A new monoterpene acid from Marrubium vulgare with potential antihepatotoxic activity.

The whole plant of Marrubium vulgare L. afforded a new terpenoid, characterised as p-menthane-5,6-dihydroxy-3-carboxylic acid (1), which has been designated as marrubic acid. Its structure has been elucidated on the basis of spectral and chemical analyses. The compound (1) also exhibited a significant antihepatotoxic activity by reducing the elevated levels of serum enzymes such as serum glutamate oxaloacetate transaminase (SGOT) by 40.16%, serum glutamate pyruvate oxaloacetate transaminase (SGPT) by 35.06%, and alkaline phosphatase (ALP) by 30.51%. On the other hand, total protein (TP) levels were increased by 34.07%, as compared to the standard drug silymarin, which decreased SGOT by 53.04%, SGPT by 55.96%, ALP by 35.87% and increased TP levels by 59.59%. These biochemical observations were also supplemented by histopathological examinations of liver sections.