A. sparsifolia is a deciduous shrub unique to the arid desert region of Xinjiang and is one of the “three treasures” of the Gobi Desert in preventing land desertification, resisting wind and sand erosion, and improving saline soil (Liu, 1985; Zhang et al., 2002; Arndt et al., 2004; Thomas et al., 2008; Jiang, 2017). There are seven species of the Alhagi genus worldwide, of which three are distributed in China and one is A. sparsifolia in the Flora of China (Zhang et al., 2008; Jin et al., 2014). In regions of high temperatures and low precipitation, the injured stems and leaves of A. sparsifolia secrete Tarangabin (Li et al., 1996; Wang, 2003; Mikeremu et al., 2016).

A. sparsifolia is a semi-shrub approximately 25–40 cm tall with an upright, glabrous stem having thin stripes. The leaves are alternate and ovate, obovate, or rounded ovoid, measuring approximately 8–15 mm long and 5–10 mm wide. The apex is round with short, hard tips, and the base is cuneate, entire, and glabrous with a short petiole. The flower is racemose, axillary, and 8–10 mm long. The rachis transforms into hard, sharp thorns that are 2–3 times as long as the leaves. The thorns of annual branches have 3–6 (or 3–8) flowers, but the older ones do not. The bract is subulate and up to 1 mm long, whereas the pedicel is 1–3-mm long. The calyx is campanulate, 4–5-mm long, and pubescent. The calyx teeth are triangular or subulate-triangular and one-third to one-fourth the length of the calyx tube. The corolla is reddish purple with a standard oblong-ovate shape and is 8–9-mm long, with an obtuse or truncated apex. The base is cuneate with a short petiole, the wing is oblong and three-quarters the length of the standard, and the carina is about the same length as the standard. The ovary and legume are linear and almost glabrous (Flora of China Editorial Committee, 1998). The harvest time of the various medicinal parts of A. sparsifolia differ. Flowers and leaves are collected in early summer (april to early May), Tarangabin is collected during midsummer (June to August), the seeds are collected in autumn (July to September), and the whole grass or aboveground parts are picked during the growing period of the year (Wang, 2003).

A. sparsifolia is distributed in Central and East Asia, mainly in China, Kazakhstan, Uzbekistan, Turkmenistan, Kyrgyzstan, and Tajikistan (GBIF, 2021; Nishanbaev et al., 2016) (Figure 2). The official website, Flora of China, states that A. sparsifolia plants are mainly found in Inner Mongolia, Gansu and Qinghai provinces, Xinjiang Autonomous Region, China (Flora of China Editorial Committee, 1998). The latest MaxEnt model simulations predict that the suitable habitats of A. sparsifolia will decrease due to the climate change scenarios of RCP 2.6 and 8.5 on the whole, indicating that the abundance of this species will show a downward trend in the future (Yang et al., 2017).

A. sparsifolia belongs to the Fabaceae family, which consists of over 24,505 species belonging to 946 genera, including Glycine, Glycyrrhiza, Desmanthus, Lupinus, Medicago, Ormosia, and Styphnolobium. Among them, the genus Alhagi includes eight species, namely, A. graecorum Boiss., A. canescens (Regel) B. Keller & Shap., A. kirghisorum Schrenk, A. maurorum Medik., A. nepalensis (D.Don) Shap., A. pseudalhagi (M. Bieb.) Desv. ex B. Keller & Shap., A. sparsifolia Shap., A. sparsifolium (Shap.) Shap. (http://www.worldfloraonline.org/taxon/wfo-0000198672/).

