Pearl (Zhenzhu): Anticancer Effects and Promoting Wound Healing
Pearl (Zhenzhu), also called Zhenzhu, bangzhu, or zhenzhizi, is produced when the mantle of the pearl oysters Pinctada martensii, Pinctada margaritifera, Pinctada maxima, or Pteria chinensis, or of the freshwater mussels Hyriopsis cumingii or Anodonta, is stimulated; that produced at Hepu in Guangxi is considered the best.Pearl is not only a common ornament but also a commonly used Chinese herb. Mingyi Bielu (Records of Famous Physicians) records that it "treats ocular membranes." Bencao Gangmu (Compendium of Materia Medica) records that it "settles the hunpo spirit, stops seminal emission and turbid urine, resolves smallpox and furuncle toxins, treats difficult labor, and expels the dead fetus and placenta." Bencao Huiyan records that it "quiets the heart, stabilizes the will, settles the hun soul, resolves bound toxins, transforms malignant sores, and closes internal ulcers and rotting flesh."Modern pharmacological research has found that pearl has anti-aging, antihypertensive, hypoglycemic, antioxidant, antitumor, sedative, anticonvulsant, anti-inflammatory, analgesic, antihistaminic, granulation-promoting, and cataract-treating effects. Animal experiments show that pearl powder has a marked inhibitory effect on mouse sarcoma S180, with an inhibition rate of 34.8%; it has a weaker but statistically nonsignificant inhibitory effect on Lewis lung cancer; and it can markedly prolong the survival time of P388/J lymphocytic leukemia mice and reduce their spleen weight.Pearl must be ground into an extremely fine powder before medicinal use. Haiyao Bencao records: "Pearl as medicine must be ground for a long time until like powder before it can be taken; if not ground fine, it injures the organs." In modern Chinese-medicine textbooks, pearl is classified among the wind-extinguishing and spasm-stopping herbs. Chinese medicine holds that it is sweet and salty in flavor and cold in nature, entering the heart and liver meridians, with the effects of calming the spirit and stopping convulsions, improving vision and dissipating eye membranes, resolving toxins and generating flesh, and moistening the skin and fading spots. Many eye drops and cosmetics use pearl powder; pearl powder is also used in external plasters to promote wound healing. Pearl treats palpitations and insomnia, convulsions and epilepsy, red eyes with nebulae, mouth and tongue sores, ulcerated throat, and unhealed sores; it can also fade spots and moisten the skin, so it is often used for skin pigmentation and chloasma.Pearl can treat various hard-to-heal wounds and burns. Zhao Bingnan Linchuang Jingyan Ji (Clinical Experience of Zhao Bingnan) records the "Zhu Huang San" often used by Master Zhao: pearl (calcined, ground) 4.5 g, Dangmenzi (i.e., musk) 1.5 g, amber powder 15 g, mastic (Ruxiang) 30 g, all ground into an extremely fine powder and sprinkled thinly on the affected area. After sprinkling, a scab forms quickly; never remove the scab, lest it interfere with epithelial growth. Master Zhao was a famous great master of Chinese external medicine; although this formula uses precious herbs, none of the herbs is toxic and the safety is high, so it is worth trying for hard-to-heal wounds.Historically, some famous formulas for unhealed sores also used pearl. For example, the Zhenzhu San in Waike Zhengzong (Orthodox External Medicine) is made by finely grinding "five fen of qinggang flower, one qian of pearl (ground extremely fine), and one liang of true calomel (Qingfen)," used for skin lesions and rotting flesh with unbearable pain caused by various sores. But the calomel in this formula is a mercury preparation with great toxicity and poor safety, so it is mostly not used today.Pearl both resolves toxins and reduces swelling and is good at generating flesh and closing sores, making it a relatively ideal herb for ulcerating tumors and for tumor patients with bedsores after prolonged bed rest. If the patient's tumor has ruptured with an ulcer that is hard to close, or the bedsore is severe, one may take pearl powder internally or make it into a powder for external use according to Master Zhao Bingnan's Zhu Huang San formula. If the ingredients of Master Zhao's formula cannot be assembled, one may also grind pearl alone into an extremely fine powder and sprinkle it directly on the wound.The internal dose of pearl should not be too large; 0.01-0.5 g at a time is best, preferably starting from a small dose and gradually increasing if there is no discomfort. Moreover, pearl is a precious herb and relatively expensive, so it is not suitable for large doses. Pearl powder is relatively hard to swallow and may be put in capsules; pregnant women should use it cautiously.