Morphological, phytochemical, and pharmacological properties of the genus Tamarix in Kazakhstan species: a review

Flavonoids

Various Tamarix species in Kazakhstan and China have presented flavonoids and their derivatives, such as T. hispida Willd., T. hohenackeri Bunge, T. laxa Willd., T. ramosissima Ledeb, and T. elongata Ledeb. The primary flavonoids indentified in this process include quercetin, kaempferol with its derivatives, and flavonoids associated with the genus Tamarix (tamarixetin and its derivatives) (Bikbulatova & Korul’kina, 2001; Xing et al., 2014; Umbetova et al., 2004a; Sultanova et al., 2002; Sultanova et al., 2004b; Utkin, 1966; Ren et al., 2019; Hong et al., 2018; Sultanova et al., 2001; Umbetova et al., 2005; Zhang & Tu, 1994). Interestingly, a distinctive compound isolated from T. ramosissima Ledeb. has also been reported as, 8-(1-(1-(3,4-dihydroxyphenyl)ethyl)-3′,4′-dimethoxy-3,5,7-trihydroxyflavone (ramosissimin) (Hong et al., 2018).

Phenolic acids

Considering the diverse biological activities of the genus Tamarix, phenolic acids serve as essential constituents in its phytochemical profiles. Previous studies asserted that phenolic acids were extracted from the aerial components of three species in Kazakhstan and China: (i) T. hispida Willd., (ii) T. hohenackeri Bunge, and (iii) T. ramosissima Ledeb. (Bikbulatova & Korul’kina, 2001; Xing et al., 2014; Ren et al., 2019; Sultanova et al., 2004a; Xiao et al., 2013). These studies identified the presence of gallic, ellagic, ferulic, caffeic, and protocatechuic acids within the various components with antioxidant and anti-inflammatory effects.

Triterpenoids

Triterpenes are abundant in Tamarix plants within Kazakhstan and China, such as T. hispida Willd., T. hohenackeri Bunge, T. laxa Willd., T. ramosissima Ledeb., and T. elongata Ledeb. (Xing et al., 2014; Sultanova et al., 2004b; Umbetova et al., 2004b; Sultanova et al., 2013). Specifically, a triterpenoid compound (isotamarixen) extracted from T. hispida Willd is a potential novel compound exhibiting antioxidant, anti-inflammatory, anti-tumor, and neuroprotective effects (Sultanova et al., 2004b).

Other phytochemicals

A range of phytochemical constituents have been identified in Tamarix species, including alkaloids, coumarins, anthraquinone glycosides, lactams, tannins, tetraterpenes, and phytosterols (Xing et al., 2014; Orabi et al., 2013; Umbetova et al., 2004b). These compounds exhibit diverse pharmacological activities. Notably, the lactam derivative (E)-3-(4-hydroxy-3-methoxybenzylidene)-4-(4-hydroxy-3-methoxyphenyl) pyrrolidine-2-one (commonly referred to as tamaractam) was isolated from the branches and leaves of T. ramosissima Ledeb. (Yao et al., 2017). Therefore, phytochemicals demonstrate significant biodiversity, offering several potential applications in pharmaceuticals and medicine due to their complex interactions with biological systems. Figs. 2, 3, 4 and 5 provide an overview of the chemical compounds in the Tamarix genus.

Primary metabolites

Although most phytochemical investigations on Tamarix have focused on secondary metabolites, several studies have also explored the presence of primary metabolites, including amino acids, carbohydrates, vitamins, fatty acids, and minerals. These components not only play crucial physiological roles but also contribute to the adaptive potential of Tamarix species under extreme environmental conditions (Abilov & Sultanova, 2018).

Amino acids

The amino acid composition of Tamarix species—particularly T. hohenackeri Bunge and T. ramosissima Ledeb.—includes tryptophan, cysteine, threonine, glutamic acid, methionine, asparagine, glutamine, and arginine. Additional amino acids such as aspartic acid, serine, glycine, alanine, proline, tyrosine, valine, histidine, isoleucine, leucine, phenylalanine, and lysine have been identified in T. ramosissima (Abilov & Sultanova, 2018).

Kazakhstani studies further report the presence of 18 free amino acids in T. elongata Ledeb., T. laxa Willd., T. ramosissima Ledeb., and T. hispida Willd., with alanine, proline, leucine, and serine being predominant. The amino acid content was notably higher in samples collected from saline soils, suggesting a possible correlation with environmental salinity stress (Abilov & Sultanova, 2018).

