(4R,5R,6S,7R,8S,9R,10S,13S)-7,8β-Epoxy­momilactone-A

The title compound, C(20)H(26)O(4), was extracted from Leucas Urticifolia, a wild Lamiaceae herb distributed in the Punjab, Baluchistan, Sindh and the Rajputana desert of Pakistan. The plant is utilized for various medicinal applications by the local community. The title compound is based on the pimarane–diterpene skeleton. The mol­ecule exhibits an ep­oxy ring fused to momilactone-A, leading to a penta­cyclic mol­ecular structure. The absolute configuration was assigned by comparison with the crystal structure of momilactone, but needs further verification. The crystal structure is governed by four inter­molecular hydrogen-bond inter­actions of the C—H⋯O type.