Variability of antioxidant and biological activities of Rhus tripartitum related to phenolic compounds

Rhus species are known in traditional medicine for their therapeutic virtue and their extracts showed numerous important properties including antimalarial, antimicrobial, antiviral, and hypoglycemic and anticonvulsant activities. Rhus tripartitum (Ucria) is a medicinal plant widely used in Tunisia folk medicine against chronic diarrhea and gastric ulcer. This study was designed to examine in vitro and ex vivo antioxidant, anti-inflammatory and anticancer activities of four extracts of Rhus tripartitum root cortex with increasing solvent polarity (hexane, dichloromethane, methanol and water). HPLC was used to identify and quantify phenolic compounds in Rhus extract. Water extract showed the highest antioxidant activity using oxygen radical absorbance capacity (ORAC method) with 8.95 ± 0.47 µmol Trolox/mg and a cell based-assay with 0.28 ± 0.12 µmol Trolox/mg as compared to the other fractions. Moreover, methanol extract displayed the strongest anti-cancer activity against human lung carcinoma (A-549) and colon adenocarcinoma cell lines (DLD-1) with an IC₅₀ value of 60.69 ± 2.58 and 39.83 ± 4.56 µg/ml (resazurin test) and 44.52 ± 5.96 and 55.65 ± 6.00 µg/ml (hoechst test), respectively. Besides, the highest anti-inflammatory activity, inhibiting nitric oxide (NO) release, was exhibited by dichloromethane extract with 31.5 % at 160 µg/ml in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. The HPLC analysis showed that catechol and kaempferol were the major phenolics. These data suggest the richness of all fractions of Ucria root on interesting bioactive molecules with different polarity and confirm the known traditional therapeutics virtues of this species for the treatment of dysentery, diarrhea and gastric ulcer.

Effects of Rhus tripartitum fruit extract on CCl4-induced hepatotoxicity and cisplatin-induced nephrotoxicity in rats

Rhus tripartitum D.C., Anacardiaceae, has traditionally been used in Tunisia against many illnesses. The present study investigates, for the first time, the protective effects of the methanol extract of Rhus tripartitum fruit (MERT) against CCl4-induced hepatotoxicity and cisplatin-induced nephrotoxicty in Wistar rats. ALT, AST, LDH, GGT, creatinin, urea, and uric acid levels were studied. The changes in antioxidant parameters such as malondialdehyde (MDA) and protein carbonyl contents were also determined. The increased levels of MDA (30.97 and 11.50 nmol MDA/mg protein in liver and kidney, respectively) and protein carbonyls (13.4 and 17.95 nmol/mg protein in liver and kidney, respectively) were attenuated by MERT pretreatment (19.35 and 6.1 nmol MDA/mg protein and 9.15 and 12 nmol/mg protein in liver and kidney, respectively). The MERT pretreatment significantly reduced the increased biochemical parameters of liver and kidney caused by CCl4 and cisplatin treatment. The histopathologic observation showed that MERT pretreatment restores the altered tissues. The observed results could be due to the high phenolic content and to MERT's important antioxidant potential. This study supports the hepatoprotective and nephroprotective effects of R. tripartitum.