Study On The Chemical Constituents And Bio-activities Of The Leaves Of Tribulus Terrestris L.

Tribulus terrestris is a plant of the genus Tribulus in the Zygophylaceae family,whose Latin name is Tribulus terrestris L.,it has a long history of medicinal use,and the whole plant including fruits,flowers,stems,leaves,and roots can be used as medicine.Pharmacological studies have shown that Tribulus terrestris L.has various pharmacological effects such as hypoglycemia,hypotension,and anti-tumor.Studies have shown that the leaves of Tribulus terrestris L.contain more active steroidal saponins than the whole herb and other medicinal parts,but there are more reports on the chemical composition of fruits and whole herb of Tribulus terrestris L.,but very few reports on the chemical composition of Tribulus terrestris L.leaves.Therefore,in this paper,the leaves of Tribulus terrestris L.were studied in-depth.Using modern isolation methods,23 monomeric compounds（JL-1～JL-23）were isolated and identified from dried Tribulus terrestris L.leaves,among them,compounds JL-12,JL-13,JL-19,JL-22 are new compounds,JL-7 and JL-14 are the first isolated compounds from Tribulus terrestris L.,and JL-4,JL-5,JL-10,and JL-11are the first isolated compounds from the leaves of Tribulus terrestris L.,respectively.Among these new compounds,JL-13 is a new spirostane-type saponin,characterized by an S-configuration at the C-25 position in the parent nucleus and a molecule of glucose attached to the C-24 position.JL-22 is a new pregnastere-type saponin,characterized by the formation of a lactone bond between the C-16 and C-22 positions of the parent nucleus.JL-12 and JL-19 are new furostane-type saponins,characterized by four sugars（including branched chains）in the sugar group,and Only the C-3position of glucose has a molecule of xylose attached.These new compounds isolated in this paper and those obtained for the first time further enriched the variety and quantity of steroidal saponins in Tribulus terrestris L.,laying the foundation for further study based on the pharmacodynamic substances of Tribulus terrestris L.Based on the chemical constituents study,a method for the determination of two spirosteroidal saponins,JL-4 and JL-7,in the leaves,fruits,and stems of Tribulus terrestris L.was established by using matrix solid phase dispersion（MSPD）sample pretreatment combined with high-performance liquid chromatography evaporative light scattering detector（HPLC-ELSD）.Firstly,the optimal conditions for matrix solid phase extraction were established by single-factor investigation,they are as follows:0.5000 g of dried Tribulus terrestris L.leaves were weighed precisely,crushed and passed through a 60 mesh sieve,added 2.0 g of silica gel in an agate mortar and mixed and grinded for 2 min,and then transferred to a 20 m L syringe,washed with 20 m L of petroleum ether,eluted with 50 m L of 75%（V/V）ethanol-water.The solvent was recovered,dissolved in 1 m L volumetric flask with the appropriate amount of methanol,fixed to the inscribed line,shaken well,passed through 0.22μm microporous membrane,and the filtrate was used as the test solution.Next,the chromatographic conditions for content determination were determined and the methodological investigation was carried out.The results showed that the linearity was good in the range of 0.370～29.619μg for JL-4 and 0.366～14.646μg for JL-7with the R²value of both being 0.9992.In addition,all the RSD values of precision,reproducibility,stability,and spiked recoveries of the method were less than 1.5%（n=6）,indicating that the method has the advantages of good precision,high accuracy,and high sensitivity.The results of content determination showed that the contents of JL-4 and JL-7 in the leaves,fruits,and stems of Tribulus terrestris L.varied widely,with the highest contents of 3.483 mg.g^-1and 1.992 mg.g^-1in the leaves,followed by0.593 mg·g^-1and 0.199 mg·g^-1in the fruits,and the lowest contents were 0.519 mg·g^-1and 0.146 mg·g^-1in stems,respectively.This paper investigated the inhibitory effects of various steroidal saponin monomers isolated from the leaves of Tribulus terrestris L.on pancreatic lipase activity using the p NPP method.The results showed that two spirosteroidal saponins,JL-3 and JL-4,had inhibitory effects on pancreatic lipase activity,and their semi-inhibitory concentrations(IC₅₀)on pancreatic lipase were 3.597±0.084 mmol·L^-1and 68.905±0.851 mmol·L^-1respectively.The results showed that some of the spirosteroidal saponins in the leaves of Tribulus terrestris L.could effectively inhibit pancreatic lipase activity and have the potential to be developed into natural weight loss products.In summary,this thesis presents an in-depth study of the chemical composition of the leaves of Tribulus terrestris L.,and establishes an MSPD-HPLC-ELSD method for the determination of two spirosteroidal saponins in the s leaves,fruits,and stems of Tribulus terrestris L.,and investigates the inhibitory effect of Tribulus terrestris L.saponins on pancreatic lipase activity.The results of this thesis provide a new scientific basis for the in-depth study of the pharmacodynamic substances of the leaves of Tribulus terrestris L.and the development and utilization of steroidal saponins in the leaves of Tribulus terrestris L.