Doi: 10. 1016/j chroma

1. Introduction

Cistanche Hoffmg. Et Link, one of the genera of the Orobanchaceae family, with 22 species in the world, is mainly distributed in the arid lands and deserts in the northern hemisphere, such as
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Xinjiang, Inner Mongolia, Ningxia autonomous regions, and Gansu, Qinghai provinces of China, as well as Iran, India, Mongolia, etc. [1]. Their growth environments are very severe: extreme arid climate, severe variation of temperatures, intensive sunshine, less than 250mm of annual precipitation and depauperate soils [2,3]. The Cistanche species belong to the perennial parasite herbs, which commonly attach onto the roots of sand-fixing plants, such as Haloxylox ammodendron, H. persicum, KalidiumfoliatumandTamarix plants, etc. [3]. There are six Cistanche species in China, according to the record of Taxonomical Index of Chinese Higher Plants [4]. However, a further study confirmed that only four species and one variation of Cistanche exist in China, i.e. Cistanche deserticola Y.C. Ma, C. tubulosa (Schenk) R. Wight, C. salsa (C.A. Mey.) G. Beck, C. salsa var. albiflora P.F. Tu et Z.C. Lou and C. sinensis G. Beck [5].
Rou Cong Rong (Herba Cistanche), first recorded in Shen Nong’s Chinese Materia Medica, refers to the dried succulent stems of the Cistanche plants. Herba Cistanche has been considered as a superior tonic and earned the honor of “Ginseng of the deserts”. The scientific values of Herba Cistanche lie in the treatment of kidney deficiency, impotence, female infertility, morbid leucorrhea, profusemetrorrhagiaandsenileconstipation[6,7].Ithasbeenthemost frequently prescribed drug against kidney deficiency in China for successive dynasties. Among Cistanche species, only C. deserticola has been reordered in the Chinese Pharmacopoeia (2000 edition) [8], and C. tubulosa was added to the 2005 Chinese Pharmacopoeia as an alternative, for its similar chemical constituents, pharmacological activities, and its relatively affluent resource compared to C. deserticola [9–11]. However, in recent years, the wild C. deserticola is on the edge of extinction due to over-harvesting, and it has been collected as one of the Class II plants needing protection in China. Due to the deficiency of the natural resources of the official Herba Cistanche, other species of this genus, such as C. salsa and C. sinensis, are also used as substitutes in many areas [10].
Scientific research on Cistanche plants started in the 1980s [12], and the chemical analysis indicated that various compounds, including essential oils, phenylethanoid glycosides (PhGs), iridoids, lignans, alditols, oligosaccharides and polysaccharides are the main constitutes of Cistanche plants [13,14]. Pharmacological research showed that the extracts from Cistanche plants possess a wide spectrum of activities, such as curing kidney deficiency and senile constipation, advancing the ability to learn and memorize, treating Alzheimer’s disease, enhancing immunity, anti-aging and antifatigue [14–21]. With the improvement of living standards and the coming of aging society, Cistanche plants have gained more attentions and have been used more and more widely due to their distinguished pharmacological activities.
There have been several reviews on the study of chemical constituentsandpharmacologicalactivitiesofCistancheplants[13–15]. The present paper focuses on the chemical analysis of this genus and the progress on the chemical constituent studies.