Pharmacological Properties and Health Benefits of Capsicum Species: A Comprehensive Review

Abstract

Since the start of history, natural medicine has been of great interest and attention to humankind. A heap of empirical research indicates that spices have undoubtedly made our lives more interesting and may also make them longer. Capsicum is a highly regarded indispensable spice all over the globe for its umpteen culinary and medicinal facets. It has been used for more than 7000 years in Mexico and is believed to have originated in tropical Central America. Mainly, this botanical contains a good source of vitamin C, vitamin A, vitamin E, vitamin B5, potassium, magnesium, iron, calcium, phosphorus, and carotenoids. Interestingly, capsicum phenolic compounds are helpful in preventing and treating many ailments. So, it intends as a beneficial milestone in the pharmaceutical industry and a boon to humanity. This chapter highlights the tremendous pharmacological uses and health benefits of capsicum species and its active compounds in multifarious aspects.

1. Introduction

Capsicum is a popular vegetable and spice crop belonging to the nightshade family Solanaceae, which is amply cultivated for its succulent berries and seeds in tropical and subtropical climate regions all around the globe. The word “Capsicum” comes from the Greek word kapsimo, meaning “to bite” or “to swallow.” Astonishingly, Capsicum pods have been well known since the beginning of civilization in the Western hemisphere and have been part of the human diet since 7500 BC. Habitually, people eat this botanical spice in raw, dried, and cooked form, and it is also used in making paste, pickle, and sauce. Although, from place to place, the name and type of Capsicum berries vary, the most common variety is called “pepper or chili pepper,” which itself can vary greatly in color, shape, size, appearance, flavor, and pungency. Basically, the color diversity of Capsicum fruit is linked to the presence of pigments like chlorophyll (green), anthocyanins (violet/purple), α-carotene, β-carotene, zeaxanthin, lutein, and β-cryptoxanthin (yellow/orange) [1]. Surprisingly, approximately 35 species of capsicum exist in nature; only five have been domesticated for human consumption, namely Capsicum annuum (ancho/poblano, bell, cayenne, thai, jalapeno, paprika, pimiento, piquin, and serrano), Capsicum baccatum (aji amarillo, aji limon, criolla sella, malawi piquante, and bishop’s crown), Capsicum chinense (scotch bonnets, trinidad scorpions, bhut jolokia, and carolina reaper), Capsicum frutescens (tabasco, bird-eye, kambuzi, malagueta, and siling labuyo), and Capsicum pubescens (rocoto pepper) (Figure 1) [2]. Of these species, the Capsicum annuum is the most economically important crop due to its pungent odor and taste.

Figure 1.

Five major domesticated species of Capsicum.

Chili peppers are perennial woody plants grown as herbaceous annuals. It is said to be the first-ever domesticated crop in America [3]. The size of the plant can range from two to four feet tall, depending on the species. Typically, leaves are smooth, simple, entire, glabrous, and flat. The flowers are usually solitary, creamy white, and the seeds are straw-colored. Figure 2 highlights the different types of chili plants. In addition, chili plants are grown for ornamental purposes, owing to their bright, shining fruits with a diverse range of colors [4]. Most abundantly, chili crops are grown in Pakistan, India, China, Ethiopia, Myanmar, Mexico, Vietnam, Turkey, Peru, Ghana, Bangladesh, Japan, Africa, and America (Table 1). As per 2019 world production statistics, the total global produce of chili pepper is 38 million tons [5]. China ranks first, producing over 18,978,027 tons of chili in 2019. In terms of nutritional standpoint, chili is considered to be one of the most nutritionally dense foods on earth, and it plays a vital role in alleviating human micronutrient deficiencies [6, 7]. Traditionalistically, it is harnessed in different systems of medicine to combat a wide variety of diseases and/or disorders due to the presence of therapeutically significant active constituents [8]. A total of 200 phytoconstituents have been identified from chilies [9]. Chili pepper’s extremely hot or burning sensation is due to capsaicinoids, a family of compounds consisting of acid amides of vanillylamine and a C₈–C₁₃branched-chain fatty acid [10]. Capsaicin and dihydrocapsaicin are the two prominent capsaicinoids present in chili peppers, accounting for over 90% of the total capsaicinoids [11]. Particularly, capsaicin has been at the center of intense research to elucidate the basis of its pharmacological properties and exploit its therapeutic potential [12, 13]. In recent times, this chemical substance has been employed as an analgesic in topical ointments, nasal sprays, and dermal patches to treat pain, typically in concentrations between 0.025 and 0.1%. It is also used to reduce the symptoms of peripheral neuropathy, such as postherpetic neuralgia caused by shingles [14]. Other capsaicinoids, such as nordihydrocapsaicin, homocapsaicin, and homodihydrocapsaicin, are present in small amounts in chili peppers, accounting for less than 10% of the total capsaicinoids [15]. Therefore, this chapter aims to discuss the nutritional value, phytochemical profile, pharmacological properties, and health benefits of Capsicum species.

