Aqueous leaf extract of Tulsi (Ocimum sanctum) protects against high fat diet-induced injury to rat liver through antioxidant mechanisms: a dose- and time-dependent study

Background: Consumption of high fat induces oxidative stress by disturbing the activity of a number of antioxidant enzymes in rat liver. The present study was designed to investigate the efficacy of the aqueous leaf extract of Tulsi (Ocimum sanctum) to provide protection against the High Fat Diet (HFD) induced oxidative injury in rat liver. Objective: The aim of the present study was to examine whether administration of aqueous extract of the leaves of Ocimum sanctum (Tulsi) do possess a protective effect against HFD-induced oxidative stress in rat liver. Materials and method: The dose and time dependent changes were studied in the liver of male Wistar rats following the oral feeding of the rats with HFD for a period of 5 days, 10 days and 15 days to determine the maximum oxidative damage in the hepatic tissue of rats without any mortality. Pre-treatment of rats with aqueous leaf extract of Tulsi (TLE) was also studied by oral administration of TLE with the increasing doses (50, 100, and 200 mg/kg BW) against HFD induced oxidative stress in rat liver to determine the minimum effective dose of Tulsi, which can provide protection to the liver damage and minimize the alterations in a concentration dependent manner. The alterations in the activity of some of the important different bio-markers of hepatic damage, biomarkers of oxidative stress, and activities of the antioxidant enzymes were studied. Histo-pathological and histo-chemical alterations were also studied through H-E staining and Picrosirius red staining. Scanning electron microscopy was done to see the structural integrity of hepatic tissue surface. Result: The studies revealed that the extract protected the biomarkers of organ damage, oxidative stress, antioxidant enzymes, pro-oxidant enzymes and oxidative stress index from being altered in the rat hepatic tissue following treatment with HFD. Conclusion: It can be concluded from the current work that this aqueous leaf extract of Tulsi possess antioxidant properties and may be used as a potential antioxidant supplement to combat oxidative stress-induced tissue damages due to high fat diet consumption.