Thanks to its benefits of easy use, reliable effect, and low toxicity, senna leaf, also called Fan Xie Ye in Pinyin, is one of the most common laxatives today. Senna herb has been used as mild laxative for many centuries by people from North Africa and Southwest Asia. In addition, ancient India and ancient Greek medicine have discovered senna leaves’ efficacy and begun to apply them for medical purpose since the 9th century. Currently this herb is used more in diet for weight loss. As a matter of fact, tons of popular dieter’s teas out there can find the ingredient of senna. Being a natural herb, it often leads many people to falsely believe that it is 100% safe and free of dangers. However, that is so wrong and in recent years the senna leaf tea side effects were frequently reported in newspapers. So, are senna leaves good or bad? Is senna leaf good for you? To answer these questions, we are going to elaborate this Chinese herb from the point of view of Traditional Chinese medicine (TCM) as follows.
What is senna leaf?
Also known as Folium Sennae, it means the dried leaflets from Cassia angustifolia Vahl. or Cassia acutifolia Delile., plants in the family legume. The former is mainly produced in India, Egypt and Sudan, and that latter is mainly from Egypt and cultivated in some regions of China, such as Guangdong, Guangxi and Yunnan. It is usually harvested in September, dried and used raw.
Leaves of Cassia angustifolia Vahl. are ovate-oblong or ovate-lanceolate, 1.5 to 5cm long, 0.4 to 2cm wide, and with entire margin, abruptly pointed blade tip, and slightly asymmetrical leaf base. Up surface is yellow-green while lower surface is pale yellowish green, glabrous or nearly glabrous, and with slightly ridgy veins. It is leathery, slightly sticky, and with weak but peculiar odor and slightly bitter taste. Leaves of Cassia acutifolia Delile. are lanceolate or ovate, slightly curly, and with short-pointed or slightly convex blade tip, asymmetrical leaf base, and surface covered with short soft fuzz.
As for chemical constituents, C. angustifolia Vahl. mainly contains sennoside A, B, C, D, chrysophanol, emodin, physcion, 3-methyl-8-methoxy-2-acetyl-1, 6-naphthalenediol-6-O-β-D-glucoside (tinnevellin glucoside), and kaempferol in its lobules. C. acutifolia Delile. mainly contains sennoside A, B, C, D, chrysophanol, emodin, and physcion. Young leaf contains kaempferol. In addition, Cassia auriculata, the plant in the same genus, contain leucoanthocyanins in leaves and polyphenoloxidase in bark.
Senna leaf benefits
As one of the most important laxatives, the lapactic effect of senna leaf herb is pretty obvious, which is the main reason why nowadays this herb is widely used for colon cleansing and detox and a variety of conditions like constipation, irritable bowel syndrome (IBS), bloating, hemorrhoids, and so on. Actually a series of ready-made products, such as senna leaf tea, extract, powder, capsules, extract syrup, and concentrate, have been developed for easy consumption. However, it may violently stimulate the gastrointestinal tract. That’s being said, it gives health benefits, meanwhile, leaves side effects. And its pharmacology can reveal it all.
Modern pharmacological actions
1. It contains anthraquinone derivatives, whose purgative effects and irritation are stronger than other anthraquinone-containing laxatives. As a result, diarrhea induced by senna tea may accompany by abdominal pain;
2. Its main active ingredients are sennoside A, B, which are absorbed by stomach and small intestine, and then resolved by liver. The decomposition products follow the blood circulation and excite the pelvic ganglion, which thus leads to the contraction of the large intestine and causes diarrhea.
3. Anthraquinone inhibits various bacteria, such as Staphylococcus aureus, E. coli, etc., and skin fungi.
Proven senna leaves related herbal remedies
This Chinese herb is considered as sweet bitter in flavor and cold in medicinal properties. It covers the meridian of the large intestine. Its vital functions are purgating heat and bowels, removing food retention, and arresting bleeding. And main senna leaves uses include heat-accumulation induced constipation, habitual constipation, bloating and indigestion, edema, gastroduodenal ulcer and bleeding, and so on. Recommended senna leaf dosage is from 3 to 6 grams in decoction, usually decocted later, or 1.5 to 3 grams in making herbal tea or powder.
Constipation by heat knot
Since this herb is good at inducing diarrhea, it is ideally used for heat-knot inducing constipation, habitual constipation and senile constipation. More often than not, it is used after being infused in hot water or decoction alone. Small doses can be used as mild laxative while large doses as cathartic prescription. In the case of heat knotted constipation accompanied with abdominal fullness and pain, this herb usually combines with Zhi Shi (Immature Bitter Orange) and Hou Po (Magnolia Bark) in an herbal recipe to enhance the role of purgative action.
Swelling in ascites
Since it is a purgating drug and diuresis, which can help alleviate water retention and swelling in ascites. And it can be used alone or in recipes along with Qian Niu Zi (Morning Glory Seed) and Da Fu Pi (Areca Peel).
Clinically it is also used, in small doses to replace tea, for comma in stroke. It facilitates bowel movement and thus relieve symptoms for a soon recovery.
Potential senna leaf side effects, toxicity and contraindications
1. The median lethal dose of sennosides intraperitoneal injection in mice is 1.141g/kg;
2. Senna leaves or pods can cause abdominal pain, vomiting, or aggravate the original intestinal inflammation (especially in the larger dosage);
3. There were reports that it caused a variety of adverse reactions, including facial numbness, dizziness, insentience or itching during defecation, varying degrees of hypalgesia in the distributional regions of trigeminal nerve, and urinary retention and sudden blood pressure changes after taking large doses of senna.
4. According to the records of 102 patients who used senna, no obvious abnormalities were found before and after the treatment on routine urine test, serum creatinine, urea nitrogen, glutamate pyruvate transaminase (GPT), icterus index, electrocardiogram, and other tests.
5. It was reported that some patients suffering from habitual constipation showed signs of senna dependency in long term use of organic senna leaf. And the senna discontinuation was followed by various side effects, including facial flushing, fever, anxiety, sleeplessness, loss of appetite, speedy respiratory rate, high blood pressure, body aches, nausea, stomach discomfort, cramps, diarrhea, and so on. What’s more, it may increase the risk of developing colon cancer and liver damage.
From the perspective of TCM, use senna leaf and stem with care while nursing, during pregnancy and menstruation, and in the case of weakness.