As an extremely tough weed, nut grass is very difficult to kill. Its strong root and nodule, better known as Xiang Fu in traditional Chinese medicine (TCM）, is also called “nut” simply because it appears like a small nut although it isn’t. While nutgrass can be a nightmare to many a lawn, TCM practitioners have used its underground tuber as an important part of many herbal remedies for various conditions, in particular gynecological disorders, for hundreds, if not thousands, of years.
What is nut grass?
This perennial plant is a species of sedge (Cyperaceae). It is also called cyperus rotundus, purple nutsedge, Java grass, and so on. It can grow up to 55 inches, with 5–20 cm long leaves, bisexual flowers, three-angled achene fruit, and up to 25 mm white fleshy rhizomes.
Medicinally, the rhizomes should be harvested in autumn. After that, people will singe them to remove the fibrous roots, blanch or steam them, and dry them in the sun. Sometimes, people dry them right after the tubers are singed. And the finished one, called Cyperus Rhizome, Nut Grass Rhizome, or Rhizoma Cyperi Rotundi, is mostly spindle-shaped, and sometimes slightly curved, 2 to 3.5cm in length, and 0.5 to 1cm in diameter.
Rhizoma cyperi benefit
This is a versatile herb, thanks to its valued medicinal properties. And some studies have found that it can provide health benefits as follows.
1. Traditionally it is considered a primary Qi-regulating herb. It can be used in the treatment of chest and abdominal distention and pain caused by liver Qi stagnation. And it is often combined Chai Hu (Radix Bupleuri) and Qing Pi (Pericarpium Citri reticulatae Viride) to treat left or right side chest pain and Gao Liang Jiang (Rhizoma Alpiniae Officinarum) to treat cold-pathogen induced stomach ache.
2. TCM believes that it can treat irregular menstrual periods and pain in lower abdomen due to liver Qi stagnation. When used together with Ai Ye (Folium Artemisiae Argyi), it treats abdominal pain during period due to stagnation of Qi caused by the pathogenic cold.
3. It can inhibit the uterine contraction in vitro and relax uterine muscle tension. In addition, it contains oil that has a weak estrogen effect.
4. Programmed electrical stimulation has shown that subcutaneous injection of 20% alcohol extract (0.5 ml / 20 g) could significantly increase the pain threshold in mice.
5. Nutgrass root has antibacterial activity, and its extract has an inhibitory effect against certain fungi. For example, its volatile oil can inhibit Staphylococcus aureus and Shigella sonnei.
6. Scientific research shows that it has anesthetic effect.
7. Its alcohol extract has antipyretic effect. That’s to say, it is useful for fever.
8. Experiments show that it can help lower the rectal temperature.
9. It has a certain therapeutic effect for swollen feet and other symptoms caused by inflammation.
10. It has a protective effect on bronchospasm.
11. TCM holds that it is able to treat nausea and vomiting.
12. It can help calm the mind. So, it makes sense in the treatment of liver Qi stagnation and distraction due to the impetuous mood.
13. It can help lower blood pressure gradually and the effect can last for 0.5 to 1 hour.
14. It has a tonic effect on the action of the heart. The active ingredients of cardiotonic effect include alkaloids, flavonoids, glycosides, phenols and so on. In addition, it can slow down heart rate too.
Sample Xiang Fu recipes on herbal remedies
The Chinese Pharmacopoeia says that it is acrid in flavor and slightly cold and non-toxic in nature. It goes to meridians of liver, lung, spleen, stomach and Sanjiao. Basic functions are to regulate the Qi, dispel the stagnation, and regulate the menses to reduce menstrual cramps. Primary nutgrass uses and indications include distending pain in hypochondrium area, breast swelling pain, hernia pain, irregular menstruation cycle, epigastralgia, belching, acid regurgitation, vomiting, nausea, painful menstrual periods, metrorrhagia and metrostaxis, morbid leucorrhoea, excessive fetal movement, and more. Recommended dosage is from 5 to 10 grams in decoction. Besides, it can be used in the forms of pill and powder too.
1. Kuai Qi Tang from the Tai Ping Hui Min He Ji Ju Fang (Imperial Grace Formulary of the Tai Ping Era). It is for abdominal fullness and bloating, chest tightness and choking, belching, regurgitation of stomach acids to the esophagus, vomiting due to excess mucus, hangover, and loss of appetite. Other main herbal ingredients include Sha Ren (Fructus Amomi) and Gan Cao (Radix Glycyrrhizae).
2. Xiao Wu Chen Tang from Ju Fang. It is mainly used in the treatment of stabbing pain in abdominal area. Other two ingredients include Wu Yao (Radix Linderae) and licorice root.
3. Yue Ju Wan from San Yin Ji Yi Bing Zheng Fang Lun (Three Key Factors of Disease Pattern Formulas). It is used for all stagnations. Other herbs are Cang Zhu (Rhizoma Atractylodis), Chuan Xiong (Szechuan Lovage Rhizome), Shen Qu (Medicated Leaven), and Zhi Zi (Fructus Gardeniae).
4. Xiang Jing San from San Yin Fang. In this formula it is combined with Jing Jie Sui (Herba Schizonepetae) to treat rectal prolapse.
5. Tie Zhao San from Zhong Zang Jing (Master Hua’s Classic of the Central Viscera). It is used together with Zi Su Ye (Folium Perillae) to prevent miscarriage.
Side effects and contraindications of cyperus rotundus
According to TCM, Xiang Fu shouldn’t be used in patients have Qi deficiency but without stagnation or blood heat due to yin deficiency.
When it comes to the toxicity of alcoholic extract of Cyperus rotundus rhizomes, the median lethal dose is around 1.5 g per kg weight in mice. In other words, its toxicity is very low, and the rats have good tolerance to it when the feed contains no more than 25% of it. But the growth of animals will be inhibited when its content accounts for 30% to 50% in the feed.