The Fabaceae family is rich in flavonoids, which have anti-inflammatory, antibacterial, and antitumor activity (Wang S. et al., 2019). Flavonoids have been the focus of attention in the field of drug research and development owing to their multiple biological activities and complex mechanisms (Qi and Dong, 2020). So far, over 53 flavonoids (1–53) have been reported in A. sparsifolia, including 30 flavones, 11 isoflavones, five catechins, five proanthocyanidins, and two flavanones (Guo et al., 2016; Ouyang et al., 2018; Guo et al., 2020). There are 26 flavonoid glycosides containing glucose (5–6, 8–9, 15, 20, 28), galactose (2, 46, 53), arabinose (16, 19), rhamnose (23), robinobiose (10, 19), rutinose (4, 11, 13–14, 24), sophorose (17), neohesperidose (43), and trisaccharides (39–41) (Malik et al., 1997; Su et al., 2008; Zhou et al., 2017). The parent structures of the flavonoids in A. sparsifolia are flavones, isoflavones, and catechins, all of which have phenolic hydroxyl substituents. Butin (1), the main active monomer in A. sparsifolia, can significantly inhibit the proliferation and migration of human cervical cancer Hela cells, human colon cancer HT-29 cells, human liver cancer HepG2 cells, human gastric cancer BGC823 cells, and human oral epidermoid carcinoma kB cells in vitro and was found to have synergistic anti-tumor effects in combination with 5-fluorouracil (Ma et al., 2015; Ma et al., 2018). Isorhamnetin-3-O-glucoside (2), isorhamnetin (3), and isorhamnetin-3-O-rutinoside (4) are the most abundant flavonoids and are often considered important indicators for the quality control of this plant (Xu et al., 2012; Sanawar et al., 2014). Moreover, differences in the total flavonoid content of different parts of the plant have also been reported, with the fruit and aerial parts having the highest content of total flavonoids, suggesting that different medicinal parts can be selected based on clinical use to maximize the utility of this plant (Chen et al., 2014).

Alkaloids are important chemical compounds and a good research area for drug discovery. Numerous alkaloids screened from medicinal plants are known to exert antiproliferative and anticancer effects in several cancers both in vitro and in vivo (Mondal et al., 2019). To date, seven alkaloids have been isolated from this plant, including two organic amines (59, 63), six pyrrolidines (54, 57–58, 60–62), and three acylamides (55–56, 64) (Cheng, 2010; Zou et al., 2012; Liu G. C. et al., 2014; Zhou et al., 2017). Alhagifoline A (54) was the first novel compound isolated from the dried aerial parts of this plant; however, pharmacological studies related to its activity are lacking.

Thirty-three organic acids including phenols (65–66, 69–71, 78–79), phenolic acids (67–68, 72–77, 80), and amino acids (81–97) have been identified from A. sparsifolia (Liu G. C. et al., 2014; Cheng et al., 2014; Guo et al., 2016; Zhou et al., 2017; Ma et al., 2018b; Muratova et al., 2019). The substituents of these compounds include hydroxyl, carboxyl, methoxy, amino, and carbonyl groups. Seventeen amino acids have been isolated from the alkaline essential oils of this plant and were reported as the main components of drought resistance in this desert plant (Liu G. C. et al., 2014). The compounds 3-methoxy-4-vinylphenol (65) and 3,4-dihydroxybenzaldehyde (66) have been shown to inhibit tumor cell proliferation in the concentration range of 25–87 μM. Moreover, owing to their selectivity, these compounds may be used in the development of antitumor drugs in the future (Ma et al., 2018).

The stems of A. sparsifolia are rich in polysaccharides; thus, the isolation and purification of polysaccharides have been the emphasis of research with respect to the chemical constituents of this plant. The 19 isolated polysaccharides (AP1-1, AP1-2, AP1-3, AP1-4, AP1-5, AP2-1, AP2-2, AP2-3, AP2-4, AP2-5, SAP-1, SAP-1, SAP-3, APP50-1-1, APP50-1-2, APP50-2, APP70-1, APP70-2, APP70-3-1, APP70-3-2) contain different amounts of Rha, Ara, Xyl, Man, Glc, Gal, GlcA, and GalA (Chang et al., 2016; Jian et al., 2012; Jian et al., 2014; Li, 2020; Ma et al., 2018; Zheng, 2016; m). The possible chemical structures of seven of these polysaccharides (AP1-1, APP50-1-1, APP50-1-2, APP50-2, APP70-1, APP70-2, APP70-3-1, APP70-3-2) are summarized in Figure 9. The crude polysaccharide extract of A. sparsifolia and its monomeric components have significant antioxidant activity and can effectively scavenge free radicals in vivo. The higher the molecular weight, the stronger is the scavenging effect (Zhao et al., 2015; Ma et al., 2018). A study has reported the potential hypoglycemic effect of the crude polysaccharide of A. sparsifolia and that different doses can prevent the increase in fasting blood glucose levels in diabetic mice. The hypoglycemic mechanism may not be related to oxidative stress capacity (Zhao, 2016). In addition, two oligosaccharides (103–104) and 11 oxygen-containing glycosides (97–107) have been identified from A. sparsifolia, including alcoholic glycosides (99–102, 105, 107) and phenolic glycosides (97–98, 103–104, 106).

