LIPOPHILIC CONSTITUENTS IN HDBRG TOBACCO

Abstract

Harvel De Bouxo Rio Grande (HDBRG) tobacco, popularly known as HD Burley tobacco, which is a high yielding, sun-cured, burley type of tobacco grown under irrigated conditions in the heavy black soils of Andhra Pradesh and used in blend in cigarette manufacture. It has specific characteristics of responding to nitrogen fertilization, producing the highest biomass and seed. Lipophilic constituents play an important role in quality/aroma of tobacco. Representative cured leaf samples of HDBRG tobacco were analyzed for lipophilic constituents by soxhlet hexane extraction, alkaline hydrolysis and fractionation by column chromatography. The total hexane extractables in HDBRG tobacco was high (9.94%) and solanesol accounted for 24.24% of the extract. The general lipid profile of fractions indicated the presence of alkanes, fatty acids, sterols, terpenes and fatty alcohols. In the non-polar fraction, the odd-numbered paraffinic homologues were predominant, accounting for ~66% of the fraction. In respect of the combined total of normal and iso alkanes, the relative content of hentriacontane was the highest (~40%) followed by dotriacontane (~19%). In the polar fraction of the hydrolysate from powder, the proportion of saturated fatty acids (C14:0 + C15:0 + C16:0 + C17:0 + C18:0) was ~58%, while that of unsaturated fatty acids (C18:2 + C18:3) was ~42%. Palmitic acid (C16:0: 585 μg/g) was the major fatty acid. In terms of relative contents, stigmasterol (41.6%) was the major phytosterol, followed by campesterol (20.8%), cholesterol (20.4%), β β β β βsitosterol (12.5%) and fucosterol (5.1%). HDBRG tobacco had higher levels of α α α α α-tocopherol (vitamin E) (50.7%) and fatty alcohols. The LC-MS analysis of solanesol in the APCI ( + ) mode revealed abundant stable (M-H2O + H) ion (m/z at 613.7) with low abundance of other fragmentation ions thus confirming the presence of solanesol in the fractions. The results showed that, higher levels of total hexane solubles and solanesol in the fraction are the characteristic features of this tobacco. Among the lipids, isohentriacontane, palmitic acid, stigmasterol, α α α α α-tocopherol and solanesol were the principal constituents in the respective groups.