Doi: 10. 1016/j chroma

4. Conclusions

In this review, the chemical constituents of Cistanche species and their analysis methods have been described. Among the existinganalyses,themajorityhasbeenconcentratedonPhGs,andHPLC hasbeenthemostwidelyusedmethodduetoitshighefficiencyand accuracy. Through analysis of the previous research works, combining with our years of study on Cistanche species, some major problemsexistingintheanalysisofCistancheplantshavebeensummarized as follows: the first is the mix usage of species source: C. deserticola and C. tubulosa are two official species collected in Chinese Pharmacopoeia. However, two other Cistanche species, C. salsa and C. sinensis are also used in some areas due to resource shortage. Although, there have been several publications referring to the comparison between different species [6–8], they are not persuasive enough due to the limited sample batches and markers. Thus, it is necessary to establish a comprehensive method, such as fingerprinting technology to analyze comparatively the crude drugs of different sources. The second is that the quality inconsistency of Herba Cistanches has not been paid much attention to. Cistanche species are parasite herbs. There are many factors influencing their quality, such as climate, habitats, hosts, harvested time, processing method, and different parts of the same plant. Our studies showed that the quality of Cistanche species is not stable, especially that of the wild C. deserticolia [80,82,92]. However, this problem had been neglected in some of the previous analyses, and only one or two samples had been used [74,76], which might lead to inaccurate conclusion. So, in the future, much more samples should be collected and analyzed to obtain a more objective conclusion. The third is that the present analyses mainly concentrate on two major PhGs, ethinacoside (11) and acteoside (2), but as we know, the pharmacological action of TCM is the cooperation of multi-components or different types of constituents. Thus, simultaneous determination of the active multi-components is more meaningful for the quality control of TCM. However, up to now, there has been no quantitative analysis for more than three PhGs in Herba Cistanches, even there is no report on the analysis of benzyl glycosides, iridoids and lignans. Then, future research should reinforce on their analytical and pharmacological study.
Overall, the present research on the analysis of Cistanche species is still in a lower level state. Herba Cistanches are important tonic drugs, but actually, their quality could not be controlled effectively only by two representative PhGs [9]. Combination of multi-components determination with fingerprint has been regarded as a powerful approach for the quality control of TCMs. In the future, the research level of Cistanche species on these two fields should be further improved. To establish a method, which could simultaneous qualitative and quantitative analysis of PhGs, iridoids and other active constituents in Herba Cistanches will be a meaningful research direction.