## 3 Plant Raw Materials and Compounds with Proven Immune-Enhancing Effects
### Uncariae Cortex--Uncaria tometosa ([PERSON].) DC.
#### 3.10.1 Pharmacological Properties  
There are two chemical varieties of vilcoxon in nature. One contains mainly pentacyclic oxoinode alkaloids, and the other contains tetracycline alkaloids. The two groups ofthese alkaloids act in different ways, and sometimes even in opposite ways. Oxoindole tetracyclic alkaloids affect the central nervous system, whereas oxoindole pentacyclic alkaloids affect the immune system. Therefore, determining the chemical variety of a plant is very important for unidirectional phytotherapy [76].  
In Western Europe, the measurement of the content of isopteropodine--the alkaloid with the strongest immunostimulating properties--is used to standardize preparations. Extracts should contain 97% of pentacyclic oxoindole alkaloids from the sum of all oxoindole alkaloids found in the raw material, i.e., 1.3-1.75% [77; 78].  
The bark of vilcoxon acts as an antioxidant and has immune-stimulating properties by stimulating and developing phagocytes and anti-tumor properties. In cases of existing cancer, it prevents metastasis and causes its regression. It also possesses anti-inflammatory and antiviral properties and promotes the production of white blood cells. In vitro studies have shown that an aqueous extract of the raw material inhibits the growth of cancer cells, and its mechanism of action is based on the selective induction of apoptosis, as explained by the so-called induction of DNA breaks. The compound that apparently showed this effect was unkarine F. In addition, pentacyclic oxoindole alkaloids present in the raw material stimulate the production of a factor that regulates lymphocyte proliferation, and tetracyclic oxoindole alkaloids have an antagonistic effect. Vilacora alkaloids were also tested in two chemoluminescence models (granulocyte activation and phagocytosis) to determine their phagocytic capacity. Isopteropodine showed the strongest effect. In vitro studies also confirmed that the mechanism of the immunostimulatory effect of extracts from the bark of tansy capsaicin is related to the stimulation of interleukin IL-1 and IL-6 production in alveolar macrophages and an increase in leukocyte and lymphocyte production [35].  
In just two pharmacological studies involving healthy volunteers, the use of an aqueous extract of vilcoxon at a dose of 350 mg per day, for 6 weeks, was shown to stimulate the immune system by increasing the number of leukocytes. Additionally, with a dose of 350 mg twice a day, an increase in peripheral blood lymphocytes and neutrophils was observed over a 5-month period. However, there are no controlled clinical studies to confirm this effect [36].  
Thanks to its immune system-boosting properties, vilcoxon is used in various cancers, mainly against leukemia and gastrointestinal cancers. Standardized preparations based on this raw material, registered as pharmaceuticals, are recommended by the World Health Organization for, among other things, cancer diseases for patients with a poor prognosis--not eligible for radical treatment--or to prolong life. Vilacora preparations are helpful in reducing the side effects of chemotherapy and radiation therapy [79].