Figure 2.

Different types of chili plants.

Rank	Country	Production (tons)
1	China	18,978,027
2	Mexico	3,238,245
3	Turkey	2,625,669
4	Indonesia	2,588,633
5	Spain	1,402,380
6	Egypt	764.292
7	Nigeria	753.116
8	Algeria	675.168
9	United States of America	624.982
10	Tunisia	443.632

Table 1.

List of the top ten chili pepper producing countries in 2019.

Source: FAOSTAT [5].

2. Nutritional value and phytochemical constituents

Chili peppers are a good source of dietary fiber, riboflavin, thiamin, folate, niacin, iron, protein, phosphorus, and copper. Aside from that, it also contains high amounts of vitamin A, vitamin C, vitamin K, vitamin E, vitamin B6, potassium, and manganese [16]. The nutritional composition of chili peppers per 100 g is listed in Table 2. Chili fruits are also rich in many phytochemicals such as carotenoids (lutein, β-carotene, β-cryptoxanthin, zeaxanthin, violaxanthin, and capsanthin), capsaicinoids (capsaicin, dihydrocapsaicin, nordihydrocapsaicin, homocapsaicin, homodihydrocapsaicin, and nonivamide), and flavonoids (quercetin, luteolin, kaempferol, catechin, epicatechin, rutin, apigenin, myricetin, and cyanidin) [17, 18]. The following Figure 3 shows the chemical structures of the various phytochemical constituents.

S. No.	Types of nutrient	Amount
1	Water	88.02 g
2	Energy	40 kcal
3	Protein	1.87 g
4	Fat	0.44 g
5	Carbohydrate	8.81 g
6	Fiber	1.5 g
7	Sugars	5.3 g
	Minerals
8	Calcium	14 mg
9	Iron	1.03 mg
10	Magnesium	23 mg
11	Phosphorus	43 mg
12	Potassium	322 mg
13	Sodium	9 mg
14	Zinc	0.26 mg
	Vitamins
15	Vitamin C	143.7 mg
16	Thiamin	0.072 mg
17	Riboflavin	0.086 mg
18	Niacin	1.244 mg
19	Vitamin B-6	0.506 mg
20	Folate	23 μg
21	Vitamin A	48 μg
22	Vitamin E	0.69 mg
23	Vitamin K	14 μg
	Lipids
24	Fatty acids, total saturated	0.042 g
25	Fatty acids, total monounsaturated	0.024 g
26	Fatty acids, total polyunsaturated	0.239 g

Table 2.

Nutritional composition of chili pepper (per 100 g).

Figure 3.

Chemical structures of various phytochemical constituents in chili pepper.

3. Pharmacological uses

The mechanism behind the therapeutic potential of chili pepper has been apprised in several hefty pieces of literature. Chili is effective against a great number of ailments such as cancer, rheumatoid arthritis, bronchitis, macular degeneration, anemia, osteoporosis, coronary heart disease, diabetes, obesity, hypertension, sinus infection, migraine, neurological disorders, menopausal problems, and digestive complications [19, 20, 21, 22, 23, 24, 25]. Figure 4 displays the pharmacological activities of chili pepper. Herein, the immense potential of chili in battling severe illnesses, as well as the mechanisms associated with health-promoting actions, have been illustrated in detail.

Figure 4.

Pharmacological activities of chili pepper.

