Microdiagnostic characteristics of powdered Curcuma longa rhizome

Introduction. Turmeric (Curcuma longa L.), known as a spice, is not only a valuable medicinal raw material in traditional Indian medicine due to its biologically active components (curcuminoids) but also a promising component for the development of modern pharmaceuticals. Curcumin was considered as one of the potential components of COVID-19 treatment regimens due to its anti-inflammatory and immunomodulatory properties. Turmeric raw material is included in the Indian, Ayurvedic, Chinese, Japanese, American Herbal, European, and British Pharmacopoeias. A draft monograph for the State Pharmacopoeia of the Russian Federation (15th edition) has currently been developed. However, it only describes the whole raw material of Curcuma longa L. Since ground raw material is often supplied to the domestic pharmaceutical market, it is relevant to study the identity indicators using the microscopic method.

Aim. To identify the microdiagnostic characteristics of turmeric rhizome powder.

Materials and methods. The study objects were powdered turmeric rhizomes (India) available on the domestic market. For microscopic analysis, the samples were clarified by boiling in a 2.5 % sodium hydroxide solution and prepared as microscopic slides in accordance with the requirements of OFS.1.5.3.0003 "Microscopic and Microchemical Analysis of Herbal Drug Materials and Herbal Medicinal Products". The slides were examined using a Leica DM1000 LED light microscope (Germany) at magnifications of 100× and 400×.

Results and discussion. Characteristic features of turmeric (Curcuma longa L.) rhizomes, powdered to a fine state, have been identified. The conducted quantitative analysis of the raw material's micro-diagnostic features revealed differences in the number of cork layers and the sizes of parenchyma cells and cells containing starch. It has been established that the raw material is characterized by the presence of individual fragments typical of the whole raw material (scalariform-reticulate vessels, multilayered cork, cells with orange content, large starch grains, tabular remnants of the epidermis, and trichomes). All the identified features are consistent with the requirements of foreign pharmacopoeias and can be used for inclusion in the draft monograph for the State Pharmacopoeia of the Russian Federation (XV edition).

Conclusion. Characteristic features of Curcuma longa rhizome powder available on the Russian pharmaceutical market were identified. The raw material was found to contain specific fragments typical of whole crude drug, including scalariform-reticulate vessels, multilayered cork, cells with orange-colored contents, large starch grains, tabular epidermal remnants, and trichomes. All identified characteristics comply with the requirements of foreign pharmacopoeias and can be used for inclusion in the draft monograph for the State Pharmacopoeia of the Russian Federation.

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