Anti-Cancer and Anti-HIV Effects of Castor Beans and Castor Oil
The castor bean is the seed of Ricinus communis, a plant of the Euphorbiaceae family and the Ricinus genus. Castor is an annual tall herb distributed throughout the country; in tropical or southern regions it often becomes a perennial shrub or small tree. The castor bean, castor leaf, and castor root can all be used as medicine. The fatty oil extracted from castor beans (castor oil) is also used medicinally; the medicinal effects of castor oil are similar to those of castor beans, while the effects of castor leaves and castor roots differ from those of castor beans and castor oil.
Castor beans contain ricin and ricinine; the fatty oil contains triglycerides and glycerides, sterols, phospholipids, free fatty acids, hydrocarbons, and waxes. Castor beans have a certain toxicity and also have a laxative effect, which is related to castor oil.
Castor oil itself is non-irritating and even has a skin-lubricating effect when applied externally, but after oral administration it is hydrolyzed in the small intestine by pancreatic lipase to produce ricinoleic acid and glycerol. Ricinoleic acid reduces the absorption of electrolytes and water by the small intestine and speeds up the transit of intestinal contents; this is the mechanism by which castor beans cause purgation.
Besides purgation, castor beans are also toxic. Animal experiments show that the LD50 of raw castor beans in mice is 4.557 mg/kg, but the toxicity of processed castor beans (castor beans mixed with egg and heated at 100 degrees Celsius for 3 hours) is significantly reduced, with an LD50 greater than 10 g/kg, essentially approaching non-toxicity. Therefore, when using castor beans clinically, one should try not to use raw castor beans but use processed ones instead.
Castor beans cause considerable liver damage; experimental animals with acute poisoning usually develop liver injury. In addition, castor beans are also nephrotoxic. Castor bean poisoning usually presents with chronic spasms, opisthotonos, respiratory paralysis, and diarrhea; it also causes a decrease in white blood cells and a marked increase in the micronucleus rate of polychromatic erythrocytes in the bone marrow, and in severe cases can be fatal. There are also reports of severe anaphylactic shock from external application of castor beans.
The common processing method for castor beans is to stir-fry them hot, then wrap them in oil-absorbing paper and press out the oil. This operation is repeated several times until the product is dry, loose into a powder, and no longer cakes together. This is the traditional "frost-making" processing method, and the processed product is called castor bean frost. Modern research has found that castor beans mixed with egg and heated are even less toxic, and this safer method should be considered in pharmaceutical preparation.
Traditional Chinese medicine holds that castor beans are sweet and acrid in taste, neutral in nature, and slightly toxic, entering the liver, spleen, lung, and large intestine meridians. They have the actions of drawing out toxin, guiding out stagnation, unblocking collaterals, and opening orifices, and are mainly used for welling-abscess and swellings, scrofula, breast abscess, throat obstruction, scabies and tinea sores, burns, edema and distention, dry constipation, facial deviation, and traumatic injuries. Among the welling-abscess swellings, scrofula, and breast abscess mentioned here, some are what modern medicine calls cancer, and edema and distention are similar to ascites. In ancient times castor beans were even used as an oxytocic; for example, Materia Medica of Daily-Use Values (Rihuazi Bencao) records that castor beans could be used to hasten labor by applying them externally to the palms and soles of the mother-to-be.
TCM classics through the dynasties have recorded the efficacy of castor beans in treating tumor-like diseases. For example, the Bai Gao Yao (White Plaster) in Prescriptions for Universal Relief (Pu Ji Fang) is made by peeling castor beans, grinding them into a paste, and spreading it into a plaster to apply to the affected area, in order to reduce swelling and draw out toxin, treating welling-abscesses, back carbuncles, and bone-attached abscesses—all of which include various benign and malignant tumors and tuberculosis. Supplementary to Materia Medica (Bencao Yanyi) records a single-herb formula for scrofula: "Fry castor beans until cooked, peel them, chew them thoroughly, and take two or three before bed, gradually increasing to over ten." Scrofula refers to diseases such as lymph node tuberculosis and lymphoma in modern medicine. This usage in Supplementary to Materia Medica is a very safe method of gradually increasing the dose; even the ancients, when using castor beans, had already taken note of preventing their toxic side effects.
