Triterpenoids principle of Wedelia calendulacea attenuated diethynitrosamine-induced hepatocellular carcinoma via down-regulating oxidative stress, inflammation and pathology via NF-kB pathway

Abstract

The aerial part of Wedelia calendulacea have been used in Ayurveda, Unani, Tibetan, Siddha and other folk medicine systems to protect the liver and renal tissue. Liver is considered as primary metabolizing site of body, which is prone to damage by endogenous and exogenous toxicants. A reason for liver toxicity, and major causes of the hepatocellular carcinoma (HCC). 19-α-Hydroxyurs-12(13)-ene-28 oic acid-3-O-β-D-glucopyranoside (HEG), a triterpenoids found in the higher plants, has been known to possess protective effect against various toxicants. The aim of the current study was to scrutinize the hepatoprotective mechanism of HEG against DEN-induced oxidative stress, hyperproliferation, inflammation and apoptosis tissue injury in Wistar rats. Invitro cell lines study of HEG scrutinized against the Hep-G2 and HuH-7 cells. A single dose of DEN (200 mg/kg) and double dose of phenobarbitol were administered to induce the liver damage in rats; the dose treatment of HEG was terminated at the end of 22 weeks. Macroscopical study was performed for the confirmation of hepatic nodules. The serum and hepatic samples were collected for further biochemical and histopathological analysis. Hepatic; non-hepatic; Phase I and II antioxidant enzymes were also examined. Additionally, we also scrutinized the inflammatory cytokines viz., tumor necrosis factor-α, interlukin-6, interlukin-1β, and Nuclear factor kappa beta (NF-kB), respectively. Histopathological study was also performed for analyzing the changes during the HCC. HEG confirmed the reduction of growth and deoxyribonucleic acid synthesis of both cell lines. DEN successfully induced the HCC in all group, which was significantly (p < 0.001) altered by the HEG in a dose-dependent manner. The decreased level of pro-inflammatory cytokines and altered membrane-bound enzyme activity were also observed. HEG inhibits the phase I, II and antioxidant enzymes at the effective dose-dependent manner, which were considered as the precursor of the HCC. The alteration of phase I, II and antioxidant enzymes confirmed the inhibition of inflammatory reaction and oxidative stress, which directly or indirectly inhibited the NF-kB expression. Collectively, we can conclude that the HEG inhibited the growth of Hepatocellular carcinoma via attenuating the NF-kB pathway.

Keywords: Diethylnitrosamine; Membrane bound enzymes; Oxidative stress; Phase I antioxidant enzymes; Pro-inflammatory cytokines.