Construction Of Nano Drug-loading System Based On Natural Diterpenoids From Pinus Koraiensis Pine Cone And Its Anti-breast Cancer Research

Breast cancer is one of the greatest threats to women's health all over the world and chemotherapy is one of the common treatments.Paclitaxel?PTX?which is a common chemotherapeutic agent in the clinical treatment was limitted due to extremely low water solubility,bioavailability and poor tumor targeting ability.It will produce resistance and accelerate the transfer rate after long-term use.In recent years,the development of a series of nanocarrier based on synthetic polymers and inorganic molecules has been limited due to side effects on the human body,while natural products have the potential to be designed as a nanoplatform due to good biological activity and low toxicity.The natural product of diterpenoids with self-assembly properties in this paper is regarded as a nanocarrier to achieve drug loading for breast cancer therapy,which lay a good foundation for the development of a new nanoplatform in the field of drug delivery.The main research contents and results of this article are as follows:Firstly,the diterpenoids were extracted from the Pinus koraiensis and identified the structure.The dichloromethane extract was fractionated by column chromate-graphy,compounds 1 and 2 were separated and purified from the petroleum ether eluate,compounds 3 and 4 were separated and purified from the dichloromethane eluate.Combined with spectral data,physical and chemical properties,the compounds 1-4 were identified as dehydroabietic acid,abietic acid,12-hydroxy-abietic acid and 15-hydroxydehydroabietic acid,respectively.Secondly,nanoparticles based on natural diterpenoids were prepared and investigated the intermolecular forces.Nanoprecipitation and emulsion-solvent evaporation method were used to prepare nanoparticles and emulsion-solvent evaporation method was selected due to high yield and low PDI value.Nanoparticles based on compounds 1-4 were prepared by emulsion-solvent evaporation method,AA was selected as nanocarrier due to better morphology.After optimization,the preparation factors of AA NPs were determined with the solvent was dichloromethane,the oil to water ratio was 1:3 and the surfactant was 2.5%PVA.The SEM image showed that the morphology of AA NPs were spherical,particle size was 255 nm,PDI value was 0.086 and the zeta potential was-29.4 mV.The hydrogen bond and the hydrophobic interaction were confirmed to be the driving force for the formation of AA NPs by infrared spectroscopy?IR?,contact angle and X-ray diffraction?XRD?.Finally,the PTX was loaded in AA NPs to prepare drug-loaded nanoparticles,in vitro nanoeffect evaluation and in vitro and in vivo anti-breast cancer efficiency were performed.Drug-loaded nanoparticles?AA-PTX NPs?were prepared by emulsion-solvent evaporation method,showing that the encapsulation efficiency was 65.12%and the loading rate was 11.70%.In vitro release and stability analysis indicats that AA-PTX NPs have a certain sustained release property and good stability.MTT results showed that AA-PTX NPs had severe killing effect on breast cancer cells?4T1 and MCF-7?.The IC₅₀0 values were 3.70?g/mL and 2.94?g/mL after 72 h incubation,respectively.The hemolysis rates of of AA-PTX NPs were analyzed to verify their good biocompatibility.In vivo results showed that AA-PTX NPs had significant inhibitory effects(P^**<0.01),the tumor volume inhibition rate and weight inhibition rate were 81.83%and 85.50%,respectively.There was no significant change in body weight during the entire administration period,indicating that it did not induce toxic side effects and organ index was closest to normal.Nano drug-loading system based on AA exhibited better biocompatibility and excellent anti breast cancer efficiency,that highlights the advantages of natural products.