Chemical composition of extracts from green, brown and black leaves of Bergenia crassifolia L

Siberian tea Bergenia crassifolia L. is widely used in Russian ethnomedicine. Black leaves which have passed 2 winters are used as adoptogen; furthermore, they are used to treat struma. Green leaves are used as an anti-inflammatory preparation for the treatment of burns, as a diuretic and an antimicrobial remedy. B. crassifolia rhizomes have been included in the Russian State Pharmacopoeia. The chemical composition of bergenia rhizomes has been studied quite extensively. However, the comparative composition of secondary metabolites from green, brown and black leaves has not been studied to date. The purpose of the present work was to study the chemical composition of different leaves of B.crassifolia by the technique of reverse phase-high performance liquid chromatography (RP-HPLC) coupled with photodiode array detection (PDA).

Green, brown (after 1 winter) and black (after 2 winters) leaves of B.crassifolia were obtained from the MTT Agrifood Research Finland. The air-dried botanical material was extracted by MeOH. The results of the qualitative-quantitative analysis of the B.crassifolia methanol extracts are shown in Table 1.

Table 1. Extract yield, total phenolics, and HPLC-PDA qualitative-quantitative data for methanol extracts of B. crassifolia.

Sample	Extracts	Total	Identified components [mg/g]
	yield	phenolics	Arbutin	Hydroquinon	Gallic acid	Protocat. acid	Bergenin	Ellagic acid
Green	30.4	49.5	70.87±8.48	0.08±0.03	1.02±0.09	ND	5.58±0.89	0.47±0.09
Brown	16.8	49.2	15.06±0.24	15.57±0.43	8.57±0.27	0.37±0.03	6.90±0.66	2.00±0.09
Black	8.4	32.5	2.79±0.28	5.62±0.32	6.51±0.36	0.06±0.02	5.05±0.23	1.95±0.13

The amount of extractable components after 2 winters natural fermentation decreased from 30.4mg/g (green) to 8.4mg/g (black). Maximal changes in composition of leaves were observed for arbutin (decreased 25 times), hydroquinone (increased 194 times after first year and decreased 3 times after 2 years), protocatechuic acid (increased 37 times after first year and decreased 6 times after 2 years) and ellagic acid (increased 4 times). However, the concentration of total phenolics decreased only 35%.

Acknowledgements: Authors are grateful to Mr. B. Galambosi from MTT Agrifood Research Finland for providing of B. crassifolia samples