Determination of Tannin Content in Various Parts of Six Citrus Species

Abstract

Tannin content of roots, stems, stem barks, leaves and peels of six species of Citrus was investigated. They include Citrus aurantifolia (Christm.) Swingle (Lime), C. grandis Osbeck (Shaddock/Pummelo), C. limon (L.) Burm. f.(Lemon), C. paradisii Macf. (Grapefruit), C. reticulata Blanco (Mandarin/Tangerine) and C. sinensis (L.) Osbeck (Sweet orange). The study showed that tannin was present in all parts of these Citrus species. The highest level of tannin was contained in the leaves of C. aurantifolia [1.44±0.02%] and C. limon [1.30±0.02%] respectively; whereas the least concentrations were found in the roots of C. reticulata [0.06±0.02%] and C. sinensis [0.08±0.04%] respectively. The roots, stems, stems barks, leaves and peels extracts of these Citrus species could be employed in ethnomedicine as drugs, due to the therapeutic values of tannin. In addition, they could be regarded as potential rich sources of natural tannin which could be isolated and utilized in cosmetic industry as antimicrobial agents, pharmaceutical industries for production of drugs, agriculture for reduction of emission of methane gas from ruminants, tannery industry for manufacture of leather, as additives in wine production to ameliorate the astringency and in manufacture of adhesives.