Sennosides.
"Sennosides" is a collective term used to describe substances in the anthraquinone group. These substances are found in plants of the Caesalpiniacea family. The plants of this family - e.g. senna shrubs - are primarily found in tropical regions.
Sennosides have a highly laxative effect. Senna leaves or senna pods are dried and comminuted and the resulting material is used as a tea or further processed to produce coated tablets, pills or capsules.
The leaves and/or pods from the following shrubs are used for pharmaceutical purposes:
- Cassia senna L. (also known as Cassia acutifolia)
- Alexandrian senna
- Cassia angustifolia, Tinnevelly senna
Some of these names have historical origins, indicating the ports from which the plants were exported:
The leaves and pods of the Cassia senna shrub are shipped along the River Nile from their natural habitat in the Sudan and the upper Nile region of Egypt to Alexandria, from where they are transported across the Mediterranean Ocean to Europe. The city of Trieste was the only storage place until 1841. Egypt held the monopoly on these plants and had leased it to an Italian merchant.
Cassia angustifolia comes from Arabia and the coastal regions of Somalia. In an effort to break the Cassia senna monopoly, the British began to cultivate Cassia angustifolia in their former crown colony India. The produce was shipped via the Indian town of Tinnevelly, which is where the name Tinnevelly senna came from.
Senna leaves contain virtually no sennosides when fresh. They are formed as a result of the enzymatic degradation (oxidation) processes that take place after the leaves have been harvested. Sennoside all have similar structures and are distinguished from one another by the additional letter A, B, C, D, E or F. The monograph on senna pods and senna leaves in the European Pharmacopoeia (Ph. Eur.) contains a photometric assay. This is a so-called group assay, which means that all of the sennosides present in the plant are detected, but the content values are all converted in line with a single sennoside (sennoside B). This is referred to as a conventional method.
First of all, the anthraquinones are extracted from the matrix and the free anthraquinones are subsequently removed. After the oxidation process, the sugars attached to the anthraquinone skeleton are eliminated and the free anthraquinones isolated. These are then added to an alkaline solution. The resulting red colouring then undergoes photometric quantitation.
The pharmacopoeia (Ph. Eur.) demands a minimum sennoside content for senna drugs as these are the constituent substances that determine the value of the product. In its capacity as an accredited, specialised testing laboratory, PhytoLab is in a position to be able to determine whether the analysed samples meet the requirements of the pharmacopoeia.
PhytoLab verifies the identity of senna samples. Other tests that are relevant to quality (e.g. testing for the presence of heavy metals, pesticides and mycotoxins, such as aflatoxins and ochratoxin) are also carried out in our laboratory.
PhytoLab tests for adulteration by members of the Cassia family which are not approved by the pharmacopoeias (e.g. Cassia auriculata) or by foreign plants (false or mistaken identity).
Senna plants contain other anthraquinones (e.g. rhein, aloe-emodin, chrysophanol, emodin etc.) as well as sennosides A B, C, D, E and F. PhytoLab is able to selectively determine the anthraquinones individually thanks to the use of ultra-modern HPLC systems and methods developed especially for this purpose.
In its capacity as a service laboratory, PhytoLab has been specialising in the analysis of plant-based drugs and such natural substances as sennosides for more than 10 years now. The sennoside content can even be determined in complex samples matrices as coated tablets, pills or granules, for example. PhytoLab is bound to have the right method for your senna products, or can develop a new one, tailored to your specific requirements and exclusively for you.