3.1 Anticancer activity

Cancer is a group of diseases characterized by uncontrolled growth and the spread of abnormal cells. It is the world’s second leading cause of death, with a 10 million fatality rate annually [26]. A series of changes in the activities of cell cycle regulators are usually hooked up for cancer development and progression [27]. Generally, cancers are often named for the organ or cell type where the abnormal cells first form. Lung, prostate, colorectal, stomach, and liver cancer are the most prevalent types of cancer in men, while breast, colorectal, lung, cervical, and thyroid cancer are the most endemic among women [26]. Current chemotherapeutic drugs are enormously utilized to destroy cancer cells. Still, in addition to targeting the diseased cells, it also kills healthy blood cells, skin, stomach, hair follicles, bone marrow, etc. As a consequence of the undesirable properties and side effects of synthetic drugs, natural products have become increasingly popular over the past few decades. Capsaicin, the spicy ingredient of hot chili peppers, exhibits anti-neoplastic activity in a vast number of cancers like pancreatic cancer, colon cancer, liver cancer, lung cancer, prostate cancer, breast cancer, bladder cancer, and skin cancer [28, 29, 30, 31, 32, 33, 34, 35, 36]. The significant anticancer capacity of capsaicin targets multiple signaling pathways and cancer-associated genes in different phases of tumor development, including initiation, promotion, progression, and metastasis [37]. Table 3 shows that various in vitro and in vivo models have been used to demonstrate the anticancer effects of capsaicin.

Table 3.

Anticancer effects of capsaicin on various cancers in in vitro and in vivo models.

3.1.1 Pancreatic cancer

Pancreatic cancer, one of the most lethal malignancies, is the seventh leading cause of cancer-related fatality globally. This disorder is broken down into two forms: pancreatic adenocarcinoma (85%, with a very poor prognosis) and pancreatic neuroendocrine tumors [50]. In patients with advanced pancreatic cancer, the survival rate is less than one year. Numerous studies have explored the possibility of improving survival in pancreatic cancer with new therapies. Over the past few years, researchers have studied the effects of capsaicin on various pancreatic cancer cell lines, including BxPC-3, AsPC-1, PANC-1, SW1990, MiaPaCa-2, and L3.6pl. Based on the results of these studies, anti-proliferative activities of capsaicin are mainly attributed to the inhibition of oxidative stress and angiogenesis, cell cycle regulation, and apoptosis induction [38, 51, 52]. The first report on the involvement of endoplasmic reticulum stress (ERS) in the induction of apoptosis in PANC-1 and SW1990 cells using capsaicin was described by Lin et al. [38]. The authors demonstrated the potency of capsaicin on the mRNA expression of two key ERS markers (GRP78 and GADD153) in PANC-1 and SW1990 cells. According to real-time PCR analysis, capsaicin significantly increased the mRNA expression of GRP78 and GADD153 in a time and dose-dependent manner, suggesting ERS-mediated apoptosis and cell growth inhibition.

3.1.2 Colon cancer

Globally, colon cancer is one of the most prevalent forms of cancer, posing a major public health threat. In 2020, approximately 1,148,515 people were diagnosed with colon cancer, and 576,858 people died from this disease worldwide [53]. The onset of colon cancer is associated with excessive cell proliferation and dysregulation of both cell-cycle progression and apoptosis. Additionally, “neoangiogenesis” plays an essential role in the development, growth, and metastasis of colon tumors [54]. In the majority of cases, colon tumors are only diagnosed in the later stages of the disease, because they do not manifest as pain-like symptoms. Over time, several strides have been made in researching and treating colon cancer. However, its survival rate has not significantly improved. The five-year survival rate is still less than 15% due to the available therapeutic agents showing strong adverse effects and poor effectiveness [55]. Recent research reported that capsaicin has cytotoxic effects on different human colorectal cancer cell lines, including colo 205 and RKO [42, 56]. In a 2004 study, Kim et al. presented salient findings regarding the capsaicin-induced apoptotic cell death by activating peroxisome proliferator-activated receptor

(PAPR

) in HT-29 human colon cancer cells [40]. In addition, the latest study has shown that capsaicin mediates cell cycle arrest and apoptosis in two different human colon cancer cells (HCT116 and LoVo) via stabilizing and activating p53 in a time-dependent manner [41].

