Senna

Names and identification

Language	Name
English	Senna
Latin/Botanical	Cassia angustifolia Vahl (syn. Senna alexandrina Mill.)

Key Phytochemical Constituents

• Sennosides A and B (rhein dianthrone glycosides - primary active)
• Sennosides C and D (rhein-aloe-emodin heterodianthrones)
• Rhein and rhein-anthrone (active metabolites)
• Aloe-emodin
• Kaempferol and its glycosides
• Isorhamnetin
• Chrysophanol
• Mucilage and polysaccharides

How does it work?

• Laxative mechanism: sennosides are hydrolyzed by colonic bacteria to release rhein-anthrone, which acts as a local irritant stimulating colonic peristalsis and inhibiting water/electrolyte absorption
• Anthraquinone-mediated antimicrobial action through disruption of bacterial membrane integrity and interference with DNA/RNA synthesis
• Antioxidant mechanism through phenolic and flavonoid constituent scavenging of free radicals, reducing oxidative cellular damage

Which traditional uses are supported by research?

These summaries come from the source notes, which do not name the studies behind them.

• Traditionally used as a bowel stimulant (Virechana dravya). Clinical studies and pharmacological research have reported laxative activity.
• Traditionally used beyond purgation. In vitro studies have reported antimicrobial activity against several bacterial and fungal strains.
• Preclinical studies have reported anti-inflammatory activity, though this is not the primary traditional use.

What do recent studies show?

• Alshehri MM, Quispe C, Herrera-Bravo J and others 2022. A Review of Recent Studies on the Antioxidant and Anti-Infectious Properties of Senna Plants. Oxidative medicine and cellular longevity. PMID 35154569 · doi:10.1155/2022/6025900
  Documented significant antioxidant and anti-infectious properties of Senna species beyond traditional laxative use, with potential applications in antimicrobial therapy.

Only studies that could be traced to a published paper are listed here. An absence here means we could not identify the source, not that no work exists.

Recent safety updates

• The EMA monograph (2018) limits use to 1 week, and the WHO monograph (1999) says use for more than 2 weeks requires medical supervision; chronic use may lead to electrolyte imbalance (hypokalemia), melanosis coli, and rarely hepatotoxicity (LiverTox likelihood score D - possible rare cause)
• Severe hepatotoxicity is unusual but documented in cases of chronic overuse; one case of acute liver failure with portal vein thrombosis reported; Cassia angustifolia extract was found not hepatotoxic at doses higher than normal in controlled in vitro/in vivo study

What is it made of?

Key Active Markers

• Rhein
• Glycosides
• Emodin
• Kaempferol
• Isorhamnetin
• Chrysophanol
• Mucilage
• Polysaccharides

Dosage forms and preparation

Dosage Forms: Tablet, Capsule, Tea/Infusion, Syrup, Granules, Churna (powder), Standardized extract tablet

Standard Dosage: 15-30 mg sennosides (calculated as sennoside B) per day for adults; 0.5-2 g leaf powder; 1-2 g pod powder; not to be used for more than 1 week (EMA herbal monograph on senna leaf, Revision 1, 2018)

Optimal Timing: Single dose at bedtime for morning bowel movement (6-12 hour onset); take with adequate water (250 mL minimum)

Storage: Store below 25 deg C, protected from light and moisture. Sennosides are photolabile, amber or opaque packaging required. RH <60%.

Marker Compounds: Sennoside A, Sennoside B, Rhein, Aloe-emodin, Kaempferol, Isorhamnetin

Synergistic Combinations

• Haritaki (Triphala-based laxative formulations)
• Fennel/Saunf (carminative addition to reduce griping)
• Psyllium husk (bulk-forming + stimulant laxative combination)
• Ginger (traditionally combined to offset nausea and griping associated with senna)