Carbohydrates

The carbohydrate profiles of T. elongata, T. laxa, T. ramosissima, and T. hispida include monosaccharides such as glucose, galactose, rhamnose, and arabinose. Another study reported the presence of glucose, arabinose, xylose, galactose, and sucrose in T. hohenackeri and T. ramosissima (Abilov & Sultanova, 2018).

Vitamins

Vitamin analysis of T. elongata, T. laxa, T. ramosissima, and T. hispida revealed low levels of vitamin C, ranging from 0.003% to 0.046%. Vitamin E content in samples collected in the Almaty region ranged between 0.054% and 0.086% (Abilov & Sultanova, 2018).

Fatty acids

Fatty acid profiling of T. elongata, T. laxa, T. ramosissima, and T. hispida revealed a consistent qualitative composition across species, with 11 major saturated and unsaturated fatty acids identified. These include myristic, pentadecanoic, palmitic, palmitoleic, stearic, oleic, linoleic, eicosenoic, eicosadienoic, eicosatrienoic, and arachidonic acids. Quantitative variations among species were also noted (Abilov & Sultanova, 2018).

Mineral composition

Ash residue analysis of Tamarix species revealed the presence of essential macro- and microelements such as potassium, sodium, calcium, magnesium, copper, iron, zinc, cobalt, lead, nickel, and manganese. Sodium, potassium, and calcium were the most abundant macroelements (Abilov & Sultanova, 2018).

Antioxidant properties

Antioxidant effectiveness is associated with considerable polyphenolic contents (such as flavonoids and tannins), which are known for their ability to neutralize free radicals and protect cells from oxidative stress. Significant examples include T. laxa, T. elongata, T. hispida, and T. ramosissima, possessing antioxidant attributes arising from terpenoid compounds (ursolic acid and isotamarixene) for capturing free radicals and preventing cell and DNA damage. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical capture method also presents that T. ramosissima extracts containing hispidulin and circymaritin exhibit potent antioxidant potential (Bahramsoltani et al., 2020). Furthermore, an inhibitory effect on α-glycosidase activity and significant antioxidant properties have been denoted in triterpenoid isotamarixene (3-α-[3, 4-dihydroxy-trans-cinnamoyloxy]-D-friedoolean-14-en-28-oic acids) within a 50% T. hispida ethanol extract (Sultanova et al., 2002; Ren et al., 2019; Li et al., 2024; Karker et al., 2024a).

The N-hexane extract of T. arceuthoides demonstrates protective effects on DNA from oxidative damage caused by H₂O₂, indicating notable antioxidant potential. This outcome signifies that the active compounds in the extract can inhibit or diminish oxidative damage to cellular structures. Multiple studies have also reported the antioxidant activities of other plant species for the genus Tamarix. This necessity has been attributed to the plant’s high levels of phenolic compounds and flavonoids. Consequently, these studies have stated that phenolic acids and flavonoids can effectively protect against oxidative stress, positioning them as promising candidates for medical applications to treat oxidative process-related diseases (neurodegenerative disorders and cardiovascular diseases). The data have successfully confirmed the significant potential of the Tamarix genus in developing natural antioxidant agents (Umbetova et al., 2004b; Sultanova et al., 2013; Yao et al., 2017; Bukhari et al., 2021; Zazharskyi et al., 2020; Gupta, Dubey & Kumar, 2016; Karker et al., 2024b; Zar Kalai et al., 2024; Samejo et al., 2023; Esma et al., 2023; Iqbal et al., 2022; Nisar et al., 2023).

Antibacterial activity

Different extracts of Tamarix ramosissima have shown varying antibacterial potential depending on the plant part and extraction solvent. A water–acetone leaf extract demonstrated in vitro activity against 15 microbial strains, with minimum inhibitory concentrations (MICs) ranging from 12.5 to 100 µg/mL and antifungal effects observed at 400 µg/mL. In contrast, the ethanolic bark extract was tested against seven bacterial and four fungal strains, showing MICs of 5–10 mg/mL and minimum bactericidal concentrations (MBCs) of 10–25 mg/mL. The bark extract exhibited stronger antibacterial activity against Gram-positive bacteria compared to Gram-negative ones (Bahramsoltani et al., 2020; Yusufoglu & Alqasoumi, 2011; Abo-Dola et al., 2015). The observed antibacterial effects may be attributed to the individual action or synergistic interactions of these identified compounds. Another example is the effective growth inhibition of various bacterial and fungal pathogens, such as Corynebacterium diphtheriae and Aspergillus niger, observed during in vitro assays using ethyl acetate and water-acetone extracts of T. ramosissima. These results highlight the potential these extracts as natural antimicrobial agents for combating infectious diseases (Rotaru & Varut, 2020).

