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Session 3: Preclinical studies of herbal and traditional medicine

Pharmacognostic Specifications and Lawsone Content of Lawsonia

inermis

Rawiwan Charoensup*, Krittapat Phairoh*, Chanida Palanuvej**,
,
Nijsiri Ruangrungsi*****
*School of Health Science, Mae Fah Luang University, Chiang Rai, Thailand 57100
**College of Public Health Sciences, Chulalongkorn University, Bangkok, Thailand 10330
***Faculty of Pharmacy, Rangsit University, Pathumthani, Thailand 12000

Background and Rationale: Lawsonia inermis L., commonly referred to henna, belongs
to the Lythraceae family and is the sole species in the genus. It has been used as traditional
or folk medicine for the treatment of a wide range of skin infectious diseases.
Objectives: To investigate pharmacognostic specifications and lawsone contents of
Lawsonia inermis leaves from various sources throughout Thailand.
Methods: Twelve samples of L. inermis leaves were collected from different geographi-
cal areas in Thailand. Pharmacognostic specifications were performed according to WHO
guideline for Quality control methods for medicinal plant materials. A simple and reliable
method to determine lawsone contents was performed by thin layer chromatography (TLC)
coupled with densitometry analysis and image analysis.
Results: Macroscopic evaluation of L. inermis was illustrated as whole plant drawing.
Microscopic evaluation of L. inermis powders showed fragment of mesophyll, fragment of
parenchyma, epidermis layer with stomata, and the rosette crystal of calcium oxalate. Physico-
chemical parameters revealed that total ash, acid insoluble ash, loss on drying, and water
content should be not less than 6.98, 1.12, 8.08, and 9.86% of dried weight respectively;
whereas ethanol and water extractive values should be not less than 19.67 and 23.06% of dried
weight respectively. Lawsone was detected in all samples of L. inermis ethanolic extracts.
The content of lawsone in L. inermis leaves by TLC-densitometry was found to be 0.76 ± 0.05
g/100 g of dried crude drug; while the lawsone content evaluating by TLC image analysis was
found to be 0.87 ± 0.11 g/100 g of dried crude drug. The validation parameters were investi-
gated according to ICH guideline. The validation of the methods revealed that both TLC-
densitometry and TLC image analysis showed good sensitivity and accuracy for lawsone
quantitation in L. inermis leaves extracts.
Conclusion: The results obtained from pharmacognostic specifications could be used
as the standardization data of L. inermis leaves and the results obtained from the development
of TLC method could be applied to determine lawsone in other plant materials.
Moreoverestablishment of pharmacognostic profile and lawsone content of L. inermis will be
able to guarantee quality, purity and identification of this plant.
Key words: Lawsonia inermis L., pharmacognostic specification, lawsone, thin layer
chromatography