Screening of various Swertia species extracts in primary monolayer cultures of rat hepatocytes against carbon tetrachloride- and paracetamol-induced toxicity

Swertia chirata Buch-Ham. (Gentianaceae), one of the oldest medicinal herbs of India, is a source of the Indian ayurvedic drug 'chirata' used for the treatment of liver disorders and malarial fevers. In this study, eight spec ies of Swertia were collected. Each of the dry whole plant was extracted in to methanol, the aqueous extract of which was sequentially extracted into h exane, chloroform and butanol extracts. The extracts were screened for thei r anti-hepatotoxic activity against carbon tetrachloride (CCl4) and paracet amol (acetaminophen (AAP)) toxicity in primary monolayer cultures of rat he patocytes. The primary cultures, 2.5 x 10(6) cells /3 ml medium/60 mm colla gen-coated plates, were exposed to 2.5 mM CCl4 or 12 mM AAP in the presence or absence of plant extracts (100 mug/ml culture medium). Cells and medium were harvested after 22 h of treatment for the assay of cellular reduced g luthathione (GSH) content and leakage of lactate dehydrogenase as biologica l end-points of toxicity. Both CCl4 and AAP at the indicated concentrations reduced GSH by almost 50 and 80%, respectively, while the enzyme leakage w as almost 15% above the untreated control. Hexane and methanol extracts of most of the species in general offered relatively good protection. The anti -hepatotoxic activity, nevertheless, was evident in all Swertia species aga inst both the toxicants. However, Swertia purpurascens, Swertia chirata, Sw ertia paniculata and Swertia cordata exhibited better activity compared wit h other species investigated. In addition, influence of various extracts (1 0-100 mug/ml medium) was examined on cellular growth of rat Reuber hepatoma cell line H4IIEC3/G(-). Except for the butanol extract of S. chirata, no o ther extracts exerted toxicity in terms of neutral red uptake by the cells. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.