**3.1 Types of phytochemicals in the Solanaceae family**

The phytochemicals are classified on the basis of their biosynthetic origin, structure, and solubility properties. The different types of phytochemicals are alkaloids, glycosides, flavonoids, saponins, terpenes, steroids, etc. [13]. The Solanaceae family is rich in phytochemicals showing their effectiveness as medicinal plants (**Table 2**). The review studies show that most of these common plants in the selective family show anticancer properties (**Figure 2**) which can enlighten the treatment of cancer in the near future.


*Phytochemicals from Solanaceae Family and Their Anticancer Properties DOI: http://dx.doi.org/10.5772/intechopen.104462*


#### **Table 2.**

*List of some phytochemicals and their classes in the Solanaceae family [14–17].*

#### **Figure 2.**

*Plants of Solanaceae family and their phytochemicals against cancer.*

The use of phytochemicals in pharmaceutical and agrochemical industries is an ongoing process that requires continuous and elaborate study.

### **4. Alkaloids in Solanaceae**

Alkaloids are cyclic nitrogenous secondary metabolites seen in many plants. They are synthesized during the biochemical synthesis of proteins and nucleic acid. These alkaloids have wide applications as drugs, narcotics, or poisons. Jerzykiewicz et al. reported, "Chenopodiaceae, Lauraceae, Magnoliaceae, Berberidaceae, Menispermaceae, Ranunculaceae, Papaveraceae, Fumariaceae, Papilionaceae, Rutaceae, Apocynaceae, Loganiaceae, Rubiaceae, Boraginaceae, Convolvulaceae, Solanaceae, and Campanulaceae are some of the families that rich in alkaloids which protect the plant from insects, pest and also give disease resistant capacity to plants" [18]. This property of alkaloids in Solanaceae can be utilized for anticancer medicine production.

Alkaloids are classified into different categories based the on nature of the precursor molecule for its biosynthesis, chemical structure, biological effect, and heterocyclic or non-heterocyclic types [19]. The biological effects of alkaloids include hallucinogens, antimalarial, tranquilizer, anticancer, CNS stimulant, insecticidal, antiviral, antihypertension, antimicrobial, antirheumatics, antiinflammatory, antioxidant, and diuretics. The alkaloids are used in the drug industry because they are the precursor for medicines for cardiovascular disease, menopause, etc.

*In vitro* and *in vivo* synthesis and production of alkaloids from the Solanaceae family were studied and showed successful results. In different members of Solanaceae alkaloid, the composition is between 0.01 and 3% [20]. "Tropane, indole, pyridine, pyrrolidine, steroidal, and glycoalkaloids" are mostly seen as classes of alkaloids of the above-mentioned group of the plant [21] (**Table 3**).


#### **Table 3.**

*List of some of the alkaloids and its source [22–24].*

*Phytochemicals from Solanaceae Family and Their Anticancer Properties DOI: http://dx.doi.org/10.5772/intechopen.104462*

The review studies show that tomatidine, solanopubamine, solamargine, solanidane; solanidine, daturametelindoles A-D (1–4) chemicals show anticancer activity in in vitro conditions by activation of caspase-3 and regulation of cell cycle to induce apoptosis. The detailed mechanism of action of these chemicals and their clinical trials will be an asset for developments in cancer medicine.

### **5. Flavonoids in Solanaceae**

Flavonoids have several potential effects in plants system such as attracting pollination, seed germination, aromatic flavors in defense mechanisms, stress tolerance, UV photoprotection, inducing root nodulation, and controlling transport of plant hormones [25–27]. Panche et al. reviewed that flavonoids have pharmaceutical, medicine, and cosmetic applications.

The different polyphenolic and glycosidic compounds had been reported from various members of the Solanaceae family (**Table 4**). Scopoletin (7-hydroxy-6-methoxycoumarin), a coumarin, was isolated from *Solanum lyratum* Thunb. showed hepatoprotective activity [28]. One of the most common flavonols in *Solanum nigrum* L. is Quercetin showed antiproliferation effect in different types of cancer models by apoptosis by inducing DNA methylation [29].

The flavonoids, such as apigenin, kaempferol, quercetin, and anthocyanin are some of the chemicals isolated from the respective family that possesses antiproliferation effects against cancer cell lines [30].


**Table 4.**

*List of flavonoid from Solanaceae [27–30].*

### **6. Saponins in the Solanaceae family**

More than 100 plant families, a few starfishes, and sea cucumber reported the presence of saponins. Dicot families, such as Leguminosae, Araliaceae, and Caryophyllaceae, are sources of triterpenoid saponins. Steroidal saponins are found in families, such as Agavaceae, Alliaceae, Asparagaceae, Dioscoreaceae, Liliaceae, Amaryllidaceae, Bromeliaceae, Palmae, and Scrophulariaceae. Solanaceae families

contain steroidal glycoalkaloids [31]. Some of the biological activities of saponins are anti- cancer activity, reducing cholesterol levels, decreasing blood glucose, antiinflammatory potentials, antibacterial, antifungal and antiviral activity [32, 33].

Figueiredo et al. isolated steroidal saponins from the roots of *Solanum sisymbriifolium* Lam. (Solanaceae)which showed a response against dengue virus and yellow fever virus [34]. Chlorogenone, (5α,25S)-Spirostan-3,6-dione are isolated from *Solanum torvum* Sw. Nuatigenosido isolated from *S. sisymbriifolium* Lam. root shows an antihypertensive effect. The antifungal property was exhibited by leaves of *Solanum chrysotrichum* Schltdl [35].

### **7. Terpenes in the Solanaceae family**

Terpenes are used in herbal medicines because of their biological activities. Some of the activities include antiplasmodial, especially antimalarial, anticancer, antidiabetic, anti-inflammatory, antioxidant, etc. Curcumin is one of the terpenes used in folk medicine Terpenes are used as flavors and fragrances in food and cosmetics [36].

Diterpene phytol was isolated from Solanum schimperianum, and Betulinic acid was isolated from Solanum buddleifolium. 3β-Hydroxysolavetivone from the root of S. abutiloides showed antifungal activities. Solavetivone and Lubimin also showed antifungal activities isolated from *S. abutiloides.*

### **8. Anticancer effects of Solanaceae family and their mechanism**

The common conventional treatment of cancer causes side effects and drug resistance in patients, so many plant species were attempted as anticancer drugs. α-chaconine a derivative of solanidine shows an antimetastatic effect individually also in combination with gallic acid by caspase-dependent apoptosis Reddivari et al. [37]. Solanine a glycoalkaloid present in *Solanum tuberosum* L. showed chemoprotective and chemotherapeutic effects. It also inhibited the proliferation of human pancreatic carcinoma cell lines, human melanoma cell lines, and human prostate cancer cells by apoptosis [38]. Solanidine a steroidal alkaloid from *S. tuberosum* L. and *Solanum americanuum* Mill. showed inhibition of cancer cells under laboratory conditions and also from the chemically derived compound of the same by the inhibition of DNA synthesis [39]. Tomatidine A steroid glycoside from *Solanum arboretum* Humb., *Solanum aculeastrum* Dunal. exhibited the suppression of cell invasion by inhibition of ERK and Akt signaling pathways in *in vitro* studies [40]. Tomatine spirosolane-type glycoalkaloids present in *Solanum cathayanum* Wu, *Lycopersicon esculentum* L. showed positive results against prostate cancer in mice when mixed with common drug for cancer by the induction of apoptosis mediated by P13K/Akt pro-signaling pathway [41].

Solamargine glycoalkaloid present in *Solanum palinacanthum, Solanum lycocarpum, Solanum melongena* reduced cell—viability by arresting cell cycle at the G2/M phase. Solasodine was evaluated by many workers for the induction of apoptosis [42]. Steroidal alkaloid soladulcidine, Beta-solamarine, and solanopubamine also show anticancer activity. Capsaicin, from *Capsicum frutescens* L., has anticancer effects on human cell lines of different origins [43]. The mechanism of action of the compound is apoptosis, cell-cycle arrest, and transcription factor regulation. Withanolides isolated from *D. metel* L. leaf extract inhibit tumor cell proliferation against human

#### *Phytochemicals from Solanaceae Family and Their Anticancer Properties DOI: http://dx.doi.org/10.5772/intechopen.104462*

colorectal carcinoma [44]. Nicotine an alkaloid from *Nicotiana tabacuum* L. inhibits cancer cells by regulation of tumor necrosis factor [45]. Anthocyanins from *S. tuberosum* L. were found to cause inhibition of cell multiplication and apoptosis in different cancer cell models [30]. Degalactotigonin was isolated from *S. nigrum* L. showed cytotoxic effect for human tumor cell lines for pancreatic cancer cells induces apoptosis and cell cycle arrest by inhibiting signaling pathway [46].

Saponins from *Solanum trilobatum* L. leaf extract showed anticancer effect and initiation of apoptosis in human larynx cancer cell lines [47]. Saponins Torvosides M, Yamoscin, Indioside H, Borassoside E, Indioside I, and Dioscin isolated from *S. torvum, Solanum violaceum,* and *Solanum indicum* showed anticancer property [48]. Sesquiterpenoids from *S. lyratum*, named solajiangxin D and solajiangxins E, and 2-hydroxysolajiangxin E were isolated and were found to show significant cytotoxicity against three human cancer lines [49]. It has been reported that *W. somnifera* L. inhibits DMBA-induced carcinogenesis in mice [50]. Cycloeucalenone,24-oxo-31-norcycloartanone isolated from *Solanum cernuum*, Lyratol D, Solajiangxin B, Blumenol A, Dehydrovomifoliol from *S. lyratum*. Flavonoids rutin, Tiliroside from *Solanum anguvi*, *Solanum elaeagnifolium* exhibit anticancer activity. *Solanum betaceum* contains flavonoids, such as keracyanin, pelargonidin 3-rutinoside, tulipanin, delphinidin 3-O-α-L-rhamnosyl-(1–6)-β-D-glucoside-3′-O-β-D-glucoside show anticancer properties [35]. The ethanol extract from ripe fruits of *S. nigrum* L. showed anticancer activity by inhibiting the proliferation of human MCF-7 breast cancer cells and inducing cell death by apoptosis [51].

The above-mentioned plants exhibit anticancer mechanisms by cell cycle arrest: The cell cycle contains several proteins at the checkpoint. Cancer cells overcome this checkpoint leads to the multiplication of cells. So inducing cell cycle arrest can be an alternative method in the treatment of cancer. Various researches show that this is possible by phytochemicals. The phytochemicals, such as solanine, solanidine, solamargine, and α-chaconine, result in cell cycle arrest at the S phase of the cell cycle and thereby induce apoptosis based on various concentrations [52] (**Figure 3**).

Studies prove that these chemicals have anticancer properties against different types of cancer, such as breast cancer, colon cancer, cervical cancer, and liver cancer.

**Figure 3.** *Mechanism of cell cycle inhibition by phytochemicals of Solanaceae [50, 52].*

#### **Figure 4.** *Anticancer mechanism of physapubenolide [53].*

Another mechanism involved in anticancer therapy is the regulation of transcription by inhibiting oncogenic transcription factors. Withaferin isolated from Withania sominifera shows antitumor activity by regulating transcription factors [5].

Physapubescin B and physapubenolide isolated from Physalis pubescens exhibit anticancer mechanisms by autophagy (**Figure 4**) and apoptosis in colorectal cancer cell lines [53].

Other mechanisms include the suppression of metabolic enzymes. Some plant molecules can cause apoptosis by breaking the mitochondrial membrane. Defensin isolated from Nicotiana alata induces necrotic-like cell death in a number of tumor cells [5]. The summary of the anticancer potential of selected plants that are economically useful to humans of the Solanaceae family with the mechanism of their action against different cancer cell lines which is reviewed in this literature from previous works by eminent workers is given in the table (**Table 5**).

The effective study of the mechanism of phytochemicals in the Solanaceae family will open a new approach to the treatment of cancer.



#### **Table 5.**

*Mechanism of action of phytochemicals in Solanaceae on different models of cell lines [30, 35, 40–54].*

Many of these are commercially interesting because of their use as flavors and fragrances in foods and cosmetics.

Many of these are commercially interesting because of their use as flavors and fragrances in foods and cosmetics.

## **9. Conclusion**

Cancer is one of the major public health problems across the world. The pandemic condition of the current world results in the delay of diagnosis and treatment that may lead to increased complications in the treatment of cancer. Phytochemicals from Solanaceae exhibit anticancer activity against various type of cancer.

#### *Medicinal Plants*

These compounds proved their efficiency in the inhibition of cancer cell line proliferation by cell cycle arrest, regulation of transcription factors, blocking the signal pathways, initiation of apoptosis, and suppression of metastasis. Most of the compound shows positive results with a combination of other phytochemicals in cancer treatment. The effective study of these biomolecules as anticancer targets can lead to clinical trials and in the future, it opens an effective area for the treatment of cancer and prevention.
