RESUMEN
The need to explore the abundance of natural products cannot be overemphasized particularly in the management of various disease conditions. In traditional medical practice, Vernonia amygdalina has been widely adopted in the management of various inflammatory disorders. The objective of this investigation was to isolate the bioactive principles from the stem-bark and root of V. amygdalina and assess the anti-inflammatory (in vitro) activity of both the crude extracts and the isolated compounds. Following extraction with the methanol, the extract was subjected to gravity column chromatography and the resultant fractions was further purified to obtained pure compounds. The structural elucidation of the compounds were based on data obtained from 1H to 13C nuclear magnetic resonance (NMR) spectroscopies as well as fourier transform infrared (FT-IR). Using diclofenac as a control drug, the albumin denaturation assay was used to determine the in vitro anti-inflammatory activity of the extracts and isolates. Three distinct compounds characterized are vernoamyoside D, luteolin-7-α-o-glucuronide, and vernotolaside, a new glycoside. When compared to diclofenac, which has an IC50 of 167.8 µg/mL, luteolin-7-α-o-glucuronide, vernoamyoside D, and vernotolaside all showed significant inhibitions with respective IC50 values 549.8, 379.5, and 201.7 µg/mL. Vernotolaside is reported for the first time from the root. The assertion that the plant is used in traditional medicine for the management of inflammatory disorder is somewhat validated by the confirmation of the existence of the compounds with the biochemical actions. Further validation of the isolated compounds would be required in animal studies.
RESUMEN
Oxidative insult by free radicals has been implicated in drug-induced hepatic damage and this has resulted in frequent episodes of liver disorders. Therapeutic efficacy of antioxidants may provide a possible solution to this menace. This study was carried out to investigate the effect of combined administration of silymarin and vitamin C in rescuing acetaminophen-induced hepatotoxicity in rats. Hepatotoxic rats were orally administered with silymarin and vitamin C at 100 and 200 mg/kg body weight, respectively. At the end of the experiment, liver function indices, antioxidant parameters and histological analysis were evaluated. We observed that the significantly increased (p < 0.05) activities of alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, as well as levels of thiobarbituric acid reactive substances and serum total bilirubin, were markedly reduced following co-administration of silymarin and vitamin C. The compounds also effectively reversed the reduced activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase and total protein concentration in the hepatotoxic rats. These findings are indicative of hepatoprotective and antioxidant attributes of the two compounds which are also supported by the histological analysis. The available evidences in this study suggest that the complementary effects of silymarin and vitamin C proved to be capable of ameliorating acetaminophen-mediated hepatic oxidative damage and the probable mechanism is via antioxidative action.