Alkaloids are a class comprising many pharmacologically active constituents. Thus far, 66 alkaloids have been found in stems, fruits, and roots of N. domestica. Depending on their chemical structure, these alkaloids can be categorized as follows: isoquinoline alkaloids (1–53), indole alkaloids (54–55), pyridine alkaloids (56–57), organic amine alkaloids (58–63), steroidal alkaloids (64), and pyrrole alkaloids (65–66). Of these, isoquinoline alkaloids isolated from N. domestica are extensively studied. Their backbones are primarily made up of berberine (1–15), protoberberine (16–22), aporphine (23–46), morphinandienone (47–49), and tetrahydroisoquinoline (50–51). Aporphine–type alkaloids, like nantenine (23) and domesticine (26) have been documented to exhibit cytotoxicity against human tumor cells (Kunitomo, et al., 1974; Moriyasu, et al., 1992). A new aporphine–type alkaloid, isocorydine (36) was isolated from the fruits (Kunitomo, et al., 1972). Peng et al. successively isolated a new steroidal alkaloid, nandsterine (64) coupled with two novel organic amine alkaloids, N–methyl–3–phenyl–N–[2(S),3R,4–trihydroxy–butyl]–acrylamide (58) and N–methyl–3–phenyl–N–[2(R),3R,4–trihydroxy–butyl]–acrylamide (59) (Peng, et al., 2014b; Peng, et al., 2020). Furthermore, two novel aporphine–type isoquinoline alkaloids, 6R,6aS–N–nantenine N _β –oxide (27) and 6S,6aS–N–nantenine N _α –oxide (28), were extracted from the seeds (Qin, et al., 2021). A phytochemical investigation of methanol extract of the fruits furnished two new pyrrole alkaloids, namely methyl–E–mangolamide (65) and methyl–Z–mangolamide (66). These compounds exhibited cell death–inducing activity against adriamycin–treated HeLa cells (Imahori, et al., 2021). According to the aforementioned–research, N. domestica is a natural resource for the extraction of alkaloids. Nevertheless, it is presently uncertain which alkaloids could be utilized as indicators of medicinal quality. Figure 2 presented the structures of the alkaloids (1–66) that were isolated from N. domestica.

Thirteen flavonoids (67–79) were discovered primarily from the leaves and fruits of N. domestica (Figure 3). These compounds are separated into flavonols (67–72), anthocyanins (73–75) as well as biflavones (76–79).

According to earlier studies, fruits were discovered to contain anthocyanins (73–75), including cyanidin 3–xylosylglucoside (73), pelargonidin 3–glucoside (74), and pelargonidin 3–xylosylglucoside (75) (Ishikura, 1971). Under the guidance of the anti-inflammatory activity, robustaflavone (78), a biflavone, was extracted from the methanol extract of N. domestica fruits (Jo, et al., 2019). Further, amentoflavone (79) was isolated from the leaves and fruits, which demonstrated notable antioxidant property and was able to inhibit the growth of Staphylococcus aureus and Escherichia coli (Bajpai, 2019). Currently, there is no research on the types and contents of flavonoids in the various medicinal parts of N. domestica. Thus, additional studies are essential to thoroughly investigate the flavonoids of N. domestica.

Only eight lignans (80–87) have been isolated and identified from N. domestica, comprising tetrahydrofurans (80–82) and furofurans (83–87) (Figure 4). Hence, the structural variety of lignans is restricted. Notably, (−)–episyringaresinol (83) was isolated from tree bark (Kunitomo, et al., 1975). Seven lignans were separated from 80% ethanol extract of the seeds of N. domestica, including gentioluteol (80), berchemol (81), berchemol–4′–O–β–D–glucoside (82), syringaresinol (84), pinoresinol (85), medioresinol (86), along with 1–hydroxypinoresinol (87). The physicochemical characteristics, NMR spectroscopy data analysis, along with comparisons with published reports were utilized to clarify their structures (Shu, et al., 2013).

