Senna Pods

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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1 DEFINITION 

Senna Pods are the dried ripe fruits of Senna alexandrina Mill., also known as Cassia acutifolia Delile (Alexandrian senna) or C. angustifolia Vahl (Tinnevelly senna), (Fam. Fabaceae). Senna Pods contain NLT 3.4% (Alexandrian senna) and NLT 2.2% (Tinnevelly senna) of anthraquinone glucosides, calculated as sennosides, on the dried basis. 

2 IDENTIFICATION 

A.

Potassium hydroxide solution: 100 mg/mL of potassium hydroxide in alcohol 

Sample: 500 mg of finely powdered Senna Pods 

Analysis: Add 10 mL of Potassium hydroxide solution to the Sample. Boil for 2 min, dilute with 10 mL of water, and filter. Acidify the filtrate with hydrochloric acid. Shake it with ether, remove the ether layer, and shake it with 5 mL of 6 N ammonium hydroxide.

Acceptance criteria: The aqueous layer is orange or bluish red. 

3 ASSAY 

Procedure 

[Note—Conduct all sample preparations with minimal exposure to subdued light, and use low-actinic glassware to protect solutions from light.] Ferric chloride solution: 105 mg/mL of ferric chloride 

Methanolic magnesium acetate solution: 5 mg/mL of magnesium acetate in methanol 

Sodium bicarbonate solution: 5 mg/mL of sodium bicarbonate 

Standard solution: 0.13 mg/mL of USP Sennosides RS in Sodium bicarbonate solution 

Sample solution: Weigh and pulverize 10 g of Senna Pods. Transfer 0.15 g to a 100-mL round-bottom flasks. Add 30 mL of water. Mix, weigh, attach a condenser, and reflux in a water bath for 15 min. Cool to room temperature, weigh, and adjust to the original weight with water. Centrifuge, and transfer 20.0 mL of the supernatant to a 150-mL separatory funnel. Add 0.1 mL of diluted hydrochloric acid, and shake with three 15-mL quantities of chloroform. Allow to separate, and discard the chloroform layer after each addition. Add about 0.1 g of sodium bicarbonate, shake for 3 min, and centrifuge. Use the supernatant as the Sample solution. 

Instrumental conditions 

(See Ultraviolet-Visible Spectroscopy 〈857〉.) 

Mode: Vis 

Wavelength: 515 nm 

Cell: Quartz 

Blank: Methanol 

Analysis 

Samples: Standard solution, Sample solution, and Blank 

Transfer 10.0 mL each of the Standard solution and the Sample solution to separate 100-mL round-bottom flasks equipped with condensers. Add 20 mL of Ferric chloride solution, and mix. Reflux in a water bath for 20 min. Add 1 mL of hydrochloric acid, and reflux for an additional 20 min, with frequent shaking, to dissolve the precipitates. Cool to room temperature, transfer the mixtures to separate 100-mL separatory funnels, and shake with three 25-mL quantities of ether previously used to rinse the flasks. Combine the ether extracts, mix, and wash with two 15-mL quantities of water. Transfer the ether layers to separate 100-mL volumetric flasks. Dilute with ether to volume, and mix. Evaporate 10.0 mL of the ether extracts to dryness, and dissolve the residue in 10.0 mL of Methanolic magnesium acetate solution. Determine the absorbance of the resulting solution from the Standard solution and the Sample solution, with a suitable spectrophotometer fitted with matched quartz cells, using the Blank. 

Calculate the percentage of sennosides in the portion of Senna Pods taken: 

Result = (A_U/A_S) × C_S × (V/W) × 100 

A_U = absorbance of the Sample solution  

A_S = absorbance of the Standard solution 

C_S = concentration of USP Sennosides RS in the Standard solution (mg/mL) 

V = volume of water to prepare the Sample solution, 30 mL

W = weight of powdered Senna Pods taken (mg)

Acceptance criteria: NLT 3.4% (Alexandrian senna) and NLT 2.2% (Tinnevelly senna) of anthraquinone glucosides, calculated as sennosides, on the dried basis 

4 CONTAMINANTS 

Microbial Enumeration Tests 〈2021〉: The total bacterial count does not exceed 105 cfu/g, the total combined molds and yeasts count does not exceed 103 cfu/g, and the bile-tolerant Gram-negative bacteria count does not exceed 103 cfu/g. 

Absence of Specified Microorganisms 〈2022〉, Test Procedures, Test for Absence of Salmonella Speciesand Test for Absence of Escherichia coli: Meet the requirements 

Articles of Botanical Origin 〈561〉, Pesticide Residue Analysis: Meet the requirements 

5 SPECIFIC TESTS 

Botanical Characteristics 

Macroscopic 

Unground Alexandrian senna pods: Occur as flattened, reniform, membranous, leathery pods; green to greenish brown with brown patches at the positions corresponding to the seeds; 40–50 mm in length and at least 20 mm wide; at one end is a stylar point and at the other a short stalk. The pods contain six or seven flattened and obovate seeds, green to pale brown, with a continuous network of prominent ridges on the testa. 

Unground Tinnevelly senna pods: Occur as flattened, slightly reniform, membranous, leathery pods; brown to yellowish brown with brown patches at the positions corresponding to the seeds; slightly longer but narrower than Alexandrian senna pods, 35–60 mm in length and 14–18 mm wide; at one end is a stylar point and at the other a short stalk. The pods contain 5–8 flattened and obovate seeds, green to pale brown, with incomplete, wavy, transverse ridges on the testa. 

Powdered Senna Pods: Brown powder 

Microscopic 

Senna Pods: Senna Pods show epicarp with very thick cuticulized polygonal cells, occasional anomocytic or paracytic stomata, and very few nonglandular, one-celled, conical, often curved hairs, with thick papillose walls, 100–350 µm in length; mesocarp consists of parenchymatous tissue containing a layer of calcium oxalate prisms and vascular bundles partially enclosed by bers; endocarp with two crossed layers of bers; seeds with a subepidermal layer of palisade cells with thick outer walls and endosperm of polyhedral cells with mucilaginous walls. 

Powdered Senna Pods: Polygonal cells with occasional small numbers of nonglandular hairs and anomocytic or paracytic stomata, bers in two crossed layers accompanied by a crystal sheath of calcium oxalate prisms, isolated hairs, masses of palisade cells of the seeds, clusters, and prisms of calcium oxalate. 

Articles of Botanical Origin 〈561〉, Methods of Analysis, Foreign Organic Matter: NMT 1.0% 

Articles of Botanical Origin 〈561〉, Methods of Analysis, Total Ash: NMT 9.0% 

Articles of Botanical Origin 〈561〉, Methods of Analysis, Acid-Insoluble Ash: NMT 2.0% 

Loss on Drying 〈731〉 

Sample: 1.0 g of finely powdered Senna Pods 

Analysis: Dry the Sample at 105° for 2 h. 

Acceptance criteria: It loses NMT 12.0% of its weight. 

6 ADDITIONAL REQUIREMENTS 

Packaging and Storage: Preserve against attack by insects and rodents. Store protected from light and moisture at room temperature. Labeling: The label states the Latin binomial and, following the official name, the part(s) of the plant contained in the article. USP Reference Standards 〈11〉 

USP Sennosides RS