Zazharskyi et al. (2020) argued that T. elongata extracts inhibited bacterial growth, including antibiotic-resistant pathogens. Based on the findings reported by Bukhari et al. (2021) the n-hexane extract of T . arceuthoides exhibited notable antibacterial activity, forming inhibition zones of 27.25 ± 0.37 mm against Micrococcus spp., 14.75 ± 0.28 mm against Staphylococcus aureus, and 14.25 ± 0.24 mm against Escherichia coli. For comparison, the standard antibiotic erythromycin produced inhibition zones of 25.35 ± 0.26 mm, 30.25 ± 0.23 mm, and 34.75 ± 0.34 mm against the same bacterial strains, respectively. Although the extract showed a larger inhibition zone than erythromycin specifically against Micrococcus spp., its overall efficacy was lower against the other tested strains.

In addition to antibacterial effects, T. arceuthoides extracts also demonstrated antibiofilm activity. The chloroform extract inhibited biofilm formation by S. aureus and E. coli by 47.36% and 45.53%, respectively, while the n-hexane extract produced slightly lower inhibition values of 45.92% for S. aureus and 38.58% for E. coli. In comparison, ciprofloxacin, used as a standard control, achieved significantly higher inhibition rates of 77.57% and 82.65%, respectively. These findings indicate that although T. arceuthoides extracts possess promising antibacterial and antibiofilm potential, their efficacy remains lower than that of standard antibiotics when assessed under controlled experimental conditions (Bukhari et al., 2021).

The antimicrobial activity of T. macrocarpa ethanol extract has been effectively evaluated, and it is active against S. aureus, Bacillus subtilis, and Candida albicans. This plant contains a high concentration of phenolic and polyphenolic compounds (gallic acid, isoferulic acid, campferol, and quercetin) based on the phytochemical analysis (Al-Shamma, Kadhum & Al-Hiti, 2005). Several studies have also computed a significant relationship between the antimicrobial properties of the genus Tamarix and the necessity of developing strategies to address pathogenic microorganisms regarding antibiotic-resistant forms. These studies have indicated that biologically active compounds in plants (flavonoids, phenolic acids, and tannins) demonstrate antimicrobial activity against bacteria and fungi. The antimicrobial activity of Tamarix is also influenced by its geographical origin and growing conditions, necessitating study to identify the most effective sources for pharmaceutical applications. Thus, studies concerning Tamarix species’ antimicrobial properties persist, presenting new opportunities for drug development to treat infectious diseases and applications within the pharmaceutical industry (Paul et al., 2022; El-Amier et al., 2021; Dawood, Al-Daody & Al-Takay, 2021; Romeilah et al., 2021; AbouZid & Sleem, 2011; Al-Omar et al., 2020; Boulaaba et al., 2015; Lefahal et al., 2010).

Antimitogenic and chemosensitizing activity

Abaza et al. (2013) indicated that syringic acid and methyl ferulate isolated from methanolic T. passerinoides Delile and T. aucheriana extracts could be adjuvant agents in colorectal cancer management (Lefahal et al., 2010; Al-Judaibi, 2020). The studies explained that the primary actions of these compounds included inhibiting tumor cell growth, inducing apoptosis, and enhancing cell sensitivity to chemotherapeutic agents. A positive correlation between syringic acid and chemotherapy efficiency was also reported. Peydayesh et al. (2020) investigated the inhibitory effect of silver nanoparticles from T. hispida extracts on the cyclin D1 protein expression in human cancer cell lines. The study described the methodology based on biosynthesized silver nanoparticles for evaluating the anti-cancer effect concerning molecular mechanisms, cell cycle regulation, and cancer cell proliferation. This method offered an alternative approach to nanoparticle production that eliminated chemicals commonly employed in nanomaterial synthesis. Therefore, the biological synthesis method could reduce toxicity and impart additional biologically active properties to nanoparticles due to compounds present in extracts (Aljubouri & Alobaidi, 2023).

