THE CORE STRUCTURE OF SHILAJIT HUMUS

The nature of the building blocks and their alignments in the humus 'core' of shilajit were determined by mild and drastic degradations and by comprehensive spectroscopic analyses of the products. Mild hydrolysis of humic acids (HAs) from shilajit afforded two new dibenzo-alpha-pyrones, viz. 3-O-palmitoyl-8-hydroxydibenzo-alpha-pyrone (1) and 3-O-beta-D-glucosyl-8-hydroxydibenzo-alpha-pyrone (2), and two new tirucallane-type triterpenic acids, viz. 24(Z)-3-beta-hydroxy-tirucalla-8,24-dien-26-oic acid (3) and 24(Z)-3-beta-hydroxy-tirucalla-7,24-dien-26-oic acid (4). The resistant HAs (RHAs), obtained after mild hydrolysis, when subjected, separately, to KMnO4 oxidation and Zn dust distillation gave several aromatic carboxylic acids, polynuclear aromatic hydrocarbons, a simple dibenzo-alpha-pyrone (= 3,4-benzo-coumarin) and fluorene. These products, except the two last-named compounds, have been reported from similar degradations of soil-sediment humus indicating the inherent structural similarities of humus from two dissimilar sources. On the basis of the above and related observations, a partial structure of the shilajit humus core, involving oxygenated dibenzo-alpha-pyrones, is postulated. Additionally, the necessity of standardization of shilajit, a panacea in oriental medicine, on the basis of its active principles and carrier molecules (e.g. fulvic acids, FAs) is suggested.