Corosolic acid

Clinical application and efficacy

Corosolic acid can be used as the novel plant-derived drug for prevention and treatment of obesity and type II diabetes drugs as well as the pharmaceutical raw materials of functional natural health food. It has currently become a hot product in the market. Currently the natural product has entered into market as a nutritional supplement in the United States and has been also subject to the Phase III clinical trials for the treatment of diabetes and will soon be approved by the FDA in the near future. Compared its efficacy in treating diabetes with that of the injections of insulin, it has various advantages such as significant oral administration effect, small toxic side effects, and being convenient for administration. Its efficacy is quite similar with injection of insulin.
The content of corosolic acid content in plants is generally low, even in the Lagerstroemia speciosa which has relative high content of Corosolic aicd. In the hot-wvater extracted concentrated extract of Lagerstroemia speciosa, the corosolic acid content is only about 0.01%. Even in the alocohol extract of Barnabas leaf, corosolic acid content is only about 1%. With years of research, Microherb has adopted advanced chromatographic separation technology for successfully isolation high purity (98%) corosolic acid, which can be further used for pharmacodynamic studies, clinical studies as well as toxicological experiment for prevention oadn treatment of obesity and type II diabetes.
The major efficacy of corosolic acid as follows:
1. it can regulate the content of insulin and blood sugar with significant trend of weight loss in a slow process without the necessary for dieting. It therefore can be used for weight loss.
2. this product has a significant hypoglycemic effect.
3. it has a significant inhibitory effect on inflammation with the anti-inflammatory effect being stronger than commercially available anti-inflammatory drug, indomethacin.
4. it has inhibitory effect on the proliferation of various kinds of tumors, and thus have wide prospects of applications in this field.

Physical and Chemical Properties

It is amorphous white powder (methanol), also known as plant insulin, 2α-hydroxy ursolic acid, and Barabbas extract or Lagerstroemia speciosa extract. It belongs to α-amyrin type or alkyl-type pentacyclic triterpenoids, and is soluble in petroleum ether, benzene, chloroform, pyridine and some other organic solvents, but insoluble in water; it is also soluble in hot ethanol, methanol. Under anhydrous conditions, when it is reacted with a strong acid (sulfuric acid, phosphoric acid, perchloric acid), the acid (TCA) or Lewis's acid (zinc chloride, aluminum chloride, antimony trichloride), there will be colorimetric reaction or fluorescence.

Figure 1 the structural formula of corosolic acid
The above information is edited by the chemicalbook of Dai Xiongfeng.

Lagerstroemia speciosa extract

Corosolic acid is a kind of triterpenoids which is naturally presented in Lagerstroemia. Its basic skeleton is the pentacyclic parent nucleus of multiple hydrogen-pinenes. It can either exist in the free form or in the form of saponins inside the plant bodies. In plants, it often co-exists with its isomers hawthorn acid (2α-hydroxy oleanolic acid) with similar structures and chemical properties between each other, thus causing difficulty in separation. In vivo results have shown that corosolic acid promotes the cellular glucose uptake and utilization through stimulating the transport of glucose, thus smoothly achieving its hypoglycemic effect. Its excitatory effects on glucose transport is similar to insulin, therefore, people also call corosolic acid as plant insulin.
Animal experiments have shown that corosolic acid has a significant hypoglycemic effect on both normal rats and genetically diabetic mice.
Corosolic acid can also lead to weight loss. Clinical study has found that orally administration of this drug can regulate insulin and blood sugar levels with significant trend of weight loss (average weight loss 0.908-1.816Kg). The whole process is slow and dieting is not necessary. Combination with exercise, drinking a lot of water and regulating the diet with products containing corosolic acid can give rise to the best weight loss efficacy.
In addition corosolic acid also has many other biological activity, such as inhibitory effects on TPA-induced inflammation whose anti-inflammation effect is stronger than commercially available anti-inflammatory drug, indomethacin; it also has a inhibitory effect on DNA polymerase, as well as inhibitory effects on a variety of tumor cell growth.

Plant sources

Lagerstroemia speciosa originates from Asian tropical area and is distributed in India, Sri Lanka, Malaysia, the Philippines and Vietnam. It is routinely cultivated in Guangdong, Guangxi, Yunnan, Hainan and Fujian of china for ornament.
Lagerstroemia speciosa is a kind of folk medicines among Southeast Asia, and is commonly known as "Barabbas ". In India, people take its roots as a kind of astringent. In Malaysia, people apply pounded leaves for treating malaria, and foot fractures. In the Philippines, the tea drinks made from its leaf is widely used in the treatment and prevention of diabetes, known as the "natural plant insulin"; orally administration is effective with no side effects and can reduce the weight without affecting the appetite. In the 90s of last century, scholars abroad, especially in Japan have conducted extensive researches on it with both its chemical composition and pharmacological effects being reported. Recent studies have found that it can lower blood sugar, cause weight loss; it also has effects of anti-tumor, have anti-inflammatory, anti-viral and anti-cardiovascular disease. Especially should pay attention to its good hypoglycemic activity which has similar physiological effects as insulin, and thus also known as "plant insulin" which draw widespread attention. It has been currently developed into various kinds of health care products both at home and abroad.

Figure 2 Lagerstroemia speciosa

Reference quality standards

1. Weight Loss by drying: ≤5%
2. Heavy metals: ≤10ppm
3. Agricultural residues: ≤2ppm
4. Solvent residue: ≤0.5%
5. Tests of microbes: Total ≤1000CFU/G, mold yeast ≤100CFU/G

Description

Corosolic acid is a triterpenoid that has been found in L. speciosa leaves and has diverse biological activities, including anticancer, anti-inflammatory, antidiabetic, antihypertensive, antihyperlipidemic, and antioxidant properties. It is cytotoxic to HepG2, A549, SNU-C4, HeLa S3, and K562 cells (EC₅₀s = 4.8, 5, 0.4, 1, and 4.3 μg/ml, respectively). Corosolic acid inhibits ear edema in mice induced by phorbol 12-myristate 13-acetate (TPA; ) with an ID₅₀ value of 0.09 mg/ear. It reduces blood glucose levels in an insulin tolerance test in a KKAy mouse model of type 2 diabetes when administered at doses of 2 and 10 mg/kg. Corosolic acid (0.072% in the diet) reduces systolic blood pressure and serum levels of free fatty acids, the oxidative stress markers thiobarbituric acid-reactive substances (TBARS) and 8-hydroxy-2’-deoxyguanosine (8-OHdG), and the myeloperoxidase markers 3-nitrotyrosine and 3-chlorotyrosine in an SHR/NDmcr-cp (cp/cp) rat model of metabolic syndrome.

Uses

(2α,3β)-2,3-Dihydroxy-urs-12-en-28-oic Acid influences inflammatory gene expression regarding inflammatory bowel disease. In addition, its extracted from the plants Gentiana farreri and shows anti-tumor activity

Definition

ChEBI: A natural product found particularly in Rhododendron species and Eriobotrya japonica.