A total of seventy–one terpenoids (88–158) have been primarily discovered from methanol extract of N. domestica leaves and fruits, which cover monoterpenoids (88–123), sesquiterpenoids (124–155), diterpenoids (156–157), as well as triterpenoids (158). Notably, all the monoterpene compounds (89–116, 118–123) apart from loliolide (117) were reported from the volatile oil of N. domestica by gas chromatography–mass spectrometry (GC–MS). One of the predominant components of N. domestica’s volatile oil was linalool (88) (Bi, et al., 2016). Bajpai et al. discovered that the volatile oil of flowers consists of mainly oxygenated mono- and sesquiterpenes, and mono- and sesquiterpene hydrocarbons. Additionally, the volatile oil of flowers was able to control food–borne pathogenic bacteria, and agricultural plant diseases (Bajpai, et al., 2008; Bajpai, et al., 2009b). In general, sesquiterpenoids can be distinguished on the backbone differences in the biosynthesis. The predominant skeletal type of sesquiterpenes isolated from N. domestica is megastigmane–type (129–136) and eudesmane–type (137–144). Nandinamegastigmanes I–IV (133–136), four new megastigmane glycosides, were extracted from the methanol extract of the fruits (Imahori, et al., 2021). An undescribed cycloartane–type triterpenoid, called 24–methylene–3–oxocycloartane 13–carboxylic acid (158) was purified from a methanol extract from the fruits (Kodai, et al., 2010). The structures of sesquiterpenoids (124–155) are displayed in Figure 5.

Twenty–one phenolic acids and their derivatives were reported from roots, leaves, flowers, fruits, and seeds of N. domestica, comprising phenolic acids (159–169), phenolic glycosides (170–177), and phenolic acid esters (178–179). Nine phenolic compounds were obtained from the ethanol extract of the seeds and their structures were elucidated as syringic acid (159), gallic acid (160), p–hydroxybenzoic acid (161), protocatechuic acid (162), caffeic acid (165), bergenin (168), ellagic acid (169), 3,3′–di–O–methylellagic acid–4–O–β–D–glucoside (170), as well as ethyl gallate (179) (Peng, et al., 2014c). Initially, two phenolic acids, caffeic acid (165) and chlorogenic acid (166), were extracted and identified from 70% ethanol extract of leaves (Taha, et al., 2019). Under the guidance of tyrosinase inhibition activity, Masuda et al. extracted a simple phenolic glucoside, 4–β–D–glucopyranosyloxybenzoic acid (171), from the ethanol extract of the leaves (Masuda, et al., 2007). Moreover, Kulkarni et al. et al. have reported the isolation and characterization of one new caffeoyl glucoside, nandinaside A (173), as well as two known caffeoylated compounds, nantenoside B (175), gastrodin–7–O–trans–caffeoyl ester (172), from the methanol extract of fruits (Kulkarni, et al., 2015). Two known phenol glucosides, 4–O–β–D–glucopyranosylbenzyl–(E)–3–(3,4–dihydroxyphenyl)acrylate (176), and 4–O–β–D–glucopyranosylbenzyl–(Z)–3–(3,4–dihydroxyphen–yl)acrylate (177), were identified from the methanol extract of the fruits (Imahori, et al., 2021). Figure 6 depicts the structures of phenolic acids and their derivatives.

Fatty acids were principally present in the seeds of N. domestica. Moreover, its leaves, flowers and fruits also contained fatty acids in their volatile oil (Wang, et al., 2022; Zhang, et al., 2014). To date, twelve fatty acids, covering saturated (180–186) and unsaturated (187–191) fatty acids, were detected from N. domestica (Figure 8). One study pointed out that the oil content of the seeds was12.26%. A total of 13 fatty acids were determined by GC–MS. Of them, unsaturated fatty acids were the predominant components of the seed oils, which were mainly composed of palmitic acid (181), stearic acid (183), oleic acid (188) and linoleic acid (189) (Wang, et al., 2014). The fatty acids (180–191) are shown in Figure 7.