3.1.3 Liver cancer

Hepatocellular carcinoma is the most-encountered primary liver cancer in adults. Overall, the incidence rate of liver cancer is approximately four times higher in males than in females, and its pathogenesis is usually considered as an overlap of long-lasting processes, such as hepatic cytolysis, inflammation, liver regeneration, and fibrosis [57]. In hepatocellular carcinoma cell line HepG2, capsaicin-induced apoptosis with the involvement of intracellular Ca²⁺, ROS, Bcl-2 family, cytochrome c protein expression, and caspase-3 activity [58]. Co-treatment with capsaicin and sorafenib potentially inhibits cell proliferation by activating caspase-9, PARP, AMPK, acetyl CoA carboxylase phosphorylation in HepG2 and Huh-7 cells [59].

3.1.4 Lung cancer

Lung cancer is the leading cause of mortality in both men and women, and it causes 1.8 million deaths annually. On the medical front, the prognosis of lung cancer is poor because it cannot produce noticeable signs and symptoms in the early stages. Being exposed to cigarette smoke/smoking is considered the most important factor involved in lung cancer development. Besides, environmental pollution and epigenetic alterations can also lead to lung cancer progression. This kind of cancer is broadly classified into two types: small cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC). NSCLC is the predominant type of lung cancer, accounting for about 85% of cases, while SCLC is responsible for 15% of lung cancer cases [60]. Capsaicin exhibited its therapeutic efficiency in lung cancer treatment by means of inhibiting Hypoxia-inducible factor (HIF)-1α accumulation by suppressing mitochondrial respiration in human lung cancer cells (H1299, H23, A549, and H2009) [61]. Furthermore, the time-dependent antitumor effects of capsaicin on lung cancer were also described in an in vivo and in vitro study on SCLC cells and nude mice. The study showed that capsaicin-induced apoptosis is mediated by transient receptor potential vanilloid subfamily member 6 (TRPV6), intracellular calcium, and calpain pathway [62]. TRPV6 is one of the most calcium selective ion channels in the TRPV family. Its main function is to regulate calcium transport, reabsorption, and homeostasis in epithelial tissues. Calpains are a family of calcium-dependent intracellular cysteine proteases that regulate multiple cellular processes.

3.1.5 Prostate cancer

Prostate cancer is the most common invasive malignancy among males. The incidence rate has increased in recent years in most regions of the world, perhaps due to improved detection methods with prostate-specific antigen (PSA) testing; however, the mortality rate has remained constant since the early 1900s. Androgen and androgen receptor (AR) play a critical role in the growth and maintenance of the prostate gland and the development of prostate tumors [63]. Prostate cancer may be connected with debilitating disease-related complications in an advanced stage, including painful bone metastases and urinary tract obstruction. microRNAs (miRNAs) are a class of small non-coding RNAs (ncRNAs) that regulate gene expression by repressing translation and have been proven to be implicated in the regulation of crucial processes, such as proliferation, differentiation, and apoptosis in various kinds of cancer [64]. Among the miRNAs, miR-449a functions as an important tumor suppressor in many types of tumors by targeting different genes. Recently, Zheng et al. found that capsaicin inhibits the proliferation of AR-positive prostate cancer cells (C4-2 and LNCaP) by inducing the restoration of miR-449a [65]. Additional convergent pieces of evidence have shown that the capsaicin combined with brassinin and docetaxel synergistically kills human prostate cancer cells (PC-3 and LNCaP) through metabolic regulator AMP-activated kinase and apoptosis [66, 67].

3.1.6 Breast cancer

Breast cancer is the second most prevalent cancer worldwide and causes a high number of deaths among women every year. In the proliferation of breast cancer cells, NF-κB—the proinflammatory transcription factor plays a key role. It regulates more than 500 different genes and governs the expression of proteins engaged in cellular signaling pathways, leading to the development of malignancies and inflammation. Capsaicin displayed the ability to affect breast cancer cell proliferation by downregulating the FBI-1-Mediated NF-κB pathway [48]. Another target that acts on the proliferation of breast cancer cells is the human epidermal growth factor receptor-2 (HER-2), a tyrosine kinase (TK) receptor belonging to the EGFR family. A recent study by Thoennissen et al. showed capsaicin causes cell-cycle arrest and apoptosis in breast cancer cells (MCF-7, T47D, BT-474, SKBR-3, and MDA-MB231) via modulating the EGFR/HER-2 pathway [68].