Castor beans can also treat sores and swellings in the throat and fish-bone impaction. Medical Standards (Yi Zhun) records: "To treat sores and swellings in the throat, use one castor bean (peeled) and one qian of mirabilite (Piao Xiao), grind together, and take with freshly drawn water"; two or three consecutive doses will be effective. Wei's Family-Secret Formulas (Wei Shi Jia Cang Fang) records a method for treating bone impaction: take seven castor beans, shell and grind them finely, add gypsum fibrosum (Hanshi Gao) powder, and mix until the moisture is uniform. When using, pick up two or three qian with a bamboo splinter and send it into the throat; after a short while, swallow water to wash down the bone. Both mirabilite and gypsum fibrosum here are sulfate-type mineral medicines. The castor beans used here are all raw castor beans, because the lubricating effect of castor oil is needed.
Ancient and folk records also exist of using castor beans to treat edema (mostly cancerous ascites). Selection of Chinese Medicinal Herbs of Shaan-Gan-Ning-Qing records of castor beans: "oral administration to unblock the bowels and drive out water; external application to activate blood and unblock collaterals, and remove putrid tissue." The "driving out water" here mainly refers to edema and ascites. The "Fazheng Bima Gao" recorded in Comprehensive Mirror of Famous Physicians (Gu Jin Yi Jian) specifically uses only the single herb castor bean, processed, to treat "ten types of water qi and five gu syndromes." Materia Medica of Daily-Use Values records castor beans as "treating edema and distention, finely ground and taken with water"; Newly Revised Materia Medica (Xinxiu Bencao) records castor beans as "chiefly treating water concretions"; and Materia Medica Condensed (Bencao Mengquan) also records that castor beans can "disperse central fullness and edema." The ancients used castor beans to treat edema and ascites mostly by grinding raw castor beans into a fine powder and taking it with water, aiming for urination to become free; overuse easily causes severe diarrhea.
Modern pharmacological research has found that castor beans indeed have anti-tumor effects. Intragastric administration of raw castor beans for 30 consecutive days has a significant inhibitory effect on transplanted human lung cancer. Intraperitoneal injection of a castor oil extract has a relatively strong inhibitory effect on mouse sarcoma S180, with an inhibition rate reaching 58% at larger doses. Castor oil also has a very significant inhibitory effect on ARS ascites carcinoma; in animal experiments, 64% of mouse ascites carcinomas were completely cured, and the life extension rate was greater than 136%. Intravenous injection of ricin can inhibit ascites formation in Ehrlich ascites carcinoma and prolong the survival of test mice. Ricin has a relatively significant inhibitory effect on leukemia P388, acute lymphoblastic leukemia, human breast cancer, Yoshida sarcoma, myeloma, and gastric cancer.
Modern research has also found a better way to reduce the toxicity of castor oil: when castor oil is encapsulated in lipids, its toxicity drops dramatically and its therapeutic effect becomes more significant, basically achieving the goal of safe medication.
In addition, modern pharmacological research has found that castor oil has a specific killing effect on HIV-infected H9 cells, while its killing effect on uninfected H9 cells is only one-thousandth of that, so castor oil also has some value for anti-AIDS.
Pregnant women and those with loose stools should not take castor beans. When taking castor beans and castor oil to treat disease, one should also avoid gas-producing foods such as beans and tubers. Materia Medica Condensed even states: "Those who have taken (castor) should avoid beans entering the mouth for a lifetime; if they accidentally violate this, abdominal distension will arise in an instant and endanger life." This record may be exaggerated, but castor beans and castor oil do have a laxative effect and indeed conflict with gas-producing foods like beans and tubers.