Product Information

Registration Status: Active

BEKUNIS HERBAL TABLET 20mg is approved to be sold in Singapore with effective from 1991-04-03. It is marketed by PHARMAFORTE SINGAPORE PTE LTD, with the registration number of SIN05517P.

This product contains Senna 20mg in the form of ENTERIC-COATED TABLET. It is approved for ORAL use.

This product is manufactured by ROHA ARZNEIMITTEL GMBH in GERMANY.

It is an Over-the-counter Medicine that can be freely obtained from any retailer



Sennosides (also known as senna glycoside or senna) is a medication used to treat constipation and empty the large intestine before surgery. The medication is taken by mouth or via the rectum. It typically begins working in minutes when given by rectum and within twelve hours when given by mouth. It is a weaker laxative than bisacodyl or castor oil. Sennoside A, one of the sennosides present in the laxative medication, has recently proven effective in inhibiting the ribonuclease H (RNase H) activity of human immunodeficiency virus (HIV) reverse transcriptase [A19231].


For the over the counter treatment of constipation [FDA Label].

Mechanism of Action

Sennoside A and B, the components of senna, are metabolized by gut bacteria into the active metabolite rheinanthrone [DB13175]. Rheinanthrone [DB13175] appears to increase cyclooxegenase 2 (COX2) expression in macrophage cells leading to an increase in prostaglandin E2 (PGE2) [A19235]. This increase in PGE2 is associated with a decrease in aquaporin 3 expression in mucosal epithelial cells of the large intestine. A decrease in aquaporin 3 expression likely produces the laxative effect by restricting water reabsorption by the large intestine thereby increasing fecal water content. The exact mechanism by which rheinanthrone increases COX2 expression is unknown. Rheinanthrone [DB13175] also stimulates peristalsis in he large intestine although the mechanism behind this effect is unknown [A19239]. Rhein [DB13174], another active metabolite is thought to excite submucosal acetylcholinergic neurons resulting in increased chloride and prostaglandin secretion. The movement of chloride ions into the large intestine would also help to draw water into the lumen [A19258].


<10% is absorbed from the gut mostly in the form of the active metabolite rheinanthrone [DB13175][L771].
Sennosides A and B are metabolised to sennidins A and B by gut bacteria [A19239]. Sennidins A and B are further metabolized to rheinanthrone [DB13175] by gut bacteria using beta-glucosidase [A19235]. Rheinanthrone [DB13175] is absorbed into systemic circulation where 2.6% is metabolized to rhein [DB13174] and sennidins A and B via oxidation [A19237] [A19248] [A19235]. Rheinanthrone [DB13175] is the major active metabolite of sennosides A and B which produces the laxative effect of the medication. Rhein [DB13174] is also an active metabolite known to have many protective effects [A19247].


Senna causes increased amounts of apoptosis in the large intestine shortly after use due to upregulated p53 activity [A19236]. This is normally reversed after 18 hours however chronic use has been shown to be associated with p53 resistance and potential carcinogenicity leading to colon cancer. The LD50 value in rats was 5000mg/kg. Subacute studies in rats receiving 20mg/kg and dogs receiving 500mg/kg did not produce signs of toxicity [A19238]. Tests for mutagenicity and reproductive toxicity do not indicate toxic effects.

Active Ingredient/Synonyms

Senna | Senna glycosides | Sennoside | Sennosides | Sennosides |

Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.


  1. Health Science Authority of Singapore - Reclassified POM
  2. Drugbank