The term “mulberry weed” refers to the white mulberry tree (Morus alba), which is sometimes considered an invasive plant outside its native range in Asia. For thousands of years, every part of this tree—the fruit, the bark, and particularly the leaves—has been employed in traditional Chinese medicine for its therapeutic properties. The white mulberry originated in China but has since been widely cultivated across the globe for its fruit and its historical role as the sole food source for silkworms. The leaves are the focus of much modern research and have been used traditionally to address conditions like fever, cough, and hypertension.
Key Nutritional Components
The health properties of the mulberry plant stem from its rich and diverse phytochemical profile, which varies significantly between the fruit and the leaves. Mulberry fruit is celebrated for its high concentration of anthocyanins, the pigments responsible for its deep red, purple, or black color. The most abundant of these compounds is cyanidin-3-glucoside, a potent antioxidant that neutralizes free radicals. The fruit also contains important vitamins, such as Vitamin C and Vitamin K, along with essential minerals like iron and potassium.
Mulberry leaves contain a unique spectrum of compounds, including high levels of flavonoids like rutin and quercetin, known for their antioxidant and anti-inflammatory characteristics. The most distinctive compound is the alkaloid 1-deoxynojirimycin (DNJ). DNJ is the primary bioactive component responsible for the leaves’ specific effect on carbohydrate metabolism. The leaves also offer a source of protein and dietary fiber.
Impact on Metabolic Regulation
Mulberry extracts, especially those derived from the leaves, are studied for their influence on metabolic functions, particularly blood sugar management. The key mechanism involves the alkaloid DNJ, which acts as an inhibitor of the digestive enzyme alpha-glucosidase. This enzyme is responsible for breaking down complex carbohydrates and starches into simple glucose molecules in the small intestine.
By inhibiting alpha-glucosidase, DNJ effectively slows the digestion and absorption of carbohydrates, resulting in a lower spike in blood glucose levels after a meal. This effect is known as postprandial glucose control and is a primary reason for the plant’s traditional use in managing blood sugar. Beyond glucose regulation, mulberry leaf extracts have demonstrated a role in lipid metabolism, contributing to anti-hyperlipidemic and anti-obesity effects. Compounds in the leaves, such as rutin and quercetin, help control blood fat levels, suggesting a reduction in total cholesterol and triglyceride levels. The anti-inflammatory and antioxidant properties of the extract have also been linked to protective effects on the cardiovascular system.
Diverse Applications in Traditional Wellness
The historical use of the mulberry tree extends beyond its modern metabolic applications, utilizing different parts of the plant in traditional wellness practices.
Leaves (Sang Ye)
In traditional Chinese medicine, the leaves have been used to dispel wind-heat, treating symptoms associated with the common cold, fever, and cough. The leaves also possess diuretic and hypotensive properties, traditionally employed to help normalize blood pressure.
Root Bark (Sang Bai Pi)
The root bark acts as an expectorant to relieve coughs and asthma, and as a diuretic to reduce fluid retention. Extracts from the root bark contain prenylated flavonoids, which have been investigated for their potential antimicrobial and anti-obesity effects.
Fruit and Bark
The fruit (Sang Shen) has been used as a restorative tonic to strengthen the kidneys and address issues like inflammation and anemia due to its high antioxidant content. The bark has a long history as a purgative and anthelmintic, traditionally used to rid the body of intestinal parasites.
Preparation Methods and Safety Considerations
Mulberry is consumed in several forms, ranging from whole foods to concentrated supplements. The fruit is commonly eaten fresh, dried, or processed into jams, juices, and wines. The leaves are often prepared as an herbal tea or infusion by steeping dried leaves in hot water. For targeted health support, concentrated extracts are available in powdered form or capsules, often standardized to contain a specific amount of the bioactive compound DNJ.
Mulberry extracts carry safety considerations, particularly for specific populations and those taking medication. Due to its blood sugar-lowering effect, individuals with diabetes taking anti-diabetic medications must monitor their glucose levels closely, as combining the two could lead to hypoglycemia. It is recommended that individuals cease consumption of mulberry products at least two weeks before any scheduled surgery, as the plant can interfere with blood sugar control during and after the procedure. Furthermore, mulberry extracts may interact with medications metabolized by the liver’s cytochrome P450 (CYP) enzymes, potentially affecting the efficacy or side effects of drugs such as statins, immunosuppressants, and certain sedatives.