Herbs to Know: The Sleepy Walnut Tree and Chicory

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The Sleep Walnut Tree
Walnuts are produced by the American black walnut tree (Juglans nigra) and the English walnut tree (Juglans regia). Herbalists use the leaves and the fleshy hulls that enclose the walnut shells rather than the nuts themselves. In traditional herbal practice, the leaves and hulls have been used as a tonic, an ­antifungal preparation, and an astringent in treating diarrhea. Recent scientific studies have reported that the leaf extracts have strong antiviral activity against a canker-sore-­inducing virus, a protective effect on the vascular system, and an inhibitory effect on certain tumors.

Now researchers at the Laboratory of Pharmacognosy and Phytotherapy in the Faculty of Pharmacy, Clermont-Ferrand, France, have studied the sedative effects of an English walnut leaf extract. Juglone, a compound present in all parts of the tree but concentrated in the leaves, is known by many gardeners; it retards the growth of certain plants. Ever try to grow a garden under a walnut tree? The juglone makes it difficult.

Compared with diazepam (Valium), chloroform extracts of juglone produced similar sedation in mice. Activity decreased markedly in 68 percent of subjects after receiving the juglone extract. Researchers also found that the extract produced a significant increase in sleep duration. Juglone’s newly discovered sedative activity will be the subject of future research.(1)

Chicory's Liver-Protective Activity Confirmed
One person’s weed is another person’s herb. More often ­maligned than appreciated in America, common chicory (Cichorium intybus) is a perennial with a deep spiraling taproot that resembles the root of dandelions. Like those of dandelions, chicory’s young leaves and roots are sometimes eaten as vegetables. The roasted root is a well-known coffee adulterant or flavor enhancer.

Chicory root has traditionally been used to aid digestion, for its diuretic and slight laxative effects, and for liver disorders. A tea of the root is believed to stimulate bile secretion and ease upset stomach. In Pakistan, the root has been used as a folk medicine for liver disease. Researchers isolated a phenolic compound, esculetin, from the roots and in tests with mice confirmed its ability to protect the liver. A water extract of the root inhibits oxidative degradation of DNA in liver tissue.

Researchers in India have recently confirmed chicory root’s liver-protecting ability. Using rats and a standard liver-toxicity test, they found that an extract from tissue-cultured root tips protected the liver better than extracts from the dried root.(2)

Researchers have found that a ­compound in ­carrot seeds (and possibly the root)—not beta-carotene—may be ­responsible for the ­antitumor activity of ­carrots.

Carrots and Cancer
Everyone knows carrots (Daucus carota) as a tasty vegetable, and in some parts of the world the plant has also been used medicinally. The root tea has been used as a diuretic and to prevent and eliminate urinary stones and worms. Science confirms these uses and has found that the tea lowers blood pressure and kills bacteria as well.

In folk medicine, carrot seeds have been used as a “morning-after” contraceptive. Experiments with mice indicate that extracts of carrot seed may prevent the fertilized egg from implanting on the uterine wall. This use cannot be recommended for humans, but future research on the seed of carrot and that of its wild cousin Queen-Anne’s-lace may yield more information.

Carrots seem to help prevent or slow the growth of cancer, but the substance responsible for this effect is unknown. Studies show that eating carrots is associated with a lower incidence of breast, colon, rectal, and lung cancers. An epidemiological study suggests that about one-third of ­cancers may be explained by inadequate consumption of beta-carotene, which is abundant in carrots, yet beta-carotene alone shows no antitumor activity.

A team of researchers in India may be on the trail to identifying the agent respon­sible for carrot’s anticancer ­potential. They found that petroleum-ether extracts of carrot seeds significantly ­increased the survival rates of mice implanted with the Ehrlich ascites tumor, a kind of cancer often used in anticancer research. The researchers speculate that a compound in carrot seeds (and ­possibly the roots)—not beta-carotene—may be responsible for antitumor activity of carrots. Further research will seek to identify an active compound and a mechanism of action.(3)

References
(1) Girzu, M., et al. “Sedative Effects of Walnut Leaf Extract and Juglone, an Isolated Constituent.” Pharmaceutical Biology 1998 36(4):280–286.

(2) Zafar, R., and S. M. Ali. “Anti-Hepatotoxic Effects of Root and Root-­Callus Extracts of Cichorium intybus L.” Journal of Ethnopharmacology 1998 63:227–331.

(3) Majumder, P. K., and M. Gupta. “Effect of the Seed Extract of Carrot (Daucus carota L.) on the Growth of Ehrlich Ascites Tumour in Mice.” Phytotherapy Research 1998 12(8):584–585.