To date, 58 volatile oils (111–168) from the secretions of A. sparsifolia have been separated and characterized using nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS) (Cheng, 2010; Guo et al., 2016; Ma et al., 2018b). The isolated compounds are mainly composed of small-molecular lipophilic compounds including monoterpenes (142–145, 148–149), a sesquiterpene (160), aliphatic hydrocarbons (111–114, 118–120, 122, 125–127, 156, 159, 162), alicyclic hydrocarbons (115, 121, 123–124, 130, 151, 167), ketones (117, 128–129, 131–133, 135, 137–138, 140–141, 144, 146–147, 150, 152, 155, 157–158, 163–164), alcohols (136, 168), ethers (134, 139, 153–154), and esters (116, 161, 165–166). The structural skeleton of the components consists of five-membered, six-membered, oxygen-containing, and other irregular ring structures. The discovery of several essential oils from A. sparsifolia has significantly enriched its chemical database.

A few lignans (169–171), sterols (176–177), triterpenes (178), and other compounds with irregular chemical structures (172–175) have been isolated from A. sparsifolia. There is no common structural skeleton among these components. Compounds (169–173) were reported to have dose-dependent anti-neuroinflammatory effects.

A. sparsifolia supposedly exhibit the mostpotent antioxidant activities determined by TEAC assays. Phytochemical studies have shown that A. sparsifolia is rich in polysaccharide components, which are closely associated with antioxidant effect (Ma et al., 2018). This indicates that the polysaccharides from A. sparsifolia may be a rich source of natural antioxidants that may help prevent and treat diseases related to oxidative stress. Liu et al. (2021) found that the aqueous extract of A. sparsifolia stem and branch (ASSBP) demonstrated dose-dependent moderate antioxidant activity when assayed against TEAC, with serum TEAC levels of mice in the low dose group (50 mg/kg) and medium dose group (100 mg/kg) comparable to the positive control group of Lentinan (630 mg/kg) and slightly higher levels in the high dose group (200 mg/kg). The results showed that ASSBP had certain antioxidant ability and enhanced immune activity in both normal and d-galactose-induced aging mice, increased spleen and thymus indices in normal mice, increased serum SOD activity and decreased MDA content in normal mice. It is suggested that its anti-aging effect may be exerted through anti-lipid peroxidation, increasing SOD activity and decreasing MDA content.

In a study, the aqueous extracts of Tarangabin at the doses of 150, 300, 600 mg/kg had significant hepatoprotective effects at different concentrations in mice with liver injury induced by N-acetyl-para-aminophenol (APAP). It showed a significant decrease in the level of serum alanine aminotransferase (ALT) and serum aspartate aminotransferase (AST). The results of content determination showed that the polysaccharide content of the extract was as high as 69.2%, thus it is supposed that the polysaccharides have a controlling effect on APAP-induced liver injury (Aili et al., 2017). The hepatoprotective mechanism of Tarangabin has been partly attributed to the reduction of oxidative stress and inhibition of the expression of cytochrome P450 2E1 (CYP2E1) (Aili et al., 2018). In alcoholic liver disease (ALD), Tarangabin regulates the expression levels of tumor necrosis factor (TNF)-α and toll-like receptor 4 (TLR4) mRNA by acting on the lipopolysaccharide-TLR (LPS-TLR) signaling pathway, thereby improving the severity of ALD. Moreover, this plant is known to bring about the effects of reducing the gene expression of TLR4, inhibiting the release of TNF-α, preventing further signal transmission, reducing the efficiency of endotoxin signal transduction, and decreasing the production of inflammatory factors, thereby preventing hepatocyte damage. Tarangabin promotes liver tissue repair and hepatocyte regeneration and protects from liver injury (Kuerbanjiang et al., 2017; Wang X. L. et al., 2019).

In addition, A. sparsifolia significantly alleviated alcohol-induced liver injury by reducing serum ALT and AST, inhibiting MDA and hydrogen peroxide (H₂O₂), and increasing SOD and glutathione (GSH) level in the liver (p < 0.05). Additionally, treatment with A. sparsifolia was found to significantly reduce the expression of TNF-α and TLR4 mRNA in the brain of mice, thus accelerating alcohol metabolism and reducing oxidative stress by downregulating CYP2E1 expression (p < 0.05), which has a protective role in ALD (Kuerbanjiang et al.. 2018).

