Then,three chlorogenic acid compounds, which are included in different extract fractions of P.mume fruit and seed,were determined by analytical HPLC.The in vitro antioxidant activities of different P. mume extracts and chlorogenic acid compounds were also determined.The in vitro urate reducing capacity of all the P.mume extracts(fruit,seed,flower,branch and leaf) were evaluated by their xanthine oxidase(XO) inhibitory activities.Subsequently,the safety evaluation of the effective fractions,which have the potential to treat hypreuricemia and gout,were carried out.Finally,the mechanisms of the effective fractions to treat hyperuricemia,hyperuricemic nephropathy and gouty arthritis were studied.Results were summarized as follows:(1) There are abundant phenols and flavonoids in the fruit and seed of P.mume. Three chlorogenic acid isomers,namely,neochlorogenic acid,chlorogenic acid and cryptochlorogenic acid,were identified from P.mume seed for the first time.Two chlorogenic acid isomers,namely,neochlorogenic acid and cryptochlorogenic acid, were identified from P.mume fruit for the first time.(2) P.mume fruit and seed extracts showed significantly scavenging activities on DPPH·,ABTS^·+,OH·and O₂^·-,and in concentration-dependent manners.All the P. mume extracts showed strong reducing power,and showed excellent antioxidant activities in biological systems,ie,rat brain homogenate system,red blood cell system and whole blood system.(3) The ethyl acetate fraction of P.mume seed extract(PMS-E) and the n-butanol fraction of P.mume flower extract(PF-B) showed strong xanthine oxidase inhibitory activities in vitro.Through acute toxicity test and 30 days feeding study methods,it can be concluded that PMS-E and PF-B are the safety resources to utilization in the pharmaceutical and functional foods fields.The maximal tolerance both PMS-E and PF-B on male and female mice were more than 12.0 g/kg,and belong to essentially non-toxic class.The maximum non-effect dose of both PMS-E and PF-B are 3.0 g/kg.(4) In three hyperuricemia models of mice,both PMS-E and PF-B have obvious capacity to reduce serum uric acid concentration and xanthine oxidase activity.This study established a perfect rat hyperuricemic nephropathy model induced by yeast feed and adenine.PF-B had stronger effect than PMS-E in reducing xanthine oxidase activity in serum and liver,and the adenosine deaminase (ADA) activity in liver of rats with hyperuricemic nephropathy.Both PMS-E and PF-B with middle dose and high dose showed significantly protective effect on rat oxidant stress,they could reduce the MDA and GSSG contents in serum,liver and kidney,and reduce the catlase activity;furthermore,they could elevate the GSH content and SOD activity in serum,liver and kidney of rats with hyperuricemic nephropathy.Both PMS-E and PF-B had obviously ameliorate on pathological changes of hepatic and renal tissues.(5) PF-B with low,middle and high dose could significantly reduce white blood cell(WBC) count in blood,and the inflammatory factors,cytokines(NO, IL-1β,IL-6,IL-8,TNF-α,PGE2) and monoamine transmitters(DA,5-HT) levels in swelling paw tissue of rats with gouty arthritis induced by monosodium urate(MSU), and in concentration-dependent manners.PF-B had excellent anti-inflammatory and analgesic effects in multi-models with rats or mice.(6) The results of preliminary human feeding trials showed the capsule and oral liquid contained P.mume flower extract(PF),which act as the main functional ingredient,were effective on patients with hyperuricemia and gouty arthritis, respectively.In conclusion,P.mume can be utilized as the sources of phenols and flavonoids. P.mume extracts have significant free radicals scavenging and antioxidant activities. The n-butanol fraction of P.mume flower extract(PF-B),which contains the most phenols and flavonoids,showed great potential in reducing uric acid levels, alleviating inflammation and analgesia,and anti-gout fields.The flavonoids contained in PF-B maybe its main biologically active components.Thus,P.mume flower can be exploited in dietary supplement,functional food,pharmaceutical intermediate and neoadjuvant therapy drug to treat hyperuricemia and gout,which is of great theoretical and practical significance.