Both Species of Isodon Herb Have Anti-Tumor Effects

Both Isodon (Xiangchacai, Rabdosia japonica var. glaucocalyx) and Isodon trichocarpus (Maoye Xiangchacai), which belong to the Lamiaceae family, have anti-cancer effects. Among them, the leaves of Isodon trichocarpus are also called Silenggan (Four-Ridges Stem), while Isodon is used with both stem and leaves together; its scientific name is simply Isodon. Both of these herbal medicines have anti-tumor effects.

The enmein (Yanmingsu) contained in Silenggan has a very pronounced anti-tumor effect. In animal transplantable tumor experiments, the crude extract of Silenggan had significant anti-tumor effects against both mouse sarcoma S180 and Ehrlich ascites carcinoma. At certain concentrations, the water extract, alcohol extract, and total diterpenoids of Silenggan were cytotoxic to Ehrlich ascites tumor cells cultured in vitro. The total diterpenoids had the strongest effect, the alcohol extract was second, and the water extract was the weakest. Intraperitoneal injection extended the survival time of Ehrlich ascites carcinoma mice by 80%, and also had a certain effect on reticulum cell sarcoma. Maoye Xiangchasu b (rabdosin b) can extend the survival rate of leukemia mice by as much as 122%.

Silenggan also has anti-inflammatory and antibacterial effects. In addition, Japan has isolated two components from Silenggan that inhibit gastric acid secretion; these are glycoproteins containing acidic glycogen and acidic proteins or acidic polypeptides.

So Silenggan is a relatively ideal anti-tumor Chinese herbal medicine, but it is rarely used clinically by physicians. It cannot be bought in the pharmacies of various Chinese medicine shops or TCM hospitals because it is not a commonly used herbal medicine. More often, it is used by local folk practitioners. The "Ningxia Chinese Herbal Medicine Manual" records the effects of Silenggan as: "clearing heat and resolving toxin, activating blood; treating gastritis, early-stage hepatitis, amenorrhea, traumatic injuries, mastitis, joint pain, and snake and insect bites."

Meanwhile, the oridonin (Xiangchacai Jia Su) contained in Isodon also has anti-tumor effects. In vitro tests on cultured human cancer cells, oridonin had significant cytotoxic effects on the human hepatoma cell line QGY-7703, human cervical cancer HeLa cells, and the human esophageal cancer cell line (CaEs-17). When oridonin was injected intraperitoneally into mice inoculated with Ehrlich ascites carcinoma, once daily for seven consecutive days, it significantly extended the lifespan of the tumor-bearing mice.

Isodon also has antibacterial and anti-inflammatory effects, and additionally has a protective effect against liver injury and a blood-pressure-lowering effect. Isodon is also not a traditionally commonly used Chinese medicine; for a long time it has been mainly used by folk herbalists. In recent years, some TCM oncologists have also begun to use Isodon in their prescriptions, but the drug source generally has to be arranged by the physician themselves, because ordinary pharmacies and TCM hospital dispensaries do not stock this herb.

According to TCM theory, the main effects of Isodon are clearing heat and resolving toxin, and activating blood and reducing swelling. Folk medicine commonly uses Isodon to treat cirrhosis, hepatitis, liver abscess, and lung abscess. It can also be used to treat lymphadenitis and arthritis; in certain places, Isodon is also used to treat venomous snake bites. It is generally used as the fresh herb, with a dosage of 15-50g per dose.