| Rhizoma Parids saponins(RPS)have a long medicinal history.Pharmacological studies have proved that RPS had good antitumor activity and analgesic effect.In this paper,in order to better study the medicinal properties of RPS,the pharmacokinetics and analgesic mechanism of RPS were systematically studied in this paper.Firstly,a single oral pharmacokinetic study was carried out in rats and beagle dogs.The results showed that no single component of RPS was detected in plasma,which suggested that the bioavailability of RPS in animals was low.Caco-2 test and S9 metabolic stability test in vitro indicated that the main components of RPS such as polyphyllin I,II,VI and VII were low permeability,slow or moderate metabolism compounds,which made RPS not easy to be absorbed.Nextly,a rapid and precise LC-MS/MS method was developed and validated for the separation and simultaneous determination of PII and PVII in rat plasma,tissues,feces and urine using ginsenoside Rg3 as the internal standard.After caudal vein administration of PII and PVII in rats,PII and PVII were rapidly distributed in organs,mainly including liver,lung and spleen.Their elimination rate was slow.Furthermore,it was also found that the plasma protein binding rates of PII and PVII in rat,mouse,dog,cynomolgus monkey and human plasma were higher than 97.4%.At the same time,blood cells are important distribution sites for PII and PVII.It was found that urine and feces were not the main ways for the excretion of RPS.Considering the oral administration of RPS in clinics,the pharmacokinetics and tissue distribution of RPS by oral administration in normal rats were studied.The results showed that RPS had tissue-target distribution after repeated oral administration.The metabolic compound like diosgenin was detected in different tissues although there was none in RPS.Each saponin can be transported by OATP1B1 transporter.The concentration of PI,PII,PVI,PVII,PH and gracillin in the spleen was the highest among these organs.The content of diosgenin was the highest in lung and brain.Caco-2 test indicated that PI,PII,PVI and PVII were low permeability and low recovery.Efflux ratio indicated that PVI should be a potential P-gp substrate.S9 assay suggested that RPS possess slow metabolic and moderate metabolic compounds.In this research,a lung metastasis model of H22 liver cancer was established to determine the distribution of different saponins in the tissues by UPLC-MS.Network pharmacology was used to supplement and verify.As a result,RPS prolonged the survival rate and inhibited the pulmonary metastasis.Besides,the concentration of PII,diosgenin,PI,and gracillin in the liver and lung was higher than that in the heart,spleen,and kidney.In order to verify whether RPS also have the characteristics of brain-target distribution,a chronic cancer pain model like H22 hepatoma cells implanted into the right hindpaw of mice was established.In this study,RPS was first demonstrated a potent effect on markedly reducing the pain induced by cancer.Cancer-induced pain model mice were randomly divided into 5 groups(n = 10)and orally administered with RPS(50-200 mg kg(-1))for 2 weeks.On the last day of treatment,the pain behavior of mice was measured using hot-plate test and open field test,and brain tissues were sampled for detection of biochemical indices,malondialdehyde(MDA),superoxide dismutase(SOD),prostaglandin E2(PGE2),serotonin(5-HT)and beta-endorphin(beta-EP).Moreover,the concentrations of NF-kappa B and IL-1 beta in the blood serum were measured by ELISA reagent kits.In addition,naloxone,the non-selective antagonist of opioid receptors,was used to identify the opioid receptors involved in RPS’s action.It has been found that RPS alleviates cancer pain mainly via the suppression of inflammatory pain induced by oxidative damage,such as decreasing MDA and PGE2 levels,renewing activity of SOD,as well as increasing 5-HT and betaEP in the brain and suppressing the expression of NF-kappa B and IL-1 beta in the serum in a concentration-dependent manner.Overall,the current study highlights that RPS has widespread potential antinociceptive effects on a mouse model of chronic cancer pain,which may be associated with the peripheral nervous system and the central nervous system.Furthermore,RPS can be transformed into diosgenin through intestinal flora.Diosgenin distributs in brain tissue through blood-brain barrier and exerts the major anti-analgesic activity for RPS.Meanwhile,PI,PII,PVI,PVII,PH and gracillin mainly distributed in tumor tissues and played the anti-tumor roles in RPS.In conclusion,RPS can target liver,lung,brain and tumor tissues,which provide a theoretical basis for the development of RPS for liver,lung and brain diseases.At the same time,RPS have clear anti-tumor and anti-cancer pain effects.Therefore,it provides an experimental and theoretical basis for clinical application of RPS in liver,lung and brain related diseases. |