Tarangabin supposedly protected against high-dose gentamicin (GM)-induced acute kidney injury in mice. Although the efficacy is attributed to the organic components and Zn, Fe, Cu, Co, Ni, Mn, and K content of Tarangabin, the specific mechanism of action needs to be further elucidated (Mikeremu et al., 2013). Wumaierjiang et al. (2014) found that Tarangabin had a certain protective effect in acute renal failure caused by mercuric chloride, and the best effect was achieved when the concentration of Tarangabin was 15% (Ma et al., 2018).

A. sparsifolia and Tarangabin have a dual regulatory effect on the small intestinal motility in mice. The aqueous extract of A. sparsifolia and Tarangabin could inhibit intestinal propulsion induced by the M-choline receptor blocker, atropine sulfate, and alleviate hyperactivity of small intestinal propulsion induced by the M-choline receptor stimulant, carbamyl-B-methylcholine chloride, in a dose-dependent manner. The dual regulation effect of A. sparsifolia and Tarangabin may be attributed to the high taurine content in the plant. It has been reported that taurine has a dual regulatory effect on intracellular Ca²⁺. A certain dose of taurine can enhance intestinal smooth muscle contraction, but the effects of different concentrations of taurine on smooth muscle are different. Low and medium doses of taurine enhance smooth muscle contraction, whereas high doses of taurine have the opposite effect (Mikeremu et al., 2017).

In a particular study, male Sprague-Dawley (SD) rats were subjected to restraint stress and fed a high-lactose diet to establish a diarrhea-predominant model of irritable bowel syndrome (IBS-D), which was further used to evaluate the regulatory effect of A. sparsifolia extract in IBS-D. The extract was found to significantly reduce the fecal water content and abdominal wall myoelectric activity, and significantly increase the volume threshold of abdominal contractile reflex and serum nitric oxide (NO) levels. Additionally, A. sparsifolia extract was found to improve visceral hypersensitivity and decrease the myoelectric activity of the abdominal wall in IBS rats, which may be related to the decrease in the secretion and release of NO (Wei et al., 2016; Ma et al., 2018c).

In a recent study, Liu et al. (2019b) have shown that in IBS-D rats, A. sparsifolia extract can decrease the abnormally elevated levels of the gastrointestinal hormones, 5-hydroxytryptamine (5-HT), substance P (SP), and motilin (MTL); regulate water metabolism to inhibit gastrointestinal motility and delay gastric emptying; and improve abdominal distension, abdominal pain, and diarrhea, which may be the mechanism of this botanical drug in the treatment of this condition. However, the tension of the intestinal smooth muscle and related intestinal electrolyte levels were not observed in this study, and the vasoactive intestinal peptide (VIP) levels following the administration of a high dose of A. sparsifolia extract was not higher than that observed after administration of a low dose of the extract. The antagonism between various components in the extract or the effect of some components in the extract as autoinducers may be the likely causes of this abnormal phenomenon.

The incidence of summer heat strokes and heat radiation in dry and hot desert environments is increasing every year. Dong et al. (2019) found that the desert plant, A. sparsifolia, can improve the heat tolerance of rats in a dry and hot environment by delaying the increase in core body temperature, thereby improving their survival rate in dry and arid conditions.

Results from in vitro cellular assays suggested that SAP-1, SAP-2, and AP1-1 promoted the proliferation and cellular immunity of splenic lymphocytes and RAW264.7 macrophages. These components could promote the secretion of cytokines IL-1β, IL-6, IL-12, and NF-κB. The mechanism of action was via the MyD88-dependent pathway, which activated the immune response of TLR4 receptors (Han et al., 2017). Results from in vivo experiments in mice indicated that the polysaccharide extract could enhance carbon particle scavenging ability, increase serum hemolysin levels in immunosuppressed mice, and also increase serum IL-2 and IL-6 levels in cyclophosphamide-induced immunosuppressed mice (Zhao, 2016; Zhao et al., 2016; Qu, 2019). In addition, A. sparsifolia extract was found to significantly increase the number of white blood cells and lymphocytes in peripheral blood, reduce the atrophy of immune organs, improve the ability of lymphocyte transformation in cyclophosphamide-induced immunosuppression, and enhance delayed hypersensitivity in mice (Ma et al., 2017).

