Research Progress on the Chemical Constituents and Quality Evaluation Methods of Spina gleditsiae

: In this paper, the relevant information on chemical constituents and quality evaluation of Spina gleditsiae were retrieved and summarized. Modern studies show that Spina gleditsiae mainly contains flavonoids, phenols, triterpenoids, coumarins, sterols, lactones, organic acids and other compounds. Then the quality evaluation methods of Spina gleditsiae were introduced. In the future research, it is necessary to explore the extraction and separation technology of its chemical constituents and active constituents, and establish appropriate models to promote its development and application. It provides a reference for the further establishment of scientific and reasonable studies on the effective components of Spina gleditsiae


INTRODUCTION
Spina gleditsiae has a long history of application in China, and also be used as compatible drug in combination with other traditional Chinese medicines to treat cancer, because which can inhibit oncogene expression.
Spina gleditsiae is a traditional Chinese medicine with low price and wide sources. Modern studies show that Spina gleditsiae mainly contains flavonoids, phenols, triterpenoids, coumarins, sterols, lactones, organic acids and other compounds. A large number of literature studies believe that the triterpenoid saponins and flavonoids in Spina gleditsiae are the active material basis of anti-cancer, antibacterial and main medicinal value of this plant medicine. Flavonoids or flavonoid glycosides in Radix Spina gleditsiae have a high content. Most modern studies focus on the extraction process of total flavonoids in Spina gleditsiae, while the extraction process and content determination of other components in Spina gleditsiae are relatively backward, and there is a lack of quality evaluation system for Spina gleditsiae in Chinese Pharmacopoeia.

TERPENOIDS
Li et al. first extracted Spina gleditsiae with different organic solvents, and then separated them by silica gel column chromatography, and obtained two triterpenes which were identified as Echinocystic acid and Gleditsia saponin C. Lim et al. isolated four steroid substances and one triterpenoid substance from Spina gleditsiae. Then, 90% MeOH was used for reflux extraction and the ethyl acetate parts were separated by repeated silica gel column chromatography. A new betulinic triterpene 2-βcarboxyl,3-β-hydroxyl-Norlupa(1)-20(29)-en-28-oic acid and five betulinic triterpenes named zizyberanalic acid, betulic acid, alphitolic acid, 3-0-trans-p-coumaroyl alphitolic acid and 2-hydroxypyracrenic acid were identified, all six compounds were isolated for the first time.
Lim et al. also isolated and identified a triterpene compound D:C-friedours-7-en-3-one in the antimutagenic activity screening experiment. It has been reported that saponins are mostly isolated from normal fruit of Spina gleditsiae or pig tooth soap (abnormal fruit of Spina gleditsiae). The aglycones are oleanolic acid or acanthic acid, and the sugar ligand mainly includes rhamnose-arabinose, glucose, xylitol, etc. There were not many saponins isolated from Spina gleditsiae. Li et al. only isolated and identified saponinsC from the n-butanol part of Spina gleditsiae.

PHYTOSTEROLS
Xu et al. used organic solvent to extract the ethanol extract of Spina gleditsiae, and then used column chromatography, thin layer chromatography silica gel and other methods to trace the extraction, which separated 8 active components, including β-sitosterol and daucosterol. Lim et al. extracted Spina gleditsiae by heating reflux with 80% methanol, and isolated 5 compounds conclude four steroids such as stigmasterol, β-sitosterol, stigmast-4-ene-3,6-dione and stigmastane-3,6-dione and the first isolated from a natural product D:C-friedours-7-en-3-one. The five compounds were isolated from Spina gleditsiae for the first time, among which stigmasterol showed the strongest anti-mutagenesis activity.

OTHER INGREDIENTS
Li et al. isolated betulinic acid derivatives from Spina gleditsiae and found that they had anti-HIV activity. Meanwhile, the extraction performance of betulinic acid derivatives from Spina gleditsiae was investigated by ionic liquid. Liu et al. studied the components of saponin saponin by pretest of chemical composition, and found that flavonoids, lactones, coumarins or their glycosides, sterols, triterpenes, phenols, organic acids, reducing sugars, triterpenes saponins and so on were clearly present in saponin saponin.
Xu et al. isolated palmitic acid from Spina gleditsiae, which is a kind of saturated fatty acid.

QUALITY EVALUATION
Li et al. isolated betulinic acid derivatives and triterpenoids from Spina gleditsiae, and found that they had anti-HIV activity. Meanwhile, the extraction performance of betulinic acid derivatives from Spina gleditsiae was investigated by ionic liquid. Liu et al. studied the components of Spina gleditsiae through the chemical composition experiment, and found that flavonoids, lactones, coumarins or their glycosides, sterols, triterpenes, phenols, organic acids, reducing sugars, triterpenes saponins and other components were clearly present in Spina gleditsiae. Li et al. studied 20 batches of Spina gleditsiae from different producing areas. After comparing the HPLC fingerprint of Spina gleditsiae, evaluating its similarity, and then conducting cluster analysis, it was found that: the chemical constituents of Spina gleditsiae from different producing areas were similar, but the content of Spina gleditsiae was different. There is a big difference between cultivated and wild Spina gleditsiae. This is probably because Spina gleditsiae is a plant of many origins. The differences above were related to light, rainfall, temperature and growth years of different areas. The similarity between the HPLC characteristic chromatogram and corresponding characteristic chromatogram was greater than 0.990, which contained 12 batches of main prickle root, branch root and tip. Heat map cluster analysis and principal component analysis can distinguish the main prickle root and tip. The results of variance analysis showed that peak 2, citipine and quercetin were the main components that caused the quality difference of different parts of Spina gleditsiae. The content of axisolin in the same radix saponicae was in the order of tip > branch root > main prickle root. This method can reflect the difference of chemical constituents in different parts of Spina gleditsiae and has important significance for quality control and overall evaluation.

CONCLUSIONS
In recent years, researches have focused on the pharmacognostical identification and pharmacological action of Spina gleditsiae, and the main chemical components of which has been discovered and separated. The studies showed that flavonoids, terpenoids, sterols and other active ingredients were the most active components in Spina gleditsiae. As a traditional Chinese herbal medicine, Spina gleditsiae has been shown to have anticancer, anticoagulant and immunological effects. In the future research, it is necessary to explore the extraction and separation technology of its chemical constituents and active constituents, and establish appropriate models to promote its development and application. It is believed that with the deepening of modern Chinese medicine research, the application of Spina gleditsiae will be more and more extensive.