Numerous studies on the Tamarix genus have garnered scientific interest regarding its potential anti-cancer properties. These studies demonstrate that Tamarix extracts are active against various cancer cell types, including breast, lung, and colon cancers. The anti-tumor effects observed in laboratory conditions also indicate a growth reduction of cultured malignant cell tumors, suggesting that these plants are promising candidates for pre-clinical studies (Abaza et al., 2013; Abaza et al., 2016; Lefahal et al., 2010; Al-Judaibi, 2020; Peydayesh et al., 2020; Nicolini et al., 2014; Abdel-Tawab et al., 2019; Boulaaba et al., 2013).

Antidiabetic activity

Given the increasing prevalence of diabetes (particularly type 2 diabetes) involving insulin resistance and metabolic disorders, studies regarding the antidiabetic properties of the genus Tamarix have attracted interest from the scientific community. Plants within this genus usually contain various biologically active compounds that can positively influence glucose and lipid metabolisms. Specifically, T. hispida possesses tannins inhibiting the enzyme α-glucosidase, preventing a rapid increase in blood sugar levels (AbouZid & Sleem, 2011). Specific antidiabetic property-related studies of extracts from several Tamarix genera have also demonstrated their capacity to reduce blood glucose levels in experimental animals. This outcome is attributed to improved insulin sensitivity and increased glucose absorption capacity of tissues (Alnuqaydan & Rah, 2021; Alnuqaydan et al., 2022; Fayed et al., 2023; Al Sobeai, 2018; Sehrawat & Sultana, 2006; Ullah et al., 2017; Hebi & Eddouks, 2017; Mahfoudhi et al., 2016).

Anti-inflammatory action

Chen et al. (2018) assessed the anti-inflammatory properties of T. hohenackeri extracts. The study identified potential neuroinflammation inhibitors from four T. hohenackeri extracts while examining their possible mechanisms of action. Consequently, reduced inflammatory response was observed due to the flavonoids and phenolic acids reducing the cytokine production in lipopolysaccharide-activated microglia. Previous studies also examined the anti-inflammatory properties of other Tamarix species (Zhumagaliyeva et al., 2021; Chen et al., 2018; Yusufoglu & Alqasoumi, 2011; Fayez et al., 2024; Hamed et al., 2024). These studies indicated that the main mechanisms of their action involved inhibiting inflammatory mediators and lowering inflammatory cells’ activity. The Tamarix plant extracts were also reported as adjunctive treatments (inflammatory conditions) and aided formulation of phytotherapeutic agents (anti-inflammatory and antioxidant properties) owing to their capacity to suppress the activity of pro-inflammatory cytokines and enzymes while reducing oxidative stress,

Inhibition of ACE and platelet aggregation

Xing et al. (2014) investigated bioactive compounds isolated from T. hohenackeri Bunge a species traditionally used in folk medicine and known for its for its radioprotective properties. The study suggested that flavonoids and phenolic compounds present in the extract exhibited inhibitory effects on angiotensin-converting enzyme (ACE) and platelet aggregation, indicating potential cardiovascular benefits. In another study, Bukhari et al. (2021) evaluated the thrombolytic activity of T. arceuthoides in vitro. The experiment involved incubating human blood clots with plant extracts at 37 ^∘C and measuring the percentage of clot lysis. Streptokinase served as the positive control, showing 70.83 ± 0.84% clot lysis. Among the tested extracts, the n-hexane extract of T. arceuthoides demonstrated thrombolytic activity of 19.72%, whereas the chloroform extract exhibited 18.57%. Although the activity was lower compared to the standard, these findings suggest the presence of bioactive compounds with potential clot-dissolving properties that warrant further investigation.

Antileishmanial activity

Akya et al. (2020) investigated the antileishmanial effects of hydroalcoholic and chloroformic extracts of Tamarix ramosissima against Leishmania major and Leishmania tropica promastigote forms. The hydroalcoholic extract reduced parasite viability at all tested concentrations, with an IC₅₀ value of 0.1 mg/mL for both species. The chloroformic extract showed moderate inhibitory effects, with a measured IC₅₀ of 50 mg/mL. These findings indicate that T. ramosissima exhibits high antileishmanial activity and holds promise as a natural source for developing novel agents against leishmaniasis (Akya et al., 2020).

Antiproliferative and apoptosis-inducing effects

The tamaractam and ramosissimin compounds isolated from T. ramosissima induce apoptosis while inhibiting the growth of synoviocytes associated with rheumatoid arthritis (Umbetova et al., 2004a; Hong et al., 2018; Yao et al., 2017).