The inhibitory effects of ethanol extracts from aerial part of A. sparsifolia on human gastric cancer (BGC-823), human esophageal cancer (Eca-109), human colon cancer (HT-29) and human hepatocellular carcinoma (HepG2) cells were investigated in vitro by MTT assay with IC₅₀ of 1.62, 1.32, 1.55 and 1.45 mg/ml, respectively. To further clarify its in vivo antitumor efficacy, a CT26 mouse model of colon cancer was established. The in vivo tumor-inhibition activity was investigated by comparing the tumor-proliferation rate, growth curve, and tumor-inhibition rate in each group of mice. The results showed that only the high dose (1,000 mg/kg, intragastric × 14 qd) led to significant in vivo antitumor activity with a tumor-inhibition rate of 24.8%. Compared with that in the negative control group, serum IL-2 levels of mice that received a high dose of the extract increased significantly. Thus, the antitumor mechanism may be related to the increase in IL-2 (Ma et al., 2015).

Two active monomers, butin (1) and 3,4-dihydroxybenzaldehyde (66), extracted from the n-butanol extract of A. sparsifolia, inhibit the proliferation and migration of human cervical cancer (HeLa) cells and exert a strong inhibitory effect in vitro with synergistic antitumor effects with 5-FU. However, the related targets and signaling pathways of its antitumor effects are still unclear (Liu et al., 2019a). Using Hela cells as the target cells, the proliferation inhibition ability of each different polar extracts on tumor cells was detected by MTT assay, and butanol and ethyl acetate extracts among them were clearly shown to have certain inhibition effect on the proliferation of tumor cells. Further studies proved that butin (1), (+)-tortoside A (98), 3-methoxy-4-vinylphenol (65), 3,4-dihydroxybenzaldehyde (66), and 1,3,3,4-tetramethyl-cyclopentene (167) were the active monomers exerting antitumor effects. They also showed good inhibitory effects on HT-29, HepG2, BGC823, and KB tumor cells, exhibiting potential as antitumor agents (Ma et al., 2018b).

Microglia cells are considered to be key innate immune cells in the central nervous system (CNS) and an important contributor to neuroinflammation. However, microglia cells are particularly sensitive to changes in their microenvironment and readily become activated in response to infection or injury. Under activated conditions, they secrete and release a mass of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interferon-γ (IFN-γ), interleukin-6 (IL-6), and free radical mediators such as nitric oxide (NO) and reactive oxygen species (ROS). Accumulation of the pro-inflammatory and neurotoxic factors might aggravate the pathogenesis of neurodegenerative diseases. The LPS-stimulated N9 cells were used to evaluate the anti-neuroinflammatory activity of 33 compounds isolated and identified from the ethanol extracts from aerial part of A. sparsifolia. Among the examined constituents, compounds 1, 3, 4, 15, 32, 36, 37, 42, 54, 65, 79, 99, 167, 169, 170, 171, 172, and 173 could considerably inhibit NO production in LPS-induced N9 microglial cells in a dose-independent manner without evident cytotoxicity at the tested concentrations. The effect of 33 compounds on the anti-neuritis activity of N9 cells by MTT assay revealed that flavonoids and lignans exhibited anti-inflammatory effects, whereas their glycosides were not as effective (compound 3 vs 40 [IC₅₀ 17.87 vs > 100], 170 vs 105 [IC₅₀ 2.68 vs > 100]). In addition, isorhamnetin (3) (IC₅₀ 17.87 μM), quercetin (4) (IC₅₀ 10.22 μM), 3′,7-dihydroxyl-4′-methoxylisoflavone (32) (IC₅₀ 17.43 μM), 3′,7-dihydroxyl-4′,6-dimethoxyl isoflavone (37) (IC₅₀ 11.21 μM), syringaresinol (170) (IC₅₀ 2.68 μM), bombasinol A (171) (IC₅₀ 7.61 μM), aurantiamide (54) (IC₅₀ 14.91 μM), and 1,3,3,4-tetramethylcyclopentene (167) (IC₅₀ 2.63 μM) showed much stronger anti-neuroinflammatory effects without obvious cytotoxicity at their effective concentration compared with the positive control, minocycline (IC₅₀ 19.89 μM). The mechanism of action may be related to the inhibition of excessive activation of microglia and thus the inhibition of the production of pro-inflammatory mediators and cytokines (Zhou et al., 2017).