In addition to the mentioned-above chemicals, various medicinal parts of N. domestica have been shown to contain hydrocarbons (191–230), alcohols (231–264), ketones (265–277), carboxylic acids (278–283), ethers (284–295), aldehydes (296–313), esters (314–338), N–containing compounds (339–363), and other compounds (364–366). Notably, the majority of the above-mentioned compounds were detected from the volatile oils of N. domestica using gas chromatography–mass spectrometry (GC–MS) (Bi, et al., 2016). Young shoots have been reported to furnish a novel cyanogenic glucoside, p–glucosyloxy–mandelonitrile (362) (Abrol, et al., 1966). Additionally, a new cyanogenic compound, nandinin (363), was obtained from the methanol extract of young leaves (Olechno, et al., 1984). A growth inhibitory substance known as p–hydroxybenzaldehyde (311) was isolated from the methanol extracts (Han, et al., 2011). Besides, the enzymes, protein, amino acids, and trace elements were also obtained from N. domestica. Two hydroxynitrile lyases with molecular mass of 24.9 kDa (NdHNL–S) and 28.0 kDa (NdHNL–L) were isolated from the young leaves containing a new amino acid sequence and possessing the potential for efficient production of (R)–cyanohydrins (Isobe, et al., 2018). Furthermore, superoxide dismutase and peroxide isoenzymes were also present in the fresh leaves of N. domestica (Tang, et al., 2008). The leaves had amino acids like Lys, Met, Phe, Val, Leu, Ile, Thr, His, Arg, Asp, and others, as well as proteins like albumin, globulin, gliadin, and glutenin (Niu, et al., 2013). Ten trace elements, including Mo, Co, Cr, Ni, Cd, Pb, Fe, Cu, Zn, and Mn, were found in the roots, stems, and leaves of N. domestica. Among them, the content of Pb and Cd was low. In contrast, the content of the eight remaining trace elements was high (Shu, et al., 1988).

The incidence of malignant tumors is rising annually around the world owing to several factors, including chronic infections, dietary habits, environmental pollution, and increasing in the age of the global population. Malignant tumors currently remain a major global public health issue. Current medications for the treatment of malignant tumors have several drawbacks, including poor efficacy, adverse effects, drug resistance, and high costs. The treatment of malignant tumors requires the use of safe, efficient pharmaceuticals or molecules derived from natural remedies. The roots, stems, leaves, and seeds of N. domestica are traditionally employed to treat pharyngeal tumors. An in vivo study demonstrated that chloroform and methanol extracts of rootbarks exhibited comparatively strong in vitro cytotoxic activity against P388 leukaemia cells with IC₅₀ of 1.5 and 3.0 μg/mL, respectively. Subsequently, berberine (1) was extracted from the aforementioned extracts and demonstrated a noteworthy cytotoxic activity against P388 leukaemia cells with IC₅₀ of 0.4 μg/mL (Funayama, et al., 1996).

The present studies on the antitumor activity of N. domestica are concentrated on its alkaloids and only for in vitro studies. A new alkaloid, nandsterine (64) isolated from the fruits, demonstrated cytotoxicity against human leukemia HL–60 cells with IC₅₀ values of 52.1 μM (Peng, et al., 2014b). Similarly, oxonantenine (41) was remarkably cytotoxic to A549 cells with an IC₅₀ value of 8.15 ± 0.34 μM. Nantenine (23) and nornantenine (24) were moderately cytotoxic to A549 cells with IC₅₀ values of 58.94 ± 2.81 and 48.98 ± 2.57 μM, respectively (Qin, et al., 2021). Two new pyrrole alkaloids, methyl–E–mangolamide (65) and methyl–Z–mangolamide (66) demonstrated cell–induced death in adriamycin–treated HeLa cells. Mechanically, P–glycoprotein inhibition might be associated with the process of inducing cell death (Imahori, et al., 2021). Protopine (52), an isoquinoline alkaloid, prevented the growth of colon cancer cells by stabilizing p53, which in turn caused apoptosis and autophagy in colon cancer cells. Specifically, protopine (52) increased p53–mediated transcriptional activity in a dose–dependent manner, improved the phosphorylation of p53 at position Ser15, which helped to stabilize the p53 protein. Moreover, protopine (52) upregulated the expression of p53 downstream genes p21WAF1/CIP1 and BAX. Protopine (52) suppressed dose–dependently the proliferation of colon cancer HCT116 cells, activated caspase 3/7 (CASP3/7), which subsequently catalyzed poly ADP–ribose polymerase (PARP) cleavage and increased the number of annexin V–FITC–positive cells. Besides, protopine (52) stimulated autophagy in tumor cells via inducing microtubule–associated protein 1 light chain 3 (LC3) puncta generation and LC3–II conversion (Son, et al., 2019). Taken together, the alkaloids of N. domestica showed anti–tumor activity.