Cyclin-dependent kinases (CDKs), a member of the serine/threonine-protein kinase family, can coordinate critical regulatory events during the cell cycle and transcription. Alterations in at least one CDK regulator or effector have been identified in almost all types of cancer. CDK8, as a member of the CDK family, serves a crucial role in gene transcription. Apart from this, phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) signaling pathways also play an important role in many aspects of cell growth and survival under both physiological and pathological conditions. Dysregulation of this pathway has been observed a various transformed cells and cancer tumors. In addition, aberrant activation of the Wnt/β-catenin signaling pathway causes β-catenin accumulation in the nucleus and can induce breast cancer. However, Wu et al. demonstrated that capsaicin inhibited breast cancer cell viability, induced G2/M cell cycle arrest, reduced CDK8 expression levels, decreased the phosphorylation of PI3K and Akt, and downregulated Wnt and β catenin expression levels in MDA MB 231 cells [69].

3.1.7 Bladder cancer

Bladder cancer is a common malignancy affecting the genitourinary system. It is generally subdivided into two types: nonmuscle invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC). About 30% of total patients are MIBC and have a high mortality rate due to distant metastases. Meanwhile, 70% of patients are NMIBC, which are likely to progress MIBC. Morphologically, bladder tumors can be divided into papillary, solid, and mixed types. However, the papillary type is predominant, especially in NMIBC [70]. A poor prognosis and resistance to chemotherapy are the two most important characteristics of this disease. Recently, Yang et al. reported capsaicin-induced cell death in human bladder cancer T24 cells through calcium entry-dependent ROS production and mitochondrial depolarization [71]. Likewise, Chen et al. also demonstrated capsaicin-induced cell cycle arrest by inhibiting cyclin-dependent-kinase in 5637 bladder carcinoma cells [72].

3.2 Antimicrobial activity

Microorganisms are liable for causing food spoilage and various foodborne illnesses every year. These illnesses can generate many ailments, ranging from stomach discomfort to spontaneous abortions in pregnant women, and can even lead to death in severe cases. Researchers have recently stated that some varieties of chili peppers and their active compounds exhibit significant antimicrobial properties, equivalent to some modern-day antibiotics [73, 74, 75, 76]. Especially, Goci et al. investigated the carbopol-based formulated capsaicin enhances the antibacterial and antifungal effects against Escherichia coli (ATCC 10536), Bacillus cereus (Peru MycA 4), Salmonella typhi (Peru Myc 7), Staphylococcus aureus (ATCC 6538), Candida tropicalis (YEPGA 6184), Candida albicans (YEPGA 6379), Candida parapsilosis (YEPG 6551), and Candida albicans (YEPGA 6183), with a minimum inhibitory concentration (MIC) value reduction of at least 50% [77].

3.3 Antidiabetic activity

Diabetes mellitus is a chronic endocrine disease characterized by disorders in the metabolism of carbohydrates, lipids, and proteins due to a deficiency in insulin production by pancreatic beta cells and/or an increase in insulin resistance in peripheral tissues. Universally, this illness affects the majority of people in both developed and developing countries. Numerous synthetic drugs have been developed for the treatment, but a safe and effective paradigm is yet to be achieved. In terms of potential as a pharmacological alternative, chili has shown good antidiabetic effect because it contains α-amylase and α-glucosidase inhibitors, which are required for the degradation of polysaccharides and disaccharides. Especially, the species Capsicum frutescens (cayenne pepper) is often used as remedies for diabetes mellitus in African traditional medicine. Based on a previous report, Islam and Choi state that Capsicum frutescens increased serum insulin concentration in high-fat (HF) diet-fed streptozotocin-induced type 2 diabetes rats after four weeks of treatment. The data of this study suggest that 2% of dietary Capsicum frutescens is insulinotropic rather than hypoglycemic in the experimental methods [78].

3.4 Antiarthritis activity

Arthritis is an autoimmune disorder that causes pain, swelling, and stiffness in the joints. There are at least 100 types of arthritis, commonly known as connective tissue disorders, which can affect people of all ages, gender, and races. However, there is significant evidence to suggest that both the elderly and women are greatly affected. More than three decades ago, capsaicin was first shown to have protective effects in experimental arthritis [79]. Further, Inman et al. observed that capsaicin concomitantly administered with methylated bovine serum albumin (mBSA) into the rat knee markedly reduced the severity of arthritis in comparison with the contralateral inflamed knee treated with vehicle, supporting a protective role for capsaicin in reducing the severity of antigen-induced arthritis in felines [80]. According to the trend, capsaicin cream is used to reduce pain caused by many types of arthritis. Specifically, it works by decreasing a certain natural substance in the human body (substance P) that helps transmit pain signals to the brain.

