Saponin: A Multifunctional Compound with Expanding Applications

Introduction to Saponin

Saponins are natural glycosides of steroids or triterpenes, exhibiting various biological and pharmacological effects such as immune regulation, anti-tumor, anti-inflammatory, molluscicidal, antiviral, antifungal, hypoglycemic, and cholesterol-lowering. Saponins have various characteristics, including sweetness, bitterness, foaming, emulsification, and hemolysis.

Figure 1 Characteristics of Saponin

Properties of Saponin

Saponin is a white amorphous powder with a pungent odor. Soluble in water, insoluble in benzene, chloroform, and ether. Shake with water to produce a lot of foam.

The production method of Saponin

After soaking the raw materials such as Chuandilong and Huangjiang in water, the saponin of Dioscorea is dissolved. The soaking solution is then subjected to pressure hydrolysis in the presence of sulfuric acid, followed by neutralization, washing, and drying. Extraction with 120 # gasoline, followed by crystallization, centrifugal filtration, and drying, will yield Saponin.

Application of Saponin

Saponins have a wide range of applications in beverages, candies, cosmetics, and pharmaceuticals. They are considered the main components of many plant medicines and folk medicines, and are believed to have multiple pharmacological properties. It is worth noting that saponins can activate the immune system of mammals, which has sparked strong interest in their potential as vaccine adjuvants. The main candidate saponin adjuvants are Quil A and its derivative QS-21, which have been included as adjuvants in vaccine formulations for guinea pigs and humans, human cancer, malaria in Aotus monkeys and mice, respiratory syncytial virus, cytomegalovirus, Toxoplasma gondii, and visceral leishmaniasis in mice. The unique ability of Quil A and QS-21 to stimulate Th1 immune responses and produce CTLs targeting exogenous antigens makes them ideal choices for subunit vaccines, vaccines targeting intracellular pathogens, and therapeutic cancer vaccines.

Disadvantages of Saponin

Saponins have serious drawbacks such as high toxicity, adverse hemolytic effects, and water phase instability, which limit their use as adjuvants in human vaccine administration. Meanwhile, excessive exploitation of oak bark has caused serious ecological damage and a severe shortage of available supply. Therefore, in the past decade, many saponins from other types of natural products have been screened and shown to have adjuvant activity. In recent years, several reports have been published on saponin based adjuvants. However, most of them involve the chemical structure and adjuvant activity of Quillaja saponins.

Biological activity of Saponin

Some saponins have a destructive effect on cell membranes, exhibiting activities such as poisoning fish, snail killing, hemolysis, spermicidal, and cytotoxicity. Saponins can cause hemolysis because most saponins can bind with cholesterol to form water-insoluble molecular complexes. The biological activity of saponins is related to the number of sugar chains they are connected to and the structure of their glycosides. For example, total ginsenosides in ginseng do not exhibit hemolysis, but after separation, ginsenosides containing ginsenotriol and oleanolic acid as glycosides have significant hemolytic effects, while ginsenosides containing ginsenediol as glycosides have anti hemolytic effects. In addition, some saponins also have biological activities such as anti-tumor, immune regulation, anti-inflammatory, cholesterol lowering, liver protection, blood glucose lowering, antimicrobial, and cardiovascular activity.

Indications for Saponin

Based on its extensive biological activity, Saponin is used as an adjuvant therapy for various diseases, including the following aspects.

Cardiovascular diseases, such as atherosclerosis, hypertension and hypercholesterolemia;

Chronic inflammatory diseases such as arthritis and colitis;

Diabetes, by reducing blood sugar and improving insulin sensitivity;

Adjuvant therapy for cancer, especially liver cancer, lung cancer, and stomach cancer;

Respiratory infectious diseases, such as bronchitis and pneumonia.

The side effects of Saponin

Although Saponin has multiple benefits, excessive intake or improper use of Saponin may also lead to side effects. For example, the following side effects

Gastrointestinal irritation: Saponin may cause symptoms such as nausea, vomiting, and diarrhea, especially when ingested in high doses.

Hemolytic effect: Saponin has the ability to destroy red blood cells, and high doses may cause hemolytic anemia.

Allergic reactions: Some people may be sensitive to the Saponin component, manifested as rash, itching, or difficulty breathing.

Toxicity risk: Some other sources of Saponin have certain toxicity and should be used with caution, especially in herbal preparations.

Reference

[1] Sun H X, Xie Y, Ye Y P. Advances in saponin-based adjuvants[J]. Vaccine, 2009, 27(12): 1787-1796.

[2] Rao A V, Sung M K. Saponins as anticarcinogens[J]. The Journal of nutrition, 1995, 125: 717S-724S.

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