In addition to the above pharmacological effects, the isolated compounds and crude extract of A. sparsifolia showed antibacterial, antidiabetic, and growth-promoting effects. The aqueous extract exhibited good antibacterial activity against Escherichia coli and Staphylococcus aureus and had a minimum inhibitory concentration (MIC) of 62.5 mg/ml (Lei et al., 2004). A gavage of the polysaccharide (at a dose of 200 mg/kg) administered to male mice with hyperglycemia significantly suppressed fasting blood glucose levels (Zheng, 2016). Moreover, the polysaccharides were found to exert growth-promoting and hemoglobin-increasing effects in mice (Hairula et al., 2014).

A. sparsifolia, as a common ethnic medicine in Uyghur medicine, has a long history of use. Presently, A. sparsifolia is not included in Pharmacopoeia of the People’s Republic of China (ChP). With continuous improvements in modern separation and identification methods, some investigators have used various methods to evaluate the chemical compounds and control the quality of A. sparsifolia. For example, Hu (2010) determined the moisture, total ash, leachate, and total flavonoid content of A. sparsifolia in Tuokexun County, Xinjiang, by referring to the identification items and standardized methods in the ChP. The specificity of isorhamnetin (3), isorhamnetin-3-O-glucoside (17), and isorhamnetin-3-O-rutinoside (12) in A. sparsifolia was determined using TLC, whereas the levels of the main chemical component, isorhamnetin-3-O-rutinoside, were determined using HPLC and found to be 0.1355%, on average. In the same year, Sanawar et al. (2012) conducted a similar study on 12 A. sparsifolia samples collected from the Turpan region of Xinjiang. In addition, they focused on describing the plant traits and determining isorhamnetin content using HPLC. The average isorhamnetin content was determined to be 0.14%. To improve the credibility and accuracy of the quality standard, the XinJiang Institute of Chinese Traditional Medica and Ethical Materia Medica conducted a more comprehensive quality standard study on samples collected from five different regions in Xinjiang by random sampling. The findings revealed that the impurities did not exceed 0.5%, moisture content did not exceed 10%, and total ash content did not exceed 12%. Moreover, unique TLC and HPLC methods for rutin were established (Xu et al., 2012). In addition, Chen et al. (2014) determined the levels of total polysaccharides and rutin in eight samples of A. sparsifolia using ultraviolet spectrophotometry (UVS) and compared its levels in different parts of the plant. The results showed that the total polysaccharide and rutin content in the fruit and aerial parts were relatively high. In another study, HPLC and similarity evaluations were used to establish the chromatographic fingerprints of 10 A. sparsifolia samples collected from different townships in Tuokexun County, Xinjiang (Sanawar et al., 2013), which revealed 11 common peaks in the fingerprints of A. sparsifolia obtained from 10 habitats. However, there were differences in the peak heights of the common peaks in A. sparsifolia obtained from different habitats, indicating differences in the levels of the primary components of botanical drugs obtained from different sources due to local climate and harvesting time. Guo et al. (2020) were the first to use UPLC-Q-TOF-MS for the qualitative analysis of flavonoids from Tarangabin. Using a web-based database and masslynx 4.1 workstation, 40 compounds were analyzed and identified, of which 22 were reported for the first time. Their study provides a scientific basis for the establishment of a compound database and quality standards. Establishment of quality standards for A. sparsifolia will accelerate its entry into the ChP and provide theoretical support and serve as a reference standard for its use in a clinical setting.

Flavonoids are the main components and active compounds in A. sparsifolia; thus, optimizing their extraction is essential for quality control and ensuring efficacy. Su et al. (2009) found that the extract (1 g: 20 ml) of A. sparsifolia collected from Tuokexun County purified with 40% ethanol (1.5 h × 3 times) could extract 1.70% of the total flavonoid based on orthogonal experiments. At a temperature of 90°C, its extracts (1 g: 20 ml) were purified with 40% ethanol (1 h × 3 times), and the extraction ratio of total flavonoids was 1.33% when A. sparsifolia samples from Urumqi, Xinjiang, were used (Shi et al., 2014). Guo et al. investigated the enrichment ability of AB-8, DM301, and D-101 macroporous resins for total flavonoids in prickly sugars, and finally selected AB-8 resin for the enrichment and purification of total flavonoids from prickly sugars. The ideal extraction process was obtained based on Box-Behnken response-surface optimization, wherein ethanol concentration was 67%, the material:liquid ratio was 1:25, extraction time was 75 min, and extraction temperature was 75°C. The average total flavonoid yield extracted from Tarangabin collected from Hotan, Xinjiang was 0.3889% (Guo et al., 2020).