The Anti-Cancer and Other Medicinal Value of Sargassum (Haizao)
A few days ago I introduced the anti-cancer and other medicinal value of Kunbu (kelp). Among marine products there is another seaweed that can also be used as medicine and is often paired with Kunbu in mutually-reinforcing combination. Like Kunbu, Haizao (Sargassum) can serve both as medicine and as food.
Haizao is the thallus of Sargassum fusiformis (Hizikia fusiformis) and Sargassum pallidum of the Sargassaceae family, mainly containing alginic acid, mannitol, iodine, and potassium oxide. Traditional Chinese medicine holds that Haizao is salty in flavor, cold in nature, and enters the liver, stomach, and kidney meridians. It dissipates phlegm and softens hard lumps, promotes diuresis and reduces swelling, and treats goiter-like tumors (yingliu), scrofula (luoli), and beriberi edema.
Modern medicine also commonly uses the iodine in Haizao to treat iodine-deficient goiter, and uses mannitol to treat various edemas. Thus although ancient Chinese medicine could not explain the mechanism by which Haizao cures disease, its records of efficacy were accurate. This practice-derived therapeutic experience remains valid even today, and the side effects of natural medicines are indeed far fewer—for example, Haizao’s diuresis does not cause potassium deficiency in the patient.
Haizao is basically non-toxic, but among the “eighteen antagonisms” of Chinese medicine, Gancao (Glycyrrhiza) and Haizao are considered mutually antagonistic herbs, suggesting the two must not be used together or medical accidents will result. However, this claim is highly doubtful, because many classic TCM formulas use both Haizao and Gancao together, and modern pharmacological experiments have found no definitive proof of extreme toxicity when the two are combined. Thus whether Haizao antagonizes Gancao remains disputed. Modern experiments have even found that combining Gancao and Haizao in a 1:2 ratio shows no subacute toxicity and instead promotes thyroid synthesis of T3, with better results than using Haizao alone. But for safety, it is generally advised not to combine Haizao with Gancao.
The ancient Chinese discovered early that Haizao cures disease. Shennong’s Classic of Materia Medica lists Haizao as a “medium-grade” herb, holding that it “manages the qi of goiter-like tumors, nodules below the neck, breaks up accumulated qi, hard swellings and abdominal masses, regulates gurgling in the abdomen, and drains the twelve types of edema.” This shows that as early as the Qin-Han period, Chinese physicians had already discovered that Haizao could treat thyroid tumors—the world’s earliest record of treating thyroid tumors with an iodine-containing natural medicine.
Ancient bencao works record Haizao’s efficacy mainly in two areas: first, softening hard lumps and dispelling nodules, dissipating phlegm and removing tumors; second, promoting diuresis and reducing swelling. Modern pharmacological experiments confirm Haizao indeed has anti-tumor effects—it treats not only goiter but also other cancers, and it has a diuretic action effective against ascites carcinoma. Thus the efficacies recorded for Haizao in ancient texts are accurate.
Modern experiments show that sargassan A from Sargassum fusiformis shows certain anti-cancer activity against mouse leukemia L615; a crude extract of Sargassum pallidum is active against cervical cancer U14, sarcoma 180, and lymphoma No. 1 ascites type. Sargassan B inhibits both mouse sarcoma S180 and Ehrlich ascites carcinoma (EAC). Sargassum polysaccharides from Haizao are anti-tumor against mouse S180, extending the lifespan of tumor-bearing mice by about 26%. A methanol extract of Sargassum kinmingianum has marked cytotoxicity against cultured P388 lymphocytic leukemia cells, with the active components possibly being hydroxy-sargaquinone and sargassum alcohol.
Like Kunbu, Haizao lowers blood pressure, anticoagulates, lowers blood lipids, fights infection, and enhances immunity. Sodium alginate, a main component of Haizao, is also abundant in Kunbu; other components such as iodine, mannitol, and potassium oxide are present in both. Hence the ancients’ record that Haizao and Kunbu have similar efficacies is also accurate.
Chinese medicine rarely treats tumor diseases with a single herb. For yingliu, Haizao is often combined with Kunbu, Beimu (Fritillaria), Jiangcan (Bombyx batryticatus), and Qingpi. For example, Haizao Yuhu Decoction from Orthodoxy of External Medicine, which treats flesh goiter (simple goiter) and stone goiter (thyroid cancer), uses Haizao, Beimu, Chenpi (tangerine peel), Kunbu, Qingpi, Chuanxiong (Ligusticum), Danggui (Angelica), Banxia (Pinellia), Lianqiao (forsythia), Duhuo (Angelica pubescens), and Gancao each one qian, plus haidai five fen, decocted in water. Effective Formulas for Successive Generations, for “snake-coiling scrofula extending between head and neck,” uses Haizao (stir-fried with buckwheat flour) and white Jiangcan (stir-fried) in equal amounts, made into pills with white plum infusion the size of parasol seeds; 60 pills taken each time with rice soup.
It should be noted here that Orthodoxy of External Medicine counts Kunbu and haidai as two drugs, but historically haidai was used as Kunbu. If one insists on treating Kunbu and haidai as two separate herbs here, then Kunbu should refer to black Kunbu (Eckloniaonia) and haidai to wakame.
Haizao treats yingliu and redundant growths both internally and externally. For example, Prescriptions for Universal Relief records a method for treating warts/excess flesh on the body: apply Haizao powder externally while also decocting Haizao in wine for internal use.
For difficult urination, Haizao is often combined with Kunbu, Fangji, Cheqianzi (Plantago seed), Dafupi (areca pericarp), Yiyiren (Coix seed), and Fuling (Poria). Haizao also treats proteinuria from nephritis; Zhejiang Medicinal Flora records using suitable amounts of Haizao, Chanyi (cicada slough), and Kunbu, decocted in water, for nephritis proteinuria.
Some modern Chinese patent medicines such as Wuhai Yingliu Pills and Neixiao Luoli Pills also contain Haizao.