3.5 Antioxidant activity

The family of free radicals generated from the oxygen is referred to as reactive oxygen species (ROS), which cause damage to other molecules by extracting electrons from them in order to attain stability. ROS are various forms of activated oxygen which include free radicals such as superoxide anion radicals (O₂⁻), hydroxyl radicals (OH⁻), non-free radicals (H₂O₂), and singlet oxygen [81]. The molecular basis of many diseases is known to involve oxidative stress caused by free radicals [82]. Recently progressive research has been directed at natural antioxidants. By using the DPPH free radical assay, Dubey et al. evaluated the antioxidant potential and free radical scavenging activities of some selective chili genotypes from the North East region of India in terms of inhibitory concentration (IC₅₀), efficiency concentration (EC₅₀), and anti-radical power (ARP) [83]. Likewise, Ayob et al. also determined the antioxidant activity of three varieties of Himalayan red chili (Kashmiri Local, Kupwari Local, and Shalimar Long) in North India by using DPPH radical scavenging activity, Hydroxyl radical scavenging activity, and Ferric reducing power, based on EC₅₀ values [84].

3.6 Cardioprotective activity

Cardiovascular disease remains a leading cause of disability and premature death globally. The disease is mimicked by the narrowed lumen of arteries and reduced blood flow to the heart. According to a report presented at the American Heart Association’s Scientific Sessions 2020, regular intake of chili peppers could significantly reduce the risk of dying from cardiovascular diseases. Moreover, very recent striking findings of a pooled longitudinal analysis by Bonaccio et al. illustrated the cardiovascular benefits of Capsicum annuum. This study was conducted on an Italian Cohort comprising over 22,000 men, and women originally enrolled in the Moli-sani study cohort. The results demonstrated that the use of Capsicum annuum is associated with a lower risk of cardiovascular mortality [85]. Most importantly, the cardiovascular system is known to be rich in capsaicin-sensitive sensory nerves, which suggests that capsaicin may regulate cardiovascular function [86]. Also, capsaicin could protect against heart disease via a transient receptor potential vanilloid subfamily member 1 (TRPV1)-mediated modulation of coronary blood flow [87]. Furthermore, the antioxidant and antiplatelet properties of capsaicin and its function in regulating energy metabolism may also contribute to its beneficial effects on the cardiovascular system [88, 89].

3.7 Neuroprotective activity

Neurodegenerative diseases such as Alzheimer’s disease are often characterized by multifactorial clinical features such as loss of memory function, protein aggregation, progressive loss of neurons, cognitive impairment, neuronal cell dysfunction, and/or death. Capsaicin is a vanilloid agonist known to activate the TRPV1, recently reported to be involved in neurodegeneration [90]. A study by Veldhuis et al. demonstrated that capsaicin and the vanilloid antagonist capsazepine, peripherally administered, have been shown to exhibit neuroprotection against ouabain-induced excitotoxicity in rats [91]. Moreover, in the latest evidence, Abdel-Salam et al. reported the effect of the TRPV1 agonist capsaicin on epileptic seizures, neuronal injury, and brain oxidative stress in a model of status epilepticus induced in the rat by intraperitoneal (i.p.) injections of pentylenetetrazole (PTZ). This study shows that 2 mg/kg of capsaicin decreased brain oxidative stress, the severity of seizures and neuronal injury, and its coadministration with phenytoin afforded neuronal protection [92].

4. Conclusion

Capsicum species is a good resource of healthy food, mainly including proteins, trace elements, vitamins, minerals, and other substances. In recent years, with the continuous enhancement of people’s pursuit of nutritious, healthy food, and increasing health care awareness, chili pepper has been developed as a medicinal health supplement, functional food, and cosmetic component, especially in the dietary aspect. Moreover, its active phytochemical constituents represent a key role in treatment and disease prevention by modulating various cellular pathways. Therefore, we hope this comprehensive and updated information on chili will help promote human-based studies to facilitate its use in human health and treat diseases in the future.

Conflict of interest

The authors declare no conflict of interest.

Medical disclaimer

The authors declare that the chapter’s content is for informational or educational purposes only and does not substitute professional medical advice or consultations with healthcare professionals.