Antioxidant/anti-inflammatory activities and total phenolic content of extracts obtained from plants grown in Vietnam

The antioxidant and tyrosinase inhibition properties of essential oil from the peel of Chinese Torreya grandis Fort

The antioxidant and tyrosinase inhibition properties of essential oil from the peel of Chinese Torreya grandis Fort. (CTGF oil) were investigated. The antioxidant properties of CTGF oil were evaluated via 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging tests, and it showed an IC₅₀ value of 0.88 ± 0.06 μg mL^-1 compared to V _C with a value of 1.0 ± 0.1 μg mL^-1 and BHT with a value of 2.9 ± 0.1 μg mL^-1. CTGF oil had relatively significant DPPH scavenging activity (p < 0.05), which could be compared to other natural oils as follows: cassia oil (92.4%) > peppermint oil (89.1%) > clove leaf oil (87.7%) > nutmeg oil (80.1%) > CTGF oil (42.6%) > lemon oil (25.5%). Furthermore, changes in the peroxide values of different treatment groups during storage for 60 days were estimated. CTGF oil displayed better antioxidant activity than lemon oil, with activity similar to that of BHT for the reduction of the peroxide value. Moreover, CTGF oil effectively inhibited the oxidation of 3,4-dihydroxy-l-phenylalanine (l-DOPA) through tyrosinase (P < 0.05). The essential oil obtained after hydrodistillation from the peel of Chinese Torreya grandis Fort. could be potentially utilized as a good new alternative source of natural antioxidants for the food and cosmetics industries.

Effect of methanol extract of Dicranopteris linearis against carbon tetrachloride-induced acute liver injury in rats

Background

Dicranopteris linearis (family Gleicheniaceae) has been reported to possess anti-inflammatory and antioxidant activities but no attempt has been made to study its hepatoprotective potential. The aim of the present study was to determine the hepatoprotective effect of methanol extracts of D. linearis (MEDL) against carbon tetrachloride (CCl₄)-induced acute liver injury in rats.

Methods

6 groups (n = 6) of rats received oral test solutions: 10% dimethyl sulfoxide (DMSO), 200 mg/kg silymarin, or MEDL (50, 250, and 500 mg/kg), once daily for 7 consecutive days, followed by hepatotoxicity induction with CCl₄. Blood and liver were collected for biochemical and microscopic analysis. The extract was also subjected to antioxidant studies (e.g. 2, 2-diphenyl-1-picrylhydrazyl (DPPH)- and superoxide anion-radical scavenging assays, oxygen radical absorbance capacity (ORAC) test and total phenolic content (TPC) determination), phytochemical screening and HPLC analysis.

Results

Pretreatment with MEDL and silymarin significantly (P < 0.05) reduced the serum levels of AST, ALT and ALP, which were increased significantly (P < 0.05) in DMSO-pretreated group following treatment with CCl₄. Histological analysis of liver tissues in groups pretreated with MEDL and silymarin showed mild necrosis and inflammation of the hepatocytes compared to the DMSO-pretreated group (negative control group). The MEDL showed higher DPPH- and superoxide anion-radical scavenging activity as well as high TPC and ORAC values indicating high antioxidant activity.

Conclusions

MEDL exerts hepatoprotective activity that could be partly contributed by its antioxidant activity and high phenolic content, and hence demands further investigation.