Atopic dermatitis (AD), occasionally referred to as atopic eczema, is a recurring, itchy, and chronic inflammatory skin disease. In China, N. domestica has been used for the treatment of sores and scrofula. From the perspective of Western medicine, sores and scrofula are understood to be purulent skin diseases. From the perspective of Chinese medicine treatment, heat-clearing and detoxification drugs are frequently used to treat sores and scrofula. Notably, N. domestica’s leaves have the effect of clearing heat and removing toxins, which might be used for sores and scrofula. Their application has also been proven in several modern research studies. In a 1–chloro–2,4–dinitrobenzene (DNCB)-induced atopic dermatitis model in NC/Nga mice, 70% ethanol extract of leaves treatment at the dose of 300 mg/kg for 5 weeks normalized the total cell number (TCN) in the spleen, axillary lymph node (ALN), and dorsal skin tissue while lowering blood immunoglobulin E (IgE) levels. Furthermore, the experiments revealed a noteworthy reduction in the quantity of CD23+/B220+ cells in the ALN and CD3⁺ cells in the dorsal skin, as well as a decline in the levels of interleukin (IL)–4, IL–5, and IL–13. Besides, the splenocytes’ expression of interferon–γ (IFN–γ) was elevated, and the claudin1 and sirt1 protein expression was notably upregulated. Taken together, 70% ethanol extract of leaves remarkably improved DCNB–induced AD (Yun, et al., 2021b). A similar study found the ethyl acetate fraction of the 70% ethanol extract from the leaves exhibited anti–eczematic activity against DNCB induced eczema in mice, which was superior to the positive control mometasone furoate in the treatment of eczema (Taha, et al., 2019).

The antidermatophytic activity of the essential oil and several chemical extracts (n–hexane, chloroform, ethyl acetate, and methanol) from flowers was assessed against fungal pathogens that caused skin infections, such as Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis. The essential oils demonstrated moderate to high antidermatophytic efficacy against all tested dermatophytes with inhibition of 51.90%–68.60%. Furthermore, essential oils displayed a strong suppression of spore germination in all tested dermatophytes and revealed a concentration–and time–dependent kinetic inhibition of Trichophyton rubrum. Additionally, the extracts showed mild to moderate antidermatophytic effect against fungal pathogens that cause skin infections with inhibition of 19.2%–55.1%. Taken together, essential oils and extracts could serve as a natural fungicide to treat skin fungus infections (Bajpai, et al., 2009a). To summarize, the different extracts of N. domestica produced promising anti–eczema and anti–skin fungal activities. Nevertheless, further research is needed to determine the main active ingredients in the extracts of N. domestica.

Inflammation is a defense response of the immune system to infection or injury. It can get rid of dangerous substances and damaged tissue but can also lead to tissue damage and malfunction. N. domestica has been used for many years in the treatment of inflammatory respiratory diseases such as asthma, whooping cough, and pharyngeal tumors. Existing modern investigations employing lipopolysaccharide (LPS)–induced models of inflammation have validated the anti–inflammatory properties of the extract of N. domestica and its active ingredients. A study demonstrated that aqueous extract from N. domestica fruits treatment at concentrations of 1∼10 μg/mL suppressed dose–dependently the expression of cyclooxygenase–2 (COX–2) and the production of prostaglandin E2 (PGE2) in LPS–stimulated human pulmonary epithelial A549 cells without affecting COX–1 expression and COX activity (Ueki, et al., 2012). A recent study investigated that 70% ethanol extract of N. domestica leaves decreased nitric oxide (NO) production and inhibited interleukin (IL)–6 and IL–1β mRNA expression in LPS–stimulated RAW 264.7 macrophages in a dose–dependent manner. 70% Ethanol extract suppressed phosphorylated activation of mitogen–activated protein kinase (MAPK) signaling pathways, encompassing extracellular signal–regulated kinase (ERK), p38 and c–Jun N–terminal kinase (JNK). Mechanistic studies indicated that 70% ethanol extract exerted anti–inflammatory effects by mediating MAPK phosphorylation and down–regulating inflammatory mediator levels (Yun, et al., 2020). An investigation using a fine dust mixture of coal, flay ash, and diesel exhausted particle (CFD)–induced lung injury mice model demonstrated that 70% ethanol extract of leaves reduced lung injury through suppressing inflammatory cytokines and reducing neutrophil accumulation. To be more precise, 70% ethanol extract of leaves suppressed the level of inflammatory cytokines such as IL–17, tumor necrosis factor–alpha (TNF–α), macrophage inflammatory protein–2 (MIP–2), and C–X–C motif chemokine 1 (CXCL–1) and dramatically decreased neutrophil counts. Furthermore, the 70% ethanol extract led to improvements in lung tissue, such as goblet cell hyperplasia and inflammatory cell infiltration, based on a histological assessment. Also, the elevation of symmetric dimethylarginine (SDMA) and asymmetric dimethylarginine (ADMA) levels was suppressed by 70% ethanol extract (Yun, et al., 2021a). In LPS–stimulated RAW 264.7 macrophages, the pro–inflammatory cytokines IL–1β, IL–6, and NO were reduced by the administration with robustaflavone (78). Furthermore, robustaflavone (78) suppressed the expression of inducible nitric oxide synthase (iNOS) and COX–2, and down–regulated nuclear factor–κB (NF–κB) expression and phosphorylation of extracellularly regulated kinases (pERK 1/2). All the findings demonstrated that robustaflavone (78) had anti–inflammatory property (Jo, et al., 2019). Besides, in LPS–mediated endothelial inflammatory responses elicited in human umbilical vein endothelial (HUVEC) cells, two caffeoyl glucosides, nandinaside A (173), and nantenoside B (175), dose–dependently suppressed LPS–induced leukocyte hyperpermeability, adhesion and migration on human endothelial cell monolayers (Kulkarni, et al., 2015). From the studies mentioned above and their remarkable results, extracts from N. domestica and its active compounds has anti–inflammatory properties. It is still necessary to thoroughly investigate additional anti–inflammatory components and conduct extensive animal model studies to fully understand the anti–inflammatory effect of N. domestica extract.

The extracts of N. domestica are confirmed to exhibit certain antioxidant activity by various antioxidant methods such as DPPH, ABTS, and superoxide radical scavenging, reducing power, and metal chelating ability assays. Some studies have shown that 70% ethanol extract and 80% methanol extract of N. domestica’s leaves dose–dependently possessed favourable DPPH radical scavenging activity (He, et al., 2003; Yun, et al., 2020). Moreover, ethanol extract of leaves demonstrated exceptionally high tyrosinase inhibitory action at 0.5 and 0.15 mg/mL, with inhibitory rates of 81.5% ± 2.0% and 65.7% ± 1.7%, respectively (Masuda, et al., 2007). One study demonstrated that the volatile oil from the flowers possessed good scavenging effects on ABTS radicals as well as metal chelating ability in a concentration–dependent manner (Zhang, et al., 2014). Another similarity study confirmed that the volatile oil from fruits exhibited relatively high ferric ion reducing power with an IC₅₀ value of 145.35 ± 4.10 μg/mL, which was equivalent to that of ascorbic acid. Moreover, the volatile oil of the fruits displayed pronounced scavenging activity against DPPH and ATBS radicals with IC₅₀ values of 28.39 ± 1.12 and 20.61 ± 0.75 μg/mL, respectively. The oil showed moderate scavenging activity against superoxide radicals with an IC₅₀ value of 53.22 ± 2.51 μg/mL. However, its anti-metal chelating activity was low with an IC₅₀ value of 92.5 ± 3.16 μg/mL (Bi, et al., 2016). Besides, amentoflavone (79) displayed potent antioxidant activity on scavenging DPPH, ABTS, superoxide, and hydroxyl radicals in a concentration–dependent manner with inhibition ranging from 19.21% to 75.52% (Bajpai, et al., 2019). According to the aforementioned findings, N. domestica exhibits favourable antioxidant activity and may be employed as a functional material with antioxidant properties.

The extracts of N. domestica stems have been found to have antibacterial effects on S. aureus, Streptococcus faecalis, B. thuringiensis. Meanwhile, the extracts of N. domestica leaves displayed antibacterial activity against Bacillus thuringiensis (Li, 2007; Li, et al., 2008). Moreover, one study showed that aqueous extract of leaves reduced the growth of both Gram-positive (S. aureus, S. pyogenes) and Gram-negative bacteria (E. coli, P. aeruginosa, A. baumannii) by disrupting the bacterial membrane. The aqueous extracts of the leaves were further separated into ethanol, petroleum ether, and ethyl acetate fractions, in which the ethyl acetate fraction exhibited the highist antibacterial activity. Using antimicrobial activity–guided fractionation, alkaloids and flavonoids were isolated from leaf extracts. Antimicrobial tests revealed that the alkaloids inhibited Gram-positive bacteria, whereas the flavonoids suppressed Gram-negative bacteria (Guo, et al., 2018). The aforementioned tests demonstrate the antibacterial activity of N. domestica’s varous extract. Additional studies may be conducted to determine the active components of the various extracts and their safety as medications.

Arsenic trioxide is used internationally as one of the targeted drugs for the treatment of acute promyelocytic leukaemia. However, arsenic trioxide inhibits antioxidant enzyme activities such as glutathione or selectively enhanced cytochrome P450–dependent monooxygenase activity during therapy, which results in oxidative damage to the liver and kidneys, which severely limits its use in clinical practice. Therefore, there is a critical need to discover the specific components responsible for the detoxifying effect. In the Qing Dynasty’s “Supplements to Compendim of Materia Medica” (本草纲目拾遗), it was documented that the aqueous extract of N. domestica’s fruits could detoxify arsenic. Many modern studies have been conducted to evaluate the detoxification effects of N. domestica on the antitumor drug arsenic trioxide using a chronic arsenic trioxide-induced hepatotoxicity and nephrotoxicity in rats. The findings showed that aqueous extract of seeds decreased arsenic trioxide-induced hepatotoxicity and nephrotoxicity. Concretely, aqueous extract of seeds treatment at the dose of 20 g/kg reduced structural damage to liver and renal tissue without hepatocellular necrosis, lowered alanine aminotransferase (ALT), aspartate aminotransferase (AST), serum creatinine (Scr), and blood urea nitrogen (BUN) levels, attenuated the decrease in endogenous creatinine clearance rate (Ccr), decreased catalase (CAT) levels and increased superoxide dismutase (SOD) and malondialdehyde (MDA) levels in the homogenates of the renal cortex, which compared to the untreated group (Peng, et al., 2014a; Liu, et al., 2015). Interestingly, 70% ethanol extracts of roots, stems, and fruits showed significant protective effects against arsenic trioxide oxidative stress-induced hepatotoxicity and nephrotoxicity, whereas N. domestica’s leaves were less effective (Sun, et al., 2019). A similar study demonstrated that total alkaloids from a 70% ethanol extract significantly ameliorated arsenic trioxide-induced cardiac, renal, and hepatic damage. Accordingly, total alkaloids were considered to present an attenuating effect on arsenic trioxide toxicity. Notably, the aporphine alkaloids, such as nantenine (23) and domesticine (26), were characterized by comparatively high content and high specificity, which could serve as indicator components for the quality control methods of N. domestica with regards to the cardiac, renal, and hepatic protective affords (Cheng, et al., 2020). Besides, a recent study demonstrated that different fractions (chloroform, ethyl acetate, n–butanol and aqueous) from the 70% ethanol extract of roots exhibited a favourable protective effect against arsenic trioxide–induced hepatotoxicity and nephrotoxicity. Notably, the most pronounced antagonistic effect on toxicity was observed with the chloroform fraction. Meanwhile, berberine (1), the principal component of the chloroform fraction, showed a dose–dependent protective effect against arsenic trioxide–induced hepatotoxicity and nephrotoxicity (Fu, et al., 2023). Based on the above–mentioned results, the extracts from N. domestica exhibit detoxifying effects on arsenic trioxide induced nephrotoxicity and hepatotoxicity.

Asthma is characterized by severe airway constriction brought on by airway inflammation. For the treatment of asthma, glucocorticosteroids are currently the first option. However, a safer and more effective asthma medication, or adjunctive therapy, is needed in the clinic considering its long duration and various observed adverse effects. Traditionally, N. domestica’s leaves, and fruits have long been used in the treatment of asthma, and chronic bronchitis in China. Remarkably, aqueous extract of leaves at the dose of 1 g/kg for 16 days showed beneficial effects on asthma symptoms, such as dyspnea, cough, and allergy in an ovalbumin (OVA)–specific asthma in guinea pig. Further investigation uncovered that alkaloids were the key constituents of the aqueous extract of leaves for asthma alleviation (Guo, et al., 2018). N. domestica additionally alleviated symptoms of asthma by relaxing smooth muscles. Tsukiyama et al. examined the impact of the aqueous extract from fruits and one of its constituents, nantenine (23), on histamine and serotonin-produced tracheal constriction in isolated guinea pigs. The findings demonstrated that histamine–induced competitive and non–competitive contractions were reduced by aqueous extract administration at doses ranging from 0.1 to 1 mg/mL. Moreover, aqueous extract treatment at the dose of 0.01–1 mg/mL suppressed serotonin–induced contractions in a competitive manner. Notably, nantenine (23) treatment at concentrations ranging from 2 to 20 μM did not impact histamine–induced contraction and only marginally decreased serotonin–induced contraction. The above–mentioned results showed that the aqueous extract had an inhibitory effect on tracheal smooth muscle contraction, whereas nantenine (23) alone could not explain the inhibitory effect of the aqueous extract on tracheal smooth muscle contraction (Tsukiyama, et al., 2007). Similarly, treatment with aqueous extract of fruits at a concentration of 1 mg/mL induced a biphasic relaxation of tracheal precontraction in response to high K⁺ stimulation in histamine–and serotonin–induced contraction of isolated guinea pig trachea. In actuality, the primary active components of the aqueous extract were higenamine (50) and nantenine (23). Furthermore, the aqueous extract of fruits relaxed tracheal smooth muscles immediately through β–adrenergic receptor stimulation by higenamine (50) and slowly through Ca²⁺ antagonism by nantenine (23) (Tsukiyama, et al., 2009; Ueki, et al., 2011). Taken together, the aqueous extract significantly inhibits the contraction of tracheal smooth muscle. However, further investigation is needed into the additional bioactive ingredients in aqueous extract besides nantenine (23).

N. domestica possesses other effects in addition to the above-mentioned pharmacological activities. Specifically, a study found that nantenine (23), isolated from methanol extract of the fruits depressed serotonin–induced contraction of isolated rabbit aorta via suppression of serotonergic receptors (Shoji, et al., 1984). Another investigation showed that intraperitoneal injection of 13.3, 20, and 30 mg/kg nantenine (23) inhibited dose–dependently 5–hydroxy–L–tryptophan (l–5–HTP) plus clorgyline–induced head twitch response (HTR) in mice through blocking the central nervous system’s 5–HT2A receptors (Indra, et al., 2002). Notably, nantenine (23) suppressed adrenergic pressor responses in pithed rats through antagonizing α ₁–adrenergic, 5–HT2A and α ₂–adrenergic receptors in a concentration-dependent manner (Tsuchida and Ohizumi, 2003). Besides, the 95% ethanol extracts of N. domestica’s fruits and leaves exhibited insect repellent activity against Aedes albopictus with effective protection time of 2.94 h and 3.125 h, respectively. Therefore, the leaf and fruit extracts could be regarded as effective repellents against A. albopictus (Hu, et al., 2022).