Mulberry has been used in traditional Ayurvedic and Chinese medicine for centuries. In recent years, extracts of the leaf and roots have gained attention for their potential in regulating carbohydrate and glucose metabolism. Some components of the plant may even have anti-cancer benefits. Like all herbal remedies, however, mulberry extract may present a few side effects in addition to its alleged medicinal properties.

Blood Sugar Effects

A small trial conducted but the American Diabetes Association investigated the effects of taking mulberry leaf extract in conjunction with a dose of sucrose on blood sugar utilization in 20 human subjects, half of which were non-diabetic control subjects and the other were type II diabetics taking oral medications. The volunteers in both groups experienced a decrease in initial serum glucose levels after eating the sugar. According to a paper published in the July 2007 issue of the “Journal of Agricultural and Food Chemistry,” this action may be due to the presence of a compound in mulberry leaf identified as 1-deoxynojirimycin, or DNJ. However, the authors of this paper also noted that the DNJ content in commercial mulberry preparations tends to be low, which suggests that the bioavailability of this substance from these sources is lacking.

Based on the results of these initial studies, mulberry extract may have an application in treating diabetes mellitus in the future. Until then, however, it seems likely that the DNJ in the extract mimics the activity of diabetes medications, which is to inhibit carbohydrate absorption. This means that if you are taking α-glucosidase inhibitors such as acarbose, mulberry extract may increase the effects of these drugs and cause a sudden or dramatic drop in blood sugar. If you have impaired glucose metabolism, or are insulin resistant, be sure to check with your doctor before using mulberry extract or any other herbs.

Skin Cancer Risks

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Mulberry extract is incorporated into skin-whitening products. The compound attributed with lightening the skin is arbutin, a form of hydroquinone that inhibits melanin release by suppressing the tyrosinase enzyme. In early 2010, a team of French researchers analyzed two cases of squamous cell carcinoma in women who had been using skin-lightening products for more than a decade. While they could not say for certain that hydroquinone agents were the direct cause of either cancer, they did note that the carcinogenic side effects of hydroquinone is well established in animal models. Arbutin is reputed to be gentler than hydroquinone, but the risk of skin cancer may still apply.

Chemotherapy Interference

According to researchers from Nihon University in Tokyo, a substance from mulberry root bark extract identified as albanol A triggers cell death in human leukemia cells. A team of Korean researchers reported a similar finding with mulberry fruit extracts in the April 2010 issue of “Nutrition and Cancer.” Clearly, this is a good thing. However, it also suggests that mulberry extracts should not be used by anyone undergoing chemotherapy without the approval and supervision of a physician.