Both species are small perennial herbaceous plants with thick, short, creeping, multi-headed rhizomes, surrounded by numerous thick adventitious roots. The aerial part consists of 2–4 large basal leaves and a short flowering stalk bearing 1–4 flowers.The leaves are nearly round in outline, palmately divided, thick and leathery, dark green, and grow on long petioles. Flowers are regular but have a unique structure: 5 large, petal-like, colored sepals; 5–12 petals modified into tubular nectaries with their tips curved inward; numerous stamens; and 3–10 carpels. The fruit is an aggregate follicle with persistent styles. The plants are poisonous.
Differences Between the Species
Caucasian hellebore has leaves divided into 5–11 lanceolate lobes with serrated margins. Occasionally, one or two lobes are further divided. Flower colors vary: carmine-red, white with red speckles and carmine margins, or muted greenish-yellow-brown. Follicles are free at the base. It flowers from December to March in the Transcaucasus and from April to May on the northern slopes of the Greater Caucasus Range.
Purple hellebore has leaves divided into 5–7 lobes, each deeply split into 2–3 secondary lobes. Flower colors are uniform: dirty violet with dark veins on the outside and greenish-violet-purple on the inside. Follicles are fused at the base and have a distinct keel on the back. It flowers in April and May.
Caucasian hellebore grows in mountain forests, along rivers, and forest edges in the Western Caucasus and isolated areas in the Talysh mountains. Purple hellebore grows in deciduous forests in Western Ukraine.
Harvesting and Uses
After seed dispersal, the rhizomes with roots (Rhizoma Hellebori) are dug out, cleaned, washed, and dried. Leaves are occasionally harvested simultaneously.
The rhizomes and roots of both species contain cardiac glycosides, though these are found in smaller amounts in aerial parts.
Key Compounds
The main glycosides have been isolated and named accordingly:
Corglyborin K (Helleborus caucasicus)
Corglyborin P (or Hellebrin, from H. purpurascens)
Both have the aglycone hellebrigenin, which belongs to the bufadienolide group. The aglycone has a steroid structure with a six-membered doubly unsaturated lactone ring, similar to strophanthidin. The sugar components differ:
Corglyborin K contains only rhamnose.
Corglyborin P contains both rhamnose and glucose.
These glycosides act similarly to strophanthin in speed and type of effect but resemble digitalis in cumulative properties and duration of action.
Preparation and Administration
«Corglyborin» is available in tablets of 0.0002 g (taken 3–4 times daily, then reduced to 1–4 times daily) and in 1 ml ampoules of 0.025% solution for intravenous use (1 ml is diluted in 10 ml